A water mass method and its application to integrated heat and electricity dispatch considering thermal inertias

Currently, most district heating networks in China are running in the heat-setting mode, which limits the adjustments of combined heat and power (CHP) units. By considering the electrical power system and district heating system together, the peak regulatory capabilities of CHP units can be improved, and renewable energy accommodation can be promoted. In this paper, a tractable integrated heat and electricity dispatch (IHED) model is described that addresses the thermal inertia characteristics of pipelines and buildings to increase flexibility. A water mass method (WMM) for pipeline thermal inertias is proposed to simplify the IHED model by removing the integer variables and differential equations. Benefiting from the WMM, the proposed IHED model is a single-level nonlinear model that is tractable. An efficient iterative algorithm based on the generalized Benders decomposition and a sequential approach combined with the iterative algorithm and Interior Point OPTimizer (IPOPT) are proposed to solve the IHED model. The WMM is tested in thermal inertia simulations compared to an existing node method (NM) and commercial simulation software. The proposed solution strategy is verified in a small-scale system and a practical system. The simulation results are discussed to demonstrate the feasibility and economy of the IHED model proposed here. (C) 2019 Published by Elsevier Ltd.