青藏联网工程VCU系统异常导致双极换相失败分析

青藏联网工程正常运行期间，出现VCU（VMve Control Unit-阀控单元）光收发PS906异常，点火系统不能正常运行，PcP极控系统请求切换，导致换流阀不能正常导通，发生双极换相失败。在介绍青藏联网工程VCU的控制逻辑的基础上，详细分析了VCU故障导致换相失败的原因，并提出将相应设备接口环节双重化及PS900板卡A／B系统接入不同的PS912背板，避免阀组因单一的设备接口故障而引起直流系统故障，提高直流系统运行的抗干扰性和稳定性。

Failure Analysis of Bipolar Commutation Failure Caused by the Anomaly of the VCU System in the Qinhai-Tibet Interconnection Project

During the operation of the QinghaiTibet Inter connection Project, an anomaly occurred to the S906 transceiver of the VCU（Valve Control Unit）, leading to failure of the igni tion system. The PCP pole control system requested switching, thus the converter valve was not able to break over, finally causing failure of the bipolar commutation. On the basis of presentation of the VCU control logic used in the project, this article presents a detailed analysis of the causes for the VCU commutation failure, and proposes to double the appropriate device interface and insert different PS912 backplane for the A/B system of the PS900 board so that the system failure caused by a single device interface system failure can be avoided and the interference immunity and stability of the DC system be improved.