Développement d'un outil portable d'analyse modale par réponse temporelle

Abstract

Modal analysis is increasingly used as a technique to characterize systems' dynamic behaviour. lts application in the study of low frequency phenomena on electrical networks offers a broad range of solutions for specifie situations. Nevertheless, the increasing size of present-day networks complicates their modeling and the use of their known variables. For these reasons, the need for a signal-based approach to modal analysis is essential to avoid the constraints of standard system-based approaches. The present research report deals with a portable software tool developed for time-response modal analysis. This product provides a reduced-order, state-space model identification method combined with Prony parameters estimation. The Single-Input-Single-Output (SISO)realization is based on the link between the time response from the analyzed system and the pulse response of the equivalent state-space model. An ERA/Prony algorithm is developed which estimates the dynamic parameters of superimposed sinusoids from a discrete time signal, without requiring any information from its original system. The reduced-order, state-space identification method is detailed and provides a singular value decomposition realization from a Hankel block matrix of the signal's samples. The order of the model is determined according to the observed singular value diagonal. Later, the Prony parameters are estimated from eingenvalue decomposition and calculation of the state matrices residues. The software features are specified and three cases of study show the validity of the algorithm. Studied cases include a simple sinusoïdal decomposition, the characterization of oscillatory phenomena on Kundur' s four machine network, and the analysis of a sampling taken from Hydro-Québec's network following a synchronization Joss between LG4 and Boucherville substations. The studies were carried out by importing the product into Hydro-Québec's signal analysis software Sc ope View. This use demonstrates the portability aspect of the product and moreover gives access to a modal analysis tool in software such as HYPERSIM and EMTPRV.

Date	5 May 2010
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Louis-A. Dessaint (Supervisor)