Calculations of Electromechanical Eigenvalues Based on Generating Unit Instantaneous Power and Angular Speed Waveforms at a Step Disturbance

• Main Authors: Piotr Pruski, Stefan Paszek
• Format: Article
• Language: English
• Published: ENERGA SA 2015-06-01
• Series: Acta Energetica
• Subjects: power system; angular stability; eigenvalues associated with electromechanical phenomena; transient states
• Online Access: http://actaenergetica.org/en/articles/acta-energetica-022015/calculations-of-electromechanical-eigenvalues-based-on-generating-unit-instantaneous-power-and-angular-speed-waveforms-at-a-step-disturbance/

The paper presents the results of calculations of eigenvalues (associated with electromechanical phenomena) of a power system model state matrix made on the basis of analysis of disturbance waveforms of generating unit instantaneous power and angular speed. The waveforms that occur after introducing a disturbance in the form of a change in the voltage regulator reference voltage in one of the power system generating units were taken into account in the calculations. The power system model included the impact of a central frequency regulator. The eigenvalue calculation method used in the investigations consists in approximation of the analysed instantaneous power disturbance waveforms by the waveforms being a superposition of modal components associated with the searched eigenvalues and their participation factors. This approximation involves the minimisation of an objective function defined as the mean square error between the approximated and approximating waveforms. For minimisation of the objective function, a hybrid optimisation algorithm consisting of serially connected genetic and gradient algorithms was used. This combination allows one to eliminate fundamental drawbacks of both algorithms.