The Overvoltage Protection & Simulink For Power Unit Of The Excited System Of Synchronous Generator

The power unit of synchronous generator excited system is essentially a controlled DC power supply, used to provide DC voltage for the excitation winding of synchronous generator. In order to meet the requirements of normal operation, the power unit must have sufficient capacity of regulating, a certain multiple of forced excitation and excitation voltage response speed.Along with the development of Chinese power industry, the single synchronous generator capacity in the growing capacity requirements of the excitation power is also growing, so the power unit of generator excited system need to be more powerful, more reliable and faster response. Because the Self-parallel Excitation System of synchronous generator has the advantage of faster regulating speed, wider range of regulation, and higher coefficient of forced excitation, it is widely used in large synchronous generators by now. In the self-parallel excitation system, the high power rectifier unit supplied by excitation transformer after machine end takes the place of exciter. The reliable operation of high power rectifier unit will have a direct effect on safety and reliability of the generator. If the power thyristor, key component of power unit of the Self-parallel Excitation System, bear more than its rated voltage and current, it will be damaged in a very short time. Therefore, to make the long-term reliable operation of SCR, We should not only select the thyristor device parameters rationally and left full margin, but also take appropriate and effective protection measures for the over-voltage.This paper summarized the outcome of the previous experience and established the mathematical model of over-voltage protection circuit, then optimized the parameters of the model by genetic algorithm, which is widely used in the field of engineering optimization. Then Matlab Simulink toolbox is used to simulate the optimization parameters. We can verify the accuracy of optimization parameters by analyzing the simulation waveform. Finally, the parameters can be used for actual components selection and actual circuit structures on-site testing. By comparison of the results of theoretical Simulation, we can draw the conclusion that this optimization method is correct and feasible.