A Sensitive Surface Acoustic Wave Sensor for Monitoring Humidity for Substation Application

Abstract

Humidity sensor is required to monitor the moisture level in the environment of substation and switchgear protection system. High humidity causes failure of the electrical apparatus in the protection yard. Simple inexpensive miniature humidity has been fabricated to monitor the humidity level in the switch gear and protection system. The sensor has been fabricated by depositing hydrophilic hydrogel film of polyvinyl alcohol on the surface acoustic wave device with resonating frequency of 433.92 MHz. Response characteristics of the sensor have been studied with vector network analyzer with the variation of humidity from $\sim 0$ to 99%RH. The sensitivity below 30%RH is suitable for gas insulated substation application.