Power outages plague St. Thomas on Wednesday after surge trips two units
Published: February 6, 2014
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ST. THOMAS - Just days after a power blackout interrupted the NFL Super Bowl, WAPA customers on St. Thomas once again fell victim to a further series of blackouts Wednesday morning.
Shopkeepers up and down Main Street stood in darkened stores talking on cell phones as cruise ship passengers began arriving in safaris at the start of a five-ship day.
Throughout downtown and the Long Bay-Havensight area, traffic lights were out as morning traffic streamed in from around the island.
The blackout struck island-wide on St. Thomas initially about 8:30 a.m., which continued off-and-on until about 1 p.m.
The V.I. Water and Power Authority blamed the outages on the failure of a protective relay, or a device that monitors the conditions of a circuit. When a fault is detected, relay responds appropriately, usually preventing an overload of a circuit.
However, on Wednesday, the protective relay failed and subsequently tripped Unit 23, WAPA's most recently purchased unit, which the utility refers to as its "workhorse" generator, because it is capable of producing 37 megawatts of power.
The failure of Unit 23 caused a "cascading effect" on WAPA's Unit 25, which then also tripped offline so that it would not overload after all of Unit 23's power unloaded onto it, according to WAPA spokeswoman Jerain Fleming.
WAPA is leasing Unit 25 from General Electric Power and Water for the next year under a contract extension for about $7.8 million after an 18-month lease at a cost of $14.6 million.
The use of the rental unit is supposed to allow WAPA to repair other older generators while some of the load is dumped onto it instead. "It's rather unfortunate," said Hugo Hodge Jr., executive director of WAPA. "Really, in the past year, we've seen a great improvement. We're working to rectify the recent issues."
Less than a half-hour after the initial outage, Unit 15 came on and service restoration began immediately, according to Fleming.
Unit 25 came back on just after 9 a.m., allowing restoration to additional feeders.
By about 11:40 a.m., Unit 23 also was fully functional and the process of reinstating all remaining feeders began, while ensuring the load remained balanced on each unit.
By 12:48 p.m. service was restored to all feeders, Fleming said.
WAPA still is uncertain as to what caused the malfunction of the protective relay in the first place, she said.
- Contact Jenny Kane at 714-9102 or email email@example.com.