Research On Improving Voltage Stability Of Wind Power Integrated System Based On TCSC-STATCOM Control

Wind power as a representative of new energy grid-connected technology has attracted wide attention over the world in the background of the gradual depletion of traditional fossil energy sources and increasingly serious environmental pollution problems.With a large number of fluctuating wind power injected into the grid,the stability of the normal operation in the original system is serious threatened.Therefore,how to improve the wind power grid stability is the current wind power grid system interconnection facing one of the major problems.Firstly,comparison of the advantages and disadvantages of the three types of wind turbines,a doubly fed wind turbine generator system is selected as the main research object.The mathematic model of the double-fed wind turbine is analyzed.The control system of rotor side converter and the control system of the power grid side are established based on the vector control technology.Secondly,with the application of MATLAB software and the principle of STATCOM and TCSC,two FACTS devices system model has been built.By the theoretical analysis and modeling simulation,two kinds of compensation device are studied respectively in the simple compensation effect in the three-phase power system.STATCOM as the parallel compensation device,when it used as reactive power compensation device in power system,is able to quickly smoothly adjust the reactive power of system,to maintain the system voltage and to improve the dynamic characteristic.TCSC as series compensation device,continuous changes its equivalent impedance in order to change the degree of series compensated transmission lines.It will make full use of the power transmission capacity of the transmission line and suppress subsynchronous oscillation in the system,further improve the transient stability of the system.Finally,in view of the voltage stability of wind power system,it is proposed to use TCSC-STATCOM control in the power system to ensure the system have enough reactive power to maintain its normal work.A double closed loop based control strategy for TCSC and STATCOM in the power system is adopted.The corresponding simulation model of the wind power integrated system is built in MATLAB/Simulink.Comparing witi the system with a TCSC,a STATCOM and TCSC-STATCOM,the study show that the TCSC-STATCOM cooperative control has good performance on improving the voltage stability of wind power integrated system and the low voltage ride-through capability by analyzing the waveform in the different situations.And the effect of the TCSC-STATCOM cooperative control that may not be achievable if only a single technique is used.