Long-Term Performance of Switch Blade Restraint for Safe Operation during Maintenance

摘要

A restraint device was developed to avoid accidental re-closure of vertical mount switch blades during maintenance operations. To verify safe implementation, long duration tests were performed to define the device's resilience to the high voltage environment in which it to be used. The restraint was exposed to continuous corona discharge for 56 days under dry conditions. The tested sample withstood this form of stress well, with only minor changes to electrical characteristics. However, a change in the sample's hydrophobicity was observed and consequently a second long duration evaluation was commenced which included period precipitation. Surface tracking and erosion under periodic precipitation conditions initiated and developed quickly. The primary function of the restraint device and corresponding acceptance criteria need to be considered when concluding the suitability of the device for its intended function. Dependent on operational strategies, several alternative approaches can be adopted.