HVDC换相失败影响因素分析

Analysis on Influence Factors of Commutation Failure in HVDC

换相失败是直流输电逆变侧的常见故障,为分析引起换相失败产生的原因,以及各种因素对产生换相失败的影响程度,从最基本的换向过程出发,分析了影响换向失败的因素为交换电压降低,直流电流增加等以及减少换相失败的措施。通过对两个直流工程的实例分析,揭示了换向失败通常是因为检测交流电网扰动和换流阀误触发、未触发。

As one of the most common faults in HVDC system , commutation failure would be affected by many factors, such as AC bus voltage in converter station, advance firing angle and the control mode of valve firing pulse, etc. So, it is very important to analyzes the reason of commutation failure and the effects of these factors on the commutation failure in HVDC transmission system. Some HVDC system parameters which relate to commutation failure are analyzed in this paper in order to unveil the relationships between commutation failure and those parameters. Since the commutation failure is not a real fault, and it is reflection of other faults. The purpose of the protection is to detect commutation failures in the twelve-pulse converter that are caused from AC net disturbances or other abnormal commutation conditions. According to the different fault type, the protection consequences are different. This paper also makesa concrete analysis of the protection purpose, range, principle and configuration in Zhengping converter station in the Long. Zheng HVDC transmission system. At last two TFR（ transient fault recorder） chart are researched as exxample of commutation failure to give out the general rules of commutation failure.