Frequency and Temperature-Dependent Power Cable Modelling for Stability Analysis of Grid-Connected Inverter

This paper presents a RLC circuit model of long transmission cable (LTC) with consideration of frequency and temperature-dependent characteristics. Per-unit-length (p.u.1.) impedance of the LTC considering frequency-dependent characteristics are first calculated and fitted by Vector Fitting (VF) algorithm. Then, the fitted model of the p.u.1. impedance is represented by a Π section, which consists of a series of RL branches and two parallel capacitors. Impedance model of LTC with arbitrary length can be established by cascading several Π sections. In addition, the effect of ambient temperature variation on electrical performance of LTC are investigated. Simulation results show that the proposed RLC circuit model is able to reveal practical frequency and temperature characteristics, which may be used to investigate effect of power cable on stability of grid-connected inverter.