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 Post subject: Ancient Load Flow Study
PostPosted: Tue Nov 27, 2012 12:03 pm 
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Anyone remember these days? This is a photo that I just took of one of my first load flow studies from around 1980. (I can't believe I kept this). The IBM 370 mainframe and card punching at it's finest. If you ever have modeling or software problems - at one time it was a lot worse :eek: .

[ATTACH=full]280[/ATTACH]


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PostPosted: Tue Nov 27, 2012 1:53 pm 
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Are you kidding? This is hysterical. Even more hysterical that you still had it.


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PostPosted: Wed Nov 28, 2012 8:14 am 
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Brings back memories. :eek:


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PostPosted: Wed Nov 28, 2012 11:03 am 
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M. Ambrose wrote:
Are you kidding? This is hysterical. Even more hysterical that you still had it.

Yes, when I moved recently, I cleaned out the basement and found a box of old stuff that hadn't seen daylight in years. This was in it. All I could do was laugh.

@JBD - more like nightmares :D

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PostPosted: Thu Nov 29, 2012 8:23 am 

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So I bet from that time frame, you also used a light box to draw time current curves?


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PostPosted: Thu Nov 29, 2012 4:36 pm 
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Catcher13 wrote:
So I bet from that time frame, you also used a light box to draw time current curves?

I used to tape them to a window.


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PostPosted: Mon Dec 10, 2012 8:58 am 

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Your comment about "load flow" is also interesting for in falls into the same category of displaced time. Load does not flow it is a POWER FLOW study to be more correct. Aka cycles and Hertz etc.
Merry Christmas


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PostPosted: Mon Dec 10, 2012 10:44 am 
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A colleague has told stories of conducting system studies by sticking a telephone receiver in a computer terminal so the terminal could communicate with the mainframe - he worked at Sohio in Cleveland in the early 80s.


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PostPosted: Tue Dec 11, 2012 8:56 am 
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I have only been doing this since DOS but i remember seeing analog computer in engineering school and being told it was used for powere system studies - see attachment


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PostPosted: Sun Dec 16, 2012 8:04 am 
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SPC300 wrote:
Your comment about "load flow" is also interesting for in falls into the same category of displaced time. Load does not flow it is a POWER FLOW study to be more correct. Aka cycles and Hertz etc.
Merry Christmas

Wow, so my college text book was wrong, the term that a very large utility used (where I worked in a past life) was wrong and so are many advertisements for services. Really kind of funny, I never thought about that perspective before but it is so obvious.
** Next debate: Electron flow vs. Current flow. :)

...and Merry Christmas to you too!

engrick wrote:
I have only been doing this since DOS but i remember seeing analog computer in engineering school and being told it was used for power system studies - see attachment


I used an analog board back in college. We used it for short circuit studies and load flow studies (oops - power flow studies). You scale everything, (per unit) and then use a huge breadboard and patch together the and dial in impedances values, patching them together with a series of male/male plug in patch cables. Then you use a specific voltage (very low) and see what percentage of current would flow to different loads and through each branch. Back in my utility days, the group I headed up still had people with the title "calculations clerk". This was more of a tech position but the title was a carry over from the days where people would just crunch numbers from the analog studies as well as other types of calculations.

jdsmith wrote:
A colleague has told stories of conducting system studies by sticking a telephone receiver in a computer terminal so the terminal could communicate with the mainframe - he worked at Sohio in Cleveland in the early 80s.


This was the "first laptop" You could have a "portable" computer i.e. not a mainframe taking up an entire room. Then you dial in, put the hand set of the hard wired land line, usually rotary dial phone (check history books :) ) into the cradle which accepted the ear and mouth end of the phone. It was slower than working with stone tablets but it did allow remote access which was an amazing feat back in the day.

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PostPosted: Wed Dec 26, 2012 7:20 am 
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engrick wrote:
I have only been doing this since DOS but i remember seeing analog computer in engineering school and being told it was used for powere system studies - see attachment


I worked on aircraft that used analog computers. The Central Air Data Computer actually contained bellows and clutches for 'Altitude Hold' and 'Mach Hold' Pitch Autopilot. These were replaced by digital (Octal) computers. I remember sitting there in the cockpit doing the math for the BIT test, sepatating out which bits were true and false. Unfortunately at that time, the BIT was unreliable, most often it was wiring that was the problem, not the indicated component.


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PostPosted: Wed Dec 26, 2012 7:24 am 
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brainfiller wrote:
Wow, so my college text book was wrong, the term that a very large utility used (where I worked in a past life) was wrong and so are many advertisements for services. Really kind of funny, I never thought about that perspective before but it is so obvious.
** Next debate: Electron flow vs. Current flow. :)


. . . Or electron flow vs. hole flow?

Hole flow or 'signal flow' (from positive to negative) is the way a LOT of troubleshooting is done


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PostPosted: Mon Feb 10, 2014 8:54 am 
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engrick wrote:
I have only been doing this since DOS but i remember seeing analog computer in engineering school and being told it was used for powere system studies - see attachment

Yes, I was going to say "that's not ancient, it's digital"

I can easily understand why Jim kept it. It probably cost several year's wages back then, depending on the size of the system that would be a quarter million dollar report in today's dollars. Too bad Jim can't go into a time machine and trade that report for equal value microsoft stock, or perhaps he did :D


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