Low voltage conductor’s ampacity derating due to stationary disturbances

This paper presents a method to estimate the derating in Low Voltage (LV) conductors due to the presence of stationary power quality disturbances. The temporary increases in the rms-values of the voltages and currents caused by stationary disturbances, i.e. waveform distortion, unbalance and phase displacement, cause increases of power losses in the conductor and operation temperature. These power losses force to study the methods to calculate the cable ampacity due to stationary disturbances. Currently available models are employed, the expected power quality disturbance levels are extracted from power quality data bases. A discussion about the effects on insulation lifetime is presented.