Ranchi, Nov. 23: Large parts of Jharkhand were plunged into darkness today after a fire on the Biharsharif transmission line in neighbouring Bihar, causing power stations in Bokaro and Ramgarh to trip simultaneously.

The multiple tripping, at Tenughat Vidyut Nigam (TVNL) at Lalpania and Patratu Thermal Power Station this afternoon, resulted in the state's generation plunging to zero, forcing blackouts in almost all districts of Jharkhand.

"All units at TVNL and at Patratu Thermal tripped at 1.05 pm today, following a fire in a breaker on main transmission lines at Biharsharif in Bihar. Since power lines from TVNL traverse via Biharsharif to the rest of Jharkhand, the fire resulted in our units tripping simultaneously," MD of TVNL Ram Awtar Sahu told The Telegraph.

Necessary repairs were being carried out at the two units of TVNL, each of which was capable of generating around 200 MW.

"We expect to light up both the units only by late evening. Normal supply is expected only around midnight," Sahu explained.

Power officials manning the state load despatch centre at Kusai in Ranchi confirmed the simultaneous tripping.

"One unit at Patratu Thermal Power Station was lit up at around 2 pm, which is currently generating around 50mw. We are drawing as much at 600 MW from external sources to keep the state lit up. However, complete normalcy could be expected once both units are lit up," an official said.

Figures released by eastern load despatch centre revealed that against a peak time demand of around 1200 MW, generation from one unit at Patratu Thermal grossed a paltry 48 MW. Though 600 MW was being sourced from the central pool and other sources, the huge demand-supply gap left Jharkhand Bijli Vitaran Nigam with no option but to enforce phase-wise blackouts in many parts of the state.