AP Crews went under streets to find and repair damage in Long Island City network.

Costs for a nine-day blackout in New York City last summer could total $67.3 million for an electric utility company if the preliminary draft report by the New York State Public Service Commission’s staff stands. The report, released Jan. 17, describes Consolidated Edison Co. of New York Inc.’s performance in preparing for and responding to the outage in July 2006 as “deficient, a gross disservice to its customers.” In response, the utility says it has invested $89 million in emergency response, permanent repairs and ongoing improvements to the affected network. The final report will be issued after comments from the parties and the public are incorporated in February.

Con Edison’s distribution system in Long Island City, in the northwestern part of the Borough of Queens, became congested July 17, 2006, as temperatures climbed into the 90s. As many as 10 of the 22 27-kV primary feeders serving the area were simultaneously out of service twice in the next two days, and equipment failures “escalated greatly,” says the report.

Public criticism of Con Edison also escalated as the outage, which began on a Monday, dragged on through the weekend. Four days after the event, the utility concluded that its count of the total number of customers out of service was not accurate and sent crews to survey the area physically. The survey boosted the utility’s count from 2,000 customers to 25,000, says the report, which also estimates that 65,000 customers lost power. Service finally was restored to the last customer by midnight, July 25.

Con Edison’s report, released in October, blamed the outage on three “unrelated events that combined to create an unprecedented set of circumstances and strain on the network system.” The first was a fire in an underground conduit caused by a short-circuited, low-voltage cable. The fire damaged two of the primary feeders and caused them to fail.

The second was a substation breaker malfunction caused by the failure of a third feeder, isolating three network feeders from the system. These two failures together created conditions that were “well beyond the design criteria of the network,” said the Con Edison report.

The third event was “inrush” current triggered by an attempt to restore one of the feeders. The surge tripped a circuit breaker and impeded efforts to restore feeders. With the primary feeders out of service, current flowed to the secondary cables, which were unable to bear it. Transformers and secondary cables began to fail.

“Staff’s analysis indicates that those three incidents were simply triggers initiating the failures in the primary voltage system; they were not the cause of the crisis that resulted,” said the Public Service Commission in a written response to ENR questions. “Among staff’s key findings is that the overriding cause of the Long Island City network event and the lengthy outage was the company’s failure to address a multitude of pre-existing problems and issues associated with the operations, maintenance and oversight of the Long Island City network, and its failure to shut the network down in light of glaring evidence that the secondary system was experiencing severe damage during early stages of the event.” Con Edison has until Jan. 31 to submit comments for inclusion in the staff’s final report.

“Our big disagreement with PSC staff is shutting down the network,” says Michael Clendenin, Con Edison spokesman. The utility insists that shutting the network would have affected all 115,000 customers as well as the subway lines and commu-ter railroad lines throughout the area, possibly affecting 1 million people, says Clendenin.

In addition, he says that restarting the network would have aggravated the outage. “Restarting a network is not like rebooting a laptop,” Clendenin notes.

Con Edison to date has spent $89 million on claims, repairs and capital improvements in the affected area, says Clendenin. The utility will seek recovery of $32 million from customers.