Study Of High Voltage SVG Based On Asymmetry Cascaded Inverter

With the wide application of power electronic devices and nonlinear loads,harmonic pollution is increasingly serious and power quality declines. Reactivepower compensation has become a major issue which the field of power electronicsand power system face. Means of regulation and the timeliness of control of theoriginal reactive power compensation device is difficult to meet the needs of themodern electric equipment. Therefore, the use of static reactive powercompensation device in dynamic reactive power compensation is one of the moreactive research areas in power electronics discipline. The research and applicationso far focus on the development of high voltage capacitor SVG. Focus of this articlecan be summarized as follows:1．The concept of reactive power and reactive power compensation device andthe development of Static Var Compensator generator is introduced. The principleand operating characteristics of Static Var Compensation generator are analyzed.Several control methods for Static Var Compensation generator are compared. Thesuperiority of the Static Var Compensator generator is obtained by comparing withother reactive power compensation device.2．A high-voltage SVG system which consists of asymmetric cascaded inverteris proposed based on theory study of SVG. The topology of the above SVG systemand its working principle are introduced in this paper, at the same time itsadvantages over the ordinary cascaded inverter high voltage SVG are demonstratedand analyzed. Control strategy of the static reactive power compensation device isintroduced by referring direct current control strategy of the high-voltage SVG andthe corresponding control block diagram is given.3．Instantaneous reactive power theory and its application on reactive currentdetection are elaborated in this paper. Several three-phase reactive current detectionmethods are analyzed in comparison and single-phase reactive current detectionprinciple based on instantaneous reactive power theory is described in detail.4． Based on the above theoretical analysis, matlab is used to carry outsimulation on the high-voltage SVG system which consists of asymmetric cascadedinverter and temporary state response map as well as steady state response map isgiven so that the effectiveness and practicality of this topology are verified.