Availability of load to provide frequency response in the great Britain power system

Control of the grid connected load in a power system is an effective means of contributing to the grid frequency control that is conventionally provided by frequency sensitive generation. The availability of domestic refrigerator and industrial bitumen tank load to provide frequency response services was investigated. The time of a day that the load is available to provide frequency response without interfering with its inherent function was measured through field investigations by Open Energi. Based on the measured periods of availability, the number of frequency responsive loads to be aggregated for frequency response over a day was estimated. Decentralised dynamic controllers were then developed which enable loads to vary their power consumption in proportion to the variation of grid frequency. The availability of the dynamically controlled refrigerator and bitumen tank load for frequency response was modelled. Variation of the availability during a severe frequency incident was simulated. The results showed that the aggregated loads were able to provide dynamic response to grid frequency continuously and repetitively over a day.