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5 SETTINGS
c) WINDINGS 1 TO 5
PATH: SETTINGS
SYSTEM SETUP
WINDING 1
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
MESSAGE
The settings specific to each winding are shown above.
Transformer differential protection uses the following calculated quantities (per phase): fundamental, second harmonic, and
fifth 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
winding, so as to obtain zero (or near zero) differential currents under normal operating conditions. Traditionally, these cor-
rections were accomplished by interposing CTs and tapped relay windings with some combination of CT connections.
The T60 simplifies these configuration issues. All CTs at the transformer are connected wye (polarity markings pointing
away from the transformer). User-entered settings in the relay characterizing the transformer being protected and allow the
relay to automatically perform all necessary magnitude, phase angle, and zero-sequence compensation.
This section describes the algorithms in the relay that perform this compensation and produce the required calculated
quantities for transformer differential protection, by means of the following example of a delta-wye (Δ-Y) connected power
transformer with the following data:
Table 5–6: EXAMPLE DELTA-WYE CONNECTED POWER TRANSFORMER DATA
DATA
Voltage Phasor Diagram
Phase Shift
Grounding
Rated MVA
Nominal φ-φ Voltage
CT Connection
CT Ratio
Auxiliary Cooling
The abbreviated nomenclature for applicable relay settings is as follows:
Rotation
=
SETTINGS
w
=
SETTINGS
total
Compensation
=
SETTINGS
Source [w]
=
SETTINGS
GE Multilin
TRANSFORMER
WINDING 1 SOURCE:
SRC 1
WINDING 1 RATED MVA:
100.000 MVA
WINDING 1 NOM φ-φ
VOLTAGE:
220.000 kV
WINDING 1
CONNECTION: Wye
WINDING 1 GROUNDING:
Not within zone
WINDING ~ ANGLE WRT
WINDING 1:
WINDING 1 RESISTANCE
3φ:
10.0000 ohms
WINDING 1
Δ
(DELTA) CONNECTION
0°
In-zone grounding bank
100/133/166 MVA
220 kV
Wye
500/5
Two stages of forced air
SYSTEM SETUP
POWER SYSTEM
SYSTEM SETUP
TRANSFORMER
SYSTEM SETUP
TRANSFORMER
SYSTEM SETUP
TRANSFORMER
T60 Transformer Protection System
WINDING 1(4)
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
(or the user-defined name)
Range: 0.001 to 2000.000 MVA in steps of 0.001
Range: 0.001 to 2000.000 kV in steps of 0.001
Range: Wye, Delta, Zig-zag
Range: Not within zone, Within zone
Range: –359.9 to 0.0° in steps of 0.1, ('~' > 1)
(shown when viewed Winding is not Winding 1)
0.0°
Range: 0.0001 to 100.0000 ohms in steps of 0.0001
Y (WYE) CONNECTION
30° lag (i.e. phases of wye winding lag
corresponding phases of delta winding by 30°)
100/133/166 MVA
Two stages of forced air
PHASE ROTATION
GENERAL
NUMBER OF WINDINGS
GENERAL
PHASE COMPENSATION
WINDING w
WINDING w SOURCE
5.4 SYSTEM SETUP
WINDING 2
Ungrounded
69 kV
Wye
1500/5
5-81
5
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