To the railway power transmission lines, they are narrow and long,  with long distance power supply,bad environment, and frequent accidents, especially in mountainous areas, jungles and river networks, and inconvenient traffic. Once the line fails, it is very difficult to find the fault point and maintain, with high labor intensity and long time to restore power supply, which will seriously affect the reliability of power supply. The main way to change this situation is to improve the quality of sequential equipment products and improve the automation level of the existing power system, especially the use of power telecontrol technology and self-closing/through-line automation technology. Under normal conditions, it can realize the automatic monitoring and control of power system and line; In case of fault, it can automatically detect the fault and automatically determine the fault location, realize the automatic isolation of the fault section through line segmentation, quickly restore the power supply of the non fault section, reduce the power outage scope, reduce the power outage time, and improve the power supply reliability, so as to meet the needs of safe, reliable and efficient operation of the train.

  The operation of railway power through line is to segment the longer power supply line with switches (generally in stations), and then install switch monitors for each section switch. FTU will automatically monitor the switchgear, and cooperate with the dispatching master station to complete line fault detection, fault location and automatic isolation of fault line segments and rapid restoration of power supply of non fault line segments. The railway system distribution automation terminal FTU is installed on the outdoor pole, and the surrounding electromagnetic environment is relatively harsh. Due to the long outdoor wiring line and the relatively large induced lightning current, it is necessary to install an Anhui Jinli Electric surge protection device inside it for lightning protection to ensure that the FTU and the entire distribution automation system can still operate safely in thunderstorms.