Accurate numerical method to evaluate the capacitances of multi-conductor power cables

•Capacitance coefficient matrix for a multi-conductor transmission line is computed.•The conductors sections are completely arbitrary.•The transmission line can be filled with heterogeneous dielectric materials.•Potential and charge densities at conductor’ surfaces are computed.•Results are compared with analytical calculations and experimental results.

This paper presents an accurate method to evaluate the capacitances of multi-conductor power cables. The method developed can also be applied to cables presenting multilayer dielectrics. Strips of charge are used to represent the electric charge distribution on conductors’ surface, as well as to characterize the polarization charge distribution on interfaces separating two different dielectrics. The advantage of using strips of charge is to preserve charge continuity along conductor surfaces and dielectric interfaces. This methodology is accurate since the proximity effects among conductors are taken into account. Validation of the method is performed comparing experimental, other software and analytical results with those obtained by using the proposed numerical method. A cylindrical non-concentric capacitor is used for the analytical validation and a three-phase power cable is used on experimental tests.