The power outage that affected much of the Westover area this morning was due to an internal fault within the mobile substation that is in temporary service.
The mobile unit shut down at 7:30 a.m. Service was restored at 9:24 a.m.
The unit will remain in service until the conventional power transformer that was damaged earlier this week can be repaired or replaced. A blown lightning arrester damaged a bushing in the transformer.
“Contractors have removed the damaged bushing and sent it off for further analysis, so we hope to have more information next week,” Utilities Director Jason Grey said. “We are fortunate to have a new mobile unit that we can dedicate to Westover customers.”
Grey cautioned that the mobile unit in use for Westover is not designed to withstand temporary events such as a car accident that breaks a pole or fallen trees that make contact with distribution lines.
“Mobile substations do not have the capability built into them to react to these events,” Grey said. “If an event of this nature occurs, crews would have to be dispatched to verify that the event has cleared and then reactivate the mobile substation.
“As a result, our customers in the Westover area may experience more frequent outages, especially during storms, while the mobile unit remains in service. We understand the disruption that this will cause, but the mobile unit is our best alternative in the interim.”
The conventional power transformer at the Westover substation was knocked out of service Monday afternoon. Crews were able to temporarily restore service that evening to some customers by switching the load to other substations. The mobile substation was transported to Westover that evening, and installation completed on Tuesday to serve all customers.
The mobile unit is one of two recently purchased at the cost of $2.6 million for rapid response when problems develop.
“Many electrical providers do not have the luxury of mobile substations that can be deployed,” Grey said.
Grey said age will be a factor in the repair of the damaged Westover transformer, which has served that area for more than 50 years.
Danville Utilities has established an aggressive transformer replacement and renovation plan. Two substation transformers have been upgraded. Two substations are currently under renovation to be completed by June 2020, and two are currently being engineered and slated to be completed by summer 2021.
New transformers cost several million dollars and can take up to two years for design and construction. Additional transformers are planned for replacement. The typical lead time to purchase a substation transformer is 10-12 months.
“We cannot upgrade them all at once because the electrical load is pushed to other areas while the ones we upgrade are being renovated,” Grey said. “We are taking on the responsibility of improving reliability in the system, and it will take time to implement.”
Danville Utilities provides natural gas, water, wastewater and telecommunications services in Danville and distributes electricity to approximately 42,000 customer locations in a 500-square-mile service territory covering Danville, the southern third of Pittsylvania County, and small portions of Henry and Halifax counties.