GE 845 Instruction Manual page 192

SYSTEM
4–88
XFMR THERMAL CAPACITY
Range: 0.00 to 200.00 kWh/°C in steps of 0.01
Default: 1.00 kWh/°C
The setting is available from the transformer nameplate data. If not, refer to the
following calculations.
For the "OA" and "FA" cooling types:
C = 0.06 (core and coil assembly in lbs) + 0.04 (tank and fittings in lbs) +1.33 (gallons of
oil), Wh/°C; or
C = 0.0272 (core and coil assembly in kg) + 0.01814 (tank and fittings in kg) + 5.034 (L of
oil), Wh/°C
For the "Non-directed FOA/FOW" (non-directed forced-oil-air/forced-oil-water) or
"Directed FOA/FOW" (directed forced-oil-air/forced-oil-water) cooling types, the
thermal capacity is given by:
C = 0.06 (core and coil assembly in lbs.) + 0.06 (tank and fittings in lbs.) + 1.93 (gallons of
oil), Wh/°C; or
C =0.0272 (weight of core and coil assembly in kg) + 0.0272 (weight of tank and fittings in
kg) + 7.305 (L of oil), Wh/°C
For dry-type power transformers:
C = 0.048 x (weight of copper winding); or
C = 0.015 x (weight of core and copper windings from the nameplate); or
C = 0.12 x (weight of aluminum windings); or
C = 0.02 x (weight of core and aluminum coils from the nameplate)
WNDG THERMAL TIME CONSTANT
Range: 0.25 to 15.00 min in steps of 0.01
Default: 2.00 min
This setting is required for the insulation aging calculation. If this value is not available
from the transformer data, select "2 min."
ENERGIZATION WINDING SOURCE
Range: None, CT Bank 1-J1, CT Bank 2-K1, CT Bank 2-K2
Default: None
Required for generating transient record or oscillography during an energization event
of the transformer. This setting enables you to capture current waveform through
corresponding CT on the winding side where energization happens on the transformer
and compute/pick various parameters during an energization event. Voltage bank J2
will be taken into consideration for generating voltage waveform based on the 845 order
code.
YEAR OF MANUFACTURE
Range: 1950 to 2100
Default: 1950
This setting captures the manufacturing year of the transformer as present in the
transformer nameplate data or manufacturing records.
Windings
Path: Setpoints > System > Transformer > Winding 1
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS