Integrated Heat and Electricity Dispatch for District Heating Networks
with Constant Mass Flow: A Generalized Phasor Method
Abstract
Using thermal inertia in district heating systems (DHSs) to improve the
dispatch flexibility and economy of integrated heat and electricity
systems (IHESs) is a research hotspot and difficulty. In most existing
studies, the partial differential equations (PDEs) of thermal inertia
are approximated by discrete-time models, making it difficult to
accurately describe the continuous dynamic processes. In this paper, we
propose a novel generalized phasor method (GPM) for thermal inertia in
DHSs with constant mass flow. Based on the analytical solution of the
PDEs and the Fourier transform, the intractable PDEs are transformed
into a series of complex algebraic equations represented by phasors. The
GPM has higher accuracy compared to traditional discrete models because
it is essentially a continuous model in the time domain. Then, we
present a different representation of an integrated heat and electricity
dispatch (IHED) model combining a DHS model in phasor form and a
traditional electrical power system model. The IHED model is a convex
programming problem and can be easily solved. The effectiveness of the
proposed GPM and dispatch model is verified in three test systems.
Compared with traditional methods for modeling the thermal inertia, the
proposed GPM is more accurate.