Analysis of impact of DG on LVDC distribution network protection

Abstract

Compared with traditional AC distribution network, DC distribution network, which stands for future distribution network is suitable for distribution generation (DG) to multiple access. DG access changes the structure of low-voltage DC (LVDC) distribution network, affecting the reliability of relay protection. To eliminate the influence, a protection strategy which is based on Hall DC transformer is proposed. First, study about the effect of DG access on relay protection when DG is connected is discussed in detail for different capacities and locations. Then analysis shows that the integration of DG will cause rejection or malfunction, which may threaten the reliability of LVDC distribution system. Finally, the analysis shows that the optimization strategy based on Hall DC transformer can eliminate the effect by changing operation conditions.