IMPACT OF FAST FREQUENCY RESPONSE ON POWER SYSTEM TRANSIENT STABILITY

This paper investigates the impact of fast frequency response (FFR) on the transient stability of power systems. Focus is paid on the effects of FFR injection location within the transmission network. To allow the analysis to be easily generalised to other low inertia systems, a test system incorporating wind generation and HVDC interconnectors has been used. The FFR is provided by distributed storage devices with grid-following converters. It is shown that FFR can reduce transient stability despite the fact that frequency excursions are arrested. Synchronous generators in the system that are initially operating with a high relative angle displacement and which have low synchronous kinetic energy are considered critical with respect to this analysis. FFR delivered electrically close to critical generators is shown to cause larger angle divergence and will result in a greater chance of transient instability. Variations in system inertia, FFR capacity, disturbance location and network topology have also been stud-ied to establish how severely the transient stability is affected when FFR is delivered at different locations within the system.