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Mumbai faces major power outage, high-level probe ordered
On 12 October 2020, Mumbai had come to a halt for a few hours due to a massive power outage. It took up to 24-hour for supply to be restored in some areas.
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In a second major outage since 2020, Mumbai faced an hour-long power disruption on Sunday as planned outages for linear infrastructure projects and a fire on a hillock at Trombay affected electricity transmission. While the impact on the commercial and financial sectors was minimal as most establishments were closed on the weekend, the partial outage disrupted suburban train services for a brief period.
Tata Power Company (TPC), in a statement, said that around 9:50 am, power supply in South Mumbai, Chembur, Bandra, Santacruz was affected due to the tripping of Maharashtra State Electrical Transmission Company Limited’s (MSETCL) line at the MSETCL Trombay receiving station that connects to the Tata Power transmission system.
“This resulted in the tripping of Trombay Generation and cascade tripping of some internal lines affecting 850 MW load of all Discoms in Mumbai. Tata Power immediately stepped up a hydro generation to full capacity for faster restoration and avoidance of a larger outage. The power supply was restored completely in around an hour,” it added.
At 9:48 am, when the outage occurred, Mumbai was being supplied 2,083 MW of power by the Brihanmumbai Electricity Supply and Transport Undertaking (BEST), which caters to the island city, the TPC, which largely covers bulk consumers, and Adani Electricity Mumbai Limited (AEML) for the suburbs. After the outage, the power supply dwindled to just 1,077 MW at 9:50 am.
On 12 October 2020, Mumbai had come to a halt for a few hours due to a massive power outage. It took up to 24-hour for supply to be restored in some areas.
Mumbai has a generating capacity of 1,877 MW, including 500 MW with AEML and TPC’s 1,377 MW.
“We restored the power supply within one hour; stepped up our hydro generation to full capacity; and avoided a much larger damage. The detailed investigation of this outage is on. We are coordinating with all agencies, including SLDC, to find out the exact reason and see how we can avoid such incidents in the future,” said Sanjay Banga, President (T&D), Tata Power.
Energy minister Nitin Raut on Sunday ordered a high-level inquiry into the power failure. “Serious note has been taken and orders for a high-level probe have been given. Necessary action will be taken against those who will be found guilty,” he said.
A senior official from the MSETCL said that of their four power transmission lines at Trombay, two (Sonkhar-Trombay and Chembur-Trombay) were under scheduled outage from February 4 and 5 due to work on the Mumbai metro railway project (Metro 2B).
“These two lines were under an outage as the demand for electricity in Mumbai was low (around 2,000 MW). Hence, it is the right time to complete this work,” he explained.
One Salcette-Trombay line belonging to the TPC was also under an outage from Saturday for the Metro-4 project. Two 110 KV lines are also shut till July for work on an under-development 440 KV line.
“This left just two lines, Kalwa-Trombay and Mulund-Trombay. Generation at the Tata Power plant at Trombay was around 500 MW due to lower demand. At 8:44 am, there was a fault in the Mulund-Trombay line (with a 154 MW load) at location 72 in the Bhabha Atomic Research Centre (BARC) campus,” he added.
“The Maharashtra State Load Dispatch Centre (MSLDC) control room telephonically instructed TPC to pick up thermal and hydro generation to full capacity and at 9:36 am, an email was also sent… but the Kalwa-Trombay line (332 MW load) also tripped at 9:49 am due to a fire in some grass near the same spot, at location 72/73,” the MSETCL official said.
The incident isolated Trombay and the only Salcette-Trombay line also tripped due to overload and the generation at Tata’s thermal units 5 and 8 failed, affecting supply in South Mumbai and parts of central Mumbai and the suburbs.
Supply was restored within 50 to 65 minutes. At 10:05 am, the Salcette-Trombay line was restored, leading to the power supply being restarted at Carnac Bunder, Backbay, Parel and Mahalaxmi between 10:13 am and 10:30 am.
The MSETCL’s Nerul-Chembur, Kalwa-Trombay, Sonkhar-Trombay lines and the units at TPC’s thermal power station at Trombay were also brought online. Complete supply restoration took place at 11:10 am.
Nearly 62 BEST substations were affected and senior officials from the BEST undertaking said most areas in the island city and central Mumbai like Fort, Kalbadevi, Bhuleshwar, Sion, Cumballa Hills and Cuffe Parade were severely affected.
“The power grid in the main transmission line was restored in an hour following which, our team of technicians made local site visits to restore the internal faults that were caused due to the main power outage,” said a senior BEST official.
“In areas like Back Bay, Cumballa Hills and Sion we had to restore local transformers following which electric supply became normal in these areas,” the official added.
An AEML spokesperson said: “Adani Electricity consumers were largely unaffected by today’s power outage as we were able to ramp up our generation at Dahanu in a very short time. This helped the early restoration of consumers in South Mumbai as well.”
