针对现行地铁供电系统保护方案在应用过程中暴露出的一些不足，提出一种以智能变电站GOOSE网络通信技术为基础的数字电流保护方法，并详细介绍其动作逻辑、组网方案、硬件系统设计及应用情况。通过比较发现，相对于其他地铁网络保护方法，数字电流保护方法通过合理运用IEC61850技术和最新软硬件技术，在可靠性和稳定性方面得到很大提升。利用Smartbits测试仪和RTDS仿真系统，对数字电流保护方法进行试验验证。该保护方法已经在南京地铁的部分线路中投入运行，并在多次故障中正确动作。

With the shortage of the present normal current protective relay being taken into account，a new digital network over current relay was proposed based on intelligent transformer substation and GOOSE network． The action logic，network and hardware were illustrated in detail． Compared with other metro network protection methods，the digital network over current relay method has improved greatly in terms of its reliability and stability by reasonable use of IEC61850 technology and the latest hardware and software technology appropriately． The effectiveness and correctness of the digital network over current relay is verified by the simulation system of ＲTDS and Smartbits tester． The protection method has been used in part of Nanjing subway lines and corrected action responded in multiple faults．