Transformer Differential Relay Slope Characteristics

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anaz

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Dear All

Can anyone help me,
1.how to calculate howmuch current we have to inject ( Idiff and Irest.) , to test the differential characteristics for simens diffrential relay 7UT613,setting:Idiff=0.3I/In,slope1=0.25,slope2=0.50,Basepoint1=0,basepoint2=2.5 and Idiff>>=11 I/In,inorder to plot the slope characteristics
 
transformer differential relay testing..

transformer differential relay testing..

Dear all..

anybody have excel spreadsheet to do slope test for transformer differential relays (Siemens,ABB & Alstom make)

regards..
 
Anaz...

Slope settings compensate for CT errors! Can you provide specifics:

o Xfmr-size;

o Primary, Secondary, Tertiary (if any) kV;

o Pri'y, Sec'y, Tert'y, winding configuration (Delta or Wye);

o Pri'y, Sec'y, Tert'y, line-CT sizes and ratios!

Regards, Phil Corso
 
o Xfmr-size;40MVA

o Primary, Secondary, Tertiary (if any) kV;115/13.8kV,No teritiary

o Pri'y, Sec'y, Tert'y, winding configuration (Delta or Wye);Pri-Delta,Sec-Yn1

o Pri'y, Sec'y, Tert'y, line-CT sizes and ratios! Pri- 300/5A, Sec- 2000/5A

Relay settings are as given below
Idiff=0.3I/In,slope1=0.25,slope2=0.50,Basepoint1=0,basepoint2 =2.5 and Idiff>>=11 I/In

we are using 7ut613 siemens relay,manual shows Idiff=/I1+I2/, I rest=/I1/+/I2/ and i want to test slope for Single phase to Ground fault,Phase-Phase fault, and three phase fault
so,how to inject and how much amps.Also,how to find out kneepoint1 and kneepoint2

thank you sir
 
Anaz...

For ground-fault, the NGR value is needed!

Actually, you need Protective Relaying 101! For that I rcommend:

Prof J. Lewis Blackburn's, "Siient Sentinals" (ca 1957-1984)

The "Modern" Version is "Applied Protective Relaying"; Library of Congress # 76-6880!

Both texts have a Template which simplifies the Ratio-Check procedure!

Phil Corso
 
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