  Currently, most district heating networks are running in a heat-setting mode,
limiting the adjustment of the electrical power of combined heat and power
(CHP) units. By considering the electrical power system (EPS) and district
heating system (DHS) together, the peak regulatory capability 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 dynamic characteristics of pipelines and buildings
to increase flexibility. To deal with the complexity of the optimization model,
a water mass method (WMM) for pipeline thermal dynamics is proposed. Benefiting
from the WMM, the proposed IHED model is an ordinary, non-linear model. An
iterative algorithm based on the generalized Benders decomposition, and a
sequential approach combined with the iterative algorithm and IPOPT, are
proposed to solve the IHED model. Compared with a steady state model without
thermal dynamics, considering the thermal dynamic characteristics in the DHS
can further expand the peak regulatory capabilities of CHP units. The WMM is
tested in the thermal dynamic simulations compared to an existing node method
and a commercial simulation software. And the proposed solution strategy is
verified in a small-scale system and a practical system. The simulation results
of case studies are discussed to demonstrate the feasibility and economy of the
dispatch model proposed here.
