Reliability Evaluation of an Active Distribution Network Considering DR and Load Reduction Strategies

Introduction: Traditional reliability assessment methods are no longer sufficient to cope with the changes triggered by the emergence of microgrids, especially when user-side factors are not sufficiently considered. In this paper, an innovative two-tier load optimization model based on price-responsive Demand Response (DR) and load shedding strategies is proposed to improve the reliability and economic efficiency of distribution networks. Method: In this paper, a two-layer optimization model is developed. The upper-layer model considers the time-shifting characteristics of demand response to optimize the total electricity costs of users during all time periods after load response. The lower-layer model considers the distance and importance of load reduction to minimize economic losses caused by power shortages. Combined with the two-layer load optimization model and the Sequential Monte Carlo (SMC) algorithm, a reliability assessment process is proposed. Result: An improved reliability assessment index system incorporating economic factors was adopted and validated through simulation in the IEEE RBTS BUS6 F4 system. The simulation results showed that the proposed two-layer load optimization model reduces the system reliability index by 14.38% to 48.9% and the economic index by 40.6%. discussion: The reliability metrics - SAIFI, SAIDI, CAIDI and EENS reflect the frequency and duration of interruptions for both the system and the user. As shown by the data, both upper and lower layer optimization can improve the reliability metrics and the combined upper and lower layer optimization is the most effective. Also ECOST and Pisland proposed in this paper reflect the good economics of the method and the importance of successful operation of the islanding model. Conclusion:: Compared to existing methods, the proposed two-layer load optimization model demonstrates significant advantages in improving reliability while also considering economic efficiency, thereby achieving a win-win situation for both the power grid and users.