Demonstration of Frequency Regulation via Autonomous Load Control

With the increasing proliferation of photovoltaic (PV) and wind power globally, frequency regulation by balancing generation and load in power systems is becoming increasingly difficult owing to reductions in dispatchable power and inertia. One countermeasure is autonomous load control, in which thermostatic loads and electric vehicle chargers quickly adjust the power consumption based on the grid frequency monitored by themselves without communication. However, testing the impact of such load controls on the frequency in actual power systems is too expensive. Therefore, a laboratory-scale isolated power system was prepared as a test bed to examine autonomous load control based on the rate of change of frequency (RoCoF) and the frequency deviation to cope with steep frequency fluctuations. Moreover, the experimental system was simulated numerically using MATLAB/Simulink. The experimental and simulation results are comparable, indicating that the simulation can be used to determine the total capacity and threshold when planning the introduction of autonomous control loads. The experimental and simulation results also show that frequency fluctuations can be mitigated by introducing autonomous control loads to the grid, and the response time can be improved by approximately 1 s by controlling the load based on the RoCoF.