Performance Of Transformer Differential Protection And Monitoring Functions; Transformer Differential Protection; Matching Factors; Circuitry Fault Alarm - GE P642 Technical Manual

P64x
3 PERFORMANCE OF TRANSFORMER DIFFERENTIAL PROTECTION AND
MONITORING FUNCTIONS
3.1

TRANSFORMER DIFFERENTIAL PROTECTION

Pick-up
Drop-off
Pick-up and drop-off repeatability
Low set differential element operate time (High
Break Contact)
Low set differential element operate time (Standard
Contact)
High set 1 differential element operate time
High set 2 differential element operate time
DT operate time (High Break contact)
DT operate time (Standard contact)
Operate time repeatability
Disengagement time
2nd harmonic blocking pick-up
2nd harmonic blocking drop-off
5th harmonic blocking pick-up
5th harmonic blocking drop-off
3.2

MATCHING FACTORS

CT Type Max. sensitivity
Standard 43 mA
3.3

CIRCUITRY FAULT ALARM

Pick-up
Drop-off
Pick-up and drop-off repeatability
DT operate
Operate time repeatability
Disengagement time
Timer
P64x-TM-EN-1.3
Accuracy
Formula +/-5% or 20 mA, whichever is greater
0.95 x formula +/- 5%
< 1%
< 33 ms (currents applied at 1.2x pickup level or higher)
< 36 ms (currents applied at 1.2x pickup level or higher)
< 15 ms (currents applied at 2x pickup level or higher)
< 25 ms (currents applied at 2x pickup level or higher)
< 33 ms, whichever is greater (currents applied at 1.2x pickup level or
higher
< 36 ms, whichever is greater (currents applied at 1.2x pickup level or
higher
< 2 ms
< 15 ms
Setting +/-5% of setting
0.95 x setting +/-5%
Setting +/-5% of setting
0.95 x setting +/-5%
Permitted Matching Factor range
0.05 - 15
Formula +/-5%
0.95 x formula +/- 5%
< 4%
< 26 ms (currents applied at 2.5x pickup level or higher)
< 8 ms
< 26 ms
+/- 2% or 50 ms, whichever is greater
Chapter 21 - Technical Specifications
Matching factor for typical setting
Is1 = 0.2 pu
4.65
459