Estimation of insulation overheating in Medium Voltage and Low Voltage conductors and transformers due to stationary disturbances

Abstract

This paper presents a method to estimate the insulation lifetime reduction for Medium Voltage (MV) and Low Voltage (LV) conductors and transformers due to the presence of stationary power quality disturbances. Insulation aging can be accelerated by temporary increases of rms values of voltages and currents caused by stationary disturbances, i.e. harmonics. A short duration increase of rms values cannot cause a significant reduction of insulation’s lifetime, but its recurrent presence during long time periods will produce a cumulative effect. Currently available models for insulation aging are employed.