Tata Power said that the power failure was attributed to cascade tripping at MSETCL sub-stations and transmission lines of state-run transmission company leading to grid failure at Mumbai that resulted in power outages on Monday morning, October 12th 2020.
A central team comprising of the officials from the Central Electricity Authority (CEA) is investigating the power breakdown in the city which occurred on Monday. Tata Power is supporting the central team by providing information and data related to the chain of events which transpired on the day of the outage.
On the day of the power outage, Tata Power in its statement said that as per its preliminary assessment of the situation, many parts of Mumbai experienced an unforeseen electricity failure in the morning due to tripping of MSETCL's 400 KV transmission system at Kalwa, which supplies power to Mumbai and adjoining areas. There are four incoming Ckt /lines to MSTECL Kalwa receiving stations for further transmission of power to Mumbai . Out of these four lines , MSETCL's 400kV Pune-Kalwa line was under forced shutdown since October 10th 2020.
On Monday, October 12th, 2020, early in the morning MSETCL had taken emergency shutdown on another 400 KV Kalwa- Padghe line -1 to attend to fault and was expected to be revived by 09:30hr, but MSTECL could not revive it.
As per the chain of events, with two lines out of service , the third line tripped at 09:58hrs 400kV Kalwa-Padghe-2 carrying 644 MW power to the city tripped. This led to over loading of fourth ckt and subsequent tripping at 10:05 which led to sudden load drop and power outage in Mumbai system.
Mumbai's islanding system that saves the city from major power outages was successfully separated at 9.58 am, however it could not hold sudden 1000 MW load drop at 10:05hrs. Tata Power rapidly initiated restoration by bringing in power from its three Hydro Units and activating its Trombay gas and coal units as soon as the MSETCL transmission lines were connected. Simultaneously, Tata Power started restoring supply to its consumers progressively from 12 noon onwards and throughout the course of the day.
The inconvenience caused to the Mumbai consumers was due the MSTECL transmission system failure which led to cascading impact on all the downstream suppliers of electricity including Tata Power and BEST.
About Tata Power
Tata Power is India's largest integrated power company and, together with its subsidiaries & jointly controlled entities, has an installed/ managed capacity of 12,742 MW. A pioneer in the field, it has a presence across the entire power value chain - generation of renewable as well as conventional power including hydro and thermal energy, transmission & distribution, trading and coal & freight logistics. With nearly 2.6GW of renewable energy assets in solar and wind accounting for 30% of the company's portfolio, Tata Power is a leader in clean energy generation. In line with the company's view on sustainable and clean energy development, Tata Power is steering the transformation of utilities to integrated solutions by looking at new business growth in EV charging & storage, distributed generation & rooftops, micro grids and home automation & smart meters. It has successful public-private partnerships in generation, transmission & distribution in India, namely 'Tata Power Delhi Distribution Ltd.' with Delhi Vidyut Board for distribution in North Delhi; 'Tata Power Ajmer Distribution Ltd.' with Ajmer Vidyut Vitran Nigam Ltd. for distribution in Ajmer; 'Powerlinks Transmission Ltd.' with Power Grid Corporation of India Ltd. for evacuation of Power from Tala hydro plant in Bhutan to Delhi; 'Maithon Power Ltd.' with Damodar Valley Corporation for a 1050 MW Mega Power Project at Jharkhand. Tata Power is serving more than 2.6 million distribution consumers in India and has developed the country's first 4000 MW Ultra Mega Power Project at Mundra (Gujarat) based on super-critical technology.
With its 105 years track record of technology leadership, project execution excellence, world-class safety processes, customer care and driving green initiatives, Tata Power is poised for multi-fold growth and committed to 'lighting up lives' for generations to come.
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Email: shalinis@tatapower.com
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