GURGAON: Overheated equipment, an oil spill, and a blast. The snag that took down a large section of the city’s power grid was triggered by a cocktail of problems that hit the critical Sector 72 substation of Haryana Vidyut Prasaran Nigam (HVPN) on Friday evening. Officials said the disruption began around 7pm when a technical fault hit two circuits at the Sector 72 substation, a key node that draws power from a 440 kV line and feeds two 220 kV substations. The fault led to oil leakage from a current transformer, which caught fire and exploded before the breaker could trip.
With the mercury at 42.7°C and demand having touched a record 2,372 MW a day earlier, the grid was already under intense strain. “In a matter of minutes, overheated equipment failed and flames tore through critical infrastructure. Homes and offices plunged into darkness and commuters on the Rapid Metro were left stranded in the heat,” an official said. The blast not just damaged the transformer, but also nearby poles and associated equipment, triggering a cascading failure across the system. “The flames spread quickly and damaged the network of circuits and current transformers, causing a complete breakdown,” the official said. The fallout was immediate. Supply to 220 kV substations in sectors 52 and 56, and 66 kV substations in sectors 15, 38, 44 and 46 – besides the Maruti plant area – was disrupted. Large stretches of Golf Course Road, Sohna Road, MG Road, Palam Vihar and parts of sectors 15, 38, 44, 45, 46, 47, 50, 51, 52, 56 and 57 were affected. Rapid Metro services were hit between 7.50pm and 8.30pm because it depends on a single-source supply from the Sector 56 substation. Delhi Metro’s Yellow Line continued to run as it draws power from both Delhi and Haryana. “By 8.30pm, one circuit was restored, allowing Rapid Metro to resume operations. It was our top priority,” said HVPN executive engineer Anil Malik. Teams from HVPN and DHBVN then worked through the night to isolate the fault, reroute load and revive supply in phases. The entire substation system was normalised by 10.22pm, full supply was restored soon after, and the damaged current transformer was replaced by midnight. In circle 1 areas of the city, about 95% supply from the Sector 15 and Mehrauli Road substations was back by 10.30pm, with the remaining feeders restored by 1am. In circle 2, sectors 38, 44, 46, 52, 56 and the Maruti area got supply back by 11.30pm. For residents, the outage was punishing. “It’s impossible to sleep in this heat,” said Amit Sharma (38), a resident of Sector 46. In Sector 56, Ritu Arora said repeated tripping had already damaged appliances. Sumit Anand (41) of Sushant Lok said even backup came at a cost because societies had to burn expensive diesel. The blackout came just two days after a fire at the Sector 9 substation caused a nearly nine-hour outage in parts of the city, renewing concerns over how vulnerable Gurgaon’s power network has become during extreme summer load.
