Reliability Evaluation of Insulation subjected to Harmonic Voltages within the Limits set by International Standards

This paper aims at providing reliability evaluation tools for the insulation of power system components subjected to low-order harmonic voltages that match the voltage distortion limits set by International Standards. This goal does make sense from the technical-scientific viewpoint. Indeed, as show in in the first part of the paper, even in a distorted regime that matches such limits the peak and shape factors of the distorted voltage may be high enough to accelerate insulation aging, and reduce rated life and reliability of components. Thus, in the second part of the paper the so-called “harmonic voltage safety indices” are found for assessing whether power system components are at risk under a given distorted voltage waveform, even if it complies with the voltage distortion limits set by International Standards. These reliability evaluation tools are applied to LV/MV capacitors and cables, but can be extended to other insulations, e.g. those of induction motors and transformers.