Energy safety investigation outcome on 33,000 volts hardware failure
Published: 12.02.2008
Recently in the news has been an electrical safety issue regarding a cross arm supporting 33,000 volt conductors that failed.
The failure caused the insulator supporting the conductor to drop down close to another cross arm carrying 11,000 volt conductors. The resulting flashover caused an outage to a number of houses in the area. Inspections revealed no electrical safety problems in the houses.
ES and the network company involved carried out an extensive investigation into the incident to determine the cause of the cross arm failure. Although the inspection did not indicate that other cross arms were in danger of failing, ES is working with industry to increase awareness of the potential hazards of similar situations. We will continue to thoroughly investigate this type of safety issue in conjunction with our industry partners..
As part of the investigation analysis, consulting engineers engaged by the network company found that the cross arm failure caused a phase-to-phase tripping of the protection system, and no earth fault was indicated in the electronic protection relay controls. The design strengths were checked by independent engineers who concluded that the cross arms were in fact capable of supporting the loads imposed on them.
The investigation concluded that the cross arm failed due to internal rot which was not evident from a visual inspection. As a result, ES is reminding network companies that visual inspections may not be sufficient to identify the source of an electrical hazard, and thorough regular maintenance is advisable.
Related link
|
Forward
to an associate
Print
this article
Back
to headlines
