A Model to Simulate the Influence of Humidity on a Voltage Sensor used for Overhead Line Indicators

Fault localization in power supply networks is a central and important task for network operators. In this context, earth faults form a significant proportion of faults in distribution networks. In solidly grounded or isolated networks, reliable detection and localization of the fault is already state of the art. Fault direction detection of single-pole faults in compensated networks, especially in overhead line networks, poses challenges for network operators. In many cases, the overhead line indicators used in overhead line networks do not detect the voltage with sufficient accuracy to determine unambiguous fault directions. In this paper, the influence of climate, especially humidity, on a voltage measurement method for overhead line indicators is analyzed. Extensive climate chamber measurements are performed, which form the basis for the development of a simulation model to simulate the influence of humidity. The theoretical model explains the physical influences of humidity on the voltage measurement of overhead line indicators. With this knowledge recommendations for the design of overhead line indicators with lower susceptibility to interference in the presence of moisture may be optimized.