Power Engineering Guide Transmission and Distribution 4th Edition

Power Engineering Guide Transmission and Distribution Your local representative: Sales locations worldwide (EV): http://www.ev.siemens.de/en/pages/salesloc.htm Distributed by: Siemens Aktiengesellschaft Power Transmission and Distribution G roup International Business Development, Dept. EV IBD P.O. Box 3220 D-91050 Erla ngen Phone: ++ 49 - 9131-73 45 40 Fax: ++ 49-9131-73 45 42 Power Transmission an d Distribution group online: http://www.ev.siemens.de Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Foreword This Power Engineering Guide is devised as an aid to electrical engineers who ar e engaged in the planning and specifying of electrical power generation, transmi ssion, distribution, control, and utilization systems. Care has been taken to in clude the most important application, performance, physical and shipping data of the equipment listed in the guide which is needed to perform preliminary layout and engineering tasks for industrial and utility-type installations. The equipm ent listed in this guide is designed, rated, manufactured and tested in accordan ce with the International Electrotechnical Commission (IEC) recommendations. How ever, a number of standardized equipment items in this guide are designed to tak e other national standards into account besides the above codes, and can be rate d and tested to ANSI/ NEMA, BS, CSA, etc. On top of that, we manufacture a compr ehensive range of transmission and distribution equipment specifically to ANSI/N EMA codes and regulations. Two thirds of our product range is less than five yea rs old. For our customers this means energy efficiency, environmental compatibil ity, reliability and reduced life cycle cost. For details, please see the indivi dual product listings or inquire. Whenever you need additional information to se lect suitable products from this guide, or when questions about their applicatio n arise, simply call your local Siemens office. Sales locations worldwide: http: //www.ev.siemens.de/en/pages/ salesloc.htm Siemens AG is one of the worlds leading international electrical and electronics companies. With 416 000 employees in more than 190 countries worldwide, the comp any is divided into various Groups. One of them is Power Transmission and Distri bution. The Power Transmission and Distribution Group of Siemens with 24 700 emp loyees around the world plans, develops, designs, manufactures and markets produ cts, systems and complete turn-key electrical infrastructure installations. The group owns a growing number of engineering and manufacturing facilities in more than 100 countries throughout the world. All plants are, or are in the process o f being certified to ISO 9000/9001 practices. This is of significant benefit for our customers. Our local manufacturing capability makes us strong in global sou rcing, since we manufacture products to IEC as well as ANSI/NEMA standards in pl ants at various locations around the world. Siemens Power Transmission and Distr ibution Group (EV) is capable of providing everything you would expect from an e lectrical engineering company with a global reach. The Power Transmission and Di stribution Group is prepared and competent, to perform all tasks and activities involving transmission and distribution of electrical energy. Siemens Power Transmission and Distribution Group offers intelligent solutions f or the transmission and distribution of power from generating plants to customer s. The Group is a product supplier, systems integrator and service provider, and specializes in the following systems and services: s High-voltage systems s Med ium-voltage systems s Metering s Secondary systems s Power systems control and e nergy management s Power transformers s Distribution transformers s System plann ing s Decentralized power supply systems. Siemens service includes the setting up of complete turnkey installations, offers advice, planning, operation and train ing and provides expertise and commitment as the complexity of this task require s. Backed by the experience of worldwide projects, Siemens can always offer its customers the optimum cost-effective concept individually tailored to their need s. We are there wherever and whenever you need us to help you build plants bette r, cheaper and faster. Dr. Hans-Jrgen Schlo Vice President Siemens Aktiengesellschaft Power Transmission and Distribution Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Quality and Environmental Policy Quality and Environmental Our first priority Transmission and distribution equip ment from Siemens means worldwide activities in engineering, design, development , manufacturing and service. The Power Transmission and Distribution Group of Si emens AG, with all of its divisions and relevant locations, has been awarded and maintains certification to DIN EN ISO 9001 and DIN EN ISO 14001. Certified qual ity Siemens Quality Management and Environmental Management System gives our cus tomers confidence in the quality of Siemens products and services. Certified to be in compliance with DIN EN ISO 9001 and DIN EN ISO 1400, it is the registered proof of our reliabilty. Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Contents General Introduction Energy Needs Intelligent Solutions Power Transmission Systems 1 High Voltage 2 Medium Voltage 3 Low Voltage 4 Transformers 5 Protection and Substation Control 6 Power Systems Control and Energy Management 7 Metering 8 Services 9 System Planning 10 Conversion Factors and Tables Contacts and Internet Addresses Conditions of Sale s and Delivery Siemens Power Engineering Guide Transmission and Distribution 4th Edition

General Introduction Energy management systems are also important, to ensure safe and reliable operat ion of the transmission network. Distribution In order to feed local medium-volt age distribution systems of urban, industrial or rural distribution areas, HV/MV main substations are connected to the subtransmission systems. Main substations have to be located next to the MV load center for reasons of economy. Thus, the subtransmission systems of voltage levels up to 145 kV have to penetrate even f urther into the populated load centers. The far-reaching power distribution syst em in the load center areas is tailored exclusively to the needs of users with l arge numbers of appliances, lamps, motor drives, heating, chemical processes, et c. Most of these are connected to the low-voltage level. The structure of the lo w-voltage distribution system is determined by load and reliability requirements of the consumers, as well as by nature and dimensions of the area to be served. Different consumer characteristics in public, industrial and commercial supply will need different LV network configurations and adequate switchgear and transf ormer layout. Especially for industrial supply systems with their high number of motors and high costs for supply interruptions, LV switchgear design is of grea t importance for flexible and reliable operation. Independent from individual su pply characteristics in order to avoid uneconomical high losses, however, the su bstations with the MV/LV transformers should be located as close as possible to the LV load centers. The compact load center substations should be installed rig ht in the industrial production area near to the LV consumers. The superposed me dium-voltage system has to be configured to the needs of these substations and t he available sources (main substation, generation) and leads again to different solutions for urban or rural public supply, industry and large building centers. In addition distribution management systems can be tailored to the needs, from small to large systems and for specific requirements. Main substation with transformers up to 63 MVA HV switchgear MV switchgear Local medium-voltage distribution system Ring type Public supply Feeder cable Connection of large consumer Spot system Industrial supply and large buildings Medium voltage substations MV/LV substation looped in MV cable by load-break switchgear in different combin ations for individual substation design, transformers up to 1000 kVA LV fuses Ci rcuitbreaker Loadbreak switch Consumer-connection substation looped in or connec ted to feeder cable with circuitbreaker and load-break switches for connection o f spot system in different layout MV/LV transformer level Low-voltage supply system Public supply with pillars and house connections internal installation Large bui ldings with distributed transformers vertical LV risers and internal installatio n per floor Industrial supply with distributed transformers with subdistribution board and motor control center Consumers Fig. 2: Distribution: Principle configuration of distribution systems Siemens Power Engineering Guide Transmission and Distribution 4th Edition

General Introduction Despite the individual layout of networks, common philosophy should be an utmost simple and clear network design to obtain s flexible system operation s clear p rotection coordination s short fault clearing time and s efficient system automa tion. The wide range of power requirements for individual consumers from a few k W to some MW, together with the high number of similar network elements, are the main characteristics of the distribution system and the reason for the comparat ively high specific costs. Therefore, utmost standardization of equipment and us e of maintenance-free components are of decisive importance for economical syste m layout. Siemens components and systems cater to these requirements based on wo rldwide experience in transmission and distribution networks. Protection, operat ion, control and metering Safe, reliable and economical energy supply is also a matter of fast, efficient and reliable system protection, data transmission and processing for system operation. The components required for protection and oper ation benefit from the rapid development of information and communication techno logy. Modern digital relays provide extensive possibilities for selective relay setting and protection coordination for fast fault clearing and minimized interr uption times. Remote Terminal Units (RTUs) or Substation Automation Systems (SAS ) provide the data for the centralized monitoring and control of the power plant s and substations by the energy management system. Siemens energy management sys tems ensure a high supply quality, minimize generation and transmission costs an d optimally manage the energy transactions. Modularity and open architecture off er the flexibility needed to cope with changed or new requirements originating e .g. from deregulation or changes in the supply area size. The broad range of app lications includes generation control and scheduling, management of transmission and distribution networks, as well as energy trading. Metering devices and syst ems are important tools for efficiency and economy to survive in the deregulated market. For example, Demand Side Management (DSM) allows an electricity supply utility from a control center to remotely control certain consumers on the suppl y network for load control purposes. Energy meters are used for measuring the co nsumption of electricity, gas, heat and water for purposes of billing in the fie lds of households, commerce, industry and grid metering. Power system substation Power system switchgear Bay protection Overcurrent Distance Differential etc. Ot her bays Bay coordination level Bay switching interlocking Control Other bays Substation coordination level BB and BF (busbar and breaker failure) protection Switchgear interlocking Substation control Data processing Automation Metering Data and signal input/output Other substations Power network telecommunication systems Other substations Power line carrier communication Fiber-optic communication System coordination level SCADA functions Distribution management functions Grafical information systems N etwork analysis Power and scheduling applications Training simulator

Control room equipment Fig. 3: System Automation: Principle configuration of protection, control and co mmunication systems Siemens Power Engineering Guide Transmission and Distribution 4th Edition

