Hydrogenerator control-loop monitoring using graphical results obtained from a principal component analysis

A method to concentrate information from multiple transient performance criteria into simple graphical representations for the detection and localisation of faults occurring on hydrogenerator speed control loops is presented. Simple criteria such as the ISE index, the IAE index, the ITAE index, rise time, settling time and overshoot are combined and analysed by applying principal component analysis to data containing the start-up and a step in the rotational speed reference. The results are compared to a statistical model of the normal process operation and they are graphically displayed on a selected axis that has a high relevance to the process behaviour. The graphics are simple and can therefore be easily interpreted by plant operators. Simulations of a classical hydrogenerator show that six types of faults can be successfully detected and localised.