optical cables management system for 500kv hvac networks

7/29/2019 Optical Cables Management System for 500kv Hvac Networks

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D2-01 A07

OPTICAL CABLES MANAGEMENT SYSTEM FOR500KV HVAC NETWORKS

CARLOS ALBERTO DI PALMA GUILLERMO GALARZA

ARIEL CAMPOSTRANELSA CONSULTORA ABB SA TRANSENER SA

ARGENTINA ARGENTINA ARGENTINA

[email protected] [email protected] [email protected]

International council on large electric systems2011 Colloquium

STUDY COMMITTEE D2Information Systems and Telecommunication
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


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CURRENT SITUATION (part 1)

The Argentinas 500kV High Voltage Transmission System has a vast optical cablenetwork (order of 5300 km) and 127,000 km of fibers, along the whole country, as wellas a lot of new projects under development

The optical cable network is used for transporting services of:*the own Main EHV Transporter (Transener)*other 500, 330 and 220kV HV Transmission Operators*Generation Plants Agents*HV trunk distributors (sub-transmission)*etc

The services channeled by the optical cable network are mainly:*differential protection system and main protection system*teleprotection system (backup of main protection system)*data of the SCADA system

*data of stabilization resources in order to assure the high Availability figuresof the Argentinas National Interconnected System (SADI)*data exchange with other countries where HV interconnections are made*remote supervision of communication and control systems*connection of digital telephony trunks between PABXs*etc


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CURRENT SITUATION (part 2)

Nowadays, the EHV System of Transener has installed several remote managementsystems (NMS), such as:

*NMS of the SDH digital communication systems

*NMS of the digital teleprotection systems

*NMS of the SHF digital radiolinks

*NMS of the private automatic exchange networks (PABX)

*NMS of the optical amplification chain (when it is applicable)*Overall NMS

BUT the performance of fiber optic cables are not monitored yet

Consequently, it is necessary to plan the automatic supervision of all optical cablesnetworks in order to have the effectively monitoring of the whole communicationsystem

>> Optical Cables Management System (OCMS)


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MAIN BENEFITS TO BE OBTAINED (part 1)

Permanent and continue monitoring/supervision of the whole optical cable network

Reduction of failure detection time

Reduction of failure restoration time

Very precise and accurate optical cable performance information

Increase of the Total Annual Availability (Ai) of the whole optical cables network

because the irreversible failure rate (TIF) will be minimal due to:*the early detection of the performance degradation

*the fast and effective preventive actions

Reduction of preventive maintenance costs. Replacement of the annualmeasurements of each optical cable (24 optical fibers) with OTDR portableinstruments along of thousands of kilometers

Warranty of the right conditions of the optical cables in-use (and their fibers)

Maximization of the level of utilization of the communication systems (full operativecapacity), as well as the services transported by the optical cables

Linkage between the geographical documentation system (GIS) of Transener andthe location of optical cables (and their joint boxes)


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MAIN BENEFITS TO BE OBTAINED (part 2)

Reduction of the critical failures due to the permanent and continuos monitoringprocess

Online verification of the installation process of the new optical cables to beinstalled (during the commissioning period)

Audit of the quality of maintenance (repair tasks) of the existing installed opticalcables

>> After the development and explosive growth of the optical cable network, it isnecessary to focus into the quality of service (QoS) of the EHV System, as well asthe reduction of maintenance costs of the optical cable network


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OTDR AND BACKSCATTERING TECHNIQUE

OTDR module is capable of: fault location as well as the analysis of the optical fiber system

Measurements of attenuation, rate of attenuation, distance, etc

Measurements of reflectance (as ratio of reflected power to incident power of anevent /connector/splice)

additional features like automatic event detection, table of events, optical return

loss, overlapping of traces data storage capability

additional functionalities like light source, power meter


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MONITORING PROCEDURES (part 1)

CRITERION # 1

In order to monitor the quality of service of the optical cable it is possible toadopt the criterion of monitoring all fibers of the whole optical cable

That means that the monitoring process must coexist with the transmission ofinformation in the same fibers

Optical filters as well as WDM multiplexers must be used in order to combine the

monitoring wavelength m with the signal wavelength j of the communicationsystem, without interfering between them (m signal must be -60dB from j signal)


