Con Ed blames blackout on fire

The 600-page report released by Con Edison, detailing what the utility giant believes caused the 10-day blackout in northwestern Queens, pointed to an underground low-voltage cable that caught fire as the immediate cause and record power usage as the ultimate culprit.
After the cable along 30th Avenue near 44th Street in Astoria caught fire, it knocked out two high-voltage feeder cables. At the same time, a substation breaker malfunctioned causing three more feeders to fall off. With five cables offline - two of which were adjacent to one another - power had to be brought to the area, putting strain on the network. When Con Ed employees tried to restore one of the feeder cables, an &#8220excessive inrush” - meaning a very, high level of power coursing through the cable for one tenth of a second - tripped out a circuit breaker.
&#8220Con Edison had never before observed transformer magnetizing inrush current causing circuit breakers to open upon restoration of a feeder, so our operators did not recognize the phenomenon,” the report states. Normally, inrushes indicate damaged feeder cables.
With the five feeder cables still down and record power usage surging through the Long Island City (LIC) network, some of the transformers and secondary cables throughout the area began to fail. As power dropped in northwestern Queens, Con Ed kept the network online, a move that the power giant defended.
&#8220The decision to maintain the network prevented the outage from spreading to 90,000 additional customers in northwest Queens, and to hundreds of thousands who would have been affected by transportation shutdowns,” the report's executive summary states.
&#8220We know that this trust that we had with our customers was shaken and the steps that we’re taking, or announcing today, are going to rebuild that trust,” Con Ed CEO Kevin Burke told the media after the report was released on Thursday, October 12.
During the blackout, local politicians and residents blasted Burke for underestimating the number of those without power - on Wednesday, July 19, the company said that 1,600 customers were affected and later upped the number to 25,000 the following day after employees were sent out to count block-by-block those affected.
Among changes, Con Ed said it is looking at &#8220smart” customer meters to estimate the number of its customers without power - instead of the main method employed during the blackout of having customers call in.
Since the blackout, Con Edison has pumped $58 million in repairs to the LIC network, added 150 phone lines to its call system, replaced 57 transformers and 458 new secondary cable sections, and modified sensors to prevent inrush tripping, said Con Ed spokesperson Alfonso Quiroz.