The Study Of Dynamic Medium-voltage Reactive Power Compensation Device Based On Permanent Magnet Vacuum Switch

The thesis, based on a comprehensive study on the reactive power compensationtechnology development of medium voltage distribution system and the emerging problems inthe practical application, discusses the necessity of the power compensation technologyresearch and analysis of the current medium voltage power compensation device in terms ofcontrol method and device research. And it puts forward the research on dynamic reactivepower compensation device, with intelligent reactive power compensation technology andsynchronous switching technology as its core and vacuum circuit breaker with permanentmagnetic actuator as its basis. It also provides a design plan for the dynamic reactive powercompensation control device. Main research work is as following:(1) In accordance with the current-existing defects of the converting station reactive powercontrol strategy and combined with the practical experience of the converting station controland fuzzy control theory, the use of Area17fuzzy control strategy to achieve thecomprehensive control of the voltage and reactive power is proposed. And simulation tests aremade in MATLAB, lying theoretical and research foundation for the design of the controldevice. The simulation results show that this strategy could effectively improve the passingrate of the voltage, and reduce the unnecessary capacitor switching and the action of the tappingpoint caused by the switching shock in the critical region.(2) At present, according to most of the medium voltage reactive compensation devicesstill use ordinary switch capacitor switching, which could easily cause a large inrush current,over voltage and other problems. The vacuum circuit breaker with permanent magnetic actuatorovercomes the defect of traditional switch which can not achieve the precise control. And at thesame time, it maintains the advantages of the traditional mechanical switch with its largecapacity, high reliability and low cost etc. Using position feedback controlling strategies toachieve the synchronous operation could reduce the inrush current and over voltage problemsincurred in the switching operation, and could enhance the power quality and the stability of thesystem. The simulation results show that it can effectively follow the given referencetrajectory,meanwhile，it can satisfy the requirements for synchronous cutting.(3)On the basis that the processing speed of the MCU’s reactive power compensationdevices is slow and hard to meet the requirements of the complex control algorithm, thecontroller hardware circuit with powerful and easily-expanding TMS320F2812as its corecontrol chip is designed, realizing the application of the voltage reactive power Area17fuzzycontrol strategy in the controller hardware circuit. The prototype test verifies the effectiveness and consistency of the device. And the devicecould compensate reactive power of the power grid according to changes in the voltageparameters of the power grid.