Improved Procedures for Determining Harmonics - Findings of the German Research Project NetzHarmonie

Conference paper

18th Wind Integration Workshop

Authors

Larissa Ziemann

Omid Edalati

Jens Rauch

Marko Muehlberg

Rainer Klosse

Farhad Safargholi

Max Hoven

Hendrik Vennegerts

Jan Meyer

Max Domagk

Kaveh Malekian

Fritz Santjer

Published

October 1, 2019

Location: Dublin, Ireland
Links: Link
Abstract: The purpose of the project “NetzHarmonie” was to improve the procedure for determining harmonic emission of power generating units and systems (PGU / PGS). Additionally, to enhance the evaluation methods and respective harmonics models and to determine possible attenuation effects of multiple harmonic emissions. These findings are the basis for improvement of thresholds and assessment procedures. Further aspects have been investigated, e.g. the use of PGU and PGS for an active harmonic management in order to improve voltage quality within the grid. The fundamentals of the harmonics analysis and assessment have been methodically investigated. The issue of active harmonics interference was also researched. Measurement campaigns to obtain measurement data for PGU, PGS and network nodes were carried out and measurement procedures as well as measurement data were analyzed. Important findings are: e.g. measurement guidelines for synchronous measurements of harmonics, measurements of the frequency-dependent grid impedances for MV and LV grids, analyses of a wide range of details such as the evaluation procedures for dispersion and overlay effects and determination of damping and summation effects. Harmonic models for PGUs have been improved and validated, from which PGS models were created to replicate harmonics and implemented in two PGS grid models. Conditions for successful simulations of grid impedances or harmonic levels were formulated across the grid. In the area of modelling, measurements as well as analysis a number of issues emerged, that indicate more complex relationships than were anticipated by the participants. The results have been fed into working groups of national and internarial standards (e.g. FGW TR 3 and FGW TR 4) and will be implemented in future editions. Due to the publications and presentation of these in workshops the results may have already some impact on determining and analyzing harmonics and therefore on preventing problems as well as on grid connection capacity.