Two major electrical service interruptions which affected all customers in the St. Thomas – St. John district on Saturday and Sunday morning resulted from a combination of generator failures and a subsequent shortfall of generating capacity at the Randolph Harley Power Plant.
“Once a generator trips, the plant is faced with the challenge of not having adequate production capacity to satisfy the demand for electrical service in the district,” said Noel Hodge, Interim Executive Director and CEO.
On Saturday morning, all generating units tripped offline simultaneously resulting in the district-wide electrical service interruption. Over the next several hours, plant personnel worked to restore service by bringing additional units online. “The restoration process was hampered by the fact that biggest generator, Unit #23, tripped and could not be immediately restored due to repairs that were required and the fact that Unit #15 had been sidelined since an earlier outage this past week,” Hodge explained.
Repairs to Unit 15’s lube oil pump motor commenced over the weekend. While we expect repairs will be completed by Monday, we are making all efforts to expedite an earlier completion. Additionally, personnel are working today to return Unit 23 to service. The unit has issues with high temperature spreads on the fuel nozzles and failures on the Direct Current (DS) system. “Until those repairs are completed, we run the risk that any upset at the power plant may result in a major outage to customers in the St. Thomas -St. John district.”
With the two units pending repairs, the plant is unable to satisfy the demand for electrical service especially during peak periods of the day and night. The shortfall resulted in the implementation of a rotating power schedule on Saturday night. Feeders were taken offline in one-hour intervals to accommodate the service demand. A similar rotation schedule will be implemented today.
At 12:20 a.m. Sunday, the plant was unable to meet the demand for service and one of the dispatched units tripped which cascaded into another district-wide outage. Due to the equipment limitations, restoration of service took longer than usual. All customers were restored at approximately 5:50 a.m. today.
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