Using Orthogonal and Discrete Transform for Single-Phase PES Transients A New Approach

B. Dobrucky, M. Marcokova, M. Pokorny, and R. Sul (Slovakia)


Transient phenomena, Ztransform, ParkClarke transform, variable structure system, modelling, simulation


The paper deals with the methodology of a dynamic system transient solution, particularly under non harmonic supply or a periodic variable structure of the system. Basic analytic solutions are presented in a time domain in the state space acting above state variables. The method of prediction of the transient solution is explained for systems under periodic non-harmonic supply. It introduces a new method for symmetrical m-phase systems with periodic variable structure analysis. This method exploits the conjunction of linear orthogonal transform (Park-Clarke) and Z-transform. The benefits in steady-states are: calculation of integral values, average mean value, complex Fourier analysis, root mean square values only during 0 – T/4 time interval; in transient: successive computation of transient phenomena and prediction of transient behaviour from data acquisited during T/4; in real-time control: the active and reactive powers and power factor can be determined extremely fast, in each calculation step. Quite new aspect is the use of Z-transform in complex domain. It makes possible to estimate time behaviour of the whole transient phenomenon and also determine its stability and convergence solution. All that is done just based on knowledge of the situation during the first 1/2m-th of the time period.

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