Smart frequency control schemes in distribution network with renewable resources

Two smart frequency control schemes are presented in this paper. The first one is an adaptive under-frequency load shedding (UFLS) scheme, and the second one is system frequency control scheme based on energy storage and wind farm. The UFLS is developed based on a new and simplified methodology for an estimation of the magnitudes of disturbances (EMD). Using the estimation results, the UFLS can be implemented more accurately when the system operating in emergency condition. For the frequency control scheme on energy storage and wind farm, the active power generated by the battery and wind turbine can be controlled consistently to the system frequency variation. This paper consists of two parts. In the first part, the methodology of the EMD will be presented and tested in a distribution network model. In the second part, the frequency control schemes on energy storage and wind farm are presented and tested in the network model. The network model is built in DIgSILENT software package, consisting of conventional consumers and mixed renewable energy sources.