Insulation coordination in distribution liveline maintenance

Abstract

Insulation coordination principles are applied to assess the expected performance of distribution liveline maintenance equipment. Rubber gloves are used as an example. Breakdown probability distributions for Class II, III, and IV gloves are given for AC and slow-front surge voltages. Available data on observed surge magnitudes in sample distribution systems are quoted. Although quantitative evaluation of the risk of failure of liveline maintenance equipment cannot be performed due to insufficient data on surge performance of distribution systems, some qualitative conclusions can be derived. Based on available glove breakdown voltage values (electric strength) and in-service surge magnitudes (electric stress), it is apparent that flexible liveline maintenance equipment should be able to perform without failure. Additional extensive data on electric stresses (surges) in distribution systems are needed for quantitative insulation coordination studies. >