Study On Control Strategy And Device Of Statcom In Power Distribution Systems

The problem of electric energy quality menaces seriously the safe operation of power network, especially reactive power and harmonics. As a new Var compensator, the Static Synchronous Compensator (STATCOM) attracts extensive attention for its perfect performance such as smooth regulation of Var and dynamic capability.The existing compensation devices are compared and the STATCOM superior performance is analyzed. In this thesis, the compensation performance of STATCOM is studied according to dynamic compensation theory. Based on the theory of dq reference frame transformation the dynamic mathematical model of D-STATCOM in dq reference frame was deduced by introducing switch function. A few kinds of control strategy for both device-level and element-level were analyzed and compared. A simple no resistance feedback control strategy was proposed at device-level control strategy. The result shows the steady-state performance of simple no resistance feedback control strategy is superior to that of Differential Geometry control strategy, and its decoupling performance is superior to that of Inverse System control strategy. In accordance with the requirements of full use of DC side voltage and facility, space vector PWM was chosen as the element -level control strategy. A simple no resistance feedback+ space vector PWM was chose. Based on physical model of D-STATCOM, some simulations were performed by using MATLAB/SIMULINK to validate the ability of improving power factor.A hardware platform based on double DSP is carried out and the±5kvar D-STATCOM system is designed. It introduces the modular structure of D-STATCOM's software.