Applications of Spectral Analysis Techniques for Estimating the Nordic Grid’s Low Frequency Electromechanical Oscillations

For power networks such as the Nordic Grid, that have operation constraints limits imposed by the existence of low-damped electromechanical oscillations, the estimation of electromechanical mode properties is of crucial importance for providing power system control room operators with adequate indicators of the stress of their network. This article addresses the practical application of different spectral analysis techniques that can be used for the estimation of electromechanical mode properties using data emerging from real synchronized phasor measurement units (PMUs) located at both the low-voltage distribution and high-voltage transmission networks of the Nordic grid. Emphasis is made on providing systematic approaches to deal with imperfect data found in practice so that accurate estimates can be computed.