Tripping caused by overdrawal
Umesh Dewan/TNS

Patiala, July 21
It was not a technical snag but overdrawal of power, contrary to claims made by the authorities of the Power Corporation, which was responsible for the tripping of seven units of two thermal plants - Lehra Mohabbat and Bathinda- yesterday. The functionaries of the Northern Regional Load Despatch Centre (NRLDC) have claimed that tripping was due to the overdrawal of power to the extent of 500-MW by the Punjab State Transmission Corporation Limited (PSTCL). Holding Punjab responsible for violating the transfer capability limits, the General Manager, NRLDC, V.K.Agarwal, has shot off a letter to Director (Technical), PSTCL, Ravinder Singh, asking him to take measures to restrict the overdrawal within the schedule and given transfer capability limits.

Because of the tripping of seven units of the two thermal plants yesterday, there was disruption in the power supply for about three hours in some districts of the state. To tackle the overdrawal by the states, NRLDC - which controls the system parameters of the northern- region, has fixed transfer capability limits. Presently, the transfer capability limit for Punjab is 4800-MW, which implies that Punjab can draw maximum of 4800-MW, which includes power from central sector allocations, BBMB, open access and power purchase from traders etc.

“Presently, Punjab can cater to a maximum demand of about 7800-MW (3000-MW from own generation and 4800-MW from other sources), whereas the maximum demand in Punjab has already touched 8400-MW”, informed a Punjab State Power Corporation Limited (PSPCL) official, on the condition of anonymity. He claimed that in wake of the Punjab Assembly elections scheduled for early 2012, the state government doesn’t want power cuts to be imposed and hence in order to meet the gap between the demand and supply of the power, Punjab was indulging in overdrawal of power.

Excerpts of Agarwal’s letter, a copy of which is with The Tribune reads, “In the recent past, the tripping of Inter-Connecting Transformers (ICTs) in Punjab due to overloading/cascading has become frequent. Before the tripping of the thermal plants at Bathinda and Lehra Mohabbat on July 20, there was tripping of ICT at Malerkotla on July 12, 2011 and Patiala on July 14. There have been continuous communications to the Punjab State Load Despatch Centre (SLDC) from our control room to restrict drawal of power within prescribed limits. However, the overdrawals are not curtailed, causing danger to the security, not only to Punjab but also to the entire grid.”

Director (technical) PSTC, Ravinder Singh, said: “Our work is to ensure that the transmission system works properly. As far as the matter of the drawal of the power supply is concerned, it is being decided by the PSPCL.”