Power system restoration with distributed generation in a South African network

A major ancillary service that distributed generation (DG) can provide to the power utilities is the initial source of power during system restoration after a power outage. This paper investigates the use of DG in restoring supply to the loads in the utility network in the event of a power outage. This investigation is conducted by connecting DGs to a network based on the restoration priority given to the loads in the network. The network is then split into islands according to the location of the DGs. The loads are also divided into restoration groups and power is restored to loads based on these restoration groups, where possible. The frequency and the voltage at two main busbars of the test utility network and at the terminals of the utility slack generator are monitored. The results of the monitored voltage and the frequency show that when DG is used to restore supply to the loads the final values of the voltage and frequency after the restoration process are closer to their nominal values than when system restoration is done through utility generator.