By Matt Nauman
With water rising on Lake Oroville, and anxiety growing over the dam’s spillways, PG&E knew it needed to make sure its transmission resources were protected.
And, most importantly, that the power stayed on for customers and that everything remained safe.
Ultimately, the energy company de-energized the power lines and disconnected them from 100-foot tall transmission towers. Then the company built a temporary connection to reconnect the power lines. And, later, removed three towers.
It was a well-planned, well-executed combination of manpower and machines, of helicopters and hard work that made it happen.
“The challenge that PG&E has we have two towers that are on either side of the emergency spillway, basically somewhat on the spillway, and so were the water to come over the emergency spillway it’s going to compromise the footing of those two towers,” said Angie Gibson, PG&E manager for emergency management and public safety.
“And those two towers hold two 230kv transmission lines,” she added. “So we’ve had to look at opportunities to can we remove the towers? How can we make the situation safe? Not just for the responders from Department of Water Resources and Cal Fire … but also for the public and to secure our bulk transmission system.”
PG&E was part of the event’s incident management team, working closely with state and local agencies to ensure coordination, communication and a shared focus on goals and responsibilities.
Gibson talked about the relationship between PG&E and the agencies.
“I think it’s been fabulous,” she said. “The state brought in a Cal Fire incident management team to help the Department of Water Resources manage this incident. It happens to be one of the teams that we’ve worked with several times during our past fires. So there’s a level of credibility that we now have built up with these emergency response agencies they’re looking for us to show up. They know we’re not going to show up and say, what are you going to give me. We’re going to show up and say, what can we do for you. How can we work together where we’re all shooting for the same end goal, and that’s protection of the public.”
PG&E was able to remove the power lines and insulators before the dam’s emergency spillway became activated.
Ultimately, nearly 200,000 residents below the dam were evacuated for several days.
Once it was safe to return, the company built a shoo-fly, an engineering workaround involving poles and wires, to re-energize the transmission system. And once the rains stopped, PG&E used helicopters to remove the transmission towers and keep them out of harm’s way. In spring 2017, PG&E will install eight permanent towers to shift the line further west.
The state continues to work on the Oroville Dam and its spillways.
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