Due to multiple tripping across various substations, Mumbai city faced a power outage. Trains stopped, water supplies impacted, residential and commercial properties with no electricity among other issues that were the outcome of the power failure.
At 10 am in the morning, due to tripping of MSETCL’s 400 KV transmission system at Kalwa which supplies to Mumbai and adjoining areas, there was a power cut. But before this main event, there was a series of activities that took place.
Based on the preliminary assessment of the situation, Tata Power narrated the reason and timeline for this power cut:
How it all started:
-Yesterday, MSETCLs 400kV Pune-Kalwa line was under forced shutdown due to R-Y phase fault.
-Today morning at 6.45 am, MSETCL had taken an emergency shutdown for 400 KV Kalwa- Padghe line -1 to fix the fault.
-It was expected to be revived by 9.30 am but that did not happen.
-At 09.58 am, 400kV Kalwa-Padghe-2 carrying 633 MW tripped.
-The flow on Pune-Kharghar rose upto 900MW and tripped at 10 am resulting in load drop in Mumbai system.
-Mumbai’s islanding system that saves the city from major power outages was separated. However, it could not hold an additional 900MW load drop at 10.05 am.
-Rest is history
How did it end:
-Tata Power swiftly began restoration work to bring back supply from the three Hydro units and Trombay gas and coal units as soon as the MSETCL transmission lines were connected.
-Tata Power started restoring supply to its consumers progressively from 12 noon onwards.