故障行波特性对光纤差动保护时延的影响分析

Influence on the optical fiber differential protection delay based on characteristic of fault traveling wave

电力系统差动保护对保护两侧电气量数据传输的实时性提出了更高的要求,过大的时延将会影响数据的同步精度从而造成差动保护误动或拒动。在实际运用中,必须充分考虑保护通道时延问题。而在特高压远距离输电系统中电气量的时延效应不容忽视,传统的时延分析方法没有考虑到电气量的行波效应。综合考虑了自故障发生到保护完成故障判断的过程中,电气量行波和光纤信号在各个环节的时延效应。由于故障发生的位置不同和光纤通信设备之间的差异性导致了总时延的不确定性,并通过三种随机型分布的概率时延模型来反映总时延的差异,并对结果进行了比较和分析。结果表明正态分布模型更适合时延分布规律,总时延可以作为保护装置的选型优化和两侧数据同步提供依据。最后运用正态分布模型对广域保护通信结构时延与网络节点的关系进行了分析。

The differential protection of power system puts forward higher requirements on the real-time data transmission for double terminals＇ information. Larger transmission delay is likely to influence the synchronization precision and cause the refusing act and incorrect operation of relay protection. So the channel delay problem must be given full consideration to protect in practical application. But the delay effect caused by electrical measurement cannot be ignored in UHV long-distance transmission system, the traditional method of delay analysis without considering the effect of electric parameters as traveling wave. This paper considers the process from the failure happening to the protection completing fault diagnosis, and the delay of electric parameters traveling wave and the optical signals in each link. Different fault location and communication equipment lead to uncertainty of channel delay, then through three kinds of random distribution of delay model are used to reflect the differences in total delay and the results are compared and analyzed. The result shows that normal distribution is more suitable for delay distribution, research conclusion can be applied in optimal selection of protective devices and data synchronization on both sides. Finally, the relationship between the delay of communication and the network nodes is analyzed by using the normal distribution.