Probabilistic-possibilistic flexibility-based unit commitment with uncertain negawatt demand response resources considering Z-number method

Abstract

In recent years, there has been an increasing interest in using renewable energy resources. With the high penetration of these uncertain resources in power system studies, continuity and stability have become a principal issue for consumers. Therefore, the flexibility concept has been introduced, which has a pivotal role in the power grid to ensure energy consumption security. In this paper, an exploratory framework is presented for investigating the value of flexibility in the power system. Hence, a new index is introduced for flexibility assessment based upon maximum available capacity as well as reaction time of generating units. The results of this study indicate that the uncertain supply-side resources cause to decrease the flexibility level. Under the smart grid environment, virtual demand response resources (DRRs) can be called for compensating the uncertainty of renewable energy resources. Here, a new formulation of flexibility-based unit commitment associated with negawatt demand response resources (FBUCDRRs), is suggested. The uncertainty of DRRs is modeled using Z-number as a possibilistic-probabilistic method. The uncertainty of supply-side resources is also intended with Monte Carlo procedure. The point of FBUCDRRs is determining the optimum value of flexibility as a crucial issue, while the total operation cost accomplishes at the minimum possible level. The results indicate the improvement in the flexibility index without increasing the operation cost. Several analyses are carried out on a modified 10-unit test system and Kerman province power generation system as a practical power system to trace the capability of the proposed structure.