Train services came to a halt, homes and businesses were without electricity and people sweltered in humid heat as a grid failure resulted in massive power outages across Mumbai, Thane and Navi Mumbai on Monday morning.
As the day progressed, power restoration efforts began on "war footing". Trains have started to resume operations, beginning with CR's Harbour Line. Railway services across city on the Western Railway and Central Railway had came to a grinding halt at 1005 hrs as a result of the power outage, with both the networks blaming power cut from Tata Power (their power supplier) for it.
Tata Power, which is into both generation and distribution, attributed the power outage to a simultaneous substation tripping at 1010 hrs at state-run transmission company MSETCL's two substations in the suburbs of Kalwa and Kharghar.
Meanwhile, the company has issued a statement and "regretted the inconvenience caused to its consumers due to this unforeseen event". The company also explained the reason of the power outage based on their preliminary assessment.
Here is Tata Power's full statement:
“Based on the preliminary assessment of the situation, Tata Power would like to inform that today many parts of Mumbai experienced an unforeseen electricity failure starting 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. MSETCLs 400kV Pune-Kalwa line was under forced shutdown since yesterday due to R-Y phase fault.
It is understood that MSETCL had taken emergency shutdown for 400 KV Kalwa- Padghe line -1 at 6.54hrs today morning to attend fault and was expected to be revived by 09:30hr, but could not revive it.
As understood, at 09:58hrs 400kV Kalwa-Padghe-2 carrying 633 MW tripped. The flow on Pune-Kharghar rose upto 900MW and tripped at 10:00hrs 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 as additional 900MW load dropped at 10:05hrs.
Tata Power swiftly began restoration work to bring back supply from the 3 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.
Tata Power regrets the inconvenience caused to its consumers due to this unforeseen event in power failure due to the transmission system failure leading to the cascading impact to all downstream suppliers of electricity including Tata Power, BEST and its consumers.”
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