高压直流输电系统换相失败抑制方法

本文发现了造成直流输电系统后续换相失败的原因之一：锁相环在暂态过程中不能准锁定交流电压相位从而导致控制系统给出的指令触发角与实测的触发角存在偏差。并且较为直观的分析了这种锁相环暂态误差造成换相失败的作用机理。本文以减小锁相环暂态偏差对控制系统的不利影响为目标,在间接测量得到锁相环暂态误差的基础上设计了反馈补偿环节。在PSCAD/EMTDC平台的基础上,并在仿真模型中考虑最小熄弧时间,将输电线路等值为电感,验证本文所提的补偿环节对后续换相失败的抑制作用。算例表明本文所提的补偿环节对换相失败的抑制作用明显,本文所提的补偿环节可靠有效,具有较大的工程实际意义。

Commutation failure suppression method for HVDC transmission system

One of the reasons for commutation failure of the HVDC system is that the phase-locked loop(PLL) can not lock the AC voltage phase in the transient process, which leads to the deviation between the command trigger angle given by the control system and the measured trigger angle. Moreover, the mechanism of commutation failure caused by transient error of phase-locked loop is analyzed intuitively. In this paper, a feedback compensation link is designed to reduce the adverse effect of the PLL transient deviation on the control system on the basis of indirect measurement of the transient error of phase-locked loop. On the basis of the PSCAD/EMTDC platform and considering the minimum arc extinguishing time in the simulation model, the compensation link proposed in this paper is verified to suppress the subsequent commutation failure. The calculation example shows that the compensation link proposed in this paper has obvious ability reduce to the probability of commutation failure. The compensation link proposed in this paper is reliable and effective, and has great practical significance in engineering.