基于空载误强励灭磁对发电机过电压保护整定的研究

摘要

This paper simulates the de-excitation process of self shunt excitation 300 MW and 600 MW turbine generators on no-load fault forcing excitation condition with different over-voltage protection setting in order to study different setting value's effect on the security of generator and its de-excitation circuit.According to the simulation, generator's maximum stator voltage, de-excitation current, resister's exhaust energy and de-excitation time would be reduced with smaller setting value.It is beneficial to the security of generator and its de-excitation circuit.After testifying that the smaller over voltage protection setting would not go against the V/Hz limit in AVR, over excitation protection and generator normally operation to demonstrate the feasibility of decreasing setting value, this paper puts forward to decrease the generator over-voltage protection setting values and subjoin an additional over-voltage protection specified for generator no-load condition.%为研究发电机过电压保护设定值在空载误强励灭磁过程中对发电机本体和灭磁系统安全性的影响,分别对采用自并励励磁的300 MW和600 MW汽轮发电机组在不同发电机过电压保护设定值下进行空载误强励灭磁仿真.对比仿真结果可见,过电压保护设定值较低时相应的发电机最高定子电压、灭磁电流、灭磁电阻能耗和灭磁时间也较小,有利于发电机本体和灭磁系统的安全.为论证降低过电压保护定值的可行性,分析说明了该定值降低后并不影响励磁系统V/Hz限制、发电机过激磁保护和发电机正常运行.基于以上结论,提出了减小发电机过电压保护整定值和增设发电机空载专用过电压保护的建议.