General Introduction Overall solutions System planning Of crucial importance for the quality of power transmission and distribution is the integration of diverse components to form overall solutions. Especially in countries where the increase in power consumpti on is well above the average besides the installation of generating capacity, co nstruction and extension of transmission and distribution systems must be develo ped simultaneously and together with equipment for protection, supervision, cont rol and metering. Also, for the existing systems, changing load structures, chan ging requirements due to energy market deregulation and liberalization and/ or e nvironmental regulations, together with the need for replacement of aged equipme nt will require new installations. Integral power network solutions are far more than just a combination of products and components. Peculiarities in urban deve lopment, protection of the countryside and of the environment, and the suitabili ty for expansion and harmonious integration in existing networks are just a few of the factors which future-oriented power system planning must take into accoun t. Outlook The electrical energy supply (generation, transmission and distributi on) is like a pyramid based on the number of components and their widespread use . This pyramid rests on a foundation formed by local expansion of the distributi on networks and power demand in the overall system, which is determined solely b y the consumers and their use of light, power and heat. These basic applications arise in many variations and different intensities throughout the entire privat e, commercial and industrial sector (Fig. 4). Reliability, safety and quality (i .e. voltage and frequency stability) of the energy supply are therefore absolute essentials and must be assured by the distribution networks and transmission sy stems. Generation Transmission Distribution Consumers Applications Light Power Heat Monitoring, Control, Automation Fig. 4: Industrial applications Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Energy Needs Intelligent Solutions The changing state of the worlds energy markets and the need to conserve resource s is promoting more intelligent solutions to the distribution of mans silent serv ant, electricity. Change is generally wrought by necessity, often driven by a va riety of factors, not least social, political, economic, environmental and techn ological considerations. Currently the worlds energy supply industries principall y gas and electricity are in the process of undergoing radical and crucial chang e that is driven by a mixture of all these considerations. The collective name g iven to the factors affecting the electricity supply industry worldwide is dereg ulation. This is the changing operating scenario the electricity supply industry as a whole faces as it moves inexorably into the 21st century. How can it rise to the challenge of liberalized markets and the opportunities presented by dereg ulation? One of the answers is the better use of information technology and intel ligent control to affect the necessary changes born of deregulation. However, to achieve this utilities need to be very sure of the technical and commercial comp etence of their systems suppliers. Failure could prove to be very costly not jus t in financial terms, but also for a utilitys reputation with its consumers in wh at is becoming increasingly a buyers market. Forming and maintaining close partne rships with long-established systems suppliers such as Siemens is the best way o f ensuring success with deregulation into the millennium. Siemens can look back on over 100 years of working in close co-operation with power utilities througho ut the world. This accumulated experience allows the companys Power Transmission and Distribution Group to address not just technical issues, but also better app reciate many of the operational and commercial aspects of electricity distributi on. Experience gained over the past decade with the many-and-varied aspects of d eregulation puts the Group in an almost unique position to advise utilities as t o the best solutions for taking full advantage of the opportunities offered by d eregulation. Innovation the issue of change Although todays technology obviously plays a very important role in the companys current business, innovation has alwa ys been at the vanguard of its activities; indeed it is the common thread that h as run through the company since its inception 150 years ago. In future power di stribution technology, computer software, power electronics and superconductivit y will play increasingly prominent roles in innovative solutions. Scope for new technolFig. 5: Superconducting current limiter: lightning fast response ogies is to be found in decentralized energy supply concepts and in meeting the needs of urban conurbations. Siemens is no longer just a manufacturer of systems and equipment, it is now much more. Overall concepts are becoming ever more imp ortant. All change! Power distribution technology has not changed significantly over the past forty years indeed, the rules of the game have remained the same for a much longer period of time. A new challenge Recently decentralized power suppl y systems have cornered a growing share of the market for a number of reasons. I n developing and industrializing countries, it has become clear that the energy policies and systems solutions adopted by nations with well-established energy i nfrastructures are not always appropriate. Frequently it is more prudent to star t with small decentralized power networks and to expand later in a progressive w ay as demand and economics permit. Much benefit can also be gained if generation makes use of natural or indigenous resources such as the sun, water, wind or bi omass. Countries that struggle with population growth and migration to the towns and cities clearly need to pay close attention to protecting their balance of p ayments. In such cases, the expansion of power supplies into the countryside is a crucial factor in the economic and social development of a particular count ry. In the industrialized countries the concept of the decentralized power supply is also gaining ground, largely because of environmental concern. This has had i ts consequences for the generation of electricity: wind power is experiencing a renaissance, more development work is being carried out into photovoltaic device

s and combined heat and power cogeneration plants are growing in popularity in m any areas for both ecological and economic reasons. These developments are resul ting in some entirely new energy network structures. Additional tasks... The sco pe and purpose of tomorrows distribution systems will no longer be to simply suppl y electricity. In future they will be required to harvest power and redistribute it more economically and take into account, among other considerations, environmen tal needs. In the past it was no easy task to supply precisely the right amount of electricity according to demand because, as is well-known, electricity cannot be readily stored and the loads were continually changing. Demand scheduling wa s very much based on statistical forecasting not an exact science and one that c annot by its very nature take into account realtime variations. Demand schedulin g problems can become particularly acute when power stations of limited generati ng capacity are on line. Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Energy Needs Intelligent Solutions Nowadays these and similar problems are not insoluble because of decentralized p ower supplies and the use of intelligent control. The Power Transmission and Distr ibution Group has developed concepts for the economic resolution of peak energy demand. One is to use energy stores. Batteries are an obvious choice, for these can be equipped with power electronics to enhance energy quality as well as stor ing electricity. Intelligent energy management One of the options for matching th e amount of electricity available to the amount being demanded is, even today, t he rarely used technique of load control. Energy saving can mean much more than just consuming as few kilowatt-hours as possible. It can also mean achieving the flexibility of demand that can make a valuable contribution to a countrys econom y. Naturally, in places such as hospitals, textile factories and electronic chip fabrication plants it is extremely important for the power supply not to fail n ot even for a second. In other areas of electricity consumption, however, there is much more room for manoeuvre. Controlled interruptions of a few minutes, and even a few hours, can often be tolerated without causing very much difficulty to those involved. There are other applications where the time constant or resilie nce is high, e.g. cold stores and air-conditioning plants, where energy can be s tored for periods of up to several hours. Through the application of intelligent c ontrol and with suitable financial encouragement (usually in the form of flexibl e tariff rates) there is no doubt that very much more could be made of load cont rol. Improving energy quality Power electronics systems, for example SIPCON, can help improve energy quality an increasingly important factor in deregulated ener gy markets. Energy has now become a product. It has its price and a defined qual ity. Consumers want a definite quality of energy, but they also produce reaction effects on the system that are detrimental to quality (e.g. harmonics or reacti ve power). Energy quality first has to be measured and documented, for example w ith the SIMEAS family of quality recorders. These measurements are important for price setting, and can serve as the basis for remedial action, such as with acti ve or passive filters. Power electronics development has opened up many new poss ibilities here, although considerable progress may still be made in this area a breakthrough in silicon carbide technology, for example. Fig. 6: Silicon carbide Fig. 7: GIL Alternatives It should be appreciated, however, that decentralized power supplies are not a panacea. For those places where energy density requirements are high, large power stations are still the answer, and especially when they can supply district heating. Theoretically, it should still be possible to employ conventio nal technology to transport very large amounts of electricity to the megacities of the 21st Century. Even if the use of overhead power lines was not an option, due to say there being insufficient space or resistance from people living nearby, it would be possible to use gas-insulated lines (GIL), an economical alternative investigated by Siemens. The development aim of reducing costs has meanwhile been attained here, and costeffective applic ations involving distances of serveral kilometres are therefore possible. The sy stem costs for the gas-insulated transmission lines (GIL) developed by Siemens e xceed those of overhead lines only by about a factor of 10. Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Energy Needs Intelligent Solutions Energy management via satellite Long-distance DC transmission Wind energy Solar energy Converter station Power plants Pumping station Biomass power plant Irrigation system Switching station Energy store GIL Distribution station Fuel cells Cooling station (liquid nitrogen) Fig. 8: The mega-cities of the 21st century and the open countryside will need d ifferent solutions very high values of connection density in the former and dece ntralised configurations in the latter This has been achieved by laying the tubular conductor using methods similar to those employed with pipelines. Savings were also made by simplifying and standar dizing the individual components and by using a gas mixture consisting of sulfur hexafluoride (SF6) and nitrogen (N2). The advantages of this new technology are low resistive and capacitive losses. The electric field outside of the enclosur e is zero, and the magnetic field is negligibly small. No cooling and no phase a ngle compensation are required. GILs are not a fire hazard and are simple to rep air. Energy trade The new rules of the game that are being introduced in power sup ply business everywhere are demanding more capability from utility IT systems, e specially in areas such as energy trading. Siemens has been in the fortunate pos ition of being able to accumulate early practical experience in this field in ma rkets where deregulation is being introduced very quickly such as the United Kin gdom, Scandinavia and the USA and so is now able to offer sophisticated systems and expertise with which utilities can get to grips with the demands of the new commercial environment. In the past it was always security of supply that took t he highest priority for a utility. Now, however, although it remains an importan t subject, more and more shareholders are demanding a more reasonable return on their investment. Deregulation gen erally means privatization; profit orientation is therefore clearly going to tak e over from concern with cost. In addition this means that competition will inev itably produce some concessions in the price of electricity, which will increase the pressure on energy suppliers. Many power supply companies are striving to i ntroduce additional energy services, thereby making the pure price of energy not the only yardstick their customers apply when deciding how to make their purcha ses. nies and independent operating utilities will no longer confine their activities to just energy production; they will be expected to become increasingly involve d in energy distribution too. Potential for the future The ongoing development o f high-temperature superconductors will doubtless enable much to be achieved. Ma jor operational innovations will, nonetheless, come from the more pervasive use of communications and data systems two areas of technology where innovations can be seen every 18 months. Consequently, it will be from these areas that the ena bling impetus for significant advances in power engineering will come. Siemens the energy systems house Siemens is offering solutions to the problems t hat are governed by the new rules of the game. The company possesses considerable

expertise, mainly because it is a global player, but also because it covers the total spectrum of products necessary for the efficient transmission and distribu tion of electricity. As with other Groups within the company, Power Transmission and Distribution no longer regards itself as simply a purveyor of hardware. In future Siemens will be more of a provider of services and total solutions. This will mean embracing many new disciplines and skills, not least financial control and complete project management. One of the reasons is that in future BOT (Build, Operate & Transfer) compaSiemens Power Engineering Guide Transmission and Distribution 4th Edition

