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Largest Mismatch Tolerance Error

asked 2021-03-07 20:59:07 -0500

Automation Guy gravatar image

updated 2021-03-07 20:59:40 -0500

Hello Everyone, I have implemented ACCC automation using Python and PSS/E. I have been getting an error saying largest mismatch tolerance some big number at bus # XYZ. Most of the time the bus with largest mismatch is outside of my sub-area of interest so I can simply disconnect the generator at that bus if there is any. However, at times the mismatch is shown at non-generator bus and I'm not sure how to resolve this in Python automation. Working through PSS/E GUI, we can manually go to a nearest bus with generator to the mismatch tolerance and simply disconnecting the generator will fix the problem however, I'm not sure how to implement this in automation.

Your help and advise is much appreciated.

Thanks in advance!!

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answered 2021-03-16 11:44:07 -0500

perolofl gravatar image

It seems strange to disconnect generators in order to fix the mismatch problem. Have you tested to lock the reactive power generation instead, i.e. set Qmax=Qmin for the concerned generators instead?

Make sure that the Qmax - Qmin difference is larger than 0.002 pu for all generators with unequal Q-limits. This is 0.2 Mvar for a saved case with 100 MVA system base. Generators with a smaller difference should be locked by setting both Q limits to (Qmax + Qmin)/2. These updates shall be done in the base case, before performing N-1 analysis.

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The reason for disconnecting generators is because those generators are far away from my area and have no impact on my area at all.

Automation Guy gravatar imageAutomation Guy ( 2021-03-16 13:35:25 -0500 )edit

What you suggested makes sense and might be quite useful if bus with largest mismatch bus is generator bus. How do we deal in automation if the bus with largest mismatch is non-generator bus? Generator that's causing issue might be few buses away and it becomes complicated to do what you suggested.

Automation Guy gravatar imageAutomation Guy ( 2021-03-16 13:38:23 -0500 )edit

Disconnecting generators will change the load flow in the network and the swing bus generation. It is better to GNET the generators, i.e. replace them with a load.

perolofl gravatar imageperolofl ( 2021-03-17 02:17:20 -0500 )edit

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Asked: 2021-03-07 20:59:07 -0500

Seen: 1,274 times

Last updated: Mar 16 '21