System of fault diagnosis and operation monitoring for low-voltage distribution equipment

WU Yu-hong，ZHANG Jian-sen

（State Grid Zhejiang Deqing Power Supply Company，Deqing 313200，China）

Abstract：Aiming at heavy burden and low efficiency of fault repairing for low-voltage distribution equipment of Deqing power grid，a method for fault diagnosis of low-voltage distribution equipment and design of operation monitoring system was proposed. Firstly，some data such as surface temperature of inlet-outlet line in the distribution box and the water level of cable trench were measured by using corresponding sensors integrated in the monitoring device for low-voltage distribution equipment，and data acquisition was realized by using short message terminal. Secondly，data operation，comparison and analysis utilizing the build-in equipment parameter of short

message terminal was performed. Finally，fault forecast/alarm messages synchronously were transferred through GSM and GPRS dualchannel wireless network. The results of the processing of the system indicate that the method realizes faulty forecast and real-time transmission of an alarm message for low- voltage distribution monitoring equipments. Meanwhile，auto- isolation and self- healing technologies for the power supply circuit of low-voltage distribution box about upper limit of temperature and water level have been invented. Consequently，the safeguarding level of public transformer in a rural area has been improved.