Impact analysis of large power networks with high share of renewables in transient conditions

With the growth of distributed generators in the power grid, replacing the fossil-fuel-based conventional generation sources with renewable power resources, namely photovoltaics (PVs) or wind turbines, is inevitable. However, when rotating-kind synchronous machines that usually possess high inertia are replaced by PVs that have an inherent static nature, grid stability issues such as reduced system inertia, lack of reactive power, and decreased system damping may arise. This study investigates the stability impacts with high-PV penetration in the Texas 2000-bus network. From the impact analysis conducted under transient conditions, it is observed that high-PV penetration could negatively adversely affect the voltage and frequency stability of the system which is mainly due to the replacement of conventional generators that results in reduced network inertia and lack of reactive power support. Hence, to alleviate the adverse stability implications of PVs on power systems with reduced inertia, a long-term generator scheduling strategy is proposed considering the criticality of synchronous generators for optimally decommitting and scheduling the generators. Extensive case studies are conducted to determine the ideal dispatch strategy for the test system based on transient stability criterions.