Transient Stability Analysis of an Integrated Photovoltaic Systems in a Power System

Abstract

Integration of PV systems into the grid is growing rapidly around the world, and PV penetration plays a huge role in minimizing the effect of greenhouse gases in the atmosphere and also contributes to minimizing the impact of load shedding. However, PV systems contribute to grid integration issues such as transients, voltage, and frequency instabilities and reductions in the generator's inertia, respectively; therefore, it is essential to investigate the effect of the PV system on the grid before integrating it. This paper utilized a modified IEEE 9 bus system to investigate the impact of large-scale PV on the power system, and PSCAD software has been used for this study. Four scenarios with different PV penetration levels were considered in this paper. Moreover, for each scenario, the transient stability was assessed based on five parameters, namely: active power, reactive power, rotor angle, rotor speed, and the terminal voltage. Scenario 1 examines the PV systems integrated into a single bus and finds that the optimal PV penetration is 60% of the total power generation. Scenario 2 investigates the effect of integrating PV systems using the optimal PV penetration of 60% distributed into two buses, which was found to be the best for transient stability improvement after a fault condition. Scenario 3 investigates the impact of the power system stabilizer (PSS), using the optimal PV penetration of 60%, and the results reveal that system stability improves when a fault occurs on the bus where the PV system is also connected. Scenario 4 investigates the effectiveness of the fault clearing time on the response of the system with an integrated PV system, using the optimal PV penetration of 60%. The results revealed that a PV system only improves transient stability if the fault-clearing time is below 0.5 seconds; otherwise, the system loses stability. Overall, the study demonstrates that the system’s stability improves up to 60% of the PV penetration level of total generation power.