Coupling Characteristics and Optimal Design of High-Frequency Electromagnetic Couplers

Due to the long-term continuous operation of power cables, defects or faults are prone to occur in the cable body. Each time the line resonance analysis method (LIRA) is used to detect the defect location of the cable, power outage for several days is required, which will cause great inconvenience to people's daily life. This paper aims to solve this problem and innovatively proposes the use of high-frequency electromagnetic couplers in conjunction with the detection of cable lines, aiming to achieve online monitoring of power cables. However, the design and optimization of the coupling sensor is the key to achieving high-precision measurement of wideband impedance spectra. This paper focuses on the selection of material parameters for the magnetic core of the high-frequency electromagnetic coupler. Based on numerical calculation and circuit equivalent models, the COMSOL simulation software is used to model the electromagnetic coupling process and simulate the electric and magnetic field distributions between the sensor and the power cable. Finally, through experimental tests on the prototype sensor, it is verified that the prototype magnetic core has excellent coupling performance for high-frequency signals carrying cable information and can effectively reflect the impedance changes caused by the cable structure, providing a reference basis for real-time monitoring of cable defects based on LIRA.