Setting Guidelines For Short-Interconnected Biased Differential Protection - GE P642 Technical Manual

Chapter 6 - Transformer Differential Protection
Now set the current differential parameters as follows:
Setting in GROUP 1 DIFF PROTECTION
Trans Diff
Set Mode
Is1
K1
Is2
K2
tdiff
Is-CTS
Is-HS1
HS2 Status
Is-HS2
Zero seq filt HV
Zero seq filt LV
Zero seq filt TV
IH2 Diff Block
IH2 Diff Set
Cross Blocking
CT Saturation
No Gap
IH5 Diff Block
IH5 Diff Set
Circuitry Fail
The differential element does not protect the tertiary winding. Unloaded delta-connected tertiary windings are
often not protected. If protection is required, the delta winding can be earthed at one point through a current
transformer used to provide instantaneous overcurrent protection for the tertiary winding.
5.5 SETTING GUIDELINES FOR SHORT-INTERCONNECTED BIASED DIFFERENTIAL
PROTECTION
The P645 can be used to protect busbars. Consider the five feeders - single bus scheme and its differential
protection zone shown below:
130
Enabled
Advance
200.0e-3 PU
20.00%
1.000 PU
80.00%
0 s
1.500 PU
10.00 PU
Disabled
32.00 PU
Disabled
Disabled
Disabled
Enabled
20%
Enabled
Enabled
Enabled
Enabled
35%
Disabled
Value
P64x-TM-EN-1.3
P64x