Adaptive Frequency Control Algorithm In Off-Grid Power System Based On Photovoltaic Diesel Hybrid System And Energy Storage

Abstract

The paper gives the principles of frequency control in off-grid power system based on autonomous hybrid power plant (AHPP). AHPP is intended for territories, which aren’t connected to the centralized electric power supply. Composition of power sources in AHPP includes traditional generators, renewable energy source (RES) and electric energy storage system (EESS). The control principles are designed for limitation frequency deviations in power system, providing the balanced use of the adjustable abilities of power sources. With consideration to the stated requirements and efficiency criteria, the frequency control algorithms, the AHPP control algorithm using energy sources of several types, and algorithm maintaining EESS state of charge during control have been developed. In order to analyze effectiveness of the algorithms, the mathematical model of off-grid power system based on AHPP has been developed in MATLAB/Simulink. AHPP includes diesel generators, solar power plant and EESS. Simulation of AHPP operation in power system with abruptly variable load has been conducted. The results of calculations performed using the model have proved effectiveness of developed control principles from the viewpoint of frequency control quality and maintenance of EESS state of charge during regulation process.