- (1.) THIS petition has been filed by Northern Regional Load Despatch Centre (NRLDC) seeking directions to the constituents of the Northern Regional grid to honour the power transfer capability limits specified by NRLDC and curb the overdrawals from the grid so that the entire interconnected electricity grid is secure. It has also been prayed that State Load Despatch Centres (SLDCs) be directed to immediately follow the instructions given by NRLDC in real time. The petition was admitted by us vide order dated 28th September 2007 and parties were heard on 16th October 2007.
(2.) The petitioner has stated that synchonisation of the NR, ER and WR grids has led to a paradigm shift in system operation enabling the constituents of NEW (North- East-West) grid to reap the benefits on account of diversity in weather, loads, maintenance schedule of generating units and forced outage etc. However, it has also brought to sharp focus, the need to maintain real time power transfers within the operating limits (total transfer capability minus reliability margin) to ensure the grid security so that system can withstand at least a single contingency. Despite attempts to raise awareness of the constituents on this issue and also taking up the issue during real time system operation, the power transfer limits have been violated on several occasions. The petitioner has submitted that during such situations, any single contingency would have lead to cascade tripping leading to a black out. The petitioner has listed a few 'near-miss' situations when the grid narrowly escaped a large disturbance. NRLDC has stated that fortunately, in all such situations, the effect was localized. However, there is a serious danger of cascade failure and blackout in a larger area including other interconnected regions. In this background, the petitioner has sought appropriate directions to the constituents and SLDCs. On perusal of the details of overdrawal submitted by the petitioner for a week (14.09.2007 to 20.09.2007), we have noticed that every constituent State has resorted to overdrawal though number of occasions of overdrawal and extent of overdrawal may be varying. From the exhibits enclosed with the petition, we have observed that such overdrawals have led to sustained violation of Total Transfer Capability (TTC). This is a very serious situation as not only NR grid may be affected but entire NR-WR-ER-NER grid may suffer a blackout. If operation continues the way it has been for last few months, it is a tragedy waiting to happen. Demand in the NR is going to increase in winter months and therefore urgent action needs to be taken to tackle this problem. Only some of the constituents (namely UPPCL, RRVPNL, PSEB and HVPNL) were present during the hearing. They have tried to justify their overdrawal and have expressed their helplessness at times to follow instructions of NRLDC. However, the pace at which economy is growing, the demand of electricity is going to keep on increasing in all the regions, leading to perpetual and severe power shortages. If the State utilities do not exercise the necessary self-control, major grid disturbances in near future are very likely.
(3.) UPPCL in its affidavit dated 15.10.2007 has cited a number of reasons for overdrawing power from the regional grid during September 2007, e.g. demand increase by 9.3%, start of Ramazan, decrease of hydro generation by 20%, humidity, rise in temperature, dry spell, fall in Rihand reservoir level and NTPC's request to maintain the level, SCADA data being incorrect. It has prayed that in the light of the above no adverse action may be taken against it.;