Modeling and fault analysis of solar photovoltaic grid-connected systems under solar radiation fluctuation consideration

摘要

This paper presents photovoltaic (PV) systems modeling and fault analysis with solar energy fluctuation to discuss maximum fault current profiles. The modeled PV farm is arranged with series and parallel PV modules to offer 6.5kV power. Two-level 3-phase voltage source inverter (VSI) and dc-dc boost converter are used for all PV systems with LCL filter. A current control strategy using synchronous rotating frame method is implemented with park transformation approach. Average and aggregate models give inaccuracy, which this paper overcomes with accurate isolated single PV system, and PV-dominated feeder. Pulse width modulation and sinusoidal pulse width modulation techniques are applied. Incremental conductance maximum power point tracking technique is used to extract PV maximum power. Phase locked loop technique for grid synchronization and proportional integral voltage control technique are also applied. Here, the maximum fault current corresponds to the maximum phase current at specified time. This simple and effective method is applied on PSCAD software simulations to collect the data. Discussions on obtained results showed short-time irradiation fluctuation impacts on fault current profiles and argue on related aspects. The data comments and explanations to address analyzed protection challenges with PV penetration in distribution system are very promising.