Relay Coordination Using Microsoft Excel

[OhioAviator]

Hello All,

Can someone point me in the right direction? I would like to electronically plot the coordinated TCC curves for a simple power system. I only need to coordinate three overcurrent devices (Multilin 469, Multilin MIFII, and Multilin 750), all at the same voltage level.

Instead of (a)using expensive power system engineering software (which we don't own and can't justify purchasing) or (b)using the time-honored method of overlaying TCC tracing paper on each relay's TCC curve, is there a way to create a TCC chart electronically using Microsoft Excel?

Thanks in advance for all your help!

 

[nightfox1925]

Yes you may. You can create a graph and select the logarithmic graph type. You can plot the relay curves by adding a curve that is referenced to table. You may create a table with embedded formula corresponding to the IEC or ANSI formula given by the manufacturer (IEC A, B, C etc) and simulate by varying short circuit and values against the PMS setting. You can simulate the S.C. ratings in fine steps and a range covering your calculated S.C. Then to you may also make a range with fine steps of your relay current settings. To add some fancy stuff, you can provide a scroller for your relay current settings using visual basic toggles and rest, use your imagination and creativity. I did this once and it worked and gave me smooth relay curve and I can move the curve upwards and downwards by scrolling the time and current scroll bars.

GO PLACIDLY, AMIDST THE NOISE AND HASTE-Desiderata

 

[cuky2000]

1) For general reference regarding relay curve see the enclose information:

http://cuky2000.250free.com/Relay1.jpg

2) For Multilin application, download the instruction manual from GE site. For 469 relay sample see page 4-32 of the enclosed link.

ttp://

http://www.geindustrial.com/products/manuals/469/469man-df.pdf

 

[OhioAviator]

Thanks for your responses, folks. Much appreciated.

I already have the TCC tables for the three relays loaded into Excel and can create the curves in an Excel chart. My question is, how can I plot the curves from the three different relays, each with their own different current pickup points in Excel?

Thanks!

 

[ScottyUK]

Years ago I put together a crude calculator in Excel to deal with the GEC relays and IIRC the Merlin Gerin ST series tripping units for their Masterpact ACBs. If I can find it I will upload it to somewhere and post a link. When you improve it maybe you could post it back!


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Sometimes I only open my mouth to swap feet...

 

[ijl]

Look the program at

http://pp.kpnet.fi/ijl

It contains several more or less standard relay curves, although no (literally) Multilin relays. The user can define new curves.

 

[Rodmcm]

Make a column of currents
Make a column for each relay
Use the formulae for standard relays curves to develope tripping time in each of the relay columns using the currents in the first colum
Plot the three relay columns on one graph with the current column as the X axis
Use log/log scale
Easy

 

[tinfoil]

Look at

http://www.sandc.com/fsa/coordinaide.asp

for a free on-line tool. (Of course, the devices available are biased towards S&C's products)

 

[mls1]

Use two columns for each curve, one for time and the other for current. Then select scatter plot with connected lines for the plot type. Once the plot is created, double click each axis and choose logarithmic scale in the scale tab and adjust the scale range as desired.

With the scatter plot you can choose which column is the x values and which is the y for each curve. If you are using the same time or current points for two or more plots you can use the same column for each.