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Frequency response too slow

asked 2017-03-24 00:54:35 -0600

Wpower gravatar image

updated 2017-03-25 18:03:44 -0600

Hi guys in my dynamic simulation of a generator tripping event, the frequency recovered very slowly from the lowest point (the Nadir point or Point C in NERC's definition) to the first stable point (Point B By NERC). This simulation is to replicate a historical event which actually recovered pretty fast, only a few seconds from Point C to Point B, while my simulation takes 20 to 30 secs. Any idea what could be reasons? Thanks a lot!

Added on Mar 25: To all experts on this matter, can you list the factors that affect the recovery rate of frequency from lowest point to the first stable point? I have tried load response rate, amount of available generator governors, and droop characteristics. However, if I adjust some of these factors to provider faster frequency support, then my Nadir point could be too high compared to actual.

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answered 2017-03-24 02:29:32 -0600

perolofl gravatar image

One reason can be that your governors have hit their maximum limits during the simulation, i.e. there is not enough with spinning reserve for a fast acceleration of the system after the minimum frequency.

Is the frequency recovery normal after trip of a smaller generator?

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Thank you perolofl. I checked and my governors haven't hit limits at the lowest frequency. Many of them did hit the limits about 20 secs after the event. However, my problem is the freq recovery within the first 5-10 secs is too slow.

Wpower gravatar imageWpower ( 2017-03-25 17:59:56 -0600 )edit

Is the frequency recovery better if you trip a smaller generator, e.g. half the size? Which governor models are used? Do you have PID regulators with high derivation gain?

perolofl gravatar imageperolofl ( 2017-03-27 01:19:24 -0600 )edit

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Asked: 2017-03-24 00:54:35 -0600

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Last updated: Mar 25 '17