The reason for using optical fiber to transmit data is that it can realize the electrical isolation and reliable insulation of the first and secondary equipment in the strong electric environment, and the wired fiber link can guarantee the high reliability and real-time performance of the data transmission. We use self-developed low-power high-speed fiber head, can guarantee the stability of the signal transmission distance up to 20 meters. Compared to ordinary fiber head of 3 meters transmission distance, it not only greatly enhances the performance and also is well suitable for ring main unit, switch Cabinets and other field installation environment.