Optimization Of Dynamic Characteristics And Study On Voltage Control Of Magnetically Controlled Reactor

As an ideal reactive power compensation device for dynamic reactive power balance and voltage control of power system,MCR(Magnetically Controlled Reactor)has the advantages of continuous adjustable output inductance and simple control.However,there is still a large optimization space in the response speed of capacity regulation.In view of the performance defects of MCR with long dynamic transition time,this thesis starts from two aspects of auxiliary acceleration measures and winding structure optimization,through mathematical modeling,MATLAB simulation and related experiments,puts forward a good auxiliary excitation scheme and winding configuration strategy,which provides theoretical guidance for the further improvement of MCR dynamic characteristics.The voltage control performance of MCR with different dynamic characteristics for Extra-High Voltage(EHV)transmission lines is analyzed by simulation.The specific research contents are as follows:(1)In view of the inaccuracy of the traditional calculation method of MCR response time,the magnetization characteristic of small slope is piecewise linearized,and the transition process of control current under the condition of zero working current of MCR is divided into two stages: the linear increasing stage of DC flux and the exponential rising stage of control current,and a more accurate calculation formula of transition time is obtained..(2)Combined with the advantages of current measures to improve the response speed of MCR,an auxiliary excitation measure without additional auxiliary excitation power supply is proposed.The acceleration time of dynamic response of auxiliary excitation to MCR is quantitatively analyzed.The validity and correctness of the theoretical analysis are verified by simulation in MATLAB/Simulink,and the portability of the proposed auxiliary measures is verified by using Splitted-core Type MCR.(3)Based on the analysis of the blocking factors of the conventional MCR response process,a new winding structure scheme is proposed,which can largely eliminate the blocking factors of the dynamic process.Based on MATLAB/Simulink simulation,the dynamic process of the MCR with the conventional winding structure and the novel winding structure is compared.Finally,the rationality of the new winding structure and the correctness of the theoretical analysis are further verified by the prototype experiment.(4)In order to adapt to the situation of rapid reactive power compensation,a two-stage switching type MCR is proposed on the basis of the novel self-excited MCR.The simulation results show that the magnetization and demagnetization process of any capacity change range of the two-stage switching type MCR can be completed within two power frequency cycles with the corresponding rapid response control strategy.(5)Finally,in order to compare the reactive power/voltage control performance of MCR with different dynamic characteristics,a 500 kV EHV long-distance transmission line model is built in MATLAB/Simulink,and the voltage control system composed of MCR with different response speed is simulated.The voltage waveform and output current waveform of MCR at the end of the transmission line under different working conditions are compared and analyzed,which shows that MCR has good reactive compensation and voltage control performance,while the fast response MCR has better voltage dynamic control effect.