High Voltage Contents Page Introduction ...................................... 2/2 Air-Insulated Outdoor Su bstations ....................... 2/4 Circuit-Breakers General ................. ............................ 2/10 Circuit-Breakers 72 kV up to 245 kV .......... ................ 2/12 Circuit-Breakers 245 kV up to 800 kV ..................... ... 2/14 Live-Tank Circuit-Breakers .......... 2/16 Dead-Tank Circuit-Breakers . ....... 2/20 Surge Arresters .............................. 2/24 Gas-Insulated S witchgear for Substations Introduction ..................................... 2/2 8 Main Product Range ..................... 2/29 Special Arrangements ........... ....... 2/33 Specification Guide ....................... 2/34 Scope of Supply .. ........................... 2/37 Gas-insulated Transmission Lines (GIL) ........ ...... 2/38 Overhead Power Lines ................. 2/40 High-Voltage Direct Curr ent Transmission .................... 2/49 Power Compensation in Transmission Sy stems .................. 2/52 2

High-Voltage Switchgear for Substations Introduction 1 High-voltage substations form an important link in the power transmission chain between generation source and consumer. Two basic designs are possible: Air-insu lated outdoor switchgear of open design (AIS) AIS are favorably priced high-volt age substations for rated voltages up to 800 kV which are popular wherever space restrictions and environmental circumstances do not have to be considered. The individual electrical and mechanical components of an AIS installation are assem bled on site. Air-insulated outdoor substations of open design are not completel y safe to touch and are directly exposed to the effects of weather and the envir onment (Fig. 1). Gas-insulated indoor or outdoor switchgear (GIS) GIS compact di mensions and design make it possible to install substations up to 550 kV right i n the middle of load centers of urban or industrial areas. Each circuitbreaker b ay is factory assembled and includes the full complement of isolator switches, g rounding switches (regular or make-proof), instrument transformers, control and protection equipment, interlocking and monitoring facilities commonly used for t his type of installation. The earthed metal enclosures of GIS assure not only in sensitivity to contamination but also safety from electric shock (Fig. 2). Gas-i nsulated transmission lines (GIL) A special application of gas-insulated equipme nt are gas-insulated transmission lines (GIL). They are used where high-voltage overhead lines are not suitable for any reason. GIL have a high power transmissi on capability, even when laid underground, low resistive and capacitive losses a nd low electromagnetic fields. 2 3 4 Fig. 1: Outdoor switchgear 5 6 7 8 9 10 Fig. 2: GIS substations in metropolitan areas 2/2 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

High-Voltage Switchgear for Substations Turnkey Installations High-voltage switchgear is normally combined with transfor mers and other equipment to complete transformer substations in order to s Stepup from generator voltage level to high-voltage system (MV/HV) s Transform volta ge levels within the high-voltage grid system(HV/HV) s Step-down to medium-volta ge level of distribution system (HV/MV) The High Voltage Division plans and cons tructs individual high-voltage switchgear installations or complete transformer substations, comprising high-voltage switchgear, medium-voltage switchgear, majo r components such as transformers, and all ancillary equipment such as auxiliari es, control systems, protective equipment, etc., on a turnkey basis or even as g eneral contractor. The spectrum of installations supplied ranges from basic subs tations with single busbar to regional transformer substations with multiple bus bars or 1 1/2 circuit-breaker arrangement for rated voltages up to 800 kV, rated currents up to 8000 A and short-circuit currents up to 100 kA, all over the wor ld. The services offered range from system planning to commissioning and after-s ales service, including training of customer personnel. The process of handling such an installation starts with preparation of a quotation, and proceeds throug h clarification of the order, design, manufacture, supply and cost-accounting un til the project is finally billed. Processing such an order hinges on methodical data processing that in turn contributes to systematic project handling. All th ese high-voltage installations have in common their high-standard of engineering , which covers power systems, steel structures, civil engineering, fire precauti ons, environmental protection and control systems (Fig. 3). Every aspect of tech nology and each work stage is handled by experienced engineers. With the aid of high-performance computer programs, e.g. the finite element method (FEM), instal lations can be reliably designed even for extreme stresses, such as those encoun tered in earthquake zones. All planning documentation is produced on modern CAD systems; data exchange with other CAD systems is possible via standardized inter faces. By virtue of their active involvement in national and international assoc iations and standardization bodies, our engineers are 1 Major components, e.g. transformer Substation Control Control and monitoring, me asurement, protection, etc. Structural Steelwork Gantries and substructures Civi l Engineering Buildings, roads, foundations Env Fire protection iron pro menta tec tion l 2 3 Design AC/DC es ri auxililia ab les Contro l and signal c ables we rge s Su erter div g in th a r te m E s sy Ancillary equipment 4 Li gh

tn ion lat n ti Ve frequ. Carrier- ent equipm rc in g Po 5 Fig. 3: Engineering of high-voltage switchgear 6 Know how, experience and worldwide presence A worldwide network of liaison and s ales offices, along with the specialist departments in Germany, support and advi se our customers in all matters of switchgear technology. Siemens has for many y ears been a leading supplier of high-voltage equipment, regardless of whether AI S, GIS or GIL has been concerned. For example, outdoor substations of longitudin al in-line design are still known in many countries under the Siemens registered tradename Kiellinie. Back in 1968, Siemens supplied the worlds first GIS substatio n using SF6 as insulating and quenching medium. Gas-insulated transmission lines have featured in the range of products since 1976. always fully informed of the state of the art, even before a new standard or spe cification is published. Quality/Environmental Management Our own high-performan ce, internationally accredited test laboratories and a certified QM system testi fy to the quality of our products and services. Milestones: s 1983: Introduction of a quality system on the basis of Canadian standard CSA Z 299 Level 1 s 1989: Certification of the SWH quality system in accordance with DIN EN ISO 9001 by t he German Association for Certification of Quality Systems (DQS) s 1992: Repetit ion audit and extension of the quality system to the complete EV H Division s 19 92: Accreditation of the test laboratories in accordance with DIN EN 45001 by th e German Accreditation Body for Technology (DATech) s 1994: Certification of the environmentalsystems in accordance with DIN EN ISO 14001 by the DQS s 1995: Mut ual QEM Certificate 7 8 9 10 Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/3

Design of Air-Insulated Outdoor Substations Standards 1 Air-insulated outdoor substations of open design must not be touched. Therefore, air-insulated switchgear (AIS) is always set up in the form of a fenced-in elec trical operating area, to which only authorized persons have access. Relevant IE C 60060 specifications apply to outdoor switchgear equipment. Insulation coordin ation, including minimum phaseto-phase and phase-to-ground clearances, is effect ed in accordance with IEC 60071. Outdoor switchgear is directly exposed to the e ffects of the environment such as the weather. Therefore it has to be designed b ased on not only electrical but also environmental specifications. Currently the re is no international standard covering the setup of air-insulated outdoor subs tations of open design. Siemens designs AIS in accordance with DIN/VDE standards , in line with national standards or customer specifications. The German standar d DIN VDE 0101 (erection of power installations with rated voltages above 1 kV) demonstrates typically the protective measures and stresses that have to be take n into consideration for airinsulated switchgear. Protective measures 2 3 Stresses s Electrical stresses, e.g. rated current, short-circuit current, adequ ate creepage distances and clearances s Mechanical stresses (normal stressing), e.g. weight, static and dynamic loads, ice, wind s Mechanical stresses (exceptio nal stresses), e.g. weight and constant loads in simultaneous combination with m aximum switching forces or shortcircuit forces, etc. s Special stresses, e.g. ca used by installation altitudes of more than 1000 m above sea level, or earthquak es Variables affecting switchgear installation Switchgear design is significantly influenced by: s Minimum clearances (dependin g on rated voltages) between various active parts and between active parts and e arth s Arrangement of conductors s Rated and short-circuit currents s Clarity fo r operating staff s Availability during maintenance work, redundancy s Availabil ity of land and topography s Type and arrangement of the busbar disconnectors Th e design of a substation determines its accessibility, availability and clarity. The design must therefore be coordinated in close cooperation with the customer . The following basic principles apply: Accessibility and availability increase with the number of busbars. At the same time, however, clarity decreases. Instal lations involving single busbars require minimum investment, but they offer only limited flexibility for operation management and maintenance. Designs involving 1 1/2 and 2 circuit-breaker arrangements assure a high redundancy, but they als o entail the highest costs. Systems with auxiliary or bypass busbars have proved to be economical. The circuit-breaker of the coupling feeder for the auxiliary bus allows uninterrupted replacement of each feeder circuit-breaker. For busbars and feeder lines, mostly wire conductors and aluminum are used. Multiple conduc tors are required where currents are high. Owing to the additional shortcircuit forces between the subconductors (pinch effect), however, multiple conductors ca use higher mechanical stressing at the tension points. When wire conductors, par ticularly multiple conductors, are used higher short-circuit currents cause a ri se not only in the aforementioned pinch effect but in further force maxima in th e event of swinging and dropping of the conductor bundle (cable pull). This in t urn results in higher mechanical stresses on the switchgear components. These ef fects can be calculated in an FEM (Finite Element Method) simulation (Fig. 4). 4 5

