Edison must inspect even more of its Long Beach power grid

Frequent power outages in Long Beach have prompted California state utility regulators to order Southern California Edison to do intensive new inspections of its electrical system.

Downtown Long Beach residents put up with exploding manhole covers and widespread power outages lasting several days in July. Edison responded by conducting detailed inspections of 300 underground power vaults downtown.

Edison's downtown power network is designed differently from the rest of Long Beach, and the company has maintained that two related days-long outages beginning July 15 and 30 did not affect the rest of its Long Beach service area.

Then came the heat of August and more outages occurring outside the downtown area. They affected fewer customers and lasted only hours, not days. Edison blamed customers overloading the system during hot spells, keeping the equipment from cooling down overnight.

But the California Public Utilities Commission says the outages and recent reports of smoking electrical vaults outside downtown raise concerns for the safety and continued reliability of the Long Beach power grid. In a Sept. 1 letter, it ordered Edison to inspect vaults and certain types of electrical equipment citywide. It also told the company to tether all manhole and vault covers so they can't be blown into the air if an explosion occurs in the electrical equipment underground.

Greg Ferree, an Edison executive, says the company is still trying to figure out how extensive the new inspections will be.

"Some of the requirements appear to be much broader in scope than the downtown Long Beach networked area," he said.

Ferree said the company is analyzing service outage records in an effort to demonstrate that the frequency of this year's power losses are not unusual, if the July outages are taken out of the equation.

Most of the city and the remainder of Edison's 50,000-square-mile service area has what the company calls a radial design, where outages can be isolated along system branches. The August power outages occurred in this part of the system.

Downtown Long Beach's power system downtown is what Edison calls a networked system, with every circuit connected to every other circuit. Similar systems operate in New York and Chicago. It has the advantage that when power fails in one part of the network, current can flow in from another part of the network.

But that same interconnectivity creates the disadvantage seen in Long Beach in July, when a failed cable splice caught fire and exploded in an underground vault. Fire from one vault spread via underground conduits to other vaults, causing several to explode.

In some cases, vault covers were hurtled skyward in the blasts. One vault cover that flew off July 30 damaged the side of an apartment building. Power to about 30,000 customers had to be cut to restore the system during those outages.

Ferree said Edison has made changes in the downtown system, adding additional cables to increase the capacity of the power grid. It also added additional pathways for the power to flow between potential trouble spots. The company had already begun the work of tethering the downtown manhole covers — now it appears it will have to expand that work to a wider territory.

In contrast, the Los Angeles Department of Water and Power has been adding tethers to its underground vaults for the past several years. However, it will still be several years before that large job is completed.

And on top of the PUC scrutiny, Edison executives face questioning by the Long Beach City Council on Tuesday.

CPUC letter directing Edison to inspect power equipment