Optimal Virtual Power Plant Operation for Promoting Energy Efficiency of Distribution Systems

Page 1

Optimal Virtual Power Plant Operation for Promoting Energy Efficiency of Distribution Systems Ya-Chin Chang *1, Rung-Fang Chang2 Department of Electrical Engineering, Cheng Shiu University, Kaohsiung, 833, Taiwan

1

Department of Electrical Engineering, Kao Yuan University, Kaohsiung, 821, Taiwan

2

*1ycchang@csu.edu.tw; 2rfchang@cc.kyu.edu.tw Abstract In this paper, an optimal virtual power plant (VPP) operational method is proposed to maximize the benefit obtained with respect to the power supply limit of the distribution transformers and the system security constraints. In the method, an iterative dynamic programming optimal BESS schedule approach and a PSO-based DR scheme optimization approach are executed alternatively until the maximum benefit reached. With the TOU rate each hour, test results had confirmed the validity of the proposed method with obviously decreased power supply needed on peak-load hours and largely reduced electricity cost or maximum benefit accordingly. Keywords Virtual Power Plant; Battery Energy Storage System; Distributed Energy Resource; Demand Response

Introduction The VPP with the regulable loads participating in DR action can optimize the DR scheme by suitably regulating the demand powers of the loads over the 24 hours to help improve system security of a whole day. The definition of DR in the Federal Energy Regulation Commission (FERC) is: changes in electric usage by demand-side resources from their normal consumption patterns in response to changes in the price of electricity over time (TOU, dynamic pricing, critical peak pricing, peak-time rebate, etc.), or to incentive payments designed to induce lower electricity use at times of high wholesale market prices or when system reliability is jeopardized [1]. Recently, many DR strategies have been introduced to solve peak-load shedding and shifting problems. In [2], as a load shaping tool, a DR strategy is proposed to alleviate the potential new load peaks with minimal infrastructure investments. While in [3], with price uncertainty modeled through robust optimization techniques, a real-time DR model with a linear programming algorithm is used to adjust the hourly load level of a given consumer in response to hourly electricity prices. Energy storage systems (ESSs) are increasingly drawing more attention from utility engineers and regulators for its potential to address a variety of technical challenges in the management of electric power [4-8]. Utilities face the need to economically serve uncertain peak load growth at substations, the desire to provide enhanced reliability and resilience in adaptive smart grids, and the need to use highly variable and unpredictable renewable energy sources. All these matters could potentially be addressed using storage technologies. In this study, the objective of the proposed method is to maximize the benefit (or minimize the electricity cost) of the supply powers from the distribution transformers over the 24 hours under the VPP operation by optimizing the charging/discharging schedules of each BESS and the DR scheme simultaneously. Composed of an iterative dynamic programming optimal BESS schedule approach and a PSO-based DR scheme optimization approach, the proposed optimal VPP operating is achieved by respecting the power supply limit of each distribution transformer and the system security constraints.. International Journal of Automation and Control Engineering, Vol. 4, No. 1—April 2015 2325-7407/15/01 045-6 Š 2015 DEStech Publications, Inc. doi:10.12783/ijace.2015.0401.11

45


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.