Aggregate Temporally Coupled Power Flexibility of DERs Considering Distribution System Security Constraints

Abstract

This letter proposes a novel inner approximation method for the aggregated temporally-coupled power flexibility of distributed energy resources (DERs). Previous inner approximation methods were proposed without knowing the explicit formulation of the exact flexibility aggregation model of DERs. Recently, we have derived that explicit formulation [1], so its properties are exploited to develop an inner approximation in this letter. The proposed method significantly improves the accuracy and computation speed. Numerical tests verify the effectiveness of the proposed method.

An Analytical Method for Delineating Feasible Region for PV Integration Capacities in Net-zero Distribution Systems Considering Battery Energy Storage System Flexibility

“…To address this issue, it is imperative to analyze the spatiotemporal coupling flexibility of a DS using a region-based method. References [13] and [14] separately obtained the temporal coupling regulation power of aggregated flexible resources at the point of common coupling (PCC) by using external approximations and analytical methods, respectively. However, these methods may not be able to analyze the effect of BESSs on multiple PV locations.…”

“…Given that our study considers the impact of temporal coupled BESSs, the calculation of the feasible region must be based on an accurate measure of flexibility. However, embedding the nonlinear AC power flow equations and the temporally coupled constraints in the flexibility analysis problem is computationally intractable [14]. Consequently, existing literature considering nonlinear power flow does not take into account the temporal coupling in flexibility [24], [25].…”

“…Many research works in the related field use linear power flow models, indicating that linear power flow can achieve high accuracy and computational efficacy [26]- [29]. Therefore, researchers have highlighted that the error of whether to precisely consider temporal coupled flexibility or not is more significant than that of the choice of linear or nonlinear power flow equations [14]. To accurately measure the impact of BESSs on PV hosting capability, we opt for linearized flow equations in this paper, which allows for obtaining analytical expressions for the feasible region with minimal error.…”

“…2) For network security: (3), (14), and (15). Note that ( 14) and ( 15) can be further transformed into tractable linear constraints and ξ in (4) can be removed.…”

Evaluating and aggregating the grid-support capability of energy storage clusters by considering the peak regulation requirements

“…Energy storage capability can be described as the feasible region of output power in all periods (Sajjad et al, 2016), which is influenced by its operational constraints and grid scheduling constraints . Analyzing the feasible region of an energy storage cluster requires considering the temporal coupling characteristics, such as the time dependency of charging and discharging (Wen et al, 2022a). Directly aggregating the feasible region of an energy storage cluster may lead to the curse of dimensionality (Muller et al, 2019), while approximating solutions may reduce aggregation accuracy (Chen and Li, 2021;Ayesha et al, 2023).…”