Sea-saw power trip continues in Mumbai

A family stands on their balcony after a power cut, in Malad East, on October 12, 2020. Pic/Anurag Ahire

In a déjà vu moment, parts of Mumbai and the metropolitan area were subjected to emergency power cuts on Tuesday morning. Electricity supply was restored in a couple of hours after rearranging the routes that bring power from outside. The city had such power failures in October 2020 and February 2022.

Like in the past, the lines of Mahatransco, the state's electricity transmission company, tripped. This time all 400kV and 220kV lines at Padgha substation tripped due to a 400kV bus fault. This stopped supply in some parts of Mumbai and the MMR. Subsequently, 400kV Bableshwar 1 and 2 lines were taken into service at 10.30 am and 10.33 am, respectively. Kalwa-Padgha 1 and 2 lines were taken in service at 10.33 am and 10.36 am, respectively, said Mahatransco.

Long-distance passengers wait outside Borivli railway station, as power failure disrupts train services, October 12, 2020. Pic/Satej Shinde

By 12 noon, the Mumbai network was fully restored, but not before areas like Dadar, Mahim, Dharavi, Chembur, Mankhurd, Govandi, Santacruz and Bandra, Bhandup and Mulund were subjected to power cuts. Tata Power said, in order to maintain grid balance, load shedding was initiated. Its receiving station at Dharavi tripped because of Mahatransco failure, which ultimately impacted the suburban supply of Adani. The shortage did not disrupt the suburban railway network though.

Mahavitaran's substations at Wada, Kamba, Vasai, Thane's Kolshet, Colourchem, Anandnagar and Jambhul, Palava, Bhiwandi, Ambernath, Shahapur, Murbad, Mohane, Pise, Panjarapur and Dombivli were also affected till 11.10 am. Mumbai city's supply trimmed by 2,250-2,350MW in the mor-ning peak hour. Adani claimed it restored supply in 40 minutes, Mahavitaran said it did in 70-80 minutes in its areas of distribution. Tata Power said it restored supply for its consumers in 30 minutes.

Onus on poor network

All four distribution companies - BEST, Mahavitaran, Tata and Adani - that cater to the city and the suburbs pointed fingers at Mahatransco for the failure. Tata sells its electricity to BEST for distribution in the island city, and also has its own consumers across the city. Adani supplies in the western and the eastern suburbs. Mahavitaran has consumers between Kanjurmarg and Mulund, and in the rest of Maharashtra.

However, Mahatransco insiders say the company has always been a soft target and made a scapegoat, without considering its handicap. They said the Padgha facility where the breakdown happened on Tuesday was built way back in 1994. "It has old design and equipment that cannot withstand an additional inflow of electricity. Over the years, the system is overburdened by another 4,500-5,000MW because of the rise in demand. It can't handle overload. When one of the existing transmission corridors fails for technical reasons, the situation worsens. High atmospheric temperature has been creating additional issues for the equipment," an official told mid-day, adding that it would need more time and resources to upgrade the network.

Sources said Mahatransco has served a show-cause notice to its Director (operations) Anil Kolap. He has been asked to furnish a response in three days, they added. But Kolap said he has not received anything yet. He took over as the director barely six months ago.

Delayed city projects

The city-specific transmission projects of bringing 2,000MW more power are on the anvil, but delayed. A 1,000MW high-voltage direct current link between 400kV Kudus and 220kV Aarey EHV power stations has hit a legal hurdle as Tata Power has petitioned the Supreme Court against the Appellate Tribunal for Electricity's order that upheld the Maharashtra Electricity Regulatory Commission's decision to award a Rs 7,000-crore transmission contract on a nomination basis to Adani Electricity in March 2021. Tata argues the award was not transparent, and was given without tariff-based competitive bidding route and excluded other competent companies. Adani has set a deadline of 2026 for completing the project, but it can move ahead only after the case is decided.

Another Adani project of 1,000MW, the Kharghar-Vikhroli transmission line, which was to be built by this year end, could be delayed by a couple of months, said sources. After the 2020 power failure, Adani had promised the state government to complete the corridor by December 2022.

Flashback

Previously, two major incidents within two years - on October 12, 2020 and February 27, 2022 - had exposed the vulnerability of transmission lines that bring power to Mumbai, especially the one operated by Mahatransco, which is responsible for carrying about 1,800MW of the city's total demand. The February outage lasted 70 minutes in the city, while the October 2020 failure was serious because the supply in some parts of the city was restored after only a day. It affected the city's embedded generation at Tata Power's Trombay plant, which also tripped as a cascading effect. In the aftermath, the State Load Despatch Centre accused Tata Power of not responding to its directives. On Tuesday, there was no incident at Tata's station.

In 2020, the city's islanding system, a mechanism that guards the country's economic capital against outages, failed for the first time since 1997, enforcing the prolonged blackouts. Thereafter, the government and central electricity agencies conducted a probe and recommended that the city's power infrastructure needed an urgent upgrade. More lines must be built to carry power from outside to cater to the growing demand, they said. The plan is being worked out amid constant threats of tripping of the existing infrastructure.

70-80 min
Time it took Mahavitaran to restore supply