Design of on-line monitoring device for MOA used in 10kV distribution network

Due to low cost and small failure effect, monitor of MOA used in 10 kV distribution network is always ignored. However, with massive application, wide distribution, and difficulties in failure positioning, it is necessary to monitor MOA used in 10 kV distribution network. In accordance with the actual state of MOA monitoring in China, a kind of on-line monitoring device is conducted. This device investigates the resistive component of leakage current, and the monitoring reliability is greatly improved compared to the method detecting full current. When the resistive leakage current detected reaches the set threshold, the device will give a sign of both mechanic motion and luminescence indicating the failure. Protective measures against over-voltage and misoperation are also considered. From spot operation results, this device can effectively decrease the economic loss caused by overhauls and black-outs, and improve the power-supply reliability of distribution network.