When the traditional overhead distribution lines short circuit fault, generally by the substation feeder circuit breaker protection tripping exports, and through the artificial removal of fault, restore power. In this way, the staff of maintenance of large and long power outages, low reliability. Existing distribution automation in general is based on the voltage time type FTU, does not depend on communication, when a fault occurs, still the substation feeder breaker tripping exports through cooperation between the FTU time constant by coincidence , to achieve the automatic fault recovery. This way, if a permanent fault occurs, and the fault occurs in the end, will result in the distribution network and the user equipment repeatedly shorted impact, but a longer recovery time, reliability of power supply is still low. Features improve fault isolation and recovery speed: In order to ensure rapid system by Smart DTU device in situ dynamic decisions quickly realize automatic fault recovery, effectively reducing the feeder outlet switch and disconnect switches action times, great shorten the outage time. Strengthen the reliability of system operation: In order to improve system reliability, master FTU is dynamic, when the original owners FTU failure, the lowest number in other FTU one can automatically replace the original master FTU, achieve FTU coordination function. System based on wireless communications operation. Under normal circumstances the communication, the master FTU able to accurately locate the point of failure, and through the pre-control strategy for rapid fault isolation and recovery, avoiding the voltage time type FTU several attempts of overlap, reducing fault recovery process several attacks on the system; in the case of a communication error, the device automatically according to the traditional time-of FTU voltage logic operation. Stage II of the system by nearly back-up protection, combined with the circuit breaker to protect the feeder outlet, bus protection, transformer protection, to achieve a grid substation and feeder protection of all kinds of synergies, but the system also includes a reclosing, splitting, reconstruction and other functions, and improve the self-healing smart distribution grid system to improve the quality of power supply distribution network. Provides powerful analysis capabilities: background monitoring system including system operation monitoring function, system maintenance functions, disconnect switches four remote functions, as well as backstage assisted analysis. Monitoring refers to monitoring under the normal system maintenance functions include feeder topology maintenance, control configuration policies, computing and online valuation hair down, etc., and backstage scenes assisted reproduction failure analysis capabilities include system operation behavior analysis. During operation, the system can process information troubleshooting, including the type of fault, the fault current, voltage, DTU status, communication status, segmented switch status, upload background monitoring system or distribution automation system, to achieve fault monitor the whole process of treatment and post-hoc analysis, to facilitate troubleshooting personnel exclusion, shorten the processing time accident. Reduce system maintenance: background monitoring system that provides distribution feeder topology maintenance tool that can facilitate the realization of topological online DTU device maintenance, and realize all kinds of setting value calculation, checking and online hair down, system maintenance a small amount. The system does not require distribution automation and substation distribution network master sub-station system involvement, autonomy can coincide with fault isolation and network fault recovery, installation is simple to implement, less maintenance, easy to be widely used. Strengthen investment income ratio: wireless GPRS communication is the standard overhead linear line configuration of the wireless communication system requirements do not increase investment. When capitalized, the use of fiber-optic communications and breaker segments, obtain the ideal protection selective and intelligent fault handling characteristics; when funds are tight, you can use GPRS private network, wireless bridge to establish communications networks, load switch as a sub segment means, but also to establish local intelligent FA, to achieve fast fault isolation and smart recovery. However, reducing the selectivity of fault isolation. Enhanced flexibility of deployment: for city, county and medium-sized industrial and mining enterprises in the power company or the reliability of the power supply that demand high linear overhead distribution lines. The system supports a variety of feeders topologies, including hand in hand, a single power supply and multiple power supply line.