Investigation of the impact of PV generators on harmonic resonances in electrical power distribution systems

Abstract

Modern electric power distribution systems have migrated from a passive, non-supervised structure with low level of automation to an active and supervised structure, with high level of automation due to the introduction of photovoltaic generators, smart meters, and new automatic control and reactive power compensation devices. In the case of photovoltaic generation, for example, the world installed capacity reached around 1 TW, and, in Brazil, there are more than 1,000,000 units in operation, achieving more than 11 GW. In terms of new compensation equipment, compensators are currently commercially available employing series capacitors for medium voltage networks and shunt capacitors for low voltage networks. Despite the technical and environmental advantages of this change, with the introduction of these emerging technologies, new challenges and technical issues may arise. As several of these technologies employ electronic converters with a network interface, not only there is a possibility of harmonic current injections, but there is also a risk of poorly damped or unstable harmonic resonances due to the interaction with the reactive power compensation elements. In this context, the objective of this project is to investigate the risk of harmonic resonances in medium and low voltage distribution systems with high penetration of photovoltaic generation and modern reactive power compensators via computer simulation. To properly conduct this investigation, detailed and simplified photovoltaic generators models will be used for analysis both in the time domain and in the frequency domain employing real networks.