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CRITERION # 2 In order to monitor the quality of service of optical cables, it is possible to adopt

the criterion of monitoring the dark fibers that are not used by the usefultransmission

In such case it is not necessary (exceptions that can be seen on the paper)neither to install optical switches in order to verify all fibers of the optical cable,nor install optical filters in the enlighten fibers

Consequently, the monitoring system will not interact with the communicationsystem that is transmitting in the enlighten fibers


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CRITERION # 2 (criterion of dark fibers monitoring)

The main advantages of this criterion are:

*low cost of implementation

*no interferences with the useful wavelengths

*it is not necessary to enter into systems that are in-service

*possibility of using any monitoring wavelength

*reduction of the time detection of failures because it is not necessary todo the cycle of measurements of 24 optical fibers (per cable)


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FIBER MONITORING SYSTEM (part 1)

REMOTE MEASUREMENT UNIT (MRU)

An optical coupler permits the injection and extraction of light signal to/from thedark fiber

An optical switch (automatically controlled) can select between monitoring darkfiber # 1 (main) and dark fiber # 2 (backup monitoring fiber) on each supervisedcables in the Node

The optical measurement unit includes OTDR module multitest, as well as lightsource emitter, optical power meter

The OTDR module is remotely controlled and provides the optical signals formeasurement, so as also to draw reflection graphs by bidirectional tests

The controller and data processor (CPU) will make, among others, the followingfunctions:

* control of the whole measurement process* storage of the measured data

* analysis of the obtained results* communication with the remote Server through the existing communication

systems (SDH fiber optic system; SHF digital radiolink)


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REMOTE MANAGEMENT CENTER (RMC)

It will consist of a Server that will centralize the information of several MRUnodes, as well as storage the whole information of all optical cables in its DataBase

The Server will manage the collected information and give alerts to the O&M areain order to do the consequent actions of maintenance

The measurement information will be included in the geographical system (GIS)that Transener normally uses for his whole EHV network.Consequently, the event of an optical cable failure (and their features) will beprecisely located

The RMC Center will be suitable for processing the OTDR measurements and thetraces, as well as the rest of information of each MRN node (optical cable ID; darkfiber in-use; date of events; etc)

Consequently, the failed optical cable as well as the failure location, place, etc,will be shown immediately, in spite of the network location where the event hashappened

The dynamic range of the OTDR instrument must cover:*optimal distance: 100% of the optical cable length*acceptable distance: 70-80% of the optical cable length


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STAGES

Failure detection: in case of a performance degradation of an optical fiber (cable),the Remote Unit (RMU) will send an alarm to the Server (RMC), together with itsrelated information (date, time, failure details, failure location, etc)

Processing: the Server will register the failure/degradation event received and

send a notification to the O&M office with all the details collected about the failure

Information: additionally to the GIS failure location, it will be possible to openseveral lapels with information like:

* splice details* specific span (between two splice boxes)* end-to-end optical link

* monitoring dark fiber (main dark fiber; backup one)

Additionally, the Server can add information coming from the NMS System of theSDH Communication System in order to confirm the degradation detected by theOCMS (double-checking method)


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SENSORS

They are necessary in order to verify the optical fiber performance

Humidity detectors: they are based on the Hydrogen absorption and include ahydro-absorbent material that will expand causing a fiber loss due to aconsequent macrobending of the fiber

Stress detectors: they are optical fibre sensors of distributed strain andtemperature range, for monitoring the mechanical stress. They allow to make highresolution measurements, as well as the measurement for long distance links.These sensors are based on Brillouin effect, and can measure simultaneously,both temperature and mechanical stress on optical standard fibres according toITU-T G.652 (details on paper)


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MEASUREMENT OF TRACE

The MNR node uses an OTDR module multitest in order to measure the features ofthe optical fibers (cable) that are involved in the Node

Each event of the link that could cause a reflection will be drawn on a trace of theOTDR. It will allow to obtain information related to that event:

*attenuation measurement

*reflections produced*discontinuities*etc

The failures will be represented by reflections, due to different situations as:*misalignment between optical cables and light emitter*failures due to microbending located in splicing boxes*presence of dust in optical connectors

