PROJECT TITLE :

Stability assessment for transmission systems with large utility-scale photovoltaic units

ABSTRACT:

Photovoltaic (PV) systems are gradually replacing standard synchronous generators. But, reduced system inertia and lack of dynamic grid support from PV are the main issues that might have a detrimental impact on the transient response in Power Systems when vital contingencies arise. During this study, the authors modelled and analysed transient and small-signal stability for a representative transmission system with realistic loading situations and high PV penetration levels. Initial, system eigenvalues were calculated to spot critical modes. Thereafter, the results of the small-signal analysis were additional expanded by performing transient simulations when critical contingencies. Such contingencies detrimentally excited the vital modes of the system. To hold out this analysis, they implemented a positive-sequence dynamic model of a utility-scale PV unit (USPVU) in the open programming atmosphere MATLAB/Simulink. This dynamic model is predicated on a Western Electricity Coordinating Council (WECC) generic model (full converter model), that is suitable for electromechanical transient studies. Additionally included was the model of the PV array, dc–dc converter, and associated Control Systems. The most vital factors pertaining to the detrimental or useful impact of USPVUs on stability were the unit commitment and dispatch strategy and therefore the protection/control strategy during voltage swell and DIP events for equivalent PV penetration and loading situations.