An Equivalent Voltage Index to Quantify the Impact of Harmonics on Shunt Capacitors

Harmonic distortions are known to affect the normal operation and life of power equipment. Shunt capacitor is one piece of equipment that is very sensitive to harmonics. Although limits have been established to limit the harmonic distortions experienced by a capacitor, methods to quantify the harmonic impact with easy-to-understand indices are still at large. This paper aims to address the above gap by proposing an equivalent voltage index. This index is to represent the impact of harmonic voltages and their features (such as peak value) into an equivalent increase in the fundamental frequency voltage otherwise experienced by the capacitor. The main advantage of such an equivalence is that PQ and non-PQ engineers can easily relate the impact to the general capacitor loading concept. The index is especially helpful to understand the impact of harmonics on capacitor and thus to justify harmonic mitigation projects.