A Voltage Control Scheme of Distribution Static Synchronous Compensator Based on Current Sensorless

Distribution static synchronous compensator can be used to improve the voltage quality through exchanging the reactive power between the D-STATCOM and the power system. Keep the voltage of the point of common coupling constant and balance is a very important power quality issues. The voltage control strategy which has the function of voltage compensation and balance of the D-STATCOM is investigated in detail in this paper. The power exchange in D-STATCOM system is analysed based on intantaneous power theory. The relationship between the positive and negative sequence of the output voltage of D-STATCOM is derived. Then the voltage control strategy without current regulator is presented which has the merits of simply structure and easy to design. The voltage controller of D-STATCOM consists of positive and negative sequence voltage controller.which can regulate and balance the voltage simultaneously. Theory analysis and digital simulation results verified the feasibility and validity of the voltage control strategy proposed in this paper.