Off-load tap-change transformer impact under high distributed PV generation

Distributed solar photovoltaic (PV) generation market continues to grow with increasing operational challenges for distribution network operators. In South Africa, residential solar PV system projects have also been implemented in low voltage distribution networks, and there are plans for future projects at municipal level. Residential solar PV growth introduces more technical and economic concerns in municipalities and electricity utility network operators. This paper focusses on a technical investigation of a more practical low voltage (LV) distribution transformer performance under high distributed solar PV connections on eThekwini Electricity distribution network. The main network parameters of interest investigated in this paper include LV network power flow, line voltage dynamics and distribution feeder power losses in steady state. Customer day load demand effects on network parameters are also analyzed, at discrete levels, with discrete off-load tap-changer positions and different solar PV penetration levels. A case study residential LV distribution network of eThekwini Electricity is used in this paper to assess central transformer performance.