Electrical service was restored to the St. Thomas – St. John district at approximately 10:20 p.m. Sunday, June 27 following both a districtwide and subsequent smaller-scale service interruptions.
The outage evolved into a prolonged blackout as personnel at the Randolph Harley Power Plant in Krum Bay faced what the Water and Power Authority called “escalating operational challenges” in rebuilding and maintaining an adequate level of generation to meet the power demand of customers on St. Thomas, St. John, Water Island and Hassel Island on Sunday afternoon.
In a news release issued Monday, WAPA said, “Over the past two weeks, the Harley plant has been confronted by operational challenges with several units that are usually reserved for service restoration following an outage.”
In recent times, WAPA-owned generators, Units 14, 15 and 23, have been sidelined due to various issues.
“Repairs were completed on Unit 14 and the unit was used to recover from the June 17 major outage. Unit 15 was also repaired but requires additional work. We believe Unit 15 began to lose load on Sunday after a hiccup in the propane fuel delivery system which then forced the unit to transfer from LPG gas to Number 2 oil as its fuel source. Once on oil, we noticed the unit losing capacity,” said Noel Hodge, interim executive director.
The Sunday issues with Unit 15 spread across to the three propane-fired reciprocating internal combustion engine generators, which also tripped and led to the midday districtwide outage, WAPA said.
Through late Sunday afternoon, electric system personnel worked to restore power, starting with Unit 14 (the oldest unit in the plant), then the leased unit (Unit 27), followed by the propane-fired generators. Several unsuccessful attempts were made at full restoration and the units tripped repeatedly for a variety of reasons. Personnel also faced challenges with sectionalizing distribution feeders in the system, WAPA said. Many of the sectionalizing devices were damaged in the storms of 2017 and the utility has been replacing these devices as rapidly as possible to ensure that full grid performance is achieved, it said.
On Sunday night, WAPA was successful in bringing six units online to provide the capacity needed to restore electrical service to all affected customers. The outage ended when portions of Smith Bay, Nazareth, Red Hook and St. John were fully restored, it said.
Hodge said Monday night that a renewed effort will be made to prioritize and accelerate repairs needed for each of the units.
“The authority must shore up the units it owns, especially those that have often been relied on to restore service following a major interruption. We cannot afford to continue the dispatching of all available generators 24/7. There must be a contingency plan to prevent the slightest upset on the system from having a catastrophic effect on overall power production. Just as important, should a major service interruption occur, options must be available to restore service to our customers in a more timely and efficient manner,” Hodge said.
WAPA’s news release also said the agency is making efforts to conduct a full system coordination study that will evaluate the performance of the generators, the effects of faults on the electric grid and to ensure proper sensitivity of the protection schemes to minimize the likelihood of plant outages from outside disturbances, Hodge said.
He apologized to the public for any inconvenience caused by the outage and thanked the men and women of WAPA who assisted with the restoration effort on Sunday.