Experts evaluate, make suggestions for Midway power repairs
by Lauren Williams Staff Writer
The Sampson County Board of Education received another update during its board meeting Monday night on the power surge that occurred in the Midway district a little over a month ago, the impact the surge had on both Midway High School and Midway Elementary School, and how electrical engineers and experts are advising the school system to proceed with repairs and improvements.
The power surge occurred during the third weekend in August and was the result of a car accident that took down a utility pole that serves both the high school and the elementary school.
Back in August, Anthony Vann, executive director of auxiliary services, explained to school board members that the lack of power burned some of the schools’ electrical components while the surge of power caused other components to explode. In addition to smoke filling the building, the high school lost about 200 light ballasts, its scoreboard in the gym, a freezer in the cafeteria, two waste-water pumps, pumps for the school’s greenhouses, four 30 horse-power motor drives, two 75 horse-power motor drives which cool the air that moves through the school, and several computers.
Monday night, Vann informed the school board that Watson Electrical Construction and Progressive Design Collaborative were consulted and have evaluated both of the facilities, focusing primarily on the high school, which sustained the most damage.
Mentioning that Watson Electrical Construction was involved in the high school’s electrical work when it was originally built, Vann shared that the company reported that there was “virtually nothing that could have been done based on the powerful and uncontrollable surge of power” that traveled through the facility.
According to its incident report, Watson Electrical Construction further explained that “the school, as with practically every other building in the vicinity, was the victim of destabilized voltage caused from the ‘distribution system open neutral.’ To simplify, the open neutral means the line that regulated the voltage was no longer part of the distribution process. Voltage in some areas of the school may have been 30 volts or less while voltage coming in to other areas easily was 240 volts or higher.”
“The damage done at Midway High School and every other location under the power distribution area described above was solely the result of a broken neutral,” continued the report, noting that the school’s “TVSS (Transient Voltage Surge Suppressor) is an excellent surge suppressor. However, it is not designed to nor is it capable of over-voltage protection from a lost neutral. It is designed for only very short transients.”
“The only consolation is that the school did not burn to the ground,” the report concluded. “There have been many structures not so fortunate.”
Vann then shared the report from Progressive Design Collaborative, a third-party expert company that “had nothing to do with the project.”
“They spent a day or two out at the site,” said Vann, noting that Scott T. Bosiger with the company suggested replacing several components that were burned out or damaged.
“They also suggest we contact the manufacturer of the variable speed drives on the motor,” Vann added.
“The failure of the VFD’s (Variable Frequency Drives) should have never occurred,” said Bosiger in his letter to Vann, explaining that “VFD’s are programmed with fault protection. One of these type fault protection are the loss of voltage or current on a phase. The VFD’s should have shut down when this fault occurred.”
“My recommendation would be to contact the manufacturer of the VFD’s to get them replaced and also for the manufacturer to do a failure analysis of why the VFD’s failed,” he added.
Vann assured the school board that he is in the process of making contact with that overseas manufacturer.
“He (Bosiger) said there would be more recommendations to come once he hears back from Duke Energy…He’s very concerned with how power actually comes to our facility,” Vann added.
School board member Faye Gay stressed that Union High School and Roseboro Elementary School, both new schools like Midway, should be checked to ensure that their electrical components are in proper working order.
Vann agreed, noting that both Union High and Roseboro Elementary have the “same components and drives” as Midway High.
“There about eight of our schools that have very similar components (to Midway High),” he added.
Lauren Williams can be reached at 910-592-8137, ext. 117 or via email at email@example.com.
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