Temporary overvoltage assessment and suppression in heterogeneous renewable energy power systems

Temporary overvoltage (TOV) may arise in renewable energy power systems after the fault clearance due to the plant-level delay. It is challenging to evaluate the TOV of a Multi-Infeed Power Electronic System (MIPES) considering the complex interactions among renewable power plants (RPPs). Moreover, the complexity of the evaluation is further increased when the MIPES is heterogeneous, where RPPs have different structures and control parameters. To tackle these challenges, this paper proposes a method to analytically assess TOV in a heterogeneous MIPES based on grid strength analysis. It is derived that different types of RPPs can be equivalent to similar models, i.e., current source parallel reactance. On this basis, it is obtained that the TOV and safety margin of the system can be assessed based on the heterogeneous generalized short-circuit ratio (gSCR-TOVhet) and the critical gSCR (CgSCR). Thereafter, a solution to suppress the TOV based on the configuration of synchronous condensers is proposed, which provides an effective way to improve the voltage safety of the heterogeneous MIPES. EMT simulations based on various test systems are performed to validate the effectiveness of our method.