The Research And Design Of Static Var Generator (SVG)

The basis of the national economy is electricity; it directly affects the development of our production and life. But the presence of reactive power in grid system serious threat to the power system stability and safe operation, etc. It even has become a major development obstacle of power system. Reactive power compensation has become the world’s countries an important research project to develop intelligent power grid and improve power efficiency. Because technological backwardness of the traditional reactive power compensation device technology has been unable to meet the present power system claims. The emergence of modern of static var generator (SVG) will be a new change in field of static reactive power compensation device. It has lots superior performance, such as fast response, high control precision, continuous dynamic compensate, effectively suppress the voltage fluctuation and flicker and other, so it has become an important member of Flexible AC transmission systems.In this article, firstly, the basic development of reactive power compensation device is introduced. Then reactive power compensation of the working principle of SVG is analyzed. Operating characteristics and stability of SVG are analyzed by a mathematical model. The premise of reactive power compensation is how to get reactive current signal rapidly and accurately. In this paper, the method of reactive current detection is based on the instantaneous reactive power theory, and the positive and negative sequence reactive current dual-detection method is designed based on the d-q coordinate transformation after analysis of the theory. In older to improve the control performance of SVG, the present various basic control strategy of SVG are analyzed and studied, with their advantages and disadvantages, while taking into case of the actual situation of load imbalance, a control strategy of positive sequence and negative sequence synchronous dual-sequence is designed based on the d-q coordinate transformation. It not only can achieve real-time dynamic reactive current compensation, but also generated negative sequence current when the system imbalance.Based on theoretical study of SVG, the SVG overall system simulation model is built with the powerful simulation capabilities of MATLAB. Through a variety of Operation simulation experiments to validate and optimize the reactive current detection and control strategy are designed in the paper. Simulation results show that the design of SVG has a good dynamic performance, it can achieve precise effects of reactive power compensation and the parameters are in line with the design requirements. Finally, according to simulation devices for SVG, the hardware circuit is designed and selection, and build a small-scale test platform. Software control program is writhed and debugged based on test platform.