TCC curve in excel 1

[Fazlay]

I was trying to draw TCC curve of some relays. While going through my office's old files, i found a excel file where previous employees (10-15 years ago) draw TCC curves of some relays . I couldn't figure out how they have manipulated required data.

Here is the file that i found . Relay Curve file (Also attached the file in attachment)
They plotted below relays in that excel file

it will be a great help for me if anyone give me any hints/ clue about how they make the curves .

 

[HamburgerHelper]

Each standard relay curve , ANSI or IEC, has an associated equation with pick up and time dial.

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If you can't explain it to a six year old, you don't understand it yourself.

 

[dpc]

For the old Kyle VWE TCCs, I don't think there is an equation. You would need to get an actual TCC and digitize the curve, then use a curve-fitting function to draw the curve.

 

[jghrist]

They didn't use relay equations. It looks like they got time & current values at many different points from the output of a coordination program of some sort and then modified the values by factors such as minimum trip values or CT ratios and then just plotted the values in Excel.

 

[ScottyUK]

I posted the IEC and IEEE equations fairly recently - you started another thread on this same topic: thread238-443950

 

[mgtrp]

It's not perfect, but the nice folks at Basler have made an attempt at fitting the recloser curves already. If you hunt around on their website near the bottom of the 'Technical Resources' section of any of their protection relays, you should find it.

Cheers,
mgtrp

 

[Fazlay]

@scottyUK
with your equation , I have already tried to manipulate required data.But the data doesn't match with the excel file data . That’s why I become confused

 

[Fazlay]

@dpc what do you mean by actual TCC?

 

[ScottyUK]

Fazlay,

I haven't tried the IEEE equations, but the IEC ones work fine - somewhere I have an old Excel sheet which accepts the time and current multipliers and plots the curves. I think it can handle up to four curves - if I can find it I'll post a copy.

 

[davidbeach]

Electromechanical relays, fuses, hydraulic reclosers, and the like don’t have equations per se, times are measured at various currents and plotted. Curve fits of varying quality can be made and lookup tables produced. In the IEEE/ANSI world, if not in the IEC world, the are general forms for the equations, but the exact coefficients are determined by the manufacturer.

The coefficients in the Basler paper mentioned above were hand tweaked for the best match to scanned copies of the Cooper recloser curves.

 

[Fazlay]

ScottyUK@ ... it will be a great help for me

 

[ScottyUK]

Hi Fazlay,

See if the attachment helps.

 

[Fazlay]

Thank you Mr.ScottyUK , your programme works perfectly .
Few days ago i also discussed with a senior engr. , He gave me a programme developed by copper .

With that programme they made that excel sheet