Fast frequency response in UK grid — Challenges and solution

The stability of power systems, especially regarding frequency and voltage, is gaining attention due to increasing shares of renewable sources. This development is particularly critical for island grids with ambitious renewable integration plans, such as the UK transmission system. Motivated by an expected future inertia gap, TSOs are looking for possibilities to improve their system's frequency response. This paper presents a supercapacitor based approach to damp frequency within the first 10 seconds after the frequency event. The solution is evaluated for a generic minimal grid example tuned to represent an actual critical frequency event from 2014. A rate of change of frequency (ROCOF) based control and a droop control are compared and advantages of each control regime are highlighted.