Why did the four decades old islanding system, meant to ensure uninterrupted electricity supply to the city, fail to work when the power grid tripped on Monday?
Developed by Tata Power in 1981 to handle disturbance, the islanding system is meant to ensure that the power systems of Tata and Adani plants are intentionally isolated or islanded from the external grid. This helps the power generated at the plants to be transmitted to concentrated areas and enables the authorities to continue supply to essential category customers. Of the approximate 2400MW-2600MW power supply to Mumbai, 1600MW is to be islanded, with Tata’s Trombay thermal plant’s 500MW, 600MW from hydrogeneration units in Khopoli and 500MW from Adani’s Dahanu plant. The system could not work as Tata plants failed to isolate from the rest of the grid. Adani Power’s Dahanu plant islanded 385MW (the supply has been reduced from 500MW owing to Covid).
Since 1981, the islanding system in Mumbai has worked well on 27 of the 37 occasions of grid disturbances, according to industry insiders.
