Probing signal design for enhanced damping estimation in power networks

•A probing design method guaranteeing damping estimations with a user-defined variance.•It enables trade-off between the probing signal’s power and that of the measurement.•A full mathematical elucidation of the probing method with custom parametrization.•Describes a discrete-time transfer function wrt frequencies and damping coefficients.•Nonlinear and linear power system models are developed using Modelica. Electromechanical oscillations are inherent to power networks. Although it is possible to partially damp these oscillations, it is impossible to eliminate them completely. This oscillatory behavior can lead to major breakdowns in power networks, especially when the damping is relatively low. It is therefore important to provide accurate estimations of the network’s damping values. These estimation can be obtained via system identification for which a probing signal needs to be designed. This paper presents a framework for designing a specific probing signal that is able to provide accurate damping estimations with a user-defined variance. A power spectrum of the probing signal is determined by solving an optimization problem with Linear Matrix Inequality constraints. The objective function is defined as a weighted sum of the probing signal’s power and a level of disturbance caused by probing the network. A desired level of the damping estimation’s variance is set as a constraint. The time-domain realization of the obtained power spectrum is described by a multisine, which is the actual probing signal applied to the network. The employed framework is demonstrated through nonlinear simulations using the Kundur with an embedded HVDC link and NORDIC 44 networks.