Parameter estimation technique for the semi-conducting layers in single-core XLPE cable

Partial discharge (PD) detection and location is of great significance for the power cable insulation condition monitoring, where the high-frequency (HF) model is needed to analyze PD propagation. Considering the influences of conductor skin effects and semi-conducting layers (SCL), this paper presents the equivalent ¿¿-section lumped parameter model for single-core cross-linked polyethylene (XLPE) insulation cables. The longitudinal parameters per-unit-length in the model are obtained using available geometric data by vector fitting method. Unfortunately, the dielectric characteristics of SCL in XLPE cables, especially for an installed one, are usually unknown and hard to measure. To address this issue, based on the simulated annealing algorithm, an optimization approach for estimating the transversal parameters in the ¿¿-circuit model is developed. The proposed technique is then carried out on the XLPE cable with simulated and real SCL, respectively. Furthermore, the estimation results of the real case are validated on a 603 m cable with kinds of HF pulses responses.