Study on residual current protection in low-voltage network with distributed generators

Abstract

The access of the distributed generators (DGs) in the low-voltage network would change the direction of power flow, the operation mode and fault characteristics of the system. Furthermore, it will have a great influence on the residual current protection in the low-voltage distribution network. Aimed at the radial network with DGs, the paper studies the influence of the DG's access on the installing position of the residual current protective devices (RCDs), the effect of ground point's location on the reliability of the RCDs and the effect of harmonic introduced by DGs on the setting of tripping current of RCDs. And on the basis, the corresponding configuration scheme of residual current protection is proposed to weaken and eliminate these effects. The research results in the paper can provide theoretical support for the configuration and setting of the residual current protection in 400 V low-voltage network with DGs.