tamil nadu electricity board
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TAMIL NADU ELECTRICITY BOARDMANUAL ON PRE-COMMISSIONING & PERIODICAL TESTING OF ELECTRICAL INSTALLATION
FOREWORDThe need for a comprehensive manual on Substation equipments and testing procedures for these equipments is a long felt need. Initiative for this was taken in July 1999 to prepare such a manual by constituting a Committee of experts. It is not enough if the officers of specialised field such as GRT, MRT, SS Erection, Transformer Erection etc., know about such testing procedures. The officers in charge of Substations should also have adequate knowledge of the equipments they are incharge of, so that these equipments are maintained well, operated in the way they should be done. Besides the maintenance officials, the operators of the 400 KV, 230 KV and 110 KV Substations should also be familiar about the functioning of each equipment they have to operate, observe and monitor during the course of their duty. Though piece meal instructions are available in various literature and suppliers manuals, they are not codified and written in the way the maintenance and operating officials could easily understand and carry out their function with confidence and in a systematic way. The expert committee has brought out a good manual covering pre-commissioning and periodical testing on all the equipments. I congratulate the members of the team for their excellent work particularly Thiru K. Mounagurusamy, Thiru M. Varadharajan and Thiru M. Arunachalam who have shouldered a major responsibility in bringing out this manual. Any suggestions for improvement are welcome. An updated and improved version will be published later based on these suggestions. I am confident that the manual will be of immense use to the testing, operating and maintenance personnel in the T.N.E.B.,. CHENNAI-600 002 16.02.2001 R. POORNALINGAM, CHAIRMAN Tamil Nadu Electricity Board.
INTRODUCTION:The Institute of Electrical and Electronic Engineers (IEEE) defines a relay as an electric device that is designed to interpret input conditions in a prescribed manner and after specified conditions are met to respond to cause contact operation as similar abrupt change in associated electric control circuits. Any unwanted operation or a non-operation can equally result in major system upsets. To differentiate between these two levels, a protection engineer has to be fully conversant and knowledgeable not only with the protection relay subject but also the protected equipments like generators, motors, transformers, transmission lines, distribution etc. For example, if a protection engineer is not clear about the principles of transformers, he will not be able to handle the protection of the transformers effectively. TNEBs policy has always been to the modern trends on protection system then and there and to give opportunities to its engineers to have the latest philosophy of the system. The TNEB engineers are well exposed to the protection field and are being responsible for the application of modern systems. Now the experienced engineers of the TNEB in the field of protection have developed a manual, sharing their experiences. The objective of this manual is to help the field protection engineers carry out their works effectively to the extent possible. There may be different opinions about some of the points given in this manual. This is natural since protection though a science is an art by itself and any art can not be defined or contained in a shell. It could be practically seen that decisions in protection field are depending upon individuals mainly. This manual is to furnish a minimum common base for the protection art The topics chosen are grouped in separate chapters dealing with major area Power system protection and the power line carrier communication. A sample calculation of fault levels of a small substation is given to generate the idea on the very important area to be familiarised by any protection engineer. Subjects like design, application, principles etc are not dealt with since these are available in various textbooks and brochures of relay manufactures. Care has been taken to include materials, which are not normally available in text books and relay manuals. Importance has been given to provide information and guidelines to the field engineers on the precommissioning, commissioning, periodical maintenance and analysis of relay operations. The provision of such a manual was suggested in response to Chairmans D.O.Letter No. SE/CHO/D 493223 DT 08.07.99 seeking suggestion from various officers. It is not known which officer has actually suggested this, but the subsequent efforts taken by our Chairman Thiru. R. Poornalingam IAS., has brought out this publication. The engineering fraternity should thank our chairman for having been the starter and keeping a constant drive to achieve the goal.
The suggestion was accepted in the meeting held on 17.9.99 and it was decided that Chief Engineer / Research & Development and Chief Engineer / Technical Audit shall print and distribute. A committee consisting the following officers was constituted wide LR CE/TA/EE/AEE/F.SSETP/D204/99 dt 12.11.99. 1) 2) 3) 4) 5) 6) 7) Er. A.S. Kandasamy Er. K. Mounagurusamy Er. S. Swaminathan Er. M. Arunachalam Er. P. Ponnambalam Er. ULO Chenthamizh Kodai Er. M. Varadarajan No.
It was also approved in the above ref. that the above committee shall prepare the manual and put up to the steering committee consisting of Chief Engineer / Technical Audit, Chief Engineer / Research & Development and Chief Engineer / Operation. First meeting of the committee was held on 22.11.99 and the subjects were decided along with the allocation of various subjects to the members of the committee. The members were asked to submit the materials on or before 22.12.99. The copies of materials received were furnished to all other members in order to check and avoid any technical errors and to suggest for any improvements. Subsequent meetings were held on 28.1.2000 and 28.2.2000. The subject was reviewed by Chairman on 13.11.2000 and Chief Engineer / Protection & Communication was instructed to take up the work and complete the job. The job was completed with the best cooperation of Engineers Thiru M. Arunachalam, Thiru M. Varadarajan and Thiru Ponnambalam in the final stages and a long felt need of relay engineers has been accomplished. It is our best hope that the manual will be of valuable assistance to the field engineers. Any suggestions and improvement are welcome and will be sincerely acknowledged and appreciated.
