A year after the city witnessed prolonged power cuts, Mumbaiites were again faced with a power cut on Thursday. When a transmission line failed on Thursday morning, other lines could not take on the additional load, causing the two Tata Power generation units to trip.
The problem continued till Thursday night as Tata's Dharavi to Vikhroli 110KV transmission line tripped at 9.55pm. Supply was successfully transferred to the Rinfra network and restored at 10.06pm.
Last November, two consecutive power failures had forced the Maharashtra Electricity Regulatory Commission (MERC) to take suo-motu cognisance of power cuts and tell all utilities (that transmit and distribute power in the city) to upgrade their networks as soon as possible.
Four companies supply power to the city. Tata, Reliance Infrastructure and state utilities Mahatransco use their own lines and interconnect with each other's power lines to transmit power. However, lack of sufficient carrying capacity poses a threat to uninterrupted supply.
A committee that probed the two prolonged power cuts in the city last year, recommended upgrading the city's power distribution and transmission network or face power outages. Thursday's incident vindicated the experts' stand.
"The generation units of Tata Power would not have tripped had there been stronger lines (with a higher capacity) to carry the overload," said a senior official from one of the companies. "Mumbai's transmission network is under severe overload and tripping of any other element may destabilise the network. Mumbai will either be in the dark or face power cuts," the officer said.
Uttam Zalte, director of Mahatransco, confirmed that the tripping happened because of overloading of other lines. "As the protection line on Trombay-Vashi did not operate, the line tripped and then all other lines stopped working for a while," he told HT.
Tata Power said in a statement that concrete efforts were being made to enhance the future power generation capacities of Mumbai.