6 7 8 9 10 Protective measures against direct contact, i. e. protection in the form of cove ring, obstruction or clearance and appropriately positioned protective devices a nd minimum heights. Protective measures against indirect touching by means of re levant grounding measures in accordance with DIN VDE 0141. Protective measures d uring work on equipment, i.e. during installation must be planned such that the specifications of DIN EN 50110 (VDE 0105) (e.g. 5 safety rules) are complied wit h s Protective measures during operation, e.g. use of switchgear interlock equip ment s Protective measures against voltage surges and lightning strike s Protect ive measures against fire, water and, if applicable, noise insulation. 2/4 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Design of Air-Insulated Outdoor Substations When rated and short-circuit currents are high, aluminum tubes are increasingly used to replace wire conductors for busbars and feeder lines. They can handle ra ted currents up to 8000 A and short-circuit currents up to 80 kA without difficu lty. Not only the availability of land, but also the lie of the land, the access ibility and location of incoming and outgoing overhead lines together with the n umber of transformers and voltage levels considerably influence the switchgear d esign as well. A one or two-line arrangement, and possibly a U arrangement, may be the proper solution. Each outdoor switchgear installation, especially for ste p-up substations in connection with power stations and large transformer substat ions in the extra-highvoltage transmission system, is therefore unique, dependin g on the local conditions. HV/MV transformer substations of the distribution sys tem, with repeatedly used equipment and a scheme of one incoming and one outgoin g line as well as two transformers together with medium-voltage switchgear and a uxiliary equipment, are more subject to a standardized design from the individua l power supply companies. Preferred designs The multitude of conceivable designs include certain preferred versions, which a re dependent on the type and arrangement of the busbar disconnectors: H arrangem ent The H arrangement (Fig. 5) is preferrably used in applications for feeding i ndustrial consumers. Two overhead lines are connected with two transformers and interlinked by a single-bus coupler. Thus each feeder of the switchgear can be m aintained without disturbance of the other feeders. This arrangement assures a h igh availability. Special layouts for single busbars up to 145 kV with withdrawa ble circuit-breaker and modular switchbay arrangement Further to the H arrangeme nt that is built in many variants, there are also designs with withdrawable circ uit-breakers and modular switchbays for this voltage range. For detailed informa tion see the following pages: 1 2 3 4 5

6 Vertical displacement in m 0.6 0.8 1.0 1.2 1.4 T1 1.6 Q1 M 1.8 2.0 2.2 1.4 Hori lacement in m 1.0 0.6 0.2 0 0.2 0.6 1.0 1.4 Q0 F1 = T1 Fig. 5: Module plan view M M Q8 Q8 7 Q0 M Q0 Q1 T5 T1 Q1 T5 T1 T1 M M 8

Q10 Q11 Q1 Q0 9 F1 = T1 10 Fig. 4: FEM calculation of deflection of wire conductors in the event of short c ircuit Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/5

Design of Air-Insulated Outdoor Substations Withdrawable circuit-breaker 1 2 General For 123/145 kV substations with single busbar system a suitable alternat ive is the withdrawable circuit-breaker. In this kind of switchgear busbar- and outgoing disconnector become inapplicable (switchgear 6300 17001700 without disconnectors). The isolating distance is reached with the moving of the circuit-breaker along the rails, similar to the well-known withdrawable-unit de sign technique of medium-voltage switchgear. In disconnected position busbar, ci rcuit-breaker and outgoing circuit are separated from each other by a good visib le isolating dis2500 2500 3 7600 2247 =T1 -F1 2530 7000 -Q11 -T1/ 1050 -Q12 -Q9 -T5 -Q0 -Q0 -T1 3100 625 700 0 625 3100 2500 4500 14450 21450 -Q11-Q12 4 2530 7000 3000 6400 5 6 7 Fig. 6a: H arrangement with withdrawable circuit-breaker, plan view and sections 8 9 tance. An electromechanical motive unit ensures the uninterrupted constant movin g motion to both end positions. The circuitbreaker can only be operated if one o f the end positions has been reached. Movement with switched-on circuit-breaker is impossible. Incorrect movement, which would be equivalent to operating a disc onnector under load, is interlocked. In the event of possible malfunction of the position switch, or of interruptions to travel between disconnected position an d operating position, the operation of the circuitbreaker is stopped. The space required for the switchgear is reduced considerably. Due to the arrangement of t he instrument transformers on the common steel frame a reduction in the required space up to about 45% in comparison to the conventional switchgear section is a chieved. Description A common steel frame forms the base for all components nece ssary for reliable operation. The withdrawable circuit-breaker contains: s Circu it-breaker type 3AP1F s Electromechanical motive unit s Measuring transformer fo r protection and measuring purposes s Local control cubicle All systems are prea ssembled as far as possible. Therefore the withdrawable CB can be installed quit e easily and efficiently on site. The advantages at a glance s Complete system a nd therefore lower costs for coordination and adaptation. s A reduction in requi red space by about 45% compared with conventional switchbays s Clear wiring and

cabling arrangement s Clear circuit state s Use as an indoor switchbay is also p ossible. Technical data 10 Nominal voltage [kV] Nominal current [A] Nominal short time current [kA] 123 kV (145 kV) 1250 A (2000 A) 31.5 kA, 1s, (40 kA, 3s) 230/400 V AC 220 V DC Auxiliary supply/ motive unit [V] Control voltage Fig. 6b: H arrangement with withdrawable circuit-breaker, ISO view Fig. 7: Techn ical data [V] 2/6 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Design of Air-Insulated Outdoor Substations Modular switchbay General As an alternative to conventional substations an air-insulated modular s witchbay can often be used for common layouts. In this case the functions of sev eral HV devices are combined with each other. This makes it possible to offer a standardized module. Appropriate conventional air-insulated switchbays consist o f separately mounted HV devices (for example circuit-breaker, disconnector, eart hing switches, transformers), which are connected to each other by conductors/tu bes. Every device needs its own foundations, steel structures, earthing connecti ons, primary and secondary terminals (secondary cable routes etc.). 3000 Description A common steel frame forms the base for all components necessary for a reliable operation. The modul contains: s Circuit-breaker type 3AP1F s Motoroperated disconnecting device s Current transformer for protection and measuring purposes s Local control cubicle All systems are preassembled as far as possibl e. Therefore the module can be installed quite easily and efficiently on site. The advantages at a glance s Complete system and therefore lower costs for coord ination and adaptation. s Thanks to the integrated control cubicle, upgrading of the control room is scarecely necessary. s A modular switchbay can be inserted very quickly in case of total breakdown or for temporary use during reconstructi on. s A reduction in required space by about 50% compared with conventional swit chbays is achieved by virtue of the compact and tested design of the module (Fig . 8). s The application as an indoor switchbay is possible. 1 2 3 4 Technical data 2000 2000 Nominal voltage Nominal current 8000 123 kV (145 kV) 1250 A (2000 A) 31.5 kA, 1s, (40 kA, 3s) 230/400 V AC 220 V DC 5 Nominal short current Auxiliary supply -Q8 -Q0-Q1 -T1 -Q10/-Q11 -T1 -Q1 -Q0 -F1 -T5 3000 4500 7500 4500 3000 11500 4000 =T1 Control voltage Fig. 9: Technical data 6 7 8000 9500 8

19000 3000 A A 9 9500 8000 10 7500 19000 Fig. 8: Plan view and side view of H arrangement with modular switchbays 11500 Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/7

Design of Air-Insulated Outdoor Substations 1 In-line longitudinal layout, with rotary disconnectors, preferable up to 170 kV The busbar disconnectors are lined up one behind the other and parallel to the l ongitudinal axis of the busbar. It is preferable to have either wire-type or tub ular busbars located at the top of the feeder conductors. Where tubular busbars are used, gantries are required for the outgoing overhead lines only. The system design requires only two conductor levels and is therefore clear. If, in the ca se of duplicate busbars, the second busbar is arranged in U form relative to the first busbar, it is possible to arrange feeders going out on both sides of the busbar without a third conductor level (Fig. 10). Section A-A R1 S1 T1 T2 S2 R2 Dimensions in mm 2500 8000 2 20500 8400 48300 19400 Top view 6500 End bay 4500 Normal 9000 bay A A 9000 3 4 Central tower layout with rotary disconnectors, normally only for 245 kV The bus bar disconnectors are arranged side by side and parallel to the longitudinal axi s of the feeder. Wire-type busbars located at the top are commonly used; tubular busbars are also conceivable. This arrangement enables the conductors to be eas liy jumpered over the circuit-breakers and the bay width to be made smaller than that of in-line designs. With three conductor levels the system is relatively c lear, but the cost of the gantries is high (Fig. 11). Fig. 10: Substation with rotary disconnector, in-line design 5 Dimensions in mm 3000 12500 9000 7000 18000 17000 17000 6 7 16000 8 Fig.11: Central tower design Diagonal layout with pantograph disconnectors, preferable up to 245 kV Section Bus system 13300 10000 8000 28000 48000 9

