Current partial discharge detection and positioning of substation equipment are mainly carried out for single piece of the equipment such as transformer and switch cabinet

which is of high cost

low detection efficiency

and large workload. This paper proposes a substation partial discharge monitoring method based on ring topology. In this method

only UHF monitoring terminals are installed on a single device

the monitoring terminal is connected to the ring signal line

and the time interval of the partial discharge signal bidirectionally transmitting to the signal acquisition system through ring signal line is used for location

therefore one monitoring device can realize partial discharge monitoring and preliminary positioning for multiple devices in the substation. The attenuation characteristics of UHF signals in coaxial cable are analyzed

and the partial discharge monitoring system with ring topology is used to build a partial discharge test platform for simulation test. The results show that the proposed substation partial discharge detection method based on ring topology can realize detection of partial discharge signals and preliminary positioning of partial discharge sources

and its popularization and application are easy.