Dr. Yuri Khersonsky New IEEE Power Electronics Standards for Ships

Abstract This paper provides update on the latest active and in-development IEEE Power Electronics standards for ships and ship’s applicable new IEC standards. It emphases that by combining established industrial practices with the latest innovations and modern analytical tools standards provide safe and cost effective transfer of new technologies into Navy ships. Keywords: IEEE Standards, Power Electronics,

Electric Ship Technologies, ESRDC, ONR, PEBB,

Open Systems, Zonal Electrical Delivery Systems,

Marine Industries, IEC Standards.

Introduction Almost simultaneously at the beginning of this century Office of Naval Research (ONR) and Institute of Electrical and Electronics Engineers (IEEE) focused on Electric Ship Technologies which have been identified as one of the 10 emerging technological challenges of 21th Century. IEEE started its Electrical Ships Technologies Initiative and ONR created and funded Electrical Ships Research Consortium ESRDC. Concurrence of these events created unique opportunity to bring together resources of leading electric power research institutions to advance near to mid-term electric ship concepts and IEEE Standards collective practical experience of many generations of professional electrical engineers. IEEE established bi-annual Electric Ship Technologies Symposium ESTS and formed IEEE standards working groups to accelerate revision of existing and development of the new IEEE standards applicable to Electric Ship Technologies. ONR decided to support these working groups and funded ESRDC research in many standards’ related issues such as stability analyses, MVDC grounding, fault detection, arc mitigation, etc. Supporting combined efforts of IEEE and ESRDC ONR gained a perfect tool for safe and cost effective transfer of new technologies into Navy ships.

According to P.L. 104-113 "The National Technology Transfer and Advancement Act of 1995" Federal agencies must use voluntary consensus standards and participate in the development of such standards. The IEEE develops technical standards through an open process that brings diverse industries and academia together. These standards establish a baseline for customer’s selection and acceptance of products as well as the technical base for codes, rules and regulations by different enforcing and regulating authorities. New IEEE Power Electronics Standards for Ships IEEE Std. 1662™-2008 IEEE Std. 1662™-2008 “Guide for the design and application of Power Electronics in Electrical Power Systems on Ships” states that Power Electronics equipment should:

Take self-protection actions regardless of the status of communications by reflexive actions to maintain continuity of power.

Respond to internal and downstream faults.

Sustain communications and ability to perform control actions following a loss of input voltage to permit detection, isolation, and system reconfiguration following a casualty condition.

Latch parameter values at the time of the fault and communicate status to higher level controllers.

Interact with other power electronics equipment for power flow management and fault handling.

High Resistance Grounding preferable on the source side of isolated and otherwise ungrounded three-wire, three-phase distribution systems with voltages over 1000 V and aggregated power above 1.5 MW.

PE should have a minimum efficiency of 95% (5% total losses) at rated load condition.PE should be provided with a overload rating of 150% for 1 min.

Table 1 Voltage and frequency variations

for ac distribution systems

Quantity in operation

Permanent variation

Transient variation (recovery time)

Frequency ±5% ±10% (5 s) Voltage +6%, –10% ±20% (1.5 s)

Table 2 Voltage variations for dc distribution systems

Parameters Variations Voltage tolerance (continuous) ±10% Voltage cyclic variation deviation

5%

Voltage ripple (ac root-mean-square over steady dc voltage)

10%

Three sets of tests are generally required to be conducted on power electronics equipment:

1) Type test: Test of one or more devices made to a certain design to demonstrate that the design meets certain specifications.

2) Production test: A test conducted on every unit of equipment prior to shipment

3) Commissioning test conducted when the equipment is installed to verify correct operation (also called installation testing, dock trials, or sea trials).

Type tests should include the Insulation Test, Light Load & Function Test, Rated Current Test, Power Loss, Temperature Rise Test, as well as checking the Auxiliary Devices, Properties of the Control Equipment, and Protective Devices. Dielectric withstand-voltage tests should be performed at higher than nominal voltage over a short time interval (e.g., 1 min). Medium-voltage PE equipment may be subject to additional testing prior to installation. Special tests should be conducted in accordance with an approved standard, such as IEEE Std. 1585TM-2002.A test plan should be submitted to the cognizant authority for review and acceptance. Medium-voltage PE equipment should be fully tested

IEEE Std. 1709-2010 The new IEEE Std. 1709-2010 "Recommended Practice for 1 to 35 KV Medium Voltage DC Power Systems on Ships" has been approved by IEEE Standards Board on its June 2010 meeting. This standard recommends functional MVDC block diagram on Figure 1. It assumes that all electrical power sources and loads are connected to the dc bus via power electronics. Such an approach allows limiting fault currents, relative ease of connection of different size generators, storage and loads.

