Small and large scale solar photovoltaic energy generating systems have been observed to take a leading place in power systems around the world which are aiming to move away from the use of fossil fuels. Technical and other challenges associated with such systems have become the focus areas of discussion and investigation in recent years. Among a range of technical challenges, power quality issues associated with the power electronic converters, especially the harmonics, are an important aspect in order to ensure that their stipulated limits are maintained. While harmonics caused by small-scale inverters, for example, those used in rooftop systems, are managed through their harmonic current emission compliance requirements, the harmonics caused by large scale inverters used in solar farms need to be managed at network levels which is essentially the responsibility of the network owners and operators. To be successful in this management process, the relevant generator connection require
With the growing number of grid connected solar farms, management of power quality has become an important task for the proponents of such solar farms and the network owners and operators. One major concern is the harmonic compliance at their Point of Connection, particularly at low order harmonics up to the 50th considering relatively low switching frequencies (e.g. 3 kHz) of the large inverters used in these solar farms. Norton/Thevenin models are commonly used as inverter harmonic models to determine the harmonics injected into the grid. Employing software models of inverters and their control systems, harmonic injection method is widely used to determine the parameters of these Norton/Thevenin models at specific harmonic frequencies of interest, as an alternative to experimental determination of such parameters. This paper gives a methodology for the determination of these parameters mathematically using the details of the inverters and the control system thus making the approach a