Substation overload triggers equipment fire and power cuts in Chennai

According to the Tamil Nadu electricity minister, speaking after a review meeting at the state utility's headquarters, recent power disruptions in parts of Chennai followed damage to an underground main power line during telecom repair works in the RK Nagar Stand area. Supply was restored through an alternative line from the Stanley substation, but the additional load caused equipment to overheat and catch fire, causing further disruption to consumers. The minister said the disruptions were due to these failures rather than any shortage of electricity generation, and that officials had been asked to lodge a police complaint against the telecom company whose works were said to have damaged the cable. Agencies carrying out excavation work were instructed to coordinate with the power utility beforehand. The date of the fire, any injuries and the duration of the outages were not reported.

Reported damage to an underground cable during third-party excavation and repair work carried out without prior coordination with the power utility, followed by overloading of the alternative substation feed used to restore supply, leading to equipment overheating and fire.

1. Third-party excavation and repair works near underground power cables should be coordinated with the network operator in advance and cable routes confirmed on site before digging.
2. Where supply is rerouted after a cable fault, the load on the alternative feed should be assessed against equipment ratings and monitored for overheating.
3. Clear reporting and accountability arrangements between utilities and other excavating agencies can reduce repeat third-party damage and the cascading outages that follow.

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