A New Approach to Optimal Allocation of Reactive Power Ancillary Service in Distribution Systems in the Presence of Distributed Energy Resources

Abstract

Abstract:One of the most important Distribution System Operators (DSO) schemes addresses the Volt/Var control (VVC) problem. Developing a cost-based reactive power dispatch model for distribution systems, in which the reactive powers are appropriately priced, can motivate Distributed Energy Resources (DERs) to participate actively in VVC. In this paper, new reactive power cost models for DERs, including synchronous machine-based DGs and wind turbines (WTs), are formulated based on their capability curves. To address VVC in the context of competitive electricity markets in distribution systems, first, in a day-ahead active power market, the initial active power dispatch of generation units is estimated considering environmental and economic aspects. Based on the results of the initial active power dispatch, the proposed VVC model is executed to optimally allocate reactive power support among all providers. Another novelty of this paper lies in the pricing scheme that rewards transformers and capacitors for tap and step changing, respectively, while incorporating the reactive power dispatch model. A Benders decomposition algorithm is employed as a solution method to solve the proposed reactive power dispatch, which is a mixed integer non-linear programming (MINLP) problem. Finally, a typical 22-bus distribution network is used to verify the efficiency of the proposed method.

Coordinated Volt/Var Control in Distribution Systems with Distributed Generations Based on Joint Active and Reactive Powers Dispatch

“…Although, much research on the reactive power market in a restructured power system, at the wholesale level, has been performed [16][17][18][19], in few works the potential of expansion of a reactive power market at the distribution level with DGs has been reported [3,20,21]. Additionally, the reactive power capability of DG has not been considered in the previous research on the VVC problem.…”

Distributed Optimal Economic Dispatch Based on Multi-Agent System Framework in Combined Heat and Power Systems

“…The scheduling cycle is set to one hour. The initial values can be obtained by Equation (13). Then, the proposed method is used to calculate the optimal solution.…”

“…Their maximum power output profiles are shown in Figure 8a. In this case, the scheduling cycle is set to 20 s, i.e., EOA4, EOA6 and HOA3 measure and reset their corresponding maximum power output point every 20 s. The initial values can be obtained by Equation (13). Then, the proposed method is used to find the optimal operating point during each scheduling cycle.…”

“…Moreover, both the physical and communication topology of the future CHP system are prone to have a huge and variable topology with partially-unknown characteristic, which may seriously degrade the effectiveness of centralized methods. In addition, each component in CHP system should possess the plug-and-play feature, which is one of the key characteristics of the future CHP system [11][12][13]. Thus, the centralized method is not very suitable to address the distributed features of the future CHP system.…”

Optimal Voltage Control Using an Equivalent Model of a Low-Voltage Network Accommodating Inverter-Interfaced Distributed Generators

“…Although DGs offer a variety of economic and technical benefits [1], a high penetration of DGs results in new problems for the distribution system operation, such as voltage rise [2,3]. Therefore, various volt/var optimization (VVO) methods that consider DGs and that utilize DGs as a controllable resource have been proposed for medium-voltage (MV) distribution systems (e.g., 1 kV < V MV < 100 kV) [4][5][6][7]. Using these proposed methods, the active power loss and switching operation of the on-load tap changers (OLTCs) and shunt capacitors can be reduced while maintaining the voltages within their operational bounds.…”