CHENNAI 600 002 DATE: 16.2.2001
Chief Engineer Protection & Communication Chennai 2.
CONTENTSChapter Introduction 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Need for Tests on Electrical Instalation Current Transformers Potential Transformers Capacitive Voltage Transformer Pre-commissioning Tests Commissioning Test Testing of Circuit Breaker at Site Testing of Relays Protection of Non Grid Feeders Distance Protection Er. A. S. Kandasamy CE/Transmission. Er.K. Mounagurusamy CE/P&C Er.K. Mounagurusamy CE / P&C Er.K. Mounagurusamy CE / P&C Er. P. Ponnambalam EE/ S.S Erection Er.K. Mounagurusamy CE / P&C Er. M. Varadarajan EE / O&M. Er. M. Arunachalam EE / GRT 7 19 43 48 54 75 78 81 121 156 251 267 271 290 316 Subject Author Page
Power Transformer Testing and Protection Er. M. Varadarajan EE / O&M Generator Protection Under Frequency relaying Power-line Carrier Communication HV AC/DC Test Maintenance of Relays Er.K. Mounagurusamy CE / P&C Er.K. Mounagurusamy CE / P&C Er. M. Arunachalam EE / GRT By R&D. Er.K. Mounagurusamy CE / P&C
16. 17. 18. 19. 20.
Gas Insulated Sub-Stations. Review and Analysis of Tripping Experience in protection field Under ground Cable System Batteries
Er.K. Mounagurusamy CE / P&C Er.K. Mounagurusamy CE / P&C Er.K. Mounagurusamy CE / P&C Er. M. Arunachalam EE / GRT Er. M. Arunachalam EE / GRT
322 336 353 366 370
CHAPTER-I NEED FOR TESTS ON ELECTRICAL INSTALLATIONEACH AND EVERY PIECE OF EQUIPMENT IS TESTED IN THE FACTORY BEFORE DESPATCHING TO THE SITE. PRECOMMISSIONING TESTING AT SITE IS DONE TO PROVE THAT: i) ii) iii) iv) TO ENSURE THAT EQUIPMENT WAS NOT SUBJECTED TO ANY DAMAGE DURING TRANSPORTATION. EACH EQUIPMENT HAS BEEN INSTALLED CORRECTLY. EACH EQUIPMENT IS WORKING IN CO-ORDINATION WITH OTHER EQUIPMENTS AS DESIRED. ALL THE PROTECTION AND CONTROL SCHEMES ARE WORKING IN ACCORDANCE WITH RELEVENT SPECIFICATION AND PROTECTION REQUIREMENTS. EACH EQUIPMENT HAS BEEN ADJUSTED PROPERLY IN ACCORDANCE WITH TNEBS SETTINGS. THE INSTALLATION IS SAFE FOR PUTTING IN TO SERVICE. THE PREIODICAL TESTING WILL ENSURE THE AVAILABILITY OF THE EQUIPMENT FOR THE RELIABILITY OF THE SYSTEM PERFORMANCE. THE TESTING OF PROTECTIVE SYSTEM FOR COMBINATION OF CONTINGENCIES THAT CAUSE THE SYSTEM INSTABILITY AND SEPARATION WILL EVOLVE THE DYNAMICS OF THE SYSTEM. THIS WILL ALSO HELP IN UPDATING THE SYSTEM DISASTER CONTROL MEASURES IMPLEMETED. FINALLY THIS WILL GIVE A RECOGNITION FOR THE POSSIBILITY TO FACE THE UNFORSEEN MULTIPLE CONTINGENCIES AND/OR NATURAL CALAMITY WHICH MAY CAUSE THE COLLAPSE OF THE ENTIRE SYSTEM.
v) vi) vii) viii)
PROTECTION SYSTEM FOR TRANSMISSION AND DISTRIBUTIONUNDER NORMAL CIRCUMSTANCES, THE ELECTRICAL ENERGY IN AN ELECTRICAL SYSTEM IS SAFELY CONTAINED AND CONTROLLED. WHEN EQUIPMENT FAILS, THE ENERGY IS RELEASED AND EVERY COMPONENT IN THE SYSTEM IS AT RISK. THE PROTECTIVE RELAYING SYSTEM MONITORS THE ENERGY FLOWING IN THE SYSTEM AND INITIATE ACTION WHEN DAMAGING FAULTS OCCUR.
ELECTRICAL ENGINEER NEEDS TO UNDERSTAND: ROLES OF PROTECTION EFFECTS OF FAULTS ON ELECTRICAL EQUIPMENT BASIC PROTECTIVE METHODS ZONES OF PROTECTION IN RELAYING SYSTEMS