Dynamic Modeling and Simulation of Two-stage Grid Utility Scale PV System

The recent sharp decline in the cost of photovoltaic (PV) systems has led to a significant increase in the amount of electricity generated by PV in the power grid. However, the integration of PV systems into the grid poses challenges to grid reliability, operation, and stability, which must be addressed. To study the dynamics of PV systems and minimize risks to grid reliability, various models have been developed using positive sequence simulations. Nonetheless, these simulations have limitations in identifying possible performance issues, which can be addressed by using electromagnetic transient (EMT) modeling and studies. In this study, a multi-level control architecture for a PV plant is proposed, including low-level, local-level, and plant-level controllers, to investigate the operation of a utility-scale PV plant within an EMT simulation platform. A case study of a utility-scale PV power plant, featuring PV arrays and a DC boost converter interface with maximum power point tracking (MPPT) control, is designed in PSCAD/EMTDC. The implemented PV model is extensively tested and validated against field data from a utility-scale PV system.