10 The pantograph disconnectors are placed diagonally to the axis of the busbars an d feeder. This results in a very clear, spacesaving arrangement. Wire and tubula r conductors are customary. The busbars can be located above or below the feeder conductors (Fig. 12). Dimensions in mm Bypass bus 10000 10400 Top view 5000 18000 4000 4000 5000 Fig. 12: Busbar area with pantograph disconnector of diagonal design, rated volt age 420 kV 2/8 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Design of Air-Insulated Outdoor Substations 1 1/2 circuit-breaker layout, preferable up to 245 kV The 1 1/2 circuit-breaker arrangement assures high supply reliability; however, expenditure for equipment is high as well. The busbar disconnectors are of the pantograph, rotary and vert ical-break type. Vertical-break disconnectors are preferred for the feeders. The busbars located at the top can be of wire or tubular type. Of advantage are the equipment connections, which are very short and enable (even in the case of mul tiple conductors) high short-circuit currents to be mastered. Two arrangements a re customary: s External busbar, feeders in line with three conductor levels s I nternal busbar, feeders in H arrangement with two conductor levels (Fig. 13). Planning principles 1 For air-insulated outdoor substations of open design, the following planning pri nciples must be taken into account: s High reliability Reliable mastering of nor mal and exceptional stresses Protection against surges and lightning strikes Pro tection against surges directly on the equipment concerned (e.g. transformer, HV cable) s Good clarity and accessibility 2 3 Dimensions in mm 4000 Clear conductor routing with few conductor levels Free accessibility to all area s (no equipment located at inaccessible depth) Adequate protective clearances fo r installation, maintenance and transportation work Adequately dimensioned trans port routes s Positive incorporation into surroundings 4 5 17500 8500 48000 29000 As few overhead conductors as possible Tubular instead of wire-type busbars Unob trusive steel structures Minimal noise and disturbance level s EMC grounding system 6 18000 for modern control and protection s Fire precautions and environmental 7 Fig.13 : 1 1/2 Circuit-breaker design protection Adherence to fire protection specifications and use of flame-retardan

t and nonflammable materials Use of environmentally compatible technology and pr oducts For further information please contact: Fax: ++ 49 - 9131- 73 18 58 e-mai l: Gerda.Friedel@erls04.siemens.de 8 9 10 Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/9

Circuit-Breakers for 72 kV up to 800 kV General 1 Circuit-breaker for air-insulated switchgear Circuit-breakers are the main module of both AIS and GIS switchgear. They have t o meet high requirements in terms of: s Reliable opening and closing s Consisten t quenching performance with rated and short-circuit currents even after many sw itching operations s High-performance, reliable maintenancefree operating mechan isms. Technology reflecting the latest state of the art and years of operating e xperience are put to use in constant further development and optimization of Sie mens circuitbreakers. This makes Siemens circuitbreakers able to meet all the de mands placed on high-voltage switchgear. The comprehensive quality system, ISO 9 001 certified, covers development, manufacture, sales, installation and aftersal es service. Test laboratories are accredited to EN 45001 and PEHLA/STL. 2 3 4 5 Main construction elements 6 Each circuit-breaker bay for gas-insulated switchgear includes the full compleme nt of isolator switches, grounding switches (regular or proven), instrument tran sformers, control and protection equipment, interlocking and monitoring faciliti es commonly used for this type of installation (See chapter GIS, page 2/30 and f ollowing). Circuit-breakers for air-insulated switchgear are individual componen ts and are assembled together with all individual electrical and mechanical comp onents of an AIS installation on site. All Siemens circuit-breaker types, whethe r air or gas-insulated, are made up of the same range of components, i.e.: s Int errupter unit s Operating mechanism s Sealing system s Operating rod s Control e lements. Control elements Operating mechanism Interrupter unit 7 8 9 10 Circuit-breaker in SF6-insulated switchgear Fig. 14: Circuit-breaker parts 2/10 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Circuit-Breakers for 72 kV up to 800 kV Interrupter unit two arc-quenching principles The Siemens product range includes highvoltage circuit-breakers with self-compre ssion interrupter chambers and twin-nozzle interrupter chambers for optimum swit ching performance under every operating condition for every voltage level. Selfcompression breakers 3AP high-voltage circuit-breakers for the lower voltage ran ge ensure optimum use of the thermal energy of the arc in the contact tube. This is achieved by the selfcompression switching unit. Siemens patented this arc-qu enching principle in 1973. Since then, we have continued to develop the technolo gy of the selfcompression interrupter chamber. One of the technical innovations is that the arc energy is being increasingly used to quench the arc. In short-ci rcuit breaking operations the actuating energy required is reduced to that neede d for mechanical contact movement. That means the operating energy is truly mini mized. The result is that the selfcompression interrupter chamber allows the use of a compact stored-energy spring mechanism with unrestrictedly high dependabil ity. Twin-nozzle breakers On the 3AQ and 3AT switching devices, a contact system with graphite twin-nozzles ensures consistent arc-quenching behavior and consta nt electric strength, irrespective of pre-stressing, i.e. the number of breaks a nd the switched current. The graphite twin-nozzles are resistant to burning and thus have a very long service life. As a consequence, the interrupter unit of th e twin-nozzle breaker is particularly powerful. Moreover, this type of interrupt er chamber offers other essential advantages. Generally, twin-nozzle interrupter chambers operate with low overpressures during arcquenching. Minimal actuating energy is adequate in this operating system as well. The resulting arc plasma ha s a comparatively low conductivity, and the switching capacity is additionally f avourably influenced as a result. The twin-nozzle system has also proven itself in special applications. Its speci fic properties support switching without restriking of small inductive and capac itive currents. By virtue of its high arc resistance, the twin-nozzle system is particularly suitable for breaking certain types of short circuit (e.g. short ci rcuits close to generator terminals) on account of its high arc resistance. Specific use of the electrohydraulic mechanism The actuating energy required for the 3AQ and 3AT high-voltage circuit-breakers at higher voltage levels is provi ded by proven electrohydraulic mechanisms. The interrupter chambers of these swi tching devices are based on the graphite twin-nozzle system. Advantages of the e lectrohydraulic mechanism at a glance: s Electrohydraulic mechanisms provide the 1 2 Operating mechanism two principles for all specific requirements The operating mechanism is a central module of the high-voltage circuit-breakers . Two different mechanism types are available for Siemens circuit-breakers: s St ored-energy spring actuated mechanism, s Electrohydraulic mechanism, depending o n the area of application and voltage level, thus every time ensuring the best s ystem of actuation. The advantages are trouble-free, economical and reliable cir cuit-breaker operation for all specific requirements. Specific use of the stored -energy spring mechanism The actuation concept of the 3AP high-voltage circuit-b reaker is based on the storedenergy spring principle. The use of such an operati ng mechanism in the lower voltage range became appropriate as a result of develo pment of a self-compression interrupter chamber that requires only minimal actua tion energy. Advantages of the stored-energy spring mechanism at a glance: s The stored-energy spring mechanism of3

high actuating energy that makes it possible to have reliable control even over very high switching capacities and to be in full command of very high loads in t he shortest switching time. s The switch positions are held safely even in the e vent of an auxiliary power failure. s A number of autoreclosing operations are p ossible without the need for recharging. s Energy reserves can be reliably contr olled at any time. s Electrohydraulic mechanisms are maintenance-free, economica l and have a long service life. s They satisfy the most stringent requirements r egarding environmental safety. This has been proven by electrohydraulic mechanis ms in Siemens high-voltage circuit-breakers over many years of service. 4 5 6 7 8 fers the highest degree of operational safety. It is of simple and sturdy design with few moving parts. Due to the self-compression principle of the interrupter chamber, only low actuating forces are required. s Stored-energy spring mechani sms are readily available and have a long service life: Minimal stressing of the latch mechanisms and rolling-contact bearings in the operating mechanism ensure reliable and wear-free transmission of forces. s Stored-energy spring mechanism s are maintenance-free: the spring charging gear is fitted with wear-free spur g ears, enabling load-free decoupling. 9 10 Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/11

Circuit-Breakers for 72 kV up to 245 kV 1 Siemens circuit-breakers for the lower voltage levels 72 kV up to 245 kV, whethe r for air-insulated or gas-insulated switchgear, are equipped with self-compress ion switching units and spring-stored energy operating mechanisms. Breaking operating currents During the opening process, the main contact (4) ope ns first and the current commutates on the still closed arcing contact. If this contact is subsequently opened, an arc is drawn between the contacts (5). At the same time, the contact cylinder (6) moves into the base (7) and compresses the quenching gas there. The gas then flows in the reverse direction through the con tact cylinder (6) towards the arcing contact (5) and quenches the arc there. Bre aking fault currents In the event of high short-circuit currents, the quenching gas on the arcing contact is heated substantially by the energy of the arc. This leads to a rise in pressure in the contact cylinder. In this case the energy fo r creation of the required quenching pressure does not have to be produced by th e operating mechanism. Subsequently, the fixed arcing contact releases the outfl ow through the nozzle (3). The gas flows out of the contact cylinder back into t he nozzle and quenches the arc. Major features: s s s s Self-compression interrupter chamber Use of the thermal energy of the arc Minimi zed energy consumption High reliability for a long time 2 The interrupter unit Self-compression system 3 The current path The current path is formed by the terminal plates (1) and (8), the contact support (2), the base (7) and the moving contact cylinder (6). In cl osed state the operating current flows through the main contact (4). An arcing c ontact (5) acts parallel to this. 4 5 Closed position 6 1 2 3 4 5 Opening Main contact open Opening Arcing contact open Open position 7 1 2 3 4 5 6 8

