The Research On A New Type Of Statcom

Flexible AC Transmission System (FACTS), based on the power electronic technology, is one of the most active research aspects in the study of power systems. With the successful development of High Temperature Superconductor (HTS) and continuous progress of Low Temperature Engineering, application of Superconducting in Power Systems is becoming one of the most attractive topics. As the revolutionary combination of these two technologies, Static synchronic compensator unit (STATCOM) is the studied object of the present thesis.STATCOM is a static synchronous generator operated as shunt-connected static var compensator whose capacitive or inductive output current can be controlled independent of the ac system voltage. Presently most of these commercialized STATCOM are based on the voltage source convert (VSC). Another potential topology that can be applied to STATCOM is current source convert (CSC). Due to the configuration of semiconductors in series, the conduction loss is relatively high. If better semiconductors are available, this topology can be potentially widely used.Firstly, this thesis presents the significance of applying STATCOM. The study achievements of STATCOM in various countries are also overviewed based on the recent publications. Then, the basic structure and principle of a six-pulse Current Source Convert (CSC).And a six-pulse Voltage Source Convert (VSC) based STATCOM are analyzed in detail. A time domain simulation model for a three-phase six-pulse CSC based STATCOM is built with a digital simulation tool PSB (Power System Block set) in the environment of MATLAB. Afterward, the relationship of the power factor of the STATCOM used in power system as a function of the trigging firing angle and trigging pulse width is derived from the digital simulation. Extensive digital simulation results show the effectiveness of the obtained result and the ability of the STATCOM in controlling the active and reactive power of the power system. In addition, the dynamic simulations are also performed to demonstrate the response of the Power Conditioning System (PCS) according to the conception of transient and mean power respectively. The digital simulation is modeled as active and reactive sources with a delay represented by the first lags. After obtaining the relations among performances and STATCOM parameters, a series of schemes and conclusion are presented. Finally, the effectiveness and ability of the STATCOM to enhance stability for power System is testified in far-going range by the digital simulation based on a Single-Machine Infinite-Bus system with STATCOM in the environment of MATLAB/Simulink .Experiment results verified the conclusion obtained.