The impact of diverse generation mix on power system stability

• Main Author: Horne, J. M.
• Published: Queen's University Belfast 2012
• Subjects: 621.85
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557629

Environmental drivers are the dominant reason for the current trend towards combined cycle gas turbine and wind turbine plant for new power stations. The result is a net shift in the plant mix away from traditional thermal stations. As the percentage of 'new' generation types increases, the effect on the dynamic performance of the power system needs to be investigated and quantified, and mitigating measures taken where necessary. This thesis, part funded by SONI Ltd (the system operator in Northern Ireland), has taken the two area Irish power system as a basis for this research. The focus is on the cumulative effects of increasing generation from combined cycle gas turbine and wind turbine plant on frequency and small signal stability. The research conducted has concluded that the introduction of large volumes of gas turbine plant does affect the system dynamics, but by far the greatest change for system operators will be the introduction of significant coverage of demand from wind powered generation. The reason is due to the introduction of widespread solid-state converter technology utilised in full converter and doubly fed induction generator wind turbines. In contrast, the gas turbine effects on a system relate to different dynamics of directly connected synchronous machines, which are well understood, and although they need to be considered, pose less of a technical challenge to manage. In addition to establishing an understanding of the major issues impacting on power systems of the future, this thesis has developed novel methods for power system stabiliser performance verification, and provision of high frequency response from wind turbine plant. These are required to cope with the rapid variation in plant mix and corresponding impact on system stability of networks into the future. Both methods are now in use with National Grid, the Great Britain transmission system operator.