White Rock residents left in the dark Sunday

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By The Staff

White Rock residents were left in the dark several times Sunday as power outages affected at least 2,430 people.

The outages began at 7:33 a.m., when on-call Department of Public Utilities electric linemen investigated and discovered a fault in an underground cable near Piedra Loop.

According to a press release from the DPU, engineering analyses and a review of data logs, the DPU’s switchboard recognized the 7:33 a.m. fault accurately and remained closed. However, the switchgear for the 115 KV high voltage transmission feed to White Rock, configured by Los Alamos National Laboratory, responded to the fault by opening.

The resulting effect was that power to the entire White Rock townsite was shut down.

Los Alamos and White Rock usually have two 115 KV high voltage transmission lines serving the county, which provide redundancy in the event of service interruption. However, the Norton Line has been out of service since August as the structures crossing San Ildefonso Pueblo are replaced by crews from LANL.

The construction period is expected to extend into December, and the Reeves Line, remaining feed to White Rock, has been reconfigured.

“Due to the reconfiguration of the transmission system, what should have been a minor outage in La Senda instead resulted in all of White Rock losing power,” Utilities Manager John Arrowsmith said in a DPU press release. “An underground cable that serves a cul-de-sac faulted and blew a 40-amp fuse. Apparently, this resulted in the loss of the entire 115 KV high-voltage transmission feed to White Rock.

“Further,” Arrowsmith continued, “each time the line crew attempted to replace the fuse, the transmission line would again disconnect. The outages continued until approximately 10 p.m. Sunday night when an underground cable fault was fixed, and the linemen incrementally reenergized the system.”

LANL committed to engaging a consulting engineer as quickly as possible, during an investigatory meeting held at 5 p.m. Monday between LANL personnel and DPU staff.

The consultant will be tasked with resolving the equipment coordination scheme between the Department of Public Utilities’ distribution system and LANL’s protection system for White Rock’s 115KV transmission switchgear.

The Department of Public Utilities operated the county-owned electric, gas, water and wastewater systems under the jurisdiction of the Board of Public Utilities.