6 Terminal plate Contact support Nozzle Main contact Arc contact Contact cylinder 7 Base 8 Terminal plate 9 7 10 8 Fig. 15: The interrupter unit 2/12 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Circuit-Breakers for 72 kV up to 245 kV The operating mechanism Spring-stored energy type Siemens circuit-breakers for voltages up to 245 kV are equipped with spring-stored energy operating mechanisms. These drives are based on the same principle that has been proving its worth in Siemens low and medium -voltage circuit-breakers for decades. The design is simple and robust with few moving parts and a vibration-isolated latch system of highest reliability. All c omponents of the operating mechanism, the control and monitoring equipment and a ll terminal blocks are arranged compact and yet clear in one cabinet. Depending on the design of the operating mechanism, the energy required for switching is p rovided by individual compression springs (i.e. one per pole) or by springs that function jointly on a triple-pole basis. The principle of the operating mechani sm with charging gear and latching is identical on all types. The differences be tween mechanism types are in the number, size and arrangement of the opening and closing springs. Major features at a glance s Uncomplicated, robust construction 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 2 3 9 4 5 6 7 10 11 12 13 14 15 16 17 Corner gears Coupling linkage Operating rod Closing release Cam plate Charging s haft Closing spring connecting rod Closing spring Hand-wound mechanism Charging mechanism Roller level Closing damper Operating shaft Opening damper Opening rel ease Opening spring connecting rod Mechanism housing Opening spring 1 2 3 4 5 6 with few moving parts s Maintenance-free s Vibration-isolated latches s Load-free uncoupling of chargi ng 7 mechanism s Ease of access s 10,000 operating cycles 8 18

8 Fig. 16 9 10 Fig. 17: Combined operating mechanism and monitoring cabinet Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/13

Circuit-Breakers for 245 kV up to 800 kV 1 Siemens circuit-breakers for the higher voltage levels 245 kV up to 800 kV, whet her for air-insulated or gas-insulated switchgear, are equipped with twin-nozzle interrupter chambers and electrohydraulic operating mechanisms. Arc-quenching assembly The fixed tubes (2) are connected by the contact tube (3) when the breaker is closed. The contact tube (3) is rigidly coupled to the blas t cylinder (4), the two together with a fixed annular piston (5) in between form ing the moving part of the break chamber. The moving part is driven by an operat ing rod (8) to the effect that the SF6 pressure between the piston (5) and the b last cylinder (4) increases. When the contacts separate, the moving contact tube (3), which acts as a shutoff valve, releases the SF6. An arc is drawn between o ne nozzle (6) and the contact tube (3). It is driven in a matter of milliseconds between the nozzles (6) by the gas jet and its own electrodynamic forces and is safely extinguished. The blast cylinder (4) encloses the arcquenching arrangeme nt like a pressure chamber. The compressed SF6 flows radially into the break by the shortest route and is discharged axially through the nozzles (6). After arc extinction, the contact tube (3) moves into the open position. In the final posi tion, handling of test voltages in accordance with IEC 60000 and ANSI is fully a ssured, even after a number of short-circuit switching operations. Major features s Erosion-resistant graphite nozzles s Consistently high dielectric strength s C onsistent quenching capability across the entire performance range s High number of short-circuit breaking 2 The interrupter unit 3 Twin-nozzle system Current path assembly The conducting path is made up of the t erminal plates (1 and 7), the fixed tubes (2) and the spring-loaded contact fing ers arranged in a ring in the moving contact tube (3). operations s High levels of availability s Long maintenance intervals. 4 5 6 7 Breaker in closed position 1 Precompression Gas flow during arc quenching Breaker in open position 8 2 3 6 4 5 1 Upper terminal plate

2 Fixed tubes 3 Moving contact tube Arc 9 4 Blast cylinder 5 Blast piston 6 Arc-quenching nozzles 10 2 8 7 Lower terminal plate 8 Operating rod 7 Fig. 18: The interrupter unit 2/14 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Circuit-Breakers for 245 kV up to 800 kV The operating mechanism Electrohydraulic type All hydraulically operated Siemens circuitbreakers have a uniform operating mechanism concept. Identical operating mechanisms (modules) ar e used for single or triple-pole switching of outdoor circuitbreakers. The elect rohydraulic operating mechanisms have proved their worth all over the world. The power reserves are ample, the switching speed is high and the storage capacity substantial. The working capacity is indicated by the permanent self-monitoring system. The force required to move the piston and piston rod is provided by diff erential oil pressure inside a sealed system. A hydraulic storage cylinder fille d with compressed nitrogen provides the necessary energy. Electromagnetic valves control the oil flow between the high and low-pressure side in the form of a cl osed circuit. Main features: s Plenty of operating energy s Long switching sequences s Reliable check of ener gy reserves s s Tripping: The hydraulic valve is changed over electromagnetically, thus relieving the larg er piston surface of pressure and causing the piston to move onto the OFF positi on. The breaker is ready for instant operation because the smaller piston surfac e is under constant pressure. Two electrically separate tripping circuits are av ailable for changing the valve over for tripping. 1 2 3 4 5 6 s s s s at any time Switching positions are reliably maintained, even when the auxiliary supply fails Excessive strong foundations Low-noise switching No oil leakage an d consequently environmentally compatible Maintenance-free. Fig. 19: Operating unit of the Q range AIS circuit breakers Fig. 20: Operating cylinder with valve block and magnetic releases 7 Description of function s Closing: Monitoring unit and hydraulic pump with motor P P P

P Oil tank Hydraulic storage cylinder N2 M 8 The hydraulic valve is opened by electromagnetic means. Pressure from the hydrau lic storage cylinder is thereby applied to the piston with two different surface areas. The breaker is closed via couplers and operating rods moved by the force which acts on the larger surface of the piston. The operating mechanism is desi gned to ensure that, in the event of a pressure loss, the breaker remains in the particular position. M 9 Operating cylinder Operating piston Main valve Auxiliary switch Pilot control Re leases Fig. 21: Schematic diagram of a Q-range operating mechanism 10 On Off Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/15

Live-Tank Circuit-Breakers for 72 kV up to 800 kV 1 Circuit-breakers for air-insulated switchgear Standard live-tank breakers The construction All live-tank circuit-breakers are of the same general design, as shown in the illustrations. They consist of the following main components: 1) Interrupter unit 2) Closing resistor (if applicable) 3) Operating mechanism 4) Insulator column (AIS) 5) Operating rod 6) Breaker base 7) Control unit The unco mplicated design of the breakers and the use of many similar components, such as interrupter units, operating rods and control cabinets, ensure high reliability because the experience of many breakers in service has been applied in improvem ent of the design. The twin nozzle interrupter unit for example has proven its r eliability in more than 60,000 units all over the world. The control unit includ es all necessary devices for circuit-breaker control and monitoring, such as: s Pressure/SF6 density monitors s Gauges for SF6 and hydraulic pressure (if applic able) s Relays for alarms and lockout s Antipumping devices s Operation counters (upon request) s Local breaker control (upon request) s Anticondensation heater s. Transport, installation and commissioning are performed with expertise and ef ficiency. The tested circuit-breaker is shipped in the form of a small number of compact units. If desired, Siemens can provide appropriately qualified personne l for installation and commissioning. 2 3 4 Fig. 22: 145 kV circuit-breaker 3AP1FG with triple-pole spring stored-energy ope rating mechanism Fig. 23: 800 kV circuit-breaker 3AT5 5 6 7 8 9 10 Fig. 24: 245 kV circuit-breaker 3AQ2 2/16 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Live-Tank Circuit-Breakers for 72 kV up to 800 kV 1 1 2 7 3 5 6 1 2 8 2 5 1 2 3 4 Interrupter unit Closing resistor Valve unit Electrohydraulic operating mechanis m 5 Insulator columns 6 Breaker base 7 Control unit 3 9 13 12 10 11 4 4 3 4 7 6 Fig. 25: Type 3AT4/5 5 1 2 3 4 5 6 7 8 9 10 11 12 13 Interrupter unit Arc-quenching nozzles Moving contact Filter Blast piston Blast cylinder Bell-crank mechanism Insulator column Operating rod Hydraulic operating mechanism ON/OFF indicator Oil tank Control unit 6 7 1 8 Fig. 27: Type 3AQ2 2 9 3 5 4 1 2 3 4 Interrupter unit 10 Post insulator Circuit-breaker base Operating mechanism and control cubicle 5 Pillar Fig. 26: Type 3AP1FG Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/17

