Analysis and Improvement of the Multiple Controller Interaction in LCC-HVDC for Mitigating Repetitive Commutation Failure
Analysis and Improvement of the Multiple Controller Interaction in LCC-HVDC for Mitigating Repetitive Commutation Failure
复制标题
LCC-HVDC 中多控制器交互的分析和改进，以减轻重复换相失败
DOI：
10.1109/tpwrd.2020.3017802
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发表时间：
2021-08
影响因子：
4.4
通讯作者：
Qianming Xu
中科院分区：
文献类型：
--
作者：
Lerong Hong;Xiaoping Zhou;Yifeng Liu;Haitao Xia;Hanhang Yin;Y;ong Chen;Leming Zhou;Qianming Xu
在基于线路换流变换器的高压直流（lc - hvdc）系统中，逆变器控制系统通常包括恒消角（CEA）控制器、恒流（CC）控制器、电流误差（CEC）控制器和电压相关电流限流器（VDCOL）。然而，多个控制器的交互影响可能导致重复换相失效（CF）。为此，本文深入研究了控制器交互引起的重复CF的机理和影响因素。研究发现，CEA控制器的下限值会影响控制开关过程，从而影响重复CF的概率。此外，最小伽马测量（MGM）单元使系统无法及时获取真实消光角，从而导致恢复过程中直流电流波动。此外，当高压直流逆变器接入弱交流系统或交流故障不严重但未及时清除时，控制诱发重复CF的概率要高得多。在上述分析的基础上，提出了一种改进的控制方法来提高回收性能，该方法主要通过修改CEA控制器在回收过程中的下限和上限来实现。最后，仿真和实验结果验证了理论分析和提出的控制方法。
In a line-commutated converter based high-voltage direct-current (LCC-HVDC) system, the inverter control system usually includes constant extinction angle (CEA) controller, constant current (CC) controller, current error controller (CEC), and voltage-dependent current order limiter (VDCOL). However, the interaction influence of multiple controllers may cause repetitive commutation failure (CF). For this purpose, this paper deeply investigates the mechanism and the influencing factors of repetitive CF caused by controller interaction. It is found that the lower limit value of CEA controller can affect the control switching process and thus the probability of repetitive CF. Besides, the minimum gamma measurement (MGM) unit prevents the system from acquiring the real extinction angle in time, which results in the DC current fluctuation during the recovery process. Moreover, the probability of control-induced repetitive CF is much higher when the HVDC inverter is connected to a weak AC system or the AC fault is not serious but not cleared in time. Based on the above analyses, an improved control method is proposed for recovery performance improvement, which is mainly realized by modifying the lower and upper limits of the CEA controller during recovery. Finally, the simulation and experimental results verify the theoretical analyses and the proposed control method.