A Dynamic Modelling Methodology for Protection System Performance Assessment

A variety of different approaches to power system protection have been developed over the years, from simple fuses to sophisticated modern numerical relays. In order to ensure high reliability of protection systems a number of detailed testing procedures and simulation facilities are needed.
This thesis concentrates on the development and applications of numerical dynamic modelling techniques for power system protection schemes using an object oriented approach via the C++ programming language. The developed models have been applied within an “Integrated Modelling Environment” (IME), which was also developed during the course of this research work. The IME includes not only dynamic protection relay models, but also dynamic models of the primary power system, achieved using the Electro-Magnetic Transients Programme (EMTP), measurement transducers, circuit breakers, and communications circuits.
The thesis begins with an overview of traditional testing methods, along with recent developments in the field of protection equipment testing. The limitations of conventional approaches are highlighted and the requirements for advanced testing and analysis facilities are justified. The methodology for development of the dynamic relay models is described and four different dynamic relay models have been developed and fully validated; the development and validation processes are presented in this thesis. A number of case studies are included in order to give a broad overview of the applications of the new modelling methodology and to prove the usefulness of the results and the modelling environment in general. The open structure of the IME facilitates and simplifies the extension of the relay model library and provides several opportunities for future developments, which are discussed in the concluding sections of the thesis.