Novel Temperature Sensing for Switchgear Bushings Based on the Built-in Capacitive Coupler

Due to the effects of climate change and the increasing reliance on renewable energy sources, medium-voltage switchgears as part of the distribution grid are facing an increasingly higher level of stress. This is particularly true for cable connections within these switchgears. A defect e.g., caused by a wrongly executed installation, leads to a temperature increase and a potentially damaging failure. Therefore, temperature monitoring of these connections can be an essential tool to detect an issue. However, a widespread application of external sensors would cost money and manpower. As an alternative, this paper proposes a capacitive coupler's output signal to extract approximate temperature information. Since smart short circuit indicators already utilize the output of capacitive couplers, this approach requires no additional hardware. To analyze the idea, a virtual testbed of a switchgear's connection, based on laboratory measurements, is created. This virtual testbed is then combined with current and voltage information from SimBench scenarios. This results in a virtual dataset that captures various grid behaviors, enabling thorough testing and validation of this non-conventional temperature failure detection approach.