An object-oriented railway system and power network simulator.
The increasing application of systems engineering to the design of modern
railways has placed a heavy demand on high quality software-based railway
system simulators. Very often, a simulator of this kind is not only expensive to
build but also to maintain. Modifications and extensions of an existing
simulator are always necessary. This leads to the need for investigation into
the use of advanced modelling and software engineering techniques to
improve the simulation programs such that they are robust yet easy to change.
The work described in this thesis, divided into two parts, investigates a)
software design using object-oriented technology; b) algorithms for the efficient
solution of power network in the DC railway system simulation context.
Regarding the software design, an adaptable simulation framework design
based on a subsystem-manager-database structured concept has been built
using Borland C++. A class library consisting of 66 classes has also been
developed. The simulator developed to date, working on any IBM compatible
PCs, is able to produce system performance including substation loads, train
voltage and current profiles, rail potentials and train diagrams. The simulator
models have been verified by means of comparing the results generated by the
Birmingham University Fortran multi-train simulator.
On the efficient power network solution algorithms, an extensive investigation
into the sparse matrix and iterative numerical methods has been conducted.
Several representative algorithms have been coded for a comprehensive
dynamic speed trial. According to the results, the variable bandwidth preordering
is by far the most efficient algorithm for small to medium scale
simulations, whilst the minimum degree ordering is the fastest algorithm for
simulations including rail potential calculations in which the system usually
has several hundred nodes.