Modeling of High Voltage Pollution Discharge to Investigate Hot Stick Flashover
Electric “flashover” or insulation breakdown has occurred on “hot stick” safety tools used on live AC transmission lines at Manitoba Hydro in 1997 and 2002. Investigations showed pollution flashover as the cause, whereby leakage currents cascade into flashover. Prior to reinstating live-line work with mitigation procedures, DC voltage experiments suggested an atypical flashover uncharacteristic of pollution flashover without leakage currents, which may require a different mitigation strategy. In this thesis, statistical analysis shows that relative humidity has a greater correlation than voltage with the type of flashover. Labeled a “fast flashover”, it seems to be distinct from pollution flashover, although not statistically significant. A time-stepping computer model was developed to calculate a critical voltage for flashover as a function of relative humidity. However, lack of data prevents the model from making firm conclusions. A list of recommended research is proposed to remedy these deficiencies to allow future model refinement.