Dielectric Losses of Power High Voltage Cables in a Wide Frequency Range

Abstract

A design feature of polymer-based high-voltage power cables is the presence of semiconductor shields along the conductor core and insulation to equalize the electric field on the core surface and reduce the electric field on the insulation surface. An important role in the development of power electric cables is played by research on the influence of semiconductor shields on the effective tangent of the dielectric loss angle of a three-layer insulation system, especially in the high frequency region. This is primarily due to the intensive development of networks using renewable voltage sources and the emergence of transients in such networks. The propagated surge pulses contain a wide range of components of different frequencies, which necessitates the determination of the frequency characteristics of the effective tangent of the dielectric loss angle of power cables. Experimental studies of cross-linked polyethylene-insulated cables in the high-frequency region prove the importance of semiconductor layers in determining the equivalent value of the dielectric loss tangent of the three-layer composition dielectric loss. Mathematical and physical simulations performed over a wide frequency range prove the significant influence of the thickness and electrophysical characteristics of semiconductor screens on the resulting tangent of the dielectric loss angle of high-voltage power cables. The presented algorithm for determining the effective tangent loss of a three-layer composite system is the basis for developing recommendations for reducing additional dielectric losses in a wide frequency range due to semiconductor coatings at the technological stage of manufacturing high-voltage polymer cables.