地铁中压环网数字通信过电流保护方案研究

过电流保护作为地铁中压环网的后备保护，存在级差难以配合的问题，导致保护无选择性。为解决这一问题，提出一种改进方案，即数字通信过电流保护。该方案对中压环网各进出线开关均配置数字通信过电流保护装置，该装置具备通信功能和可编程的逻辑处理功能，相邻装置间通过数据通道对相应信息进行传输和比较，从而对故障信息进行判断。通过对环网不同位置发生的故障进行分析，对方案原理及实现方法进行详细介绍，证明该方案能够准确判断故障范围，并动态调整保护装置的动作时限，能够解决过电流保护的级差配合问题，保证过电流保护的选择性和速动性。

Study on Digital Communication Overcurrent Protection Scheme of the metro medium voltage ring network

Overcurrent Protection, as backup protection of the metro medium voltage ring network, is hard to handle with time coordination, leads to no selectivity. To solve the problem, an improved scheme, Digital Communication Overcurrent Protection, is proposed. This scheme, which takes advantage of the communication and the logical processing function of the overcurrent protection device, can accurately judge the fault location and change the action time of protection device dynamically, it can solve the problem of time coordination, to ensure selectivity and speed of the overcurrent protection. Through the analysis of several ring network faults, the principle and method implemented are introduced. The communication mode and the protection setting under the condition of communication fault are also explained.