Guam -It began with a bright burst of light, first blue, then red. Helped by the reflection of off low slung clouds, the light could be seen across much of northern Guam. It was the light before an islandwide power outage that plunged the Guam into darkness Wednesday night and a brown tree snake could have set off the chain of events that caused it.
It happened just after 7 pm.
Pacific LP Gas Store Manager Ray Sylvia was up north on the NCS Golf Course in Dededo he saw it.
“I was up at Starks Golf Course and I seen a big glow in the sky and it lit it up. I actually thought it was at the airport. And then the next thing I seen was no more power. I seen dark.”
Angie Mister from Saipan was inside the airport terminal looking out. “We had arrived just from Saipan and walked into the … up the stairs at Continental and had looked out towards the hotels and there was just a big plume of red, kinda of like a big flash.” Q: What did you think? “Well the power went out so we kinda just … it was island power problems again.”
The big burst of light emanated a power pole on Ypao Road in Tamuning just across from the Day’s Inn. A 34-thousand 500 volt power line melted right threw. The power line, cut in half, fell onto the power line below it causing the burst of light.
Burn marks can be seen on the concrete pole where it happened.
Simon Camacho, Assistant Manager of Transmission and Distribution holding up a portion of the burnt power line said “This started to burn … this is the metal conductor … right here, if you look at this part here, started to burn, and there is also evidence of burning over here … anywhere where there is corrosion, it burned. And so this part fell, hit the other line and then all the arcing caused this thing to burn, there’s a burn mark as you can see right here.”
Camacho suggested that the arcing occured between a buckle that was supposed to secure the power line, and the power line itself. It acted like a blow tourch melting the line.
Camacho: “We use clamps similar to this … we’re going to use a better, a higher quality one.”
Q: That could have been a factor?
Camacho: “Could have been a factor, could have been.”
Camacho: “But, you know, on our periodic maintenance, none of this showed up. So I’m thinking that other events made this the weak link.”
Q: How, in what way?
Camacho: “A lot of current, you know, when you lose circuits, it has to go somewhere. But this is just the results, this is what can happen when things go bad.”
Camacho went onto to suggest that a surge in current might have set off that arcing between the buckle and power line.
“Its 34-thousand volts, its a transmission line. But the big issue there is the amount of current that’s passing through the line at that time. So, I’m not sure exactly what was the … at what part did this come in … but this is only one of the events that happened.”
So what was that other event that caused the sudden surge in current and created an arc between the buckle and the power line setting off the island wide power outage?
Officials don’t know what the exact cause of that surge in current was, but 12 power poles down towards the SDA Clinic was another power pole where the initial flash and line fault occurred last night. And beneath that pole GPA linemen found a dead and charred brown tree snake.
Camacho: “All I know is that we did find a dead snake and we found some burnt terminators, down at the end of the road, right before the housing.”
Q: That could have put extra stress on this?
Q: And subsequently triggered…?
Q: So this might be a brown tree snake event?
Camacho: “Humm, I’m not sure.”
Q: You can’t say so?
Camacho: “It could be coincidence. Yea. Coincidence.”
Guam Power Authority Spokesman Art Perez explained that the first line fault was detected by the 2 base load Cabras Units, 3 and 4, and that prompted them to shut down taking 15 of the island’s more than 40 circuits off line.
At that point, Perez says that protection relays at the Tamuning Substation should have kicked in to isolate the outage. But they did not.
“What didn’t happen, it failed to isolate,” said Perez on the K-57 Breakfast Show this morning, “and some of the protection relays did not work.”
About 7:15 pm, the second line fault along Ypao Road occurred, and because the protection relays didn’t work, the Tanguisson Power Plant detected the second line fault and took itself off line and an islandwide power outage was the result.
Perez said the second line fault occured at a time when the system was already under stress from the first fault.
GPA’s “defenses were pretty vulnerable at that time … taking off that much load at one time.” In addition, the 2 line faults occurred at a time when the system was under peak demand with so many residents home, cooking dinner, watching TV.
Power was eventually restored to Tumon, Barrigada, Dededo and Hagatna just before 9 am. Full power was restored by 2:30 am this morning.
The cause of the protection circuit failure remains under investigation, as well as what caused the initial fault.
However, GPA officials on the scene along Ypao Road this morning found a dead brown tree snake next to the power pole near the SDA Clinic which might have been triggered the first line fault, leading to the second line fault and triggering the blackout. But no final determination has been made.