Fault analysis of accurate PV connected system against dynamic fast solar radiation fluctuation

Renewable energies integrated systems protection issues need proper fault analysis investigation. Based on simulated solar radiation fluctuation the case of accurate 6.5 kV dc photovoltaic (PV) connected system is discussed in this paper. The detailed control strategy is PV side control and inverter side control. The synchronous rotating frame (SRF) method is applied to design a current control strategy to control three-phase voltage source inverter (VSI) using park transform. Maximum power point tracking (MPPT), voltage control, phase locked loop (PLL), sinusoidal pulse width modulation (SPWM), LCL filters, and pulse width modulation (PWM) techniques are implemented in PSCAD software based simulation. The grid has 110 kV and 100 MVA power rating connected to the 6.5 kV PV farm through two step-up delta-star transformers making use of transmission lines. Symmetrical and asymmetrical faults are analyzed during high and low levels short time and dynamic irradiation fluctuation to discuss relevant PV system variables waveforms. These results could be needed to further investigate protection problems and related issues in high PV penetration systems suffering from unpredictable nature of solar radiation.