The functional blocks are defined as follows:

“Power Generation” ” is primarily a power source which converts prime energy from fuel into MVDC (e.g. gas turbine + PM generator + rectifier)

“Shore Power Interface” is primarily a power source which adapts electric energy from the utility system on shore to MVDC

“Pulse Load” is a stand-alone load center which draws intermittent pulses of power from the system

“Energy Storage” is a stand-alone power source which primarily provides power to the system when needed but also draws power from the system to recharge.

“Propulsion” is a load center that primarily draws power from the system for propulsion of the vessel. It may also provide power during certain maneuvers such as crash back

“Ship service” is a load center that primarily draws power from the system to power ship services within zones (e.g., dc/dc converter for in-zone distribution of LVDC, dc/ac inverter for in-zone distribution of LVAC).

“Dedicated High Power Load” is a stand-alone load center which draws 1 MW or more of power in steady-state operation.

“MVDC bus” is functional block which allows interrupting and isolating sections of the MVDC system (e.g., mechanical disconnect, solid-state DC breaker).

Figure 1 Functional MVDC block diagram

Table 3 Recommended MVDC voltage classes

MVDC Class kV

Nominal MVDC Class Rated Voltage (kV)

Maximum MVDC Class Rated Voltage (kV)

Already established Classes

1.5 1.5 or ± 0.75 2 or ± 1

3 3 or ± 1.5 5 or ± 2.5

Future Design Classes

6 6 or ± 3 10 or ± 5

12 12 or ± 6 16 or ± 8

18 18 or ± 9 22 or ± 11

24 24 or ± 12 28 or ± 14

30 30 or ± 15 34 or ± 17

10-6

10-5

10-4

10-3 10

-210

-110

+010

+1

Time (seconds)

1.0

PU

2.0

3.0

0.0

2.6

0.75

Tf = Fault Clearing Time

Tf

Figure 2 MVDC Voltage Tolerances Worst Case Envelope

Table 4 Rated withstand voltages for MVDC voltage classes

MVDC class

Rated short-duration withstand voltage to ground Ud kV for 1 min

Rated lightning impulse withstand voltage to ground Up kV (peak value)

1.5 10 45

3 20 60

6 27 75

12 35 95

18 50 110

24 70 150

30 95 200

Recommended MVDC voltage classes are shown in Table 3. Steady state (continuous) DC voltage tolerances limits should be ± 10%. Tolerance envelope for MVDC voltages includes consideration of load requirements. Figure 2 represents an example of the performance of the DC bus. The time associated with zero voltage of the low voltage line is determined by how long it takes to clear a fault on the DC bus or a fault in the power source and restore the voltage to the required level.

Rated withstand voltages for MVDC voltage classes are in Table 4. The intervals of time for which the system can carry a current equal to its rated short-time withstand current is defined by the time delays in the system protection coordination. For MVDC systems with traditional switchgear, values of 0.5 s, 1 s, 2 s, & 3 s should be used. For the new designs with fast power electronics, duration values.0001 s, .001 s, .01 s, 0.05 s, 0.1 s, and 0.2 s should be used.

Mitigation of stray DC ground currents is an important issue for the MVDC power system. The primary mitigation method is to construct the system with low impedance and isolate it from all other ground references. For human safety, touch voltages should be limited to accepted standards.

Loads should be categorized into one of four QOS categories:

1. Uninterruptable: The equipment requires continuous uninterruptable power.

2. Short-term interrupt: The equipment can tolerate interruptions of less than 2 s.

3. Long-term interrupt: The equipment can tolerate interruptions of up to 5 min.

4. Exempt: The equipment can tolerate long-term interruptions or the application permits complete loss of power.

The acceptable RMS values of ripple and noise should not exceed 5% per unit.

It is recommended that in MVDC systems, power electronics should be based on commercially available power electronics building blocks (PEBBs) [6] with each PEBB having its own intelligence that is programmable and self-protecting to the appropriate extent. Automatic control should provide for smooth insertion and removal of power sources and sharing of loads as desired.

IEEE Std. 1826-2012

New "IEEE Standard for Power Electronics Open System Interfaces in Zonal Electrical Distribution Systems rated above 100 kW" standard applies in cases where power electronics are the interface between the zones and extends the application of IEEE Standards 1662 and 1676.

The required Power, Monitoring, Information Exchange, Control, and Protection Interfaces are based on technological maturity, accepted practices and allowances for future technology insertions. The standard also defines how Openness of System should be verified and validated through rigorous assessment mechanism, interface control management and proactive conformance testing to enable plug-and-play operability independently of components origin.

