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What if you initialise with too few bus numbers?

asked Jan 9 '12

JervisW gravatar image

PSSE's psseinit function asks for the number of bus numbers to initialise with. What happens if you enter a low number like 40? Is there a benefit to entering a lower number than a higher number like 80000?

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I am going to try this later today. Wish me luck!

JervisW gravatar imageJervisW (Jan 23 '12)

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answered Jan 30 '12

JervisW gravatar image

updated Oct 1 '13

PSSE must be initialised with sufficient bus numbers

I wanted to know if initalising PSSE with a low number of buses would cause a crash, or give incorrect results. I wrote a small program that initialises PSSE with 10 up to 200,000 buses and observed the memory usage, and whether PSSE crashed.

The small program then loads a saved case with 1600 buses and solves it.

The tests crashed when the initialised bus number was less than the number of buses in a raw file.

Here is a chart showing the memory usage that I observed for each number of initialised buses:

image description

I advise to select around 10,000 buses, which seems to be adequately sized, unless you know there will be more than that many in your system.

(edit)

Thanks to @EBahr for pointing out, but PSSE actually limits the number of CONs VARs, STATEs and ICONs available to the dynamics case depending on the bus limit.

So if you are doing some dynamics work, it would pay to have as many dynamic variables available to you as possible and you should set your bus limit at 150,000 buses which is the maximum number of buses.

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Hi @JervisW, I have this feeling that I am missing something here. Could you please explain how you built a saved case with 1600 buses?

amaity gravatar imageamaity (Feb 19 '12)

@amaity sorry I only just saw this comment here. We have saved cases that represent the entire australian network. There are a lot of buses inside!

JervisW gravatar imageJervisW (Jul 3 '12)
1

@JervisW Just wanted to comment that while this might make sense for power flow, it might give you some problems in dynamics. The lower the inialised buses value, the lower the amount of CONs/VARs/STATEs/ICONs that are available. ie; 12,000 buses = 80,000 CONs, 150,000 buses = 515,800 CONs.

EBahr gravatar imageEBahr (Sep 17 '13)

@EBahr are you able to expand on this a little, I'm curious about the CON limit. How would the limitation affect you?

JervisW gravatar imageJervisW (Sep 28 '13)

I have a custom piece of Fortran code that monitors frequency and voltage deviations of the entire system. So I save all the initial voltage voltage values as VARs, and each bus number as ICONs of the entire system. Then if relative voltage or frequency values go below certain thresholds

EBahr gravatar imageEBahr (Sep 29 '13)

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Asked: Jan 9 '12

Seen: 738 times

Last updated: Oct 01 '13