*cut in fibers*macrobending of the optical cable


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PROCESS

In the MRU node will be saved the right graph/trace of the optical fiber during thecommissioning period, in order to be used as the reference trace

Subsequent traces that can include a failure will differ from the original trace.Consequently, it will be produced:

*generation of an alarm*distance calculation to the event*location of the event within the GIS system

The measurement will be performed continuously, making a permanentcomparison between the original trace and new traces

Both traces (original trace; trace with failure) will be overlapped showing thedifferences as well as doing a comparative analysis

The traces will be selected by the monitoring system, as follow:*original trace (reference trace)*trace with failure (alarm trace)*overlapped traces (showing differences)


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Each MRU Node (located in a specific substation) can check more than oneoptical cable (to different routes)

Examples:

*substation Cobos can check the optical cables towards three routes:

Cobos-El Bracho; Cobos-SanJuancito; Cobos-Monte Quemado

*substation ChChoel can check the optical cables towards three routes:

CChoel-BBlanca; CChoel-PMadryn; ChChoel-PAguila

>>> It is necessary to emphasize that the monitoring system for optical cables is notintended to replace the essential steps:

*the correct choice of the best solution for both, optical cable and itsaccessories

*the right installation process necessary to be made

*the experienced subcontractors to be used

*the qualified and certified handworkers to be used


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QUESTIONS OF THE SPECIAL REPORT (part 1)

Q1.1-26. Please, further explain how you are doing at present, the method of revisionand checking of the performance of your 5300km optical cable network. Please,try to compare the time that is currently needed for detecting a failure in yourwhole optical cable network, with the expected lower time that you estimate couldbe obtained with an on-line monitoring of the optical cables

ANSWER Currently, the performance verification of the whole optical cable network is made

one time per year (measurement of 24 fibers of each optical cable; bidirectional

measurement). The current measurement time demands six months long. The expecting time by using a fiber monitoring system can be reduced to

minutes/cable (by a continue online monitoring)

Q1.1-27. Would the Utility Company accept doing the monitoring of one fiber optic percable, instead of doing the monitoring of all fibres?

ANSWER

To use a monitoring of dark fibers (instead of the enlighten ones) is considered anacceptable method because it is not too simple to interact in the communicationsystem that is in-service (including elements with the existing system)

The insertion of filters and multiplexers would add attenuation in the links in-use(undesirable attenuation in case of long haul links)

The dark monitoring method detects 85% of the possible failures in the opticalcables because the most of the failures will happen in the entire cable and rarelyhappen in a particular fiber alone


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QUESTIONS OF THE SPECIAL REPORT(part 2)

Q1.1-28. Do you have an estimation of the reduction of maintenance cost, as well asthe improvement of System Availability that the on-line optical cable monitoringcan obtain? Could you tell us if the Utility Company has saved a detailed,recorded information of each optical cable (in spite of its date of put in-service) inorder to use it for the future monitoring system of these cables (comparison ofperformance by overlapping of graphs)?

ANSWER It is not possible to calculate a precise value of maintenance costs reduction, but

it should be considered:*avoid the measurement tasks in-field that nowadays imply 1,800 man-hoursper year, plus the operative direct costs (127,000km of fibers) and indirectcosts (risks, accidents, etc)*reduction of troubleshooting time considering that it is a wide area in alarge country (see slide #25)

*reduction of expensive repair tasks, through the preventive detection andreduction of catastrophic failures*execution of more precise tasks (according to the received preciseinformation)*reduction of the out-of-service periods through the advanced perception of

degradation)


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QUESTIONS OF THE SPECIAL REPORT(part 3)

Q1.1-28. Do you have an estimation of the reduction of maintenance cost, as well asthe improvement of System Availability that the on-line optical cable monitoringcan obtain? Could you tell us if the Utility Company has saved a detailed,recorded information of each optical cable (in spite of its date of put in-service) inorder to use it for the future monitoring system of these cables (comparison ofperformance by overlapping of graphs)?

ANSWER The Availability improvement of the whole optical communication system will be

important because it will minimize failures in optical cables (through control ofthe installation process/repair process and their useful lifetime) that currently aredetected after some time has elapsed

The detailed information of each optical cable (graphs, traces) has been savedand is available for use in a future database of the OCMS

optical cables management system for 500kv hvac networks

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