Research On The Control And Parallel Operation Technology Of Medium Voltage Cascade STATCOM

With the development of economy, the requirement of power quality is strictly,and the reactive power compensation and harmonic control problem is the key factorof the power quality’s improvement. STATCOM is the newest technology of reactivepower compensation and harmonic control in medium and high voltage field, therelated control technology has been a research hotspot. The STATCOM as a powerelectronic current compensation device, like the same of the active power filter (APF)and inverter, has the circulation problem in parallel operation, especially in mediumvoltage transformers parallel situation, the energy flowing in tie-line exacerbatethe circulation problem which caused by the unbalanced load,even causedthe STATCOM break down in harmonic current compensation. This article makessome research on the control and parallel operation technology of medium voltagecascade STATCOM, get a using multi STATCOM parallel operation controltechnology.With the power quality problems, there is a necessity of reactive power andharmonic compensation for the power net.This thesis summarizes the development ofreactive compensation devices and the parallel technology of STATCOM.Basing on the basic principle of STATCOM and the actual conditions of substation,this thesis makes a detailed design of the medium voltage cascade STATCOM’maincircuit structure.And on that this thesis builds the mathematical model andanalyzes the parallel circulation of STATCOM.Based on the mathematical model, this thesis makes a research on the controlstrategy of the medium voltage cascaded STATCOM. Especially for the modulationtechnique, the AC side control method and the DC side capacitor voltage balancemethod. And through the related theoretical simulation, proves the reliability andsuperiority of these control strategies.To solve the parallel operation issues of medium voltage cascade STATCOM insubstation, this thesia makes some research on the paralle l operation techniques ofmedium voltage cascade STATCOM, and proposes a new control strategy based onthe improved same current sampling technology of STATCOM parallel system.Throughing the related MATLAB model simulation, it verifies the stability andpracticability of the control method.The thesis makes mor for the detailed software and hardware designing of the medium voltage cascaded STATCOM parallel system, and designs double±3.0Mvarmedium voltage cascaded STATCOM device prototypes last, and makes some actualexperimental tests and application effectiveness analyses, verifes the effectiveness andpracticality of the related research and design in this thesis.