Modelling of energy service networks - Modelling Distributed Energy Resources in Energy Service Networks - page 29

Chapter 3
Modelling of energy service networks

To address the challenge of analysing the interactions between electrical and natural
gas distribution networks, this work introduces an integrated power flow model where
combined heat and power (CHP) units serve as a link between both infrastructures.
However, conducting an integrated analysis of several energy networks is an elabo-
rate task. This is because it requires at an early stage to model the basic components
of each infrastructure through a steady-state load flow study. Power flow analysis
is a valuable engineering tool and for long has been considered the cornerstone of
high-hierarchy power system studies. By discussing load flow methodologies indi-
vidually for each system, it is possible to build a generic framework to solve load flow
problems in conjunction. Hence, this chapter focuses on laying the groundwork for
analysing and synthesising electrical and natural gas networks.
It is important for power systems engineers to acknowledge that some existing
electric load flow techniques can be used to solve natural gas load flow problems.
Also, it is key that each load flow process is comprehended, making it later feasi-
ble to simultaneously assess both electrical and natural gas networks. Although, as
expected, some special considerations must be taken to conduct an integrated elec-
trical and natural gas network analysis, these considerations include representing the
natural gas system components and their respective fluid flow equations in a con-
sistent manner with regard to their counterparts in electrical systems. By building
analogies power system engineers can conveniently apply their knowledge on load
flow studies directly into another key branch of energy systems, thus creating power-
ful modelling synergies which could eventually lead to exploring other infrastructures
worth analysing ( e.g. water and heat). In this chapter, basic principles and load flow
models for electrical and natural gas systems are reviewed and they are based on
References 18, 171-176.

3.1 Modelling electrical networks

3.1.1 Fundamentals of electrical systems
The aim of electrical systems is to continuously meet the demand from all customers.
In order to achieve this goal, power plants produce electrical power in distant sites
and deliver it to customers through the transmission and distribution systems on a
second-by-second basis. The complex interaction for the delivery of electrical power