Decentralised proportional-plus-integral design method for interconnected power systems

A simple and computationally efficient decentralised control design method is introduced for load-frequency control (LFC) in interconnected power systems. The method is based on the use of a reduced-order observer and a proportional-plus-integral controller in each area of the power system, and ensures zero static change in area-frequency and tie-line power. Some of the features of the decentralised scheme are decentralised implementation of a wide choice of feedback controllers, which have been designed off-line to meet the requirements of the global system; a constraint-free structure for the feedback controller; and avoidance of the need for inter-area transfer of data, for the purposes of LFC. The proposed decentralised control algorithms are tested on a computer-based simulation of a two-area interconnected power system. The simulation results demonstrate that the method can give closed-loop performance which is similar to that of the equivalent global control system.