Research On Unbalanced Operation Mode Of SVG

In recent years, as power quality problems have become increasingly concerned about, peoplehave paid more and more attention to reactive compensation devices, especially SVG, who has beenwidely recognized with its superior performance and great development potential. SVG not only canachieve real-time dynamic reactive power compensation, and also can effectively suppress the voltagefluctuation and flicker, compensate for three-phase unbalanced system to improve the stability of thegrid, presenting a very broad development prospects in the future.The article primarily describes the current situation and development trend of development ofSVG and analyzes working principle and reactive power detection theory. Then mathematical modelsin the d-q synchronous rotating coordinate system is built based on topology modeling method. Thenaccording to the mathematical models and feedforward decoupling control, double-loop controlstrategy in direct current control way which includes voltage outer and inner current loop has beendesigned to stabilize capacitor voltage of DC side and compensate for system reactive power.Meanwhile, in order to achieve SVG unbalanced operation mode, biordered synchronization controlstrategy is constructed based on method negative sequence d-q detection method to achieve reactivepower compensation and the negative sequence current compensation. When serious fault happened,pulse blockade control is adopted to effective protection of SVG.Finally, SVG simulation model is built in Matlab/Simulink platform, and the control strategiesproposed above are verified through simulation analysis respectively, and simulation waveforms arepresented.