# If Solar Generation increases in a power system, what is the expected effect on Rate of Change of Frequency (RoCoF)?

Hi, I am getting decreased RoCoF for increasing solar generation in my simulation result. I have doubt how valid this effect is? I used a simple formula to calculate this:

RoCoF= (Change in Frequency from Nominal Value till Frequency Nadir)/ (Time Required for this change)

```
For example: if the system frequency is 50 Hz and the frequency Nadir is 49.5 Hz and it took 0.5 Sec to go from 50 to 49.5 Hz, then according to the above mentioned formula,
RoCoF = ((50-49.5)/0.5) (Hz/Sec)
```

Can anybody please guide me about this basic queries? Thanks in advance