ACCURATE THERMAL MONITORING BY SENSOR EMBEDDED IN SWITCHGEAR BUSHING

Thermal monitoring of Medium Voltage (MV) connections is an important indicator of component failure and component service requirements. It allows maintenance scheduling to avoid product failure and thus minimizes or avoids down time as well as prevents further consequential losses, damages, costs and possible human injury. Focusing on Gas Insulated Switchgears (GIS) cable terminations and bushings, the conductor is hardly accessible, and it is difficult to monitor its temperature. By choosing external temperature sensors installed on the MV cable termination surface, the estimated conductor temperature is not accurate and can be improved together with the measure dispersion. In this work, a thermal monitoring innovative solution for MV GIS cable terminations is presented, it embeds the thermal sensor in the bushing and uses a reliable model of the heating transfer function to provide a robust and more accurate conductor temperature estimation. This solution is fully independent of the MV type of cable termination (shielded or unshielded) and no on-site intervention is required during installation since this architecture is fully installed and tested in the switchgear manufacturing plant. Moreover, the Zigbee Greenpower wireless communication protocol allows fast and easy integration in switchgear architecture and data management ecosystem.