Live-Tank Circuit-Breakers for 72 kV up to 800 kV 1 Technical data 2 3 4 Type Rated voltage Number of interrupter units per pole Rated power-frequency wi thstand voltage 1 min. Rated lightning impulse withstand voltage 1.2 / 50 s Rated switching impulse withstand voltage Rated current up to Rated short-time curren t (3 s) up to Rated peak withstand current up to Rated short-circuit-breaking cu rrent up to Rated short-circuit making current up to Rated duty cycle Break time Frequency Operating mechanism type Control voltage Motor voltage Design data of the basic version: Clearance Phase/earth in air across the contact gap Minimum creepage Phase/earth distance across the contact gap Dimensions Height Width Dep th Distance between pole centers Weight of circuit-breaker Inspection after Fig. 28a 3AP1/3AQ1 [kV] [kV] [kV] [kV] [A] [kA] [kA] [kA] [kA] 72.5 1 140 325 4000 40 108 40 108 123 1 230 550 4000 40 108 40 108 145 1 275 650 4000 40 108 40 108 170 1 325 750 4000 40/50 135 40/50 135 245/300 1 460 1050 /85 0 4000 50 135 50 135 or 3AP2/3AQ2 362 2 520 1175 950 4000 63 170 63 170 CO - 15 s - CO 3 50/60 3 50/60 420 2 610 1 425 1050 4000 63 170 63 170 5 6 7 O - 0.3 s - CO - 3 min - CO 8 [cycles] [Hz] [V, DC] [V, DC] [V, DC] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [k g] 3 3 3 50/60 3 50/60 3 50/60 50/60 50/60 Spring-stored energy mechanism/Electrohydraulic mechanism 60250 60250 120240, 50/60 Hz 700 1200 2248 3625 2750 3200 660 1350 1350 1250 1200 3625 3625 3300 3900 660 1700 1500 1250 1200 3625 3625 3300 3900 660 1700 1500 1500 1400 4250 4250 4030

4200 660 1850 1600 2200 1900/2200 6150/7626 6125/7500 5220/5520 6600/7000 800 28 00/3000 3000 25 years 2750 2700 7875 9050 4150 8800 3500 3800 4700 3400 3200 103 75 10500 4800 9400 4100 4100 5000 9 10 2/18 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Live-Tank Circuit-Breakers for 72 kV up to 800 kV 1 2 3 3AT2/3AT3* 245 2 460 1050 4000 80 216 80 216 300 2 460 1050 850 0 1175 950 4000 63 170 63 170 420 2 610 1425 1050 4000 550 1175 4000 63 170 63 170 or 362 4 520 1175 950 4000 CO 2 50/60 2 50/60 420 4 610 1425 1050 4000 80 200 80 4000 63 170 63 170 362 2 52 63 170 63 170 550 2 800 1 80 200 80 200 CO - 15 s 200

3AT4/3AT5* 550 4 800 1550 1175 4000 63 160 63 160 800 4 1150 2100 1425 4 5 6 4000 63 160 63 160 7 O - 0.3 s - CO - 3 min - CO 2 50/60 2 50/60 2 50/60 2 50/60 2 50/60 2 50/60 2 50/60 8 Electrohydraulic mechanism 48250 48250 or 208/120500/289 50/60 Hz 2200 2000 6050 60 70 4490 7340 4060 3000 5980 2200 2400 6050 8568 4490 8010 4025 3400 6430 2700 27 00 7165 9360 6000 9300 4280 3900 9090 3300 3200 9075 11390 6000 10100 4280 4300 8600 3800 3800 13750 13750 6700 13690 5135 5100 12500 25 years Fig. 28b Siemens Power Engineering Guide Transmission and Distribution 4th Edition * with closing resistor 9 2700 4000 7165 12140 4990 10600 6830 4350 14400 3300 4000 9075 12140 6000 11400 6830 4750 14700 3800 4800 10190 17136 6550 16600 7505 7200 19200 5000 6400 13860 22780 8400 22200 9060 10000 23400 10 2/19

Dead-Tank Circuit-Breakers for 72 kV up to 245 kV 1 Circuit-breakers in dead-tank design For certain substation designs, dead-tank circuit-breakers might be required ins tead of the standard live-tank breakers. For these purposes Siemens can offer th e dead-tank circuit breaker types. 2 Main features at a glance 3 Reliable opening and closing s Proven contact and arc-quenching system 4 s Consistent quenching performance with rated and short-circuit currents even after many switching operations s Sim ilar uncomplicated design for all voltages High-performance, reliable operating mechanisms s Easy-to-actuate spring operating 5 mechanisms s Hydraulic operating mechanisms with 6 on-line monitoring Economy s Perfect finish s Simplified, quick installation process Fig. 29a: SPS-2 circui t-breaker 72.5 kV 7 s Long maintenance intervals s High number of operating cycles s Long service li fe Individual service 8 s Close proximity to the customer s Order specific documentation s Solutions tai lored to specific problems s After-sales service available promptly worldwide 9 The right qualifications s Expertise in all power supply matters s 30 years of experience with SF6-insula ted circuit breakers 10

s A quality system certified to ISO 9001, covering development, manufacture, sales, installation and after-sales service s Test laboratories accredited to EN 45001 and PEHLA/STL Fig. 29b: SPS-2 circuit-breaker 170 kV 2/20 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Dead-Tank Circuit-Breakers for 72 kV up to 245 kV Subtransmission breaker Type SPS-2 and 3AP1-DT Type SPS-2 power circuit-breakers (Fig. 29a/b) are designed as general, definite -purpose breakers for use at maximum rated voltages of 72.5 and 245 kV. The cons truction The type SPS-2 breaker consists of three identical pole units mounted o n a common support frame. The opening and closing force of the FA2/4 spring oper ating mechanism is transferred to the moving contacts of the interrupter through a system of connecting rods and a rotating seal at the side of each phase. The tanks and the porcelain bushings are charged with SF6 gas at a nominal pressure of 6.0 bar. The SF6 serves as both insulation and arc-quenching medium. A contro l cabinet mounted at one end of the breaker houses the spring operating mechanis m and breaker control components. Interrupters are located in the aluminum housi ngs of each pole unit. The interrupters use the latest Siemens puffer arcquenchi ng system. The spring operating mechanism is the same design as used with the Si emens 3AP breakers. This design has been in service for years, and has a well do cumented reliability record. Customers can specify up to four (in some cases, up to six) bushing-type current transformers (CT) per phase. These CTs, mounted ex ternally on the aluminum housings, can be removed without disturbing the bushing s. Operating mechanism The type FA2/4 mechanically and electrically trip-free sprin g mechanism is used on type SPS-2 breakers. The type FA2/4 closing and opening s prings hold a charge for storing open-close-open operations A weatherproof control cabinet has a large door, sealed with rubber gaskets, for easy access during in spection and maintenance. Condensation is prevented by units offering continuous inside/outside temperature differential and by ventilation. Included in the control cabinet are necessary auxiliary switches, cutoff switch, latch check switch, alarm switch and operation counter. The control relays and three control knife switches (one each for the control, heater and motor) are mo unted on a control panel. Terminal blocks on the side and rear of the housing ar e available for control and transformer wiring. For non US markets the control c abinet is also available similar to the 3AP cabinet (3AP1-DT). 1 2 3 Technical data 4 5 6 7 Type Rated voltage Rated power-frequency withstand voltage Rated lighting impuls e withstand voltage Rated switching impulse withstand voltage Rated nominal curr ent up to [kV] [kV] [kV] [kV] 38 80 200 48.3 105 250 4000 40 SPS-2/3AP1-DT 72.5 160 350 4000 40 121 260 550 4000 63 145 310 650 4000 63 169 365 750 4000 63 242 425 900/1050 8

9 /850 4000 63 [A] 4000 40 Rated breaking current up to [kA] Operating mechanism type Fig. 30 10 Spring-stored-energy mechanism Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/21

Dead-Tank Circuit-Breakers for 550 kV 1 Circuit-breaker Type 3AT2/3-DT Composite insulators The 3AT2/3-DT is available with bushings made from composit e insulators this has many practical advantages. The SIMOTEC composite insulators manufactured by Siemens consist of a basic body made of epoxy resin reinforced glass fibre tubes. The external tube surface is coated with vulcanized silicon. As is the case with porcelain insulators, the external shape of the insulator ha s a multished profile. Field grading is implemented by means of a specially shap ed screening electrode in the lower part of the composite insulator. The bushing s and the metal tank of the circuit-breaker surround a common gas volume. The co mposite insulator used on the bushing of the 3AT2/3-DT is a onepiece insulating unit. Compared with conventional housings, composite insulators offer a wide ran ge of advantages in terms of economy, efficiency and safety. Interrupter unit Th e 3AT2/3-DT pole consists of two breaking units in series impressive in the shee r simplicity of their design. The proven Siemens contact system with double grap hite nozzles assures faultless operation, consistently high arc-quenching capaci ty and a long operating life, even at high switching frequencies. Thanks to cons tant further development, optimization and consistent quality assurance, Siemens arc-quencing systems meet all the requirements placed on modern high-voltage te chnology. Hydraulic drive The operating energy required for the 3AT2/3-DT interrupters is provided by the hydraulic drive, which is manufactured inhouse by Siemens. The f unctional principle of the hydraulic drive constitutes a technically clear solut ion which offers certain fundamental advantages. Hydraulic drives provide high a mounts of energy economically and reliably. In this way, even the most demanding switching requirements can be mastered in short opening times. Siemens hydrauli c drives are maintenancefree and have a particulary long operating life. They me et the strictest criteria for enviromental acceptability. In this respect, too, Siemens hydraulic drives have proven themselves throughout years of operation. For further information please contact: Fax: ++ 49 - 3 03 86 - 2 58 67 2 3 4 Technical data 5 6 7 8 Type Rated voltage [kV] [kV] [kV] [kV] [A] [kA] 3AT 2/3-DT 550 860 1800 1300 4000 50/63 Electrohydraulic mechanism 9 Rated power-frequency withstand voltage Rated lighting impulse withstand voltage

10 Rated switching impulse withstand voltage Rated nominal current up to Rated brea king current up to Operating mechanism type Fig. 31 2/22 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Dead-Tank Circuit-Breakers for 550 kV 1 2 3 4 5 6 7 8 9 Fig. 32: The 3AT2/3-DT circuit-breaker with SIMOTEC composite insulator bushings 10 Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/23

