Low Voltage Ride Through Operation Control Strategy Of Reactive Power Compensator

With the rapid development of new energy industry,its own randomness,intermittent and other characteristics also bring some problems such as grid voltage flicker,fluctuations and other issues.One of the better solutions is to use reactive power compensation technology.For example,the wind power generator's own reactive power compensation capacity is limited,especially in the low voltage through the operation of the process,additional compensation units are requiredto meet the requirements of the grid for reactive power compensation.Therefore,it is of great practical significance to study the low voltage crossing operation control strategy of reactive power compensation device.At present,reactive power compensation device commonly used in wind power generation system are mainly SVC(static var compensator)and SVG(static reactive power generator).In this paper,SVG is used to study the control strategy of symmetric drop and asymmetric drop.This paper firstly introduces the basic compensation characteristics and basic control strategies of SVC and SVG,and provides theoretical support for the research of low voltage crossing control system of reactive power compensation device.Secondly,the control strategy of SVG under symmetrical drop of grid voltage is studied,and the control target under symmetrical drop is defined,and its effect on voltage support is analyzed.Thirdly,the control strategy of SVG under the asymmetry of grid voltage is studied,and the control target under asymmetric drop is defined,and the control strategy is analyzed in detail,based on PR control and direct power control respectively.Finally,the Matlab / Simulink simulation circuit is built and the control strategy and targets are verified on the experimental platform.The control effect of SVG in symmetric voltage sag conditon and asymmetric voltage sag conditon is analyzed.The experimental results achieve the control target of the above control strategy.