GE t60 Instruction Manual page 207

5 SETTINGS
C = 0.048 × (weight of copper winding); or
C = 0.015 × (weight of core and copper windings from the nameplate); or
C = 0.12 × (weight of aluminum windings); or
C = 0.02 × (weight of core and aluminum coils from the nameplate)
• WINDING THERMAL TIME CONSTANT: Required for insulation aging calculation. If this value is not available from
the transformer data, select "2 min.".
c) WINDINGS 1 TO 5
PATH: SETTINGS SYSTEM SETUP
WINDING 1
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The settings specific to each winding are shown above.
Transformer differential protection uses the following calculated quantities (per phase): fundamental, 2nd harmonic, and 5th
harmonic differential current phasors, and restraint current phasors. This information is extracted from the current trans-
formers (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 corrections
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 Δ-Y connected power transformer
with the following data:
GE Multilin
TRANSFORMER WINDING 1(4)
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: 0.0°
WINDING 1 RESISTANCE
3φ: 10.0000 ohms
T60 Transformer Protection System
5.4 SYSTEM SETUP
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)
Range: 0.0001 to 100.0000 ohms in steps of 0.0001
5
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