Comprehensive reliability assessment method for distribution networks considering IIDG low voltage ride-through control

Abstract

Upon the large-scale integration of inverter-interfaced distributed generator (IIDG) into the grid, random faults in the distribution network can lead to momentary and sustained interruptions, significantly impacting system reliability. Although reliability methods have been widely used in distribution network adequacy assessment, using probabilistic method for reliability assessment including system dynamic security need to be investigated. To address this issue, a new method is designed to assess the reliability of distribution network using sequential Monte Carlo simulation. Firstly, the IIDG low-voltage ride-through (LVRT) control strategy is formulated, and the off-grid probability model for IIDG is developed based on the Gaussian distribution. Secondly, the component model is defined to consider the impact of random faults on power quality in security assessment. Following the fault tree analysis method, a protection action probability model was formulated to assess the failure probability of line current differential protection, IIDG anti-islanding protection, and reclosing protection. Finally, the method for momentary fault consequence analysis, based on depth-first search (DFS), and the method for sustained fault consequence analysis, based on the mixed-integer linear programming model, are developed. The study establishes a comprehensive probability reliability assessment framework. The validity of the method is demonstrated on the IEEE RBTS BUS6 F4 system, indicating good scalability.

Keywords

• Distribution networks
• Reliability assessment
• Low voltage ride through
• Temporary fault
• Permanent fault