Prequalification Scheme of a Distribution System Operator for Supporting Wholesale Market Participation of a Distributed Energy Resource Aggregator

Abstract

Increasing penetration of distributed renewable energy sources (DRESs) has resulted in the emergence of distributed energy resource aggregators (DERAs). A DERA participates in the transmissionlevel market operated by a transmission system operator (TSO), and the DERA's resources are connected to a jurisdiction of the distribution system operator (DSO). Inspired by the structure of the Korean power industry, this study assumes a minimal DSO that cannot directly dispatch the resources in its system. In this study, we develop a detailed procedure for prequalification wherein the DSO checks the DERA's bids that are submitted to the TSO markets. The proposed prequalification enables the DSO to secure the reliability of its system by providing limited network information to the DERA. The DERA modifies its bid until potential overvoltage and overflow problems are resolved, even in the worst case, including uncertainties. The proposed prequalification process is verified using the IEEE 33-bus distribution network. Compared to previous studies, the results demonstrate that the proposed prequalification can deal with distribution system constraints, even though uncertainties are included. The proposed prequalification process can be applied to power industries where the DSO does not have the full dispatch authority on DRESs.

Robust prequalification process of a distribution system operator considering N‐1 contingency

“…In the minimal DSO situation, the DSO takes the responsibility for system stability and DERAs function as producers in the WEM. Moon et al [5] proposed the decomposition of Equation (1) for minimal DSO as follows. The DSO obtains generation schedule of DRESs by DERA that solves its own optimization problem.…”

“…The basic framework of the proposed N-1 PP is based on the N-0 PP [5]. Figures 1 and 2 present the flow charts of the N-0 PP and the N-1 PP, respectively.…”

“…However, a conventional independent SO that operates the WEM and a transmission system does not monitor the state of distribution systems. Therefore, generations in the distribution system that have been accepted in the WEM can cause overvoltage and overflow problems in this system [5].…”

“…In [5], Moon et al proposed a prequalification process by the DSO that reviews the DERA's market bid. In the prequalification process, the bid is reviewed under the worstcase situation, by considering the uncertainties of DRES and demand.…”

Distribution-Level Flexibility Markets—A Review of Trends, Research Projects, Key Stakeholders and Open Questions

“…Such methods offer solution of the problems caused by DERs even without the distribution level flexibility market. In that manner Moon et al [91] used prequalification process to accommodate high DERs penetration for the case where DSO cannot directly dispatch the resources. The similar idea had the authors in [92], where DSO checks the feasibility of the bids in the day-ahead energy and reserve markets using AC OPF.…”