For a zonal power system to be Open, each device attached to the power bus shall meet these criteria:

A. Each device shall implement certain functionality that lets it “play well” with the other system components, including implementation of power control and safety features

B. Each device shall conform to standard control and information interfaces

C. Each device shall conform to standard power interfaces

Figure 3 shows the elements of a zonal power system and their power interfaces. The systems interfaces in zonal distribution systems are based on the architectural principles in Table 5 derived from the IEEE Std 2030TM, “Guide for Smart Grid Interoperability of Energy Technology and Information Technology Operation With the Electric Power System (EPS), and End-Use Applications and Loads”.

This standard Verification and Validation (V&V) processes are adapted from IEEE Std 1012-2012 “Standard for System and Software Verification and Validation” as well as the entire family of IEEE system engineering standards. They include assessment, analysis, evaluation, review, inspection, and conformance testing. Maintenance of Open Systems Interfaces shall comply with IEEE 3007.2-2011 “IEEE Recommended Practice for the Maintenance of Industrial and Commercial Power Systems”

Figure 3 Zonal Electrical Distribution System (ZEDS) block diagram

Table 5 Open Zonal Architectures Principles

Principle Description Standardization The elements of the zone and the ways in which they interrelate shall be clearly defined,

published, useful, open, and stable over time. Openness The zones shall be based on technology that is available on a nondiscriminatory basis. Interoperability The standardization of interfaces within the power system shall be organized such

that

The system can be easily customized for particular geographical, application-specific, or business circumstances, but

Customization does not prevent necessary interactions among elements of the zone to maximize stability and acceptable system behavior.

Security The zone shall be protected against unauthorized access and interference with normal operation. It shall consistently implement information privacy and other security policies.

Extensibility The zone shall not be designed with built-in constraints to extending its capabilities as new applications are discovered and developed. Toward this goal,

Its data shall be defined and structured according to a common information model.

It shall separate the definition of data from the methods used to deliver it.

Its components shall announce and describe themselves to other components.

Scalability The use of zones shall be expandable throughout the power system with no inherent limitations on the power system size.

Manageability The components of the zone shall have their configuration assessed and managed, faults shall be identified and isolated, and the components shall be otherwise remotely manageable.

Upgradeability The configuration, software, algorithms, and security credentials of the zone shall be capable of being upgraded safely and securely with minimal remote site visits.

Integrity The zone shall operate at a high level of availability, performance, and reliability. It shall re-route communications automatically, operate during power outages, and store data for intervals sufficient to recover from failure events.

IEC/ISO/IEEE 80005-1

The new IEC/ISO/IEEE 80005-1 Ed.1: Cold Ironing Part 1: High Voltage Shore Connection (HVSC) Systems – General requirements (Previously referred to as IEC/ISO/IEEE 60092-510 Ed.1: Electrical installations in ships – Special features – High Voltage Shore Connection Systems (HVSC Systems) has been developed as a joint work of IEC TC18, ISO TC8 SC 3 and IEEE, PCIC Marine Industry Subcommittee. This international standard applies to HVSC systems on board the ship and on shore and addresses:

high-voltage shore distribution system, shore-to-ship connection, transformers/reactors, semiconductor / rotating convertors, ship distribution system, control, monitoring, interlocking and

power management system. The specific requirements for system control and monitoring are:

Load transfer shall be provided via blackout or synchronization

Interlocking means shall be provided to ensure that the shore supply can only be connected to a dead switchboard. The interlocking means shall be arranged to prevent connection to a live switchboard

Load shall be automatically synchronized and transferred between the HV shore supply and ship source(s) of electrical power following their connection in parallel,

The load transfer shall be completed in as short a time as practicable without causing machinery or equipment failure or operation of protective devices and shall be used as the basis for defining the transfer time limit

Any system or function used for paralleling or controlling the shore connection shall have no influence on the ship’s electrical system, when there is no shore connection.

Industry is anxious for standards in this area especially in California where new restrictions have been placed on the operation of auxiliary diesel engines on ocean-going vessels at-berth in California ports (Section 2299.3, title 13, chapter 5.1, California Code of Regulations).

