Ask Your Question

# 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

edit retag close merge delete

## Comments

How did you change the rest of the generation when increasing solar? What type of governors do you have? Did the frequency minimum also decrease or just your calculated average RoCOF?

## 1 answer

Sort by » oldest newest most voted I think you should check following assumptions of your simulations:

1. Did your RoCoFs have the same time frame? Usually, people don't compare RoCoF of the different time frame.
2. Did you simulate the quick frequency response components? That may affect the RoCoF.
3. Check your primary frequency control? Is there any different in the droop of simulations? How many generations taking part in the frequency control in each case? How many active power reserve?

Theoretically, RoCoF at the instant of losing a generator is calculated by the formula:

RoCoF = f0Delta P/(2Hi*Si) with Delta P is the active power imbalance and Hi and Si is inertia and apparent power rating of generator i. Given the Hi of SPVs are zero. RoCoF are increase with increasing of SPV penetration rate.

more

## Comments

Which one do you mean? About the RoCoF, I need to clarify that the output is in 1/Sec. If you want to have ouput in Hz/Sec, you need to multiply the output with the rated frequency: f.

The rotating energy for a generator is Hi*Si, where Si is nominal MVA rating. The formula is RoCoF = deltaP / (2*sigma(Hi*Si)) * fn [Hz/s]. The actual electrical power Pi for the generators does not affect the RoCoF.

## Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

[hide preview]

## Stats

Asked: 2018-10-11 04:55:40 -0500

Seen: 109 times

Last updated: Oct 23 '18