Initial investigation into the power outage in Mumbai and areas around it on April 26 revealed that it was due to a “technical issue” at a power substation at Padgha near the city. The state has appointed an independent expert to look into the technical glitch, senior executives told Moneycontrol.
Parts of Mumbai suburbs, Thane and Navi Mumbai got a rude shock on a hot Monday morning as power went off a little after 10 am. Power was restored in most parts by noon.
State-run Maharashtra State Electricity Transmission Company (Mahatransco) said in a statement that the power cut was due to a “fault” that occurred at Padgha substation, which tripped the 400kv power transmission lines, Kalwa Padgha 1 and 2, which feeds power into Mumbai. “All substation supply was restored by 11:08 hours,” Mahatransco said.
MSETCL, also known as Mahatransco, is the state-run utility that provides electricity transmission in the state. Mumbai has three electricity distribution companies – the state-run BEST Undertaking and private companies Adani Electricity (a subsidiary of Adani Transmission Ltd) and Tata Power Company. Maharashtra State Electricity Distribution Company (MSEDCL) distributes power to the rest of the state.
Speaking to Moneycontrol, Mahendra Walke, chief engineer of Vashi zone at Mahatransco, who was handling the technical snag said, “The power cut was due to a technical glitch at 10:08 am on 26.04.2022 at 400kV Padgha substation, it wasn’t a human error or due to any supply-related issue.”
The substation’s equipment support insulator flashover, called pantograph isolator, snapped and tripped the power transmission line and supporting equipment. This equipment was replaced with a new one in December 2021 as a part of regular maintenance, he said.
“To avoid tripping the entire power transmission, we implemented load trimming schemes on power lines and once the problem was fixed, power was resumed,” Walke said.
The utility has engaged Hyderabad-equipment manufacturer S&S Power to investigate the technical glitch so that it does not recur, he said.
The financial capital typically does not face power outages due to an islanding scheme, introduced by Tata Power in 1981, which cuts the city off the grid and insulates it from power cuts. Maharashtra has faced major power outages since April as demand has soared and coal supply has been constrained but Mumbai has not been impacted as badly.
In October 2020, Mumbai faced an unprecedented outage across the city and nearby areas. Cyber security firm Recorded Future later said that a China-linked hacker group, RedEcho, may have been responsible for this. While this was denied by the state, recent developments have hinted that international hackers may be targeting Indian infrastructure.
On April 7, Union Minister for Power and New and Renewable Energy RK Singh said that hackers funded by the Chinese government have made two attempts to bring down Indian electricity distribution centres near Ladakh in the last eight months.
Reacting to the power outage on April 26 earlier in the day, an Adani Electricity spokesperson said, “The power outage caused due to tripping at Tata Power’s Dharavi Receiving Station due to tripping of 400 kV Mahatransco transmission system affected our consumers in Chembur, Mankhurd, Govandi, Santacruz and Bandra area. However, through proactive network rearrangements Adani Electricity could restore the entire power supply within 40 minutes of the incident.”
Tata Power said that Adani Electricity’s statement was misleading in saying that the outage was caused due to tripping at Tata Power’s Dharavi receiving station, citing Mahatransco statement that stated that it was due to a technical issue at the Padgha substation.
“This substation supplies power on Padgha to Pal 220 KV high-pressure line and it got disrupted. This had a resultant impact on the Tata Power network,” the Tata group utility said.“Tata Power today also ensured the running of its hydro, gas, and thermal plants to the full capacity to safeguard the city against further load shedding,” the company said.