发变组冲击跳闸铁磁谐振故障仿真分析

Simulation Analysis on Ferromagnetic Resonance Fault of Generator-Transformer Unit Impact Trip

铁磁谐振作为电力系统中一种常见的自激振荡,其产生的过电压和过电流对电气设备的绝缘造成极大威胁。电磁式电压互感器励磁电感因具有非线性特性往往会使其励磁饱和从而引发电路谐振,产生谐振过电压。发生互感器饱和所造成的铁磁谐振过电压,极大地影响了电网的安全稳定运行。因此对铁磁谐振过电压进行分析、计算仿真研究,并对消谐措施进行研究,是十分必要的。通过对一起水电厂发变组倒送电冲击跳闸故障进行理论计算及仿真分析,分析其铁磁谐振的产生原因,提出相关运行维护的建议,为进一步研究提供依据。

Ferromagnetic resonance is a common self-excited oscillation in power system,and the over-voltage and over-current generated by it pose a great threat to the insulation of electrical equipment.The excitation inductance of electromagnetic voltage transformers has nonlinear characteristics,which tends to saturate the excitation and cause circuit resonance,resulting in resonance overvoltage.The ferromagnetic resonance overvoltage caused by the saturation of the transformer greatly affects the safe and stable operation of the power grid.Therefore,it is very necessary to analyze,calculate and simulate the ferromagnetic resonance overvoltage,and to study the measures for eliminating resonance.Through theoretical calculation and simulation analysis of the shock tripping fault of a power generation-transmutation unit in a hydropower plant,this paper analyzes the cause of its ferromagnetic resonance.The paper also puts forward suggestions on operation and maintenance,providing a basis for further research.