Frequency Response

If demand is greater than supply the frequency falls.

Frequency is measured in Hertz (Hz) or cycles per second. Each cycle is the transition from peak to peak in a single wave

Why is it important?

When the frequency is too high then devices connected to the system may run "too hot" and blow up. When the frequency is too low, devices will not recieve enough power causing them to shut down.

The target is 50Hz.

All 'large' generators that are under grid code are required to provide mandatory frequency response.

Mandatory frequency response helps to fulfil NG's obligation to ensure sufficient generation and/or demand is held in automatic readiness to manage all frequency changes.

There is three mandatory frequency response modes:

-Primary - provision on additional active power within 10 seconds, sustained for 20 seconds

- Secondary - provision of additional active power within 30 seconds, sustained for 30 minutes

- High - The reduction in active power within 10 seconds of an event and sustained indefinitely.

In EDL we can see if any of our assets are on frequency response. These codes determine what type of frequency response is on :

- MN - Mode None - no frequency response

- MF - Mode Full - Primary, Secondary and High response

- MP - Mode Partial - Primary and High response