A static voltage stability index based on P-V curve for the medium-voltage distribution network with distributed PV

Abstract

With the rapid increase of distributed photovoltaic (DPV) generations, the static voltage stability (SVS) of distribution network (DN) is faced with more and more challenges. Considering the characteristics of DPV and the network structure, an appropriate static voltage stability index (SVSI) in the medium-voltage DN with DPV is studied in this paper. In terms of the limitation of the traditional SVSI that only reflects the load change, based on P-V curve, a novel voltage change rate - network load change rate index (M-index) is proposed. The M-index considers the impacts of double changes in DPV power output and load level. The model of classic 33-node network with a DPV source is established to investigate the proposed M-index. By changing the DPV penetration percentage and the DPV access point, and comparing with the existing Load-index, the validity and superiority of M-index is verified. Comparing with the traditional SVSI, the M-index is more propitious to evaluate the SVS for the medium-voltage DN with DPV.