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Decentralised Power System Load Frequency Control Beyond the Limit of Diagonal Dominance

journal contribution
posted on 2023-06-08, 09:10 authored by Tai Yang, Z T Ding, H Yu
The design of decentralised robust load frequency control for interconnected multi-area power systems is studied in this paper. It is shown that although the design can be naturally formulated as a large-scale system decentralised control problem, it can be translated into an equivalent problem of decentralised controller design for a multi-input multi-output (MIMO) control system. It is known that simple controllers can be designed to achieve satisfactory performances if diagonal dominance can be achieved in a multivariable system. This is further extended in this paper. Using the design method proposed in this paper, even when the diagonal dominance cannot be achieved, subject to a condition based on the structured singular values (SSVs), each local area load-frequency controller can be designed independently. The robust stability condition for the overall system can be easily stated as to achieve a sufficient interaction margin, and a sufficient gain and phase margin during each independent design.


Publication status

  • Published


International Journal of Electric Power and Energy Systems







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Department affiliated with

  • Engineering and Design Publications


This innovative idea and the related design method have a great potential for applications in power systems. The work has attracted a great interest by the National Grid plc; Dr Yang was invited to give presentations by the company (Dr S Geeves, The information about the design and implementation for the UK power system is commercially sensitive and not available here. The extension of the above work is also of interest to another company: EDF Energy. Dr Peter Lang (, Principal Network Specialist of the company, has visited Dr Yang for a demonstration based on computer simulations.

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