Petition No. 2/2010 (Suo-motu). Case: In Re: Grid disturbance in the Northern Region on 2nd January, 2010 Vs. Central Electricity Regulatory Commission
| Case Number | Petition No. 2/2010 (Suo-motu) |
| Judges | Dr. Pramod Deo, Chairperson, Shri S. Jayaraman, Member, Shri V.S. Verma, Member and Shri M. Deena Dayalan, Member |
| Issue | Electricity Act, 2003 - Sections 38, 39 |
| Judgement Date | September 20, 2012 |
| Court | Central Electricity Regulatory Commission |
Order:
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It was noted from press report that power supply in the Punjab, Haryana, Himachal Pradesh, Delhi, and Union Territory of Chandigarh was affected on 2nd January 2010 on account of grid disturbance in the Northern Region. The reasons for the grid disturbance were stated to be tripping of the several transmission lines on account of heavy fog. Accordingly, Commission vide its order dated 14.1.2010 in petition No. 2/2010 (Suo motu) directed the Central Electricity Utility (CTU) and Northern Regional Load Despatch Centre (NRLDC) to carry out a detailed study of the grid disturbances and submit and a report containing the reasons for grid disturbances, preventive steps taken so far and to suggest remedial measures. During the course of hearing on 25.5.2010, the representative of the NRLDC submitted that there were two incidents of grid disturbance, one at 0301 hrs and the second at 2154 hrs on 2.1.2010. The load loss on the first incident was about 7500 MW and on the second incident, it was about 9000 MW. He submitted that on 2.1.2010 there was high humidity and low temperature conditions causing outage of several 400 kV and 220 kV lines mainly due to insulator failure. At 03:00 hrs on 2.1.2010, there were 15 number of 400 kV lines and 80 number of 220 kV lines out due to fog related trippings. However, number of 400 kV line trippings was less as compared to incidences of grid disturbances in previous years.
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With regard to violation of the provisions of the Grid Code by the Utilities, the representative of NRLDC clarified that there might be incidents of inadequate action in accordance with the provisions of Grid Code relating to under-frequency and df/dt relays, protection system and real time data transfer including installations of RTUs by the utilities. He further submitted that against the planned relief of 1140 MW and 2420 MW from UFR and df/dt relays, the actual relief was about 128 MW and 297 MW, respectively at 03:01 hours of 2.1.2010. Similarly, the load relief from these schemes was much less than planned in the second incident at 21:54 hrs. He stated that the actions by the system operators in such incidents have to be taken in a very short span of time and emphasized the need of capacity building of the operators.
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The Commission vide Record of Proceedings dated 25.2.2010, directed the NRLDC to submit the following details:
(i) Actual vis-a vis- schedule replacement of insulator by the utilities;
(ii) The details of non-operation/mal-operation of protection system;
(iii) Details of the violation of the provisions of the gird code by the utilities, name of responsible utility; and
(iv) Non-availability of Remote Terminal Units (RTUs) along with the name of the responsible utility.
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NRLDC under its letter dated 6.7.2010 has filed the said information. According to the NRLDC, an Enquiry Committee was constituted under the Chairmanship of Member (GO&D), Central Electricity Authority to enquire into the grid disturbance occurred on 2.1.2010 and Committee submitted its report on 22.6.2010. Observation on NRLDC submission and the findings/recommendations of the Enquiry Committee are as under:
(i) Replacement of insulators in Northern Region:
(a) On perusal of the report submitted by utilities in special meeting taken by Member-Secretary, NRPC on 16.12.2009 with regard to the status of replacement of insulator prior to the gird incident, it is evident that Delhi Transco Limited, Haryana Vidyut Prasaran Nigam Limited, Uttar Pradesh Power transmission Corporation Ltd., Power Grid Corporation of India Ltd., Punjab State Electricity Board and Rajasthan Rajya Vidyut Prasaran Nigam Limited did not adhere to the schedule. The Enquiry Committee observed that in additional to already identified lines for replacement of insulators other lines should also be indentified and the work should be completed before next winter. The relevant portion of para 2 of Chapter 11 of the report is as under:
In addition they should also identify additional lines which are getting frequently affected due to fog in winter season. The work of replacement of porcelain insulators with polymer/anti-fog insulators should be carried out on the complete stretches of the lines especially in case of the critical 400 kV and 200 kV lines and evacuation lines from the generating station. The replacement of insulators of these lines with preferably polymer may be completed before reoccurrence of fog in next winter season (by Nov, 2010). The respective utilities may prepare a time line and accordingly coordinate the activities of procurement and implementation of replacement of insulators so as to avoid shutdowns during peak period/season
(b) The committee in its para 5.2.1 has also made following observation:
It has also been ascertained that though in the stretch around Dadri the insulator replacement work has been completed, the auto-reclosure / tripping were in the sections beyond Dadri in the Mainpuri...
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