Facilitating the Validation of Adaptive Power System Protection through Formal Scheme Modelling and Performance Verification

There exists a critical mass in research related to adaptive protection
approaches that address some of the shortcomings of conventional protection
functions. This is in response to concerns in the reliability of conventional
protection which manifested itself in some severe disturbances in more recent
years. Despite the fact that adaptive protection offers a compelling technical
solution to some of these performance problems, the industry has not widely
adopted adaptive protection approaches as a de facto policy for future
protection scheme implementations.
This is attributed to the difficulties associated with the testing of such schemes
where no significant work has been reported yet. Furthermore, the benefits vs.
the risks associated with such a protection strategy are not well understood.
This is coupled with the conservatism towards radical changes in the way the
power system is operated. As such the work reported in this thesis
complements the existing body of research in order to address some of the
major technical and institutional challenges associated with adopting adaptive
protection schemes for future networks, especially those networks that exhibit
flexibility in operation to deal with uncertainty in generation and to maximise
asset utilisation. These are network characteristics that adaptive protection
approaches are seen to be an effective enabler of.
This thesis focuses on formal structural and behavioural modelling of adaptive
protection schemes as means to effectively validate their functional operation
and verify their performance. Novel contributions have been made in
formalising a user requirements driven architecture for these schemes.
Furthermore, significant contributions have been made to conducting formal
algorithm verification that complements inherently limited standard protection
scheme validation techniques. The thesis makes thorough use of a proposed
adaptive distance protection scheme for circuits with quadrature booster
transformers to communicate the challenges, lessons learned and contributions
in designing, implementing and testing adaptive protection schemes.