CHENNAI: Parts of Chennai, particularly north, faced a power blackout on Friday morning for over three to four hours after the NCTPS-Sriperumbudur line tripped leading to the tripping of multiple substations and the two North Chennai Thermal Power Plant Stage I units.

According to the Southern Regional Load Despatch Centre (SRLDC) generating unit outage report, the North Chennai TPS Stage I’s unit-1 210 MW got tripped at 2.37 am on Friday after the fault-tripping of the 230 kV NCTPS - Sriperumbudur line.

Sources in the Tangedco said that the fault tripping of the NCTPS - Sriperumbudur line led to a cascading effect tripping two other transmission main lines and three backup lines cutting power sources to various substations. Due to the tripping of source lines, the substations at Manali, Alamathi and Tondiarpet also tripped. It led to the tripping of one more 210 MW unit NCTPS Stage I and another 210 MW went into house load mode to supply only auxiliary power for the plant.

NCTPS Stage I has three 210 units with a total generation capacity of 630 MW. Sources said it led to power outages in various parts of the city, particularly in North Chennai. Several areas faced three to four hours of power outages on Friday morning.

A senior Tangedco official said that except for the NCTPS-Sriperumbudur line, all other transmission lines have restored power supply. “We are hoping to complete the work on the Sriperumbudur line,” the official added.