Short-circuit analysis of grid-connected PV power plants considering inverter limits

Abstract

This paper presents a short-circuit analysis of grid-connected photovoltaic (PV) power plants, which contain several Voltage Source Converters (VSCs) that regulate and convert the power from DC to AC networks. A different methodology has been adopted in this paper for short-circuit calculation. In particular, an element-based formulation is adopted to model the studied system including the grid-support control and various current-saturation states of PV inverters during the fault. An iterative approach is presented to identify the short-circuit equilibrium point that satisfies all converters’ operation limits efficiently. Case studies have been carried out on PV power plants with different numbers of inverters. The influence of the inverter grid-support operation, the main grid strength and the MV collection grid topology on system steady-state performance during the fault has been analyzed. The obtained short-circuit equilibrium points have been validated through dynamic simulations.