Secondary Frequency Regulation Strategy With Fuzzy Logic Method and Self-Adaptive Modification of State of Charge

Abstract

Battery storage has been adopted to coordinate with generators in automatic generation control (AGC). In this paper, a control strategy of battery storage involved in secondary frequency regulation is proposed. Through the analysis of the control mode based on area control error signal and the control mode based on area regulation requirement signal in AGC, the integrated control strategy was developed, and the switch timing and the output depth of the battery storage were defined. That is, when the system frequency is deteriorated and the frequency deviation $\vert \Delta f \vert $ is large, according to the fuzzy logic method, the output power of the battery storage will be smoothened on the basis of the state of charge (SOC). When the system frequency is normal, the frequency deviation $\vert \Delta f \vert $ will be small. The remaining frequency regulation capacity of generators can be used to improve the SOC. Furthermore, according to the defined frequency regulation evaluation indexes, MATLAB/Simulink was used to simulate the battery storage coordinating generators for secondary frequency regulation. A typical continuous disturbance was selected in the simulation. The results of the simulation showed that the proposed strategy could enhance the effect of frequency regulation, improve the SOC of the battery storage, and increase the utilization rate of the generator set.