Estimation of Power Losses Caused by Supraharmonics

Alexander Novitskiy,Dirk Westermann,Steffen Schlegel,V.A Stennikov,J.-Y Yoon,N.A Yusifbeyli,S.V Alekseenko,F.-J Lin,C Rehtanz,P Changwei,S.P Filippov,N.I Voropai,M Negnevitsky,B Sereter

doi:10.1051/e3sconf/202020907008

Abstract

Nowadays increases the number of power electronic devices in distribution electrical networks rapidly. Modern generation and consumption units use high switching frequency power converters for the network connection and therefore cause the voltage and current distortion in the frequency range over 2 kHz (so-called “supraharmonics”) in addition to conventional harmonics. Supraharmonics cause additional power losses in electrical equipment. The goal of the offered paper is the estimation of power losses caused by supraharmonics. The estimation is based on the measurement results obtained in a real MV/LV network in Germany.

Highlights

The increase in the number of power electronic devices in distribution electrical networks is the characteristic trend in the development of electric power supply during many years
The results of the analysis show that supraharmonic power losses can exceed 10% regarding the power losses caused by conventional current harmonics in the MV cable under study
Method of the supraharmonic power losses estimation combining the analytic determination of AC cable resistances at the supraharmonic frequencies with the use of measurement results of supraharmonic currents in a real MV/LV cable network was considered in the paper

Summary

Introduction

The increase in the number of power electronic devices in distribution electrical networks is the characteristic trend in the development of electric power supply during many years. In [1,2,3] is shown that additional power losses in LV cables and HV transmission lines caused by conventional current harmonics can be up to 30% regarding the power losses at the fundamental frequency. The influence of supraharmonics on the additional power losses can be illustrated using the simplified assumption that the values of the line conductor resistances are proportional to the root of the frequency [2,3,4,5]: Rsh = R1. The dependences (2) are presented in Fig. 1 for some ratios of Ish / I1

Measurements of supraharmonics

Analytic calculation method

Numerical calculation method

Use of measurement results for the supraharmonic power losses estimation

Findings

Summary