Research on S-Parameter Extraction and Equivalent Circuit Modeling of Multi-Port Busbars Based on Transmission Line Theory and Vector Fitting Method

Multi-port busbars in renewable energy systems present significant challenges for power line communication (PLC) due to their complex high-frequency characteristics. This paper addresses the research gap by developing a comprehensive modeling approach integrating transmission line theory, electromagnetic simulation, and experimental verification. The methodology establishes a 3D model using CST Studio Suite for S-parameter extraction in the 200 kHz-12 MHz band. It also proposes a novel vector fitting method to derive an accurate π-type equivalent circuit. Experimental results demonstrate excellent agreement with simulations, with transmission coefficient deviations within 0.1 dB-0.8 dB. The proposed model provides reliable component-level characterization for PLC system optimization in smart grid applications.