Understanding the impact of network topology on frequency stability considering continuous spatial-temporal disturbances from wind generation

Abstract

Low-inertia power systems with a large share of variable renewable energy have less ability to maintain system frequency stability. These networks are at the mercy of the variable meteorological conditions like wind speed fluctuations. This paper investigates the temporal and spatial behaviour of wind speed, how the wind variability impacts the system frequency response, and the role network topology has on the frequency transient stability. With the use of a Markov chain, the fluctuating behaviour of wind speed is then, modelled and characterised into two categories. The results reveal that wind speed fluctuations in continuous increasing/decreasing directions deplete the inertia kinetic energy in the system and drives the system closer to instability. For non-homogeneous network topology parameters, this work shows that transmission line reactance reduces the magnitude of the RoCoF fluctuations like inertia does. Due to the transmission line reactance, and the low spatial correlations of wind speed fluctuations, the impact of the perturbations is only significant on a local level. Thus, for overall network frequency stability, the local-area frequency stability should be insured first, for power systems considering large-scale and spatially distributed variable renewable generation integration.