Thermal wear of cable lines isolation research owing to current flow of the high harmonics at oil extraction electrical generating systems

Abstract

Field observation results of current and voltage higher harmonics levels, flowing in electrical power supply systems cable lines of electric centrifugal pump units are given. The mathematical representation of the stationary thermal field calculation in underground three-phase cable lines 0,4 kV and the surrounding environment as backfill and natural soil during non-sinusoidal currents flow is developed. By means of finite-element method numeral computations is shown that cables heating in no small part is defined by soil heat conductivity. On the basis of thermographic inspection and virtual modeling in the software package ELCUT the thermal effect of cables isolation additional heating buried in backfill or natural soil of non-sinusoidal currents flow is shown. The developed technique could be used when determining output capacity of the designed buried service cable lines taking into account influence of the current and voltage higher harmonics and soil characteristics.