A new fault monitoring and location system for overhead distribution networks

摘要

A new fault monitoring and location system is available for load monitoring and fault detection of overhead distribution lines. Acquisition units (AUs) are mounted on all three phases and communicate with a data collection unit (DCU) at the bottom of the pole using short-range wireless communications. The DCU communicates with a remote master station through the mobile network, thus forming a complete fault monitoring and location system for the distribution network. The system provides high speed sampling of three-phase voltage and current signals through innovative sensors, the samples are synchronized through communications by the DCU. When a fault occurs, disturbance records are sent by the AUs to the DCU, so that zero sequence components can be calculated. This feature allows the system to detect high impedance earth faults. High speed sampling also allows transients of the signals to be derived, so that the system can be applied to unearthed and compensated networks. For such networks the earth fault current magnitude is insignificant, but there is a dominant transient signal which can be used to identify the faulty line and the faulty section. The technology used in this system and the transient-based fault detection technique are detailed in this paper. Staged fault tests were performed on a feeder with compensated earthing. Actual site fault records were also obtained. The results are presented.