Ship applicable IEEE Standards Following IEEE standards could be applied on ships:

Std 1409-2012, IEEE Guide for Application of Power Electronics for Power Quality Improvement on Distribution Systems Rated 1 kV through 38 kV

Std 1031-2011, IEEE Guide for the Functional Specification of Transmission Static Var Compensators

Std 1303-2011, IEEE Guide for Static VAR Compensator Field Tests

Std 1676-2010 IEEE Guide for Control Architecture for High Power Electronics (1 MW and Greater) used in Electric Power Transmission and Distribution Systems

Std 1534-2009, IEEE Recommended Practice for Specifying Thyristor-Controlled Series Capacitors

Std C57.21-2008, IEEE Standard Requirements, Terminology, and Test Code for Shunt Reactors Rated over 500 kVA

1585-2007, IEEE Guide for the Functional Specification of Medium Voltage (1- 35kV) Electronic Series Devices for Compensation of Voltage Fluctuations

Std 1623-2005, IEEE Guide for the Functional Specification of Medium Voltage (1 kV - 35 kV) Electronic Shunt Devices for Dynamic Voltage Compensation

Std 1566- 2005, IEEE Standard for Performance of Adjustable Speed AC Drives Rated 375 kW and Larger

Std 958-2003, IEEE Guide for Application of AC Adjustable-Speed Drives on 2400 to 13,800 Volt Auxiliary Systems in Electric Power Generating Stations

Std 1573-2003, IEEE Recommended Practice for Electronic Power Subsystems: Parameters, Interfaces, Elements, and Performance”

Std. 1515 -2000, IEEE Recommended Practice for Electronic Power Subsystems: Parameter Definitions, Test Conditions, and Test Methods

IEEE Std. 1676-2010

To encourage development of PEBB concept ONR started in 2000 support Working Group i8 "Power Electronics Building Block Concepts" under Substation Committee of Power Engineering Society PES. The i8 working group developed IEEE Std1676-2010 “Guide for Control Architecture for High Power Electronics

(1 MW and Greater) used in Electric Power Transmission and Distribution Systems”.

The standard recommends using the concept of system layers shown on Figure 4.

Highlights of this standard are:

The interface between layers should be designed to enable layer modularity such that replacement of any layer should not induce modifications in other layers.

The communication speed requirements at the lowest or hardware layer are the greatest and decline with each higher control layer.

In order to preserve the hierarchical architecture horizontal communication between layers should be avoided.

It is also recommended that each converter have its own independent switch control to serve its hardware control.

When a system is partitioned, the partition interface should be designed to meet performance requirements of different layers, including requirements on data volume and transmission rates. The proposed architecture further suggests that there may be a common converter control to serve multiple switching controls. Also, one application control may serve more than one converter control.

The function of protection is to take the necessary action as fast as required; therefore, the function of protection may go to any of the layers.

Figure 4 Control &Protection Architecture for Power Electronics

IEEE Std. 1303-2011 The IEEE Std 1303-2011, “IEEE Guide for Static Var Compensator Field Tests” is a guide for field testing and commissioning of static Var compensators (SVCs). It establishes guidelines and criteria for field testing to verify the specified performance of SVC systems. Many clauses are useful for compensator systems using gate turn-off (GTO) Thyristor technology or other semiconductor devices such IGCT. The purpose of this guide is to help users of SVCs carry out a field test program prior to placing an SVC into service. The major elements of a commissioning program are identified so that users can formulate a specific plan that is suited to their own SVC. Such a test program shall cover the following:

A. Equipment tests within the SVC system B. Tests of the various subsystems that

comprise the SVC system C. Commissioning tests for the complete

SVC system D. Acceptance testing of the complete SVC

system A comprehensive field test program includes the following major phases:

a) Overall test planning and organization, including the definition and line of authority for performing the tests.

b) Survey of documents and data, including contract, system study, factory test review, drawings, user’s manual availability, and definition of ac system requirements or limitations.

c) Preparation of ITPs for equipment, subsystem, commissioning, and acceptance tests of the SVC System.

d) Review and approval of, or concurrence with, test program by user.

e) Preparation of schedule, including coordination of installation/test schedule and coordination with

f) system operation. g) Dissemination and approval of field test

results. h) Dissemination of information, including

as-built drawings.

IEC Ship Standards

The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national Electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. IEC publishes International Standards, and Guides (IEC Publication(s)). IEC technical committee TC 18 maintains the IEC 60092 family of standards under common title Electrical Installations in Ships.

