Harmonic Emission of Large PV Installations Case Study of a 1 MW Solar Campus

Abstract

Extensive measurements were carried out at a 1 MW photovoltaic (PV) installation with focus on the analysis of harmonic emission both for classical harmonics below 2.5 kHz and higher frequency emission in the range of 2-150 kHz. The installation consists of multiple inverters with different rated power. Beside the measurement of total emission of all inverters, in one part of the measurement the inverters were switched off and on stepwise following a predefined schedule. This provides a comprehensive basis for a detailed characterisation of the interactions between the inverters in terms of harmonic emission. After a description of the measurement setup the paper discusses the total emission of the installation, the dependency of the emission on the supply voltage distortion and the potential of harmonic cancellation due to phase angle diversity between the different inverters. The results enable a better understanding of the harmonic emission behaviour of large PV installations. The paper is intended to be an contribution to the development and improvement of respective harmonic models.