Source-Grid-Load Combined Security Assessment of PV-Penetrated Distribution Network

With the increasing penetration of renewable energy, distribution network operation is threatened by uncertainties. The proposed security assessment of distribution network combining system operation risk with uncertain PV power and network topology robustness. It helps evaluate system operation status objectively and provide suggestions for renewable energy planning. First, node voltage deviation and branch overload rate are defined as system operation risks. The sparse polynomial chaos expansion (SPCE)-based stress testing is proposed to evaluate the operation risk including voltage deviation and overload. Second, the definition of topology robustness is introduced. Then, the source-grid-load combined assessment method is applied in modified IEEE 33-bus systems with different PV penetration rates. Weights for different indicators are calculated based on the improved analytic hierarchy process (IAHP). The efficiency of the method is significantly improved compared to the Monte Carlo simulation (MCS). The evaluation results also indicate that proper PV penetration improves distribution system operation security.