The Propagation of High-Frequency "Supraharmonic" Disturbances Through Low-Voltage Grids

Abstract

The recent increase of inverter-based devices like
Electric Vehicles and Photovoltaics increases the supraharmonic
emission in LV-grids, potentially affecting customer-equipment
and grid-assets. This paper aims to give an overview of
the different factors influencing supraharmonic emission and
studies the propagation of supraharmonic currents through
a small low-voltage grid. Measurements in a lab, either in
micro-grid or connected to the public grid, gave valuable
insight on primary and secondary supraharmonic emissions
from individual devices, and the propagation of them.
Emission is for some devices influenced by the grid connection,
whereas others show no difference in emission. The
supraharmonic currents mainly stay within the installation, due
to local absorption. Depending on the impedance, the voltage
can be distorted with supraharmonic components. During measurements,
several effects (phenomena) including ”frequency
beating” and intermodulation distortion are observed and
further analyzed in order to understand interaction between
devices. Finally some recommendations for further research
are given.

Date of Award	15 Aug 2019
Original language	English
Supervisor	J.F.G. (Sjef) Cobben (Supervisor 1) & V. Cuk (Supervisor 2)