Electrical Fault Damages Switchgear Unit and Transformer
Incident Investigation
Electrical Fault Damages Switchgear Unit and Transformer
December 28, 2022
Electrical
Reference Number:
II-1487206-2022(#30819)
Location: Armstrong, BC
Regulated industry sector: Electrical – High voltage electrical system (greater than 750 V)
Incident Overview
A high voltage electrical fault occurred inside an indoor 25 kV metal-clad switchgear unit at an industrial lumber mill and plywood plant. Extreme cold weather and a low-gas condition inside of the upstream 138kV breaker caused it to fail to de-energize the system when the fault occurred causing greater amounts of damage. The fault started a small fire and caused damage to an outdoor 10-15 megavolt ampere (MVA) 138 kV – 25 kV pad mount transformer in the switchyard.