Active distribution network chain fault risk assessment based on probabilistic risk of accident chains

With the decentralized access of fluctuating distributed power sources, the degree and scope of the consequence impact of active distribution grids are increasing after the occurrence of chain faults. In order to study the propagation mechanism of chained faults in distribution networks, an active distribution network chained fault operation risk assessment method based on the probabilistic risk of accident chain is proposed. First, the correlation indicators of chain fault propagation are defined by analyzing the probabilistic current changes during the chain fault process, and the accident chain prediction model is established. Then, a fault tree probabilistic risk assessment model is established based on the accident chain ensemble, and the accident chain risk is calculated based on the probabilistic risk consequences of distribution network operation in the fault chain, and the branch importance assessment model is further established to identify the active distribution network weak links. Finally, taking the IEEE33 distribution network system as an example, the accident chain risk value and branch importance of the accident set are evaluated to obtain the risk status of each link and the key risk branch in the chain fault process, which verifies the practicality and effectiveness of the proposed method.