文章从子网连接保护(SNCP)的原理入手,通过常见故障现象,分析故障产生的原因,介绍了典型故障处理案例,总结了SNCP保护倒换故障定位与排除的常用方法。 This paper starts with the principle of subnetwork connection protection (SNCP), analyzes the causes of faults by common faults, introduces typical troubleshooting cases, and summarizes the common methods of locating and eliminating SNCP protection faults.