Grid Impact Assessment of Centralized and Decentralized Photovoltaic-Based Distribution Generation: A Case Study of Power Distribution Network with High Renewable Energy Penetration

Abstract

This paper presents a grid impact assessment of a 5 MWp photovoltaic-based distribution unit on a 33 kV/23 MVA power distribution network with high penetration of renewable energy generation. The adapted network has an average load demand of 23 MVA, with a 3 MWp centralized PV system, and a number of decentralized PV systems of a capacity of 2 MWp. A grid impact assessment is done to an additional 5 MWp of PV generation as a centralized system as well as a number of decentralized systems. Power flow analysis is conducted to the grid considering different generation loading scenarios in order to study grid performance including active and reactive power flow, voltage profiles, distribution power transformers loading, transmission lines ampacity levels, and active and reactive power losses. On the other hand, the distribution of the decentralized systems is done optimally considering power distribution transformer loading and available area using the geographical information system. Finally, an economic analysis is done for both cases. Results showed that grid performance is better considering decentralized PV systems, whereas the active power losses are reduced by 13.43% and the reactive power losses are reduced by 14.48%. Moreover, the voltage of buses improved as compared to the centralized system. However, the decentralized PV systems were found to affect the power quality negatively more than the centralized system. As for the economic analysis, the decentralized PV system option is found slightly less profitable than the centralized system, whereas the simple payback period is 9 and 7 years, respectively. However, decentralized PV systems are recommended considering the technical implications of the centralized PV system.