Abnormal voltage issue causes transformer fires in Waltham

What happened

An abnormal voltage issue affected two substations in Waltham, Massachusetts, on 15 October 2022. Police reported transformer fires, traffic light failures and smoke in buildings across the city, and meters and wiring were damaged. Eversource Energy said a high voltage and equipment issue began affecting its Pine Street and Main Street substations at about 2:30 p.m. Residents near 1117 Main Street reported hearing a transformer blow or an explosion before a fire started at the rear of a home there.

The company later said crews were working at about 30 locations where meters and wiring had been damaged by an abnormal voltage issue caused by a substation event. Some customers needed an electrician to inspect their homes and make further repairs before supply could be restored. Eversource said it was still investigating the root cause.

Contributing factors

Eversource said a high voltage and equipment issue affected the Pine Street and Main Street substations, and later described an abnormal voltage issue caused by a substation event. The root cause had not been reported.

Lessons learned

1. A substation voltage event can damage meters and wiring at many customer locations at once, so restoration should include inspection before supply is returned.
2. Transformer fires, traffic signal failures and smoke in buildings may be linked to one grid event and should be treated as a city-wide response, not isolated faults.
3. Customers should be told clearly when an electrician must check a property before power can be restored, while the utility continues to investigate the cause.

Source

wcvb.com