Research on voltage stability promotion strategy of distribution network considering distributed photovoltaic grid connection

Abstract

With the continuous rise in the penetration level of distributed photovoltaics (DPVs) in distribution networks, the discrepancies in fault ride-through characteristics among photovoltaic inverters have greatly increased the difficulty of voltage stability regulation. Grid-connected distributed photovoltaic systems in distribution networks are classified into Category A and Category B according to their different fault ridethrough capabilities. Spectral clustering is employed to implement initial cluster partitioning, and the clustering results are iteratively optimized by combining the evaluation indices of voltage regulation potential and power balance degree. Subsequently, dominant parameters determining voltage responses are screened based on sensitivity analysis, and key nodes within each cluster are selected. These key nodes are adopted to characterize the overall voltage regulation performance of corresponding clusters for collaborative parameter optimization. Simulation validations on the standard IEEE 33-node test system verify that the proposed strategy can suppress voltage fluctuations caused by photovoltaic off-grid and post-fault power restoration, and improve the transient voltage stability of distribution networks.