Enhancing stability performance of renewable energy generators by utilizing virtual inertia

This paper presents a method of improving the transient stability of power systems with high penetration of distributed generation. Most distributed generators are characterized by having small or even no intrinsic rotational inertia. When small inertia sources such as micro-turbine or non-inertial sources such as PV system are integrated to the power system, the overall rotating inertia will decrease significantly. This decrease in rotating inertia may cause loss of synchronism under some fault conditions and may lead to system instability. One of the solutions to overcome this problem is to use energy storage elements to provide virtual inertia. This paper presents a new method to include the energy storage devices as virtual inertia in the transient stability studies and utilizes the energy storage devices to enhance stability in systems with embedded distributed generation, as well as to determine the size of storage energy elements to maintain system stability.