分频输电系统变频器桥臂不导通故障及相关问题

桥臂不导通是交—交变频器最常见的故障,脉冲缺失、换相失败都可以归结为这一类故障。文中分析了分频输电系统交—交变频器中性点接地方式及变频器工作在逆变条件下发生桥臂不导通故障后低频电压和电流的情况。与传统的拖动用变频器同样故障相比较,得出了两者的区别,并认为分频输电系统变频器故障可能较拖动时后果更严重。将理论分析结果与仿真结果相比较,验证了以上分析的正确性。通过分析低频故障电流与故障时基波电压、功角的关系,对变频器桥臂不导通故障的识别提出了建议。

Cycloconverter Non-conduction Fault and Related Problems in Fractional Frequency Transmission Systems

Non-conduction of bridge arms is the most common fault in a cycloconverter. Firing pulse failures and commutation failures can both cause such faults. The paper analyses the neutral point grounding mode of cycloconverter in FFTS and the voltages and currents of cycloconverter following a non-conduction fault in inverter mode. Compared with the same fault when converter works in rectifier mode, the consequence is more serious. Simulation results indicate the correctness of the above analysis. Finally, some suggestions for fault identification are proposed.