By CHRISTINA RITCHIE ROGERS
The Nov. 14 power outage that knocked out power to parts of Davidson and Cornelius started overnight when a voltage regulator at the Mt. Zion electrical substation exploded, shooting oil and fire 20 to 30 feet around the regulator, Electricities officials told Cornelius Town Board members Monday. That oil and fire burned a substation transformer, melted wires and damaged other equipment, requiring crews to rebuild about 2/3 of the station.
That information was among the details Electricities spokesman Craig Norfolk shared with Cornelius Town Board members Monday night. The preliminary results of the investigation indicate the voltage regulator winding insulation was wearing down, he said.
|POWER OUTAGE COSTS
Electricities officials estimate they will incur the following costs from the Nov. 14 explosion and power outage at the Electricities substation on Zion in Cornelius:
$337,000 – Total
Mr. Norfolk’s account on Monday was the most detailed yet provided following the incident, which left some customers on the east side of Cornelius without power for nearly 20 hours.
Here’s a chronology of the events that day:
- 1:32 a.m.: The voltage regulator explodes, shooting out oil and fire 20 to 30 feet.
- 1:45 a.m.: Electricities’ Craig Norfolk gets a phone call and heads to the substation.
- 2 a.m.: Workers investigate and assess damages, test equipment, and call the consulting engineer. After assessment, they plan to rebuild about 2/3 of the substation.
- 3:30 a.m.: With a plan in place, the work to rebuild the substation begins.
- 4 a.m.: Mr. Norfolk speaks with the Concord Electric’s director and secures a used, replacement transformer.
- 6:15 a.m.: Officials secure a crane operator.
- 8 a.m.: Concord submits an emergency application the the Department of Transportation for a permit needed to transport the massive, 35-ton transformer on state roads.
- 10 a.m.: The crane begins work at Concord to move the damaged transformer, which is 14-feet wide and 13-feet high. Transport of the oversized load requires escort vehicles to drive in front of and behind the transformer, as well as Concord and Cornelius police assistance.
- 4 p.m.: A SuperCrane arrives at the Cornelius substation and begins assembly. Before the crane can move the 35-ton transformer, it must set up properly, and requires 2 tractor-trailer loads of counter-weights to prevent it from tipping.
- 4:30 p.m.: The transformer arrives on site from Concord.
- 6 p.m.: The old transformer is moved out of the way.
- 6:30 p.m.: The replacement transformer is placed on the pad and crews begin wiring and testing.
- 8:30 p.m. Duke power prepares for power restoration.
Mr. Norfolk said he was proud of his team for their hard work in such a catastrophic situation.
“To build a substation takes months when you’re planning it, and our group rebuilt 2/3 in 19 1/2 hours,” Mr. Norfolk said.
And throughout that time, he worked hard to remain in communication with Town Manager Anthony Roberts, Cornelius Police, businesses and local media outlets, giving them the most current information and estimates for when power might be restored. Police used the reverse-911 system to send automated messages to residents with updates on Electricities’ progress.
“Communications was a big part of this,” Mr. Norfolk said, and he had staff on hand answering phones from the early hours of the morning until late at night.
Mr. Norfolk also shared with board members the costs associated with the outage.
After his presentation, board members discussed whether to purchase a back-up transformer. Currently, crews are assessing the damages to the burned transformer, and will determine whether it is reparable. If it is, officials estimate repairs would cost about $52,000.
The City of Concord has offered to sell the used transformer currently on site for $90,000 including set up, Mr. Norfolk said – an offer he says the town might want to consider.
The transformer is “very used,” but “well-maintained,” he said.
Even if the burned transformer is repaired, the town should consider buying the Concord transformer to have it as a back-up, Mr. Norfolk said, should a similar event happen in the future. A new transformer would cost $570,000, he said.
Commissioner Dave Gilroy asked if a back-up transformer truly is needed, when most transformers can last as many as 100 years on average.
“If this hadn’t happened, would I be coming to you and asking for a back-up? No,” Mr. Norfolk said. But, he said, the Mt. Zion substation is a “critical facility,” as it is Cornelius’ only substation serving the east side of town. “We’re a 1-horse town, so to speak,” he said.