An economic dispatch model for combined heat and power systems considering the characteristics of heat recovery steam generators

摘要

The installation of combined heat and power (CHP) units has rapidly increased due to their energy efficiency and environmental advantages. The broad application of CHP units requires the joint dispatch of power and heating systems, in which the modeling of CHP units plays a pivotal role. However, existing CHP models face the contradiction between accuracy and solvability. In this paper, we propose a novel CHP model that well balances these two issues. The heat exchange theory is employed to derive the models of HRSGs. Based on the models, an economic dispatch model for CHP systems that considers the characteristics of heat recovery steam generators (HRSGs) is formulated. A corresponding algorithm for solving the proposed model is presented as well. In case studies, the impacts of the HRSG characteristics on the CHP operation region and dispatch results are studied, and the performances of the proposed model and the conventional model are compared. The results indicate that the proposed model outperforms the conventional model in terms of the level of optimality achieved during economic dispatch, benefiting from the more accurate description of the electro-thermal coupling relationship of CHP units.