Design of Switched Capacitor-Based Interfacing Circuit for Lossy Capacitive Sensor in Power System Monitoring

Precise measurement of capacitance for a lossy capacitor (LC) is a challenging task using sensor monitoring systems. In this chapter, a well-suitable low-cost interfacing circuit is designed and presented for lossy capacitive sensors for the measurement of the accurate capacitance value of the lossy capacitor. Mostly of capacitive sensors are lossy in nature where the sensor's resistance varies significantly with the capacitance value. As a result, measuring the parameters of an LC sensor accurately is a difficult approach. The key objective of this paper is to design an electronic interfacing circuit for the modified type of capacitive-based sensor in order to avoid the effect of lossy parameters on the actual value of capacitance. Further, this study uses different observations to extract the actual capacitance value. The circuit is based on the Switched Capacitor Integrator (SCI) concept, with a comparator for comparing the change in output by varying the capacitive sensor's capacitance and their lossy parameters (lossy resistance and parasitic capacitances). This chapter calibrates the output of the comparator voltage wave pulse with the capacitive sensor's capacitance value for power system monitoring.