Analysis of unbalance Plug-in Electric Vehicle home charging in PEA distribution network by stochastic load model

Plug-in Electrical Vehicles (PEVs) are expected to be continuously adopted worldwide in near future. PEV charging characteristics are quite unique and depend solely on drivers´ behaviours. Accordingly, PEV charging periods are also quite uncertain. They are not only affecting the system loading but also leading to other problems in distribution network. The voltage problem due to effects of home PEVs charging, which is a slow single-phase charging, degrades power quality. This may cause the voltage unbalance in the distribution network. This study simulates the Hua-Hin (Prachuap Khiri Khan Province, Thailand) network, by selecting 4th feeder of the Hua-Hin 3 (HUC) PEA substation as the experimental model. The PEVs charging behaviour is modelled based on stochastic variables consisting of the battery SOC, arrival time for charging and the connected phase-A,-B,-C. The modelled distribution network and voltage unbalance analysis are carried out by DIgSILENT PowerFactory and DIgSILENT Programming Language (DPL). This paper presents PEVs penetration 6 case studies and compares their standard deviation values according to PEVs arrival time. Simulation results show that high penetration of PEVs single phase charging raises the voltage unbalance factor (%VUF), when customers arrived and charged at the same time. The %VUF increases gradually along the length of feeder, and has maximum value at the end of the feeder. In addition, many case studies show %VUF exceeding criterion of 2.0% of the IEC standards.