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 elaborate 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 individually 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 feasible to simultaneously assess both electrical and natural gas networks. Although, as expected, some special considerations must be taken to conduct an integrated electrical and natural gas network analysis, these considerations include representing the natural gas system components and their respective fluid flow equations in a consistent 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 powerful 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.

Chapter Contents:

• 3.1 Modelling electrical networks
• 3.1.1 Fundamentals of electrical systems
• 3.1.2 Defining the electrical load flow problem
• 3.1.3 Nodal formulation and the admittance matrix
• 3.2 Modelling natural gas networks
• 3.2.1 Fundamentals of natural gas systems
• 3.2.2 Defining the natural gas load flow problem
• 3.2.3 Nodal formulation and the incidence matrix
• 3.3 Analogies in energy service networks
• 3.3.1 Modelling components and variables
• 3.3.2 The Newton-Raphson algorithm
• 3.3.2.1 The electrical system Jacobian matrix
• 3.3.2.2 The natural gas system Jacobian matrix
• 3.3.2.3 Load flow conclusions

Inspec keywords: load flow; cogeneration; distribution networks; natural gas technology

Other keywords: steady-state load flow study; CHP units; electrical distribution networks; power systems engineers; combined heat and power unit; natural gas network analysis; integrated power flow model; power flow analysis; high-hierarchy power system study; load flow problems; energy service network modelling; integrated electrical network analysis; fluid flow equations; natural gas distribution networks; natural gas system components; electric load flow techniques

Subjects: Distribution networks; Thermal power stations and plants