ASSESSMENT OF POWER LOSSES IN A CONDUCTIVE CORE FROM TRANSIENT CURRENTS WHEN THE CABLE IS AFFECTED BY VOLTAGE WITH INTERHARMONICS

Abstract

A computer program (CP) has been developed in the LabVIEW environment to estimate the power loss from transient currents in the conductive core of a single-phase power cable (SC) when exposed to voltage with interharmonics (IH). The CP allows one to study the influence of the parameters of each IH included in the applied IH voltage. The parameters of the IG are the specified frequencies, amplitudes and initial phases. The basis of the CP is the computer model of the SC, which can be obtained from its mathematical model (MM), developed according to the equivalent circuit (EC) of the power cable in the form of a homogeneous chain circuit (HCC). The CP is designed in such a way that it is possible to investigate the influence of non-uniformities in the SC insulation on the course of the transient process of current and voltage at the SC input, which allows diagnostics of the SC state. In the latter case, the SC equivalent circuit is represented by a non-uniform chain circuit. The final part of the paper presents the results of a numerical experiment (NE), It is taken into account that the amplitude of interharmonics rarely exceeds 0.5% of the amplitude of the fundamental frequency oscillations. The CE showed that the magnitude of power losses in the cable's conductive core from transient currents depends on the composition and initial phase of the interharmonic component of the applied voltage and how interharmonics can affect the nature of the transient process in circuits with distributed parameters, which include the SC.