Jan. 7, 2002 – Although they would like to say the worst is over, Water and Power Authority officials are taking what they say is a realistic and cautious attitude about the prospects of more power outages such as those that struck St. Thomas, St. John and Water Island Sunday and Monday.
At a press conference Monday afternoon, Joseph Thomas, WAPA executive director, and Glenn Rothgeb, assistant executive director, apologized to the public for the inconvenience the outages have caused. But they also said they could not promise an easy fix for the problems behind them.
Thomas said the recent outages have "the same basic root cause as the series of major outages about two months ago." These he described as "an aging 15 KVA circuit and a 34.5 KVA circuit" which should have been overhauled or replaced years ago. "KV" means "kilovolt," or 1,000 volts. Thus, 15 KV would be 15,000 volts of electricity. "A" stands for amperes, a measure of electric current.
Circuits carry power from the generators. The 15 KVA circuit is 30 years old, and the 34.5 KVA circuit is 10 years old, Thomas said.
He said the outages have resulted from the failure of certain insulators, either at the transformer/interconnection point or on the power distribution assembly, or "bus," at the Krum Bay power plant. When an insulator fails, a short-circuit occurs. A dilemma for WAPA, he said, is when to replace the old insulators.
The entire circuit system is scheduled for replacement in July, with plans calling for the undertaking to be funded by a proposed bond issue which has not yet been approved by the WAPA board. Replacing the old insulators before that time would entail taking power down for extended periods, Thomas said. Because there was no way of predicting when the insulators might fail, he said, WAPA decided to hold off on replacing them until July. "We don't know when an insulator might fail — it could be a year from now, or tomorrow," he said.
However, in light of the two major outages in such close succession, Thomas said, "We now plan to begin replacing the oldest of these insulators during planned outages, probably in the early morning hours." He said it could take several weeks before the worst of the insulators are replaced. He stressed that the work will take place at times deemed lease inconvenient to businesses and the public. No work will be undertaken without first informing the public, he said.
Neither WAPA executive would venture to say that that the situation is currently under control. "We are still having burps," Rothgeb said. "The systems aren't entirely stable yet." Thomas said WAPA crews have been working around the clock on the problems.
When the new Unit 22 was brought on line last September, WAPA touted it as being able to meet peak demands, even with two units out of service. On Monday, Thomas said the unit "is running just fine. It is having startup burps."
Rothgeb said that because of Unit 22's "tighter tolerance," the unit tripped off a few dozen times Sunday. The relay systems between Unit 22 and the other units are incompatible, he said, something that was not evident in the testing stage and came to light only when problems arose. "The relay settings and protective devices on Unit 22 will have to be changed to correspond with island reality," he said.
WAPA is contacting Pratt & Whitney, the manufacturer of the unit, about the problems.
Thomas said the utility situation in the territory is markedly different from that on the mainland in that, "We are independent, completely responsible, and alone." On the mainland, most utilities are hooked into a grid network; so, if one unit goes out of service, there is backup and "it is not catastrophic." He said it's possible that several units could fail in a grid network, and the public would never be aware of it.
In contrast, he said, "We are a stand-alone utility." He said he is looking into networking options, one being the possibility of interconnecting with the Hovensa refinery's independent power system.
Rothgeb said the most recent outage problems started about 1 p.m. Sunday, when a fault occurred on Feeder 10A, which serves the St. Thomas waterfront. Although downtown St. Thomas was brought back on line, an insulator failure occurred on the 15 KVA power distribution assembly at the Krum Bay power plant. Units 11, 13 and 15, all operating at the time, were kicked off line when the failure occurred.
Unit 11 was repaired overnight and was back on line Monday, Rothgeb said. Unit 13, after several hours work, also was back on line. Unit 15 was still being worked on Monday afternoon, and Units 14 and 18 were being brought back on line. He said Unit 22 would be brought back on line once the entire system's voltage was stabilized. Meanwhile, Unit 12 is down for scheduled repairs.
