Effects of the synthetic inertia from wind power on the total system inertia after a frequency disturbance

Abstract

The future power systems face several challenges; one of them is the use of high power converters that virtually decouple primary energy source from the AC power grid. An important consequence of this situation is their effect on total system inertia and the ability to overcome the system's frequency disturbances. The wind power industry has created a controller to enable inertial response on wind turbines generators: Synthetic Inertial. This paper evaluates the effects of the inertia emulation of wind turbines based on full-converters and their effect on total system inertia after frequency disturbances happen. The main contribution of this paper is to demonstrate (based on simulations) that during an under-frequency transients on future power systems, synthetic inertia does not completely avoid worse scenarios in terms of under-frequency load shedding. The extra power delivered from a wind turbine during frequency disturbances can increase “momentary” the total system inertia and substantially reduce the rate of change of frequency providing time for the active governors to respond. However, synthetic inertia might not completely avoid under-frequency load shedding.