Surge Arresters Introduction 1 The main task of an arrester is to protect equipment from the effects of overvol tages. During normal operation, it should have no negative effect on the power s ystem. Moreover, the arrester must be able to withstand typical surges without i ncurring any damage. Nonlinear resistors with the following properties fulfill t hese requirements: s Low resistance during surges so that overvoltages are limit ed s High resistance during normal operation, so as to avoid negative effects on the power system and s Sufficient energy absorption capability for stable opera tion With this kind of nonlinear resistor, there is only a small flow of current when continuous operating voltage is being applied. When there are surges, howe ver, excess energy can be quickly removed from the power system by a high discha rge current. Nonlinear resistors Nonlinear resistors, comprising metal oxide (MO), have prove d especially suitable for this. The nonlinearity of MO resistors is considerably high. For this reason, MO arresters, as the arresters with MO resistors are kno wn today, do not need series gaps. Siemens has many years of experience with arr esters with the previous gapped SiC-arresters and the new gapless MO arresters i n low-voltage systems, distribution systems and transmission systems. They are u sually used for protecting transformers, generators, motors, capacitors, tractio n vehicles, cables and substations. There are special applications such as the p rotection of s Equipment in areas subject to earthquakes or heavy pollution s Su rge-sensitive motors and dry-type transformers s Generators in power stations wi th arresters which posses a high degree of short-circuit current strength s Gasinsulated high-voltage metalenclosed switchgear (GIS) s Thyristors in HVDC trans mission installations s Static compensators s Airport lighting systems s Electri c smelting furnaces in the glass and metals industries s High-voltage cable shea ths s Test laboratory apparatus. 2 3 4 MO arresters are used in medium, high and extra-high-voltage power systems. Here , the very low protection level and the high energy absorption capability provid ed during switching surges are especially important. For high voltage levels, th e simple construction of MO arresters is always an advantage. Another very impor tant advantage of MO arresters is their high degree of reliability when used in areas with a problematic climate, for example in coastal and desert areas, or re gions affected by heavy industrial air pollution. Furthermore, some special appl ications have become possible only with the introduction of MO arresters. One in stance is the protection of capacitor banks in series reactive-power compensatio n equipment which requires extremly high energy absorption capabilities. Arreste rs with polymer housings Fig. 34 shows two Siemens MO arresters with different t ypes of housing. In addition to what has been usual up to now the porcelain hous ing Siemens offers also the latest generation of high-voltage surge arresters wi th polymer housing. 5 6 7 Arrester voltage referred to continuous operating voltage /C Rated voltage R Continuous operating voltage C

8 2 9 10 1 20 C 115 C 150 C Fig. 34: Measurement of residual voltage on porcelain-housed (foreground) and po lymer-housed (background) arresters 0 10-4 10-3 10-2 10-1 1 10 102 103 104 Current through arrester Ia [A] Fig. 33: Current/voltage characteristics of a non-linear MO arrester 2/24 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Surge Arresters Fig. 35 shows the sectional view of such an arrester. The housing consists of a fiberglass-reinforced plastic tube with insulating sheds made of silicon rubber. The advantages of this design which has the same pressure relief device as an a rrester with porcelain housing are absolutely safe and reliable pressure relief characteristics, high mechanical strength even after pressure relief and excelle nt pollution-resistant properties. The very good mechanical features mean that S iemens arresters with polymer housing (type 3EQ/R) can serve as post insulators as well. The pollution-resistant properties are the result of the water-repellen t effect (hydrophobicity) of the silicon rubber, which even transfers its effect s to pollution. The polymer-housed high-voltage arrester design chosen by Siemens and the highqu ality materials used by Siemens provide a whole series of advantages including l ong life and suitability for outdoor use, high mechanical stability and ease of disposal. Another important design shown in Fig. 36 are the gas-insulated metalenclosed surge arresters (GIS arresters) which have been made by Siemens for mor e then 25 years. There are two reasons why, when GIS arresters are used with gas -insulated switchgear, they usually offer a higher protective safety margin than when outdoor-type arresters are used (see also IEC 60099-5, 1996-02, Section 4. 3.2.2.): Firstly, they can be installed closer to the item to be protected so th at traveling wave effects can be limited more effectively. Secondly, compared with the outdoor type, inductanc e of the installation is lower (both that of the connecting conductors and that of the arrester itself). This means that the protection offered by GIS arresters is much better than by any other method, especially in the case of surges with a very steep rate of rise or high frequency, to which gas-insulated switchgear i s exceptionally sensitive. Please find an overview of the complete range of Siem ens arresters in Figs. 37 and 38, pages 26 and 27. 1 2 3 For further information please contact: Fax: ++ 49 - 3 03 86 -2 67 21 e-mail: ar rester@siemens.de 4 SF6-SF6 bushing (SF6 -Oil bushing on request) 5 Flange with gas diverter nozzle Seal Access cover with pressure relief device and filter Pressure relief diaphragm Compressing spring Metal oxide resistors Spring contact Grading hood 6 7 Composite polymer housing FRP tube/silicon sheds Metal-oxide resistors Supporting rods Enclosure

8 9 10 Fig. 36: Gas-insulated metal-enclosed arrester (GIS arrester) Fig. 35: Cross-section of a polymer-housed arrester Siemens Power Engineering Guide Transmission and Distribution 4th Edition 2/25

Low-Voltage and Medium-Voltage Arresters and Limiters (230/400 V to 52 kV) Type 1 Low-voltage arresters and limiters 3EA2 3EF1 3EF2 3EF3 3EF4 3EF5 Motors, dry-type transformers, airfield lighting systems, sheath voltage limiter s, protection of converters for drives Medium-voltage arresters 3EC3 3EE2 3EH2 3EG5 3EK5 3EK7 3EQ1-B 2 Applications Lowvoltage overhead line systems 3 DC systems (locomotives, overhead contact lines) 4 Generators, motors, melting furnaces, 6-arrester connections, power plants Distribution systems metalenclosed gas-insulated switchgear with plug-in connect ion 45 52 Distribution systems and mediumvoltage switchgear Distribution systems and mediumvoltage switchgear Distribution systems and mediumvoltage switchgear AC and DC locomotives, overhead contact lines 5 Nom. syst. [kV] voltage (max.) Highest [kV] voltage for equipment (max.) 1 10 12 3 4 30 36 30 36 60 72.5 30 36 25 30 6 Maximum rated voltage Nominal discharge current [kV]

1 15 4 45 52 45 75 45 37 (AC) 4 (DC) 10 [kA] 5 1 10 10 10 10 10 10 7 8 Maximum [kJ/kV] energy absorbing capability (at thermal stability) Maximum long duration current impulse, 2 ms Maximum shortcircuit rating Housing material [A] 3EF1/2 3EF3 3EF4 3EF5 0.8 9 12.5 8 10 10 1.3 3 5

3 10 1 x 380 20 x 250 3EF4 3EF5 1500 1200 1200 1200 200 300 500 300 1200 9 [kA] 10 Line disconnection Polymer 40 40 300 16 20 20 20 40 Polymer Porcelain Porcelain Metal Porcelain Porcelain

Polymer Polymer Fig. 37: Low and medium-voltage arresters 2/26 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

High-Voltage Arresters (72.5 to 800 kV) Type 3EP1 Applications Mediumand highvoltage systems, outdoor installations 3EP4 Mediumand highvoltage systems, outdoor installations 3EP2 Highvoltage systems, outdoor installations 3EP3 Highvoltage systems, outdoor installations, HVDC, SC & SVC applications 765 3EQ1 Mediumand highvoltage systems, outdoor installations Metal-oxide surge arresters 3EQ4 3EQ3 3EP2-K 3ER3 Highvoltage systems, outdoor installations Highvoltage systems, outdoor installa tions, HVDC, SC & SVC applications 765 Highvoltage systems, metalenclosed gasins ulated switchgear 150 3EP2-K3 Highvoltage systems, metalenclosed gasinsulated switchgear 150 3EP3-K Highvoltage systems, metalenclosed gasinsulated switchgear 500 1 2 3 Nom. syst. voltage (max.) [kV] 60 150 500 275 500 Highest [kV] voltage for equip. (max.) Maximum rated voltage Nominal discharge c urrent Maximum line discharge class Maximum [kJ/kV] energy absorbing capability (at thermal stability) Maximum long duration current impulse, 2 ms Maximum short circuit rating [A] [kV] 72.5 170 550 800

300 550 800 170 170 550 4 84 147 468 612 240 468 612 180 180 444 5 [kA] 10 10 10/20 10/20 10 10/20 20 10/20 10/20 20 2 3 5 5 3 5 5 4 4 5 6

5 8 12.5 20 8 12.5 20 10 10 12.5 7 500 850 1500 3900 850 1500 3900 1200 1200 1500 8 [kA] 40 65 65 100 50 65 80

9 Minimum [kNm]2) breaking moment Maximum [MPSL] permissible service load Housing material 1) 2.12) 4.52) 12.52) 342) 10 63) 213) 723) Porcelain Porcelain 2) Acc. Porcelain Porcelain 3) Polymer1) Polymer1) Polymer1) Metal Metal Metal Silicon rubber sheds to DIN 48113 Acc. to IEC TC 37 WG5 03.99; > 50% of this value are maintained after pressure r elief Fig. 38: High-voltage arresters Siemens Power Engineering Gu