Comparison of point-of-load vs. mid feeder compensation in lv distribution networks with high penetration of solar photovoltaic generation and electric vehicle charging stations

Abstract

Increasing use of distributed generation (DG), mainly roof-top photovoltaic (PV) panels and electric vehicle (EV) charg-ing would cause over- and under-voltage problems generallyat the remote sections of the low voltage (LV) distribution feeders. Asthese voltage problems are sustained for a few hours, power electronic compensators (PECs) with input voltage control,i.e. electricsprings can not be used due to the unavailability of non-critical loads that can be subjected to non-rated voltages for long durationof time. However, PECs in output voltage control mode could be used to inject a controllable series voltage either somewhereon the feeder (mid-feeder compensation, MFC) or between thefeeder and each customer (point-of-load compensation, PoLC)both of which are effective in tackling the voltage problem without disrupting PV power output and EV charging. In this paper, acomparison between the MFC and PoLC option is presented in terms of their voltage control capability, required compensatorcapacity, network losses, PV throughput, and demand response capability. The criteria for selection of optimal location of thesecompensators is also discussed. Stochastic demand profile for different types of residential customers in the UK and a typicalEuropean LV network is used for the case study.