Variations of supraharmonic emissions in low voltage networks

Abstract

This paper describes and presents measurements of supraharmonic emission in low voltage grids in Europe, North America and Asia. One-minute average values for 2 kHz grouped components are given and a total supraharmonic distortion (TSHD) value is calculated for the frequency band 2 to 150 kHz. Statistical analyses are performed, investigating the site and time dependency of supraharmonic voltages. Results show that the average values are, with a 90% confidence within an interval of 0.09-0.56% of fundamental (FND) but higher values can occur. Based on analyses of these measurements some early conclusions can be drawn:Supraharmonic emission are present in low voltage gridsThe magnitudes and frequencies vary between sites and over timeThere is a daily pattern but also some randomness when supraharmonics appear