基于PSCAD/EMTDC的呼辽±500kV直流输电工程主设备故障仿真分析

Fault Simulation Analysis on Primary Devices of ±500 kV DC Transmission Project from Hulun Beier to Liaoning Based on PSCAD/EMTDC

为了研究呼辽±500 k V直流输电工程主设备故障的电气特征,有效区分各主设备故障,利用电磁暂态仿真软件PSCAD/EMTDC建立了呼辽±500 k V直流输电系统的详细模型,对高压直流输电系统主设备进行了详细介绍,并在此基础上对逆变侧主设备故障进行了仿真分析。仿真结果表明,交流滤波器故障后,逆变侧直流电压和电流变化很小。换流变压器故障后,逆变侧直流电压、电流持续振荡,系统失去稳定。平波电抗器发生短路故障后,逆变侧直流电流发生明显波动,且含有大量的谐波分量,逆变侧直流电压略微降低。最后,基于小波变换理论,分析和提取各故障情况下电气量的特征信息,有效地识别各类故障。

To research the electrical characteristics of primary devices malfunction of ±500 k V DC Transmission Project from Hulun Beier to Liaoning for effectively identifying different faults, an equivalent model of the ±500 k V DC transmission system from Hulun Beier to Liaoning is established based on the electromagnetic transient simulation platform PSCAD/EMTDC. The primary devices of the transmission system are introduced in detail.Electromagnetic transient simulations are performed to investigate the faults of the primary devices at inverter side.Simulation results show that： 1）The fault of AC filter results in a tiny effect on the DC voltage and current at inverter side;2）When a fault happens in the converter transformer,the DC voltage and current at inverter side oscillates sustainedly, and the system loses stability; and 3）When a short-circuit fault occurs in the smoothing reactor,the DC current at inverter side fluctuates with many harmonic components,and the DC voltage at inverter side decreases slightly. Moreover,in the case of faults, the characteristic vectors of corresponding electrical quantities are extracted and analyzed based on the wavelet analysis to effectively identify various faults.