GE 845 Instruction Manual page 193

CHAPTER 4: SETPOINTS
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
..\Transformer\Winding 1
Item Name
Signal Input
Rated MVA
Nominal Ph Ph Voltage
Connection
Grounding
Wndg Resistance (3 ph)
W 1
Path: Setpoints > System > Transformer > Winding 2(3)
..\Transformer\Winding 2
Item Name
Signal Input
Rated MVA
Nominal Ph Ph Voltage
Connection
Angle With Respect To W1
Grounding
Wndg Resistance (3 ph)
W 2
The settings specific to each winding are shown above.
All transformer windings from 845 are associated with CT bank inputs. Depending on the
selected 845 order code, the following CT banks represent the winding currents:
1. 845 orders for two-winding transformers without voltage inputs:
– Winding 1-K1 CT bank
– Winding 2-K2 CT bank
2. 845 orders for two-winding transformers with voltage inputs:
– Winding 1-J1 CT bank
– Winding 2-K1 CT bank
Voltage inputs: J2 VT bank
3. 845 orders for three-winding transformers (voltage inputs are always included):
– Winding 1-J1 CT bank
– Winding 2-K1 CT bank
– Winding 3-K2 CT bank
Voltage inputs: J2 VT bank
Transformer differential protection uses calculated quantities (per phase): fundamental,
2nd harmonic and 5th harmonic differential current phasors, and restraint current
phasors. This information is extracted from the current transformers (CTs) connected to the
relay by correcting the magnitude and phase relationships of the currents for each
Value Unit
CT Bank 1 J1
5.000 MVA
13.800 kV
Wye
Not Within Zone
10.0001 ohms
Value Unit
CT Bank 1 J1
5.000 MVA
13.800 kV
Wye
0 °
Not Within Zone
10.0000 ohms
SYSTEM
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