Characteristic leakage current of household devices and their impact on the tripping behaviour of residual current devices

Abstract

• Modern power electronics (e.g. PV inverters) can have significant leakage currents. • Leakage current depends on the frequency-dependent input impedance of devices. • Tripping behaviour of RCDs (A, B, F) of five manufacturers is studied. • Leakage current significantly impacts the tripping behaviour of RCDs of type A. • Constant supraharmonic components did not affect the tripping behaviour of any RCD. Power electronic devices can produce distorted leakage currents that might cause malfunctions in protection devices, which can lead to dangerous situations. This article analyses the leakage current of presently common power electronic household devices, electric vehicles (EVs), photovoltaic inverters (PVs) and battery storage under different network conditions and studies their impact on the tripping behaviour of residual current devices (RCDs). The article focuses on RCDs of type A as they are the most used RCDs in Central Europe, but the tripping behaviour of RCDs of types F and B is also studied. In order to get reliable results, RCDs of five different manufactures are tested. The results confirm that the leakage current has an important effect on the tripping behaviour of the RCDs. The measuring results presented in the article indicate the need for further research and possible changes or extensions of existing standards.