Impact of Reverse Power Flow in Distribution Feeders on Under-Frequency Load Shedding Schemes

This paper presents an analysis of the system effects of reverse power flow in distribution feeders. Continued increases in the number of small-scale photovoltaic (PV) panel installations within the network has led to low or reverse power flows in distribution feeders at times of high solar energy availability, and substantial weather-induced load variation, among other impacts. In the event of a large loss of generation, under-frequency load shedding of these distribution feeders is one tool that network operators use to arrest the frequency decline. The penetration of distributed PV generation leads to low availability of load to shed, or the chance of inadvertently removing generation, which can lead to power system failure. This paper explores these effects on the largest power system in Western Australia and suggests methods to mitigate the impact of increasing DER penetration on under-frequency load shedding schemes.