Non-Invasive Insulation Resistance Measurement for Passive Circuits Using a Non-Contact Voltage Excitator Allied with a Rogowski Coil

Insulation is a key factor influencing the security and performance of electrical and electronic devices and systems. To realize a non-inserted insulation resistance measurement required in some special situations, a non-invasive method which uses an electromotive force excitator allied with a Rogowski coil sensor is proposed. An operational amplifier circuit and a dual-path phase-sensitive demodulation (PSD) circuit are used to measure the insulation resistance. The measurement principle is firstly analyzed, and simulation is carried out with COMSOL Multiphysics and a circuit based on LTSpice to validate the effectiveness of the proposed method. The result shows a good performance, enabling reliable insulation resistance measurement within 300kΩ.