In view of the fact that the actual operation information of sub-station relay protection device and the point table information of relay protection fault information system are still manually point-by-point proof reading. There are still problems such as l. In view of the fact that the actual operation information of sub-station relay protection device and the point table information of relay protection fault information system are still manually point-by-point proof reading. There are still problems such as low automation, long test time and low point-to-point debugging efficiency of the relay protection fault information system. This article proposes the full-link automatic test technology of the relay protection fault information system, and expounds its principle, main modules and key technologies. The full-link automatic test platform of the relay protection fault information system includes three parts: the main station remote test module, the sub-station test management module and the automatic test module. There are organically combined to realize the remot. Main stationSub-stationFull-linkSpacer layerWhen a power grid fails, it is necessary to grasp the fault data timely and accurately in order to quickly judge, deal with and recover from the accident. The relay protection fault information system (PFIS) provides a reliable basis for analyzing and dealing with power system faults, and improves the information and intelligence level of the dispatching system to ensure the safe operation of the power grid,,. With the large scale of the power grid and the complexity of the power grid fault, the role of PFIS is more important. The point-to-point testing of PFIS information is complex. At present, the point-to-point testing of PFIS is mainly carried out through the joint debugging of the main station and sub-station. Such tests usually convene multiple main station and sub-station manufacturers to perform on-site access. This paper analyzes the advantages and disadvantages of the current research results, adopts the latest digital sub-station IEC61850 modeling technology—modular software technology design. The test center is arranged in the main dispatch station, carries out remote control with the help of dispatching data network, and carries out the overall unified test of the whole link in the order of main station and sub-station space layer device. The whole process intelligent automatic point-to-point method is used to solve various non-standard problems in the point-to-point process of relay protection, and improve the efficiency and quality of on-site point-to-point work.The full-link automatic test module of the PFIS is divided into three layers according to the tested main station and sub-statio. 3.1. Extension of state grid 103 protocolThe State Grid 103 standard protocol does not support point-to-point debugging of protection information devices one by one, and cannot be directly used for point-to-point testing of PFIS. In response to this situation, this article proposes an extension to the State Grid 103 protocol based on the construction of the PFIS, and expands the protocol on the basis of the State Grid 103 standard protocol, so that the extended 103 protocol can realize the point-to-point test of the protection device.In the 103 communication protocol, the type identifier (TYP) is a unit with a length of 8 bits. The 103 protocol uses this domain to identify different message types during the interaction between the main station and the sub-station. 1 to 127 of the type identi.