Optimal Operation of a CCHP Microgrid Using Interval Mixed-Integer Linear Programming

Abstract

Abstract-The development of combined cooling, heating, and power (CCHP) microgrids using distributed cogeneration equipment and renewable energy sources has drawn considerable research attention. In this study, we propose an interval mixed-integer linear programming (IMILP) dispatching model for supporting the economic dispatch of a CCHP microgrid under uncertainties. Our model is based on the interval programming method, where uncertainties can be incorporated and communicated into the economic dispatch problem using interval values. The proposed IMILP dispatching model is decomposed into two sets of deterministic sub-models, f -and f + , which are solved sequentially. We use a case study of a hotel in China to demonstrate how this model can be applied to support economic dispatch decisions for a CCHP microgrid. Simulation results indicated that load and PV power uncertainties mainly affect the dispatching results of the power exchange, gas boiler and electricity chiller, while the power generation unit is consistent under different uncertainty levels. The obtained dispatching results can provide more flexibility for decision makers by generating alternative decisions for CCHP microgrid dispatching under uncertainties.Index Terms-CCHP, economic dispatch, interval programming, microgrid, uncertainty. I. INTRODUCTIONThe energy crisis and rising air pollution have led to greater worldwide focus on energy efficiency methods. Combined cooling, heating, and power (CCHP) systems are also referred to tri-generation systems. They have been widely used in small-medium scale power systems to solve energy-related problems, including increasing energy demands, higher energy costs, energy supply security, and environmental concerns [1]- [6]. A CCHP microgrid integrates power generation units (PGUs, e.g. Fuel cell or Micro turbine), auxiliary boilers, heat recovery systems, refrigeration equipment (electric chiller or absorption chiller), energy storage devices (heat storage tanks or storage batteries), and renewable energy sources (e.g. photovoltaic, wind, biomass) to implement the cascade utilization of energy. The main difference between CCHP microgrid and traditional CCHP systems is that the former can not only satisfy the cooling, Manuscript received August 28, 2015; revised February 25, 2016. This work was supported by the National High Technology Research and Development Program of China (863 Program, grant no. 2011AA05A107), the National Science Foundation of China (grant no. 51277027), the Natural Science Foundation of Jiangsu Province of China (grant no. SBK201122387), the State Grid Corporation of China.Zhao Luo, Wei Gu, Zhihe Wang, and Yiyuan Tang are with the School of Electrical Engineering, Southeast University, Nanjing, Jiangsu 210096, China (e-mail: waiting.1986@live.com).Song Gao is with Jiangsu Electric Power Company, Nanjing, Jiangsu 210024, China.heating, and power demands of certain types of customers (such as office buildings, hotels, schools, commercial malls, and industrial loads), but also interacts ...