Hi all friends,
Do you have a circulating fault currents scheme in Star/delta, Delta/star, star/star transformers for differential protection? Circulating directions / current magnitudes...
Also calculations which differential relay calculate.....There s no any details in manuals.
Thanks a lot.
Hi guys,
I was trying to synhronize two lines. Voltage difference-frequency difference and angle difference is almost 0. Values are always within limits. But relay inconsistenly gives Synchron OK.
Sometimes it gives "OK", sometimes NOT. And there s no specific time for giving Synchron OK...
Hi friends,
I would like to ask you a question.
If the residual overvoltage fault occurs on F1 , What will A and B see ? Same residual overvoltage magnitude ? Or Will they see the fault ...
Hi to all,
I would like to ask you a question about routine test of circuit breakers.
I have a Medium Voltage CB to do maintenance. I know how to do contact resistance test, but I checked all standarts and I coulndt find a percentage about approving " Did the test pass or no" .
Do you have...
Hi everyone, sorry for my english..I m not well experienced guy.
I just want to know that is there any much clear document about "current flows and calculations during faults in transformer"
I checked many documents in this forum and in others.But I coulndt find it.
By the way, Can you...
hi friends,
I was entering set values of differential protection relay.
I realized that there are only 2nd and 5th harmonicc blocking.
Why dont we use 3rd or other harmonic blocking ?
Thanks
Hi guys,
I just wanna ask a question to you.
I m at Power Plant and I m using L30 Line current differential relay.
I tried to energize the line and then It trips ,I did three times and gave me same result.
In relay software,there s no CT Polarity configuration , there s no even in manual.
I...
Hi ,
I got earth fault trip on my MV incoming feeder relay. I wanna ask that if there is earth fault , how can we or relay determine the faulted phase ?Is it possible ? By the way , customer dont use the voltage information for this relay.
Thanks...
Hi friends ,
I have a problem , I export my relay parameters as xrio , But i couldnt import Omicron File. Is it possible to import parameters to Omicron file _?
Thanks
Hi friends,
I m at 1500 mw substation now.We try to make first fire of turbine..But during start up with LCI , I realized that currents were ot balanced for unit differential relay.
It seems B and C phases are swaped.Currents were enogh to see differential current, but I couldnt see any...
Friends,
I have a question about vector group YnD11.
If we assume current flows from primary to secodary, angles will be Y (0°) - D (30°).
But if current flows secondary to primary , which angles will occur ? Y (30°) - D (0°)?
Thanks for your time.
Hi frineds ,
I m starter for testing T60 relay.And I m not sure about setting of winding angles.I couldnt understand how to set.
I drawed it , can you explain that what angles should be set and why ?
Files are on attchment...
Friends ,
There is an error on screen of relay , [highlight #EF2929]" RTD meas. error, X105 Code 100"[/highlight]
I coulndt fix it.http://files.engineering.com/getfile.aspx?folder=04583a31-0ef0-4dbf-8bbb-9ca158726b76&file=20160725_173947.jpg
Hi friends ,
I m relay engineer. I m at substation now. During testing thermal overload test , I couldnt reset the thermal degree...Waiting to be zero ( degree) takes much time .
I disabled the function but still same..I just want to test from zero.
Rated Current : 1,00
Initial thermal val...
Hello friends,
I have a question...Omicron cpc100 manual says that if you want to test of transformer ratio , you should use following calculationames.
Ratio = ( Vpri / Vsec ) * sqrt (3)/2
But I couldn't understand "sqrt (3)/2" where comes from ?
Friends ,
When I try to transfer busbars ; sometimes transfer is succesfull , sometimes not .There s no time inhibit.Synchron is ok.
HSBT relay sends close command to incomers CB's .But still sometimes we cant do transfer.
But I coulndt find the problem.
Thanks...
