The Research Of Harmonic Characteristic And Suppression Of Magnetic Controlled Reactor

Reactive power is necessary for power system. With the development of economy, higher transmission voltage level, longer transmission distance, and bigger capacity is the development direction of power system. The problem of reactive power compensation and voltage control technology is relatively prominent. Magnetic controlled reactor as one kind of continuous adjustable output, simply control, and high voltage level reactive compensation power equipment, has a good application in this respect. As a result of MCR working in saturated state, inevitably produces harmonic current and harmonic pollution.In order to study the harmonic characteristic of MCR and suppress harmonic current. Firstly, the characteristics of structure and theory of MCR were analyzed, according to the conduction of thyristor and power diode, mathematics model of MCR under different stage was built. The MCR controller and magnetic controlled box with optical fiber were introduced based on reactive power compensation system of 10kV/2500kVar oil-immersed MCR, and the basic hardware design and operation principle of reactive power compensation system was explained.And then, the method of illustration was used to explain the relationship of DC magnetic bias and distortion of magnetizing current, and find out why MCR produces harmonic. The model of DC magnetic bias based on neural network by Matlab was established, for simulating hysteresis characteristic of MCR and calculating the output current. The model is reliability which comparing with the experiment waveform. FFT was used to analyze the harmonic characteristic of magnetizing current, and the amplitude-frequency characteristic and content of each harmonic was described under different DC magnetic bias.Aiming at MCR under the working condition of low magnetic saturation with high harmonic content, mathematical model of multistage of magnetic valve was built. Optimization algorithm based on PSO by Matlab was used to find out the better group, in order to offset the part of harmonic by each other internally and reduce the MCR harmonic content of magnetizing current effectively. For three-phase MCR, changing the connection mode and adding the phase-shifting winding can change the phase of the each phase harmonic, and offset the part of harmonic.Finally, limited element analysis method was used to establish the 2D model of MCR based on ANSYS, the AC/DC distribution of magnetic field was analyzed and the cloud of flux density distribution and magnetizing current of MCR was described.