IEC 60092 is a series of international standards for electrical installations in sea-going ships, incorporating good practice and coordinating, as far as possible, existing rules. These standards form a code of practical interpretation and amplification of the requirements of the International Convention on Safety of Life at Sea, a guide for future regulations which may be prepared and a statement of practice for use by ship owners, shipbuilders and appropriate organizations. The most important parts of IEC 60092 are:

IEC 60092-101: 2002, Electrical installations in ships – Part 101: Definitions and general requirements. IEC 60092-201: 1994, Electrical installations in ships – Part 201: System design – General IEC 60092-202: Electrical installations in ships. – Part 202: System design – Protection IEC 60092-204, Electrical installations in ships – Part 204: System design – Electric and electrohydraulic steering gear. IEC 60092-350: 2008, Ed. 3.0, Electrical installations in ships - Part 350: General construction and test methods of power, control and instrumentation cables for shipboard and offshore applications. IEC 60092-501:2001, Electrical installations in ships – Part 501: Special features – Electric propulsion plant. IEC 60092-503: 2007 Ed. 2.0 Electrical installations in ships - Part 503: Special features - AC supply systems with voltages in the range of above 1 kV up to and including 15 kV IEC 60092-504:2001, Electrical installations in ships – Part 504: Special features – Control and instrumentation.

CONCLUSIONS

Standards provide safe and cost effective transfer of new technologies into Navy ships

IEEE standards are making possible significant risk reduction in applying new technologies by combining established industrial practices with the latest innovations and modern analytical tools

IEEE standards are collective practical experience of many generations of engineers to do things right from the first attempt.

Standards establish baseline for customer’s selection and acceptance of products.

The best justifications for IEEE standards are famous sayings:

Engineers are not superhuman. That they make mistakes is forgivable; that they catch them is imperative Thus it is the essence of modern engineering not only to be able to check one’s own work but also to have one’s work checked and to be able to check the work of others.

“You have to learn from the mistakes of others. You won't live long enough to make them all yourself.”

ACKNOWLEDGEMENTS

Author gratefully acknowledge over 20 years support from ONR & Mr. Terry Ericsen as well as from all members of IEEE P1662, P1676, P1709, P1713, P1826 and i8 Working Groups.

REFERENCES

1. 1826™-2012 "IEEE Standard for Power Electronics Open System Interfaces in Zonal Electrical Distribution Systems rated above 100 kW"

2. 1303™-2011 “IEEE Guide for Static Var Compensator Field Tests”

3. 1709™-2010 “IEEE Recommended Practice for 1 to 35 KV Medium Voltage DC Power Systems on Ships"

4. 1676™-2010 “IEEE Guide for Control Architecture for High Power Electronics (1 MW and Greater) used in Electric Power Transmission and Distribution Systems”

5. 1662™-2008 “IEEE Guide for the design and application of Power Electronics in Electrical Power Systems on Ships”

6. Y. Khersonsky “IEEE Electric Ship Technologies Initiative”, ASNE Electric Machines Technology Symposium EMTS 2008, Philadelphia, PA, August 12-13, 2008

7. T. Ericsen, Y. Khersonsky and N. Hingorani “Power Electronics and Future Marine Electrical Systems”, IEEE Industry Applications Society 2004 Petroleum &

Chemical Industry Conference, San Francisco CA, September 13-16, 2004.

8. IEEE Power Engineering Society, "Power Electronics Building Block (PEBB) Concepts", IEEE publication

04TP170, 2004

VITA Dr. Yuri Khersonsky (ykhersonsky@ieee.org) has diverse experience in research, development, production, marketing and application of power electronics, electric drives, motion controls and ship power distribution systems. Among his achievements are Solid-State power converters and circuit breakers for the U.S. Navy, Power Conditioning systems for stationary Fuel Cell Power Plants, Servo-drives for CAT Scanners, Machine Tools & Robots, industrial drives, DC and AC PM Motors. He is a Life Senior Member of the IEEE Standards Association, IEEE Industrial Applications, Power Electronics and Power Engineering Societies and is a member of IAS Industrial

Power Conversion, Industrial Drives and Marine Industries Committees. He is the chair of IEEE Working Groups 1662 “IEEE Guide for the Design and Application of Power Electronics in Electrical Power Systems on Ships”, 1709 “IEEE Recommended Practice for 1 to 35 KV Medium Voltage DC Power Systems on Ships” and 1826-"IEEE Standard for Power Electronics Open System Interfaces in Zonal Electrical Distribution Systems Rated Above 100kW", co-chair of 519 “IEEE Recommended Practices and Requirements for Harmonic Control in Electric Power Systems”. Dr. Khersonsky is a co-founder of the IEEE Electrical Ship Technologies Symposium (ESTS) and served as Technical Chair of the ESTS in 2005, 2007 and 2009. He is a Life Member of the Naval League & Surface Navy Association, Member of the American Society of Naval Engineers, the Institute of Marine Engineering, Science and Technology and the Naval Submarine League. He holds 5 patents and has published over 80 papers and 2 books. He received his Engineer's Diploma in Electro-Mechanical Engineering and his Ph.D. in Technical Sciences from Odessa Polytechnic Institute.