Shutdowns Aim to Keep Failures From Spreading

When a city Department of Water and Power worker snipped the wrong bundle of wires at a power station in North Hollywood on Monday, leaving a wide swath of Los Angeles without electricity, he exposed a central weakness of the local power grid: Minor glitches can trigger widespread shutdowns.

Electrical grids are designed to shut themselves off -- preventing expensive equipment damage -- when voltage levels spike for whatever reason.

The system works on the principle that a problem in one part of the grid must be isolated immediately to prevent it from infecting the rest of the grid -- or the power supply in other parts of the country.

That is essentially what happened Monday, when the problem at the small power station in the Valley prompted the DWP to cut off supply to two huge generating stations, reducing the available electricity in Los Angeles.

“It is normal to have those protective systems in place,” said Gregg Fishman, a spokesman for the California Independent System Operator, the not-for-profit entity that oversees much of the state power grid. “I think what’s not normal is they get activated. You don’t have those systems activated very often.”

Officials have warned for years that the power grid needs major improvements -- in large part to keep up with huge increases in California’s population. But finding money to improve the system has always proven difficult, as was demonstrated last week when the Los Angeles City Council rejected a bond measure to pay for DWP improvements.

California receives much of its power from lines running down the coast from the Pacific Northwest, and from an eastern line through Utah, said Robert Lasseter, an electrical engineering professor at the University of Wisconsin in Madison.

California’s system appears better-designed than many, Lasseter said, because the failure in Los Angeles didn’t leave the rest of the state in the dark, as happened across the Northeast during the massive, regionwide blackout in the summer of 2003.

The local grid, however, is a tightly knit network in which an isolated failure can ripple across the system, power experts say.

A decade ago, hot weather caused power lines near a tiny Oregon town to sag into a tree, plunging much of California and the West into darkness.

Last month, a faulty sensor at a new power transfer station in Sylmar caused neighborhoods throughout Southern California to lose power.

“Blackouts and power systems are just like forest fires: You can minimize them, you can localize them, but you can’t stop them,” Lasseter said.

“If L.A. gets [power running] in an hour or so ... is that a major risk or not? How many billions of dollars do you want to put in to make sure that happens half as often?”

There was little political will in Los Angeles last week to pay for improvements. The City Council, by a 9-4 vote, rejected a $1.2-billion bond that the DWP wanted to issue to upgrade its power infrastructure.

The plan was to have up to $950 million of the bonds go to capital improvements for the power system.

Up to $250 million would have gone toward the purchase of a natural gas field to serve as a power reserve.

Another $600-million bond would have gone to upgrading the city’s vast water system.

Councilman Tom LaBonge, who voted for the bond deal, said Monday that the power outage was another reminder that the city needs to keep investing in its infrastructure.

“Los Angeles is 100 years old in the modern times -- since we had our first street lights and water system,” he said. “The infrastructure is what made the city great.”

Southern California’s booming population and variable climate also tend to strain the aging power infrastructure.

Like many places, California is “still using a transmission system that could have been built 30 years ago or 50 years ago in a way it wasn’t planned to be used,” Lasseter said. “Some lines are underutilized, some are being pushed to the limit.”

Migration patterns also play a key role in power usage.

“The population [is] moving into the inland valleys; as a result, our AC load is increasing dramatically,” said Claudia Chandler, assistant executive director of the California Energy Commission.

A hot afternoon can swell power demand by 30%, she said.

The Energy Commission has identified a widespread need for repairing and expanding electricity transmission lines to help meet the state’s power requirements, Chandler said.

Building a more resilient and redundant power grid to minimize blackouts is extremely costly, industry experts said. And those infrastructure costs, they added, would be passed on to consumers.

As a result, many power providers, such as the DWP, seek to prevent damage by creating safeguards that shut their systems down, even if it means blackouts for tens of thousands of customers.

“Short of massively redundant systems, it would be very difficult to never have problems like this come up,” said Jim Bushnell, research director for the University of California Energy Institute, based in Berkeley.

“There is a trade-off between the costs and levels of reliability that need to be considered,” he said, “and we don’t really have a good process for determining where we want that trade-off to be.”Bob Finkelstein, executive director of the Utility Network in San Francisco, a consumer advocacy group, agreed that it was probably cost-prohibitive to create a system that would dramatically reduce power outages.

To a certain degree, he said, it “may just be a risk to live with, even though when it comes to roost, it’s a pain in the butt.”

In the end, DWP officials declared their handling of Monday’s blackout a success.

“It’s better to shut it down than to burn out the whole system,” said DWP General Manager Ron Deaton.

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Lights out

The outage that left as many as 2 million people without power Monday covered slightly more than half of the Los Angeles Department of Water and Power’s service area. Here’s the sequence of events:

- 12:37 p.m. A worker cuts through wrong wires, apparently triggering a short circuit. The mishap occurs during installation of a system meant to better sense voltage fluctuations. Station E in Toluca Lake shuts down.

- Station S automatically shuts down in response to changes at Station E.

- Scattergood and Haynes, two of the DWP’s four generating plants, stop transmitting to the system.

- Within three to five minutes, the DWP management is notified.

- The DWP contains the problem by manually shutting down power in some areas of the city.

- About 1:30 p.m., DWP management learns of the causes for the blackout.

- 2 p.m. Power is restored to 90% of affected customers.

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Sources: Department of Water and Power, Times research.