GE 745 - 5.4 S2 System Setup; 5.4.1 Description; 5.4.2 Transformer

5–34 745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
S2 SYSTEM SETUP CHAPTER 5: SETPOINTS
5.4 S2 System Setup
5.4.1 Description
This group of setpoints is critical for the protection features to operate correctly. When the
relay is ordered, the phase and ground CT inputs must be specified as either 5 A or 1 A. The
characteristics of the equipment installed on the system are entered on this page. This
includes information on the transformer type, CTs, VT, ambient temperature sensor, onload
tap changer, demand metering, analog outputs and analog input.
5.4.2 Transformer
PATH: SETPOINTS  S2 SYSTEM SETUP  TRANSFORMER
To provide accurate and effective transformer protection, the parameters of both the
transformer and the system configuration must be supplied to the 745 relay.
• NOMINAL FREQUENCY: Enter the nominal frequency of the power system. This
setpoint is used to determine the sampling rate in the absence of a measurable
frequency. Frequency is measured from the VT input when available. If the VT input is
not available, current from Winding 1 Phase A is used.
 TRANSFORMER [] NOMINAL FREQUENCY:
60 Hz
Range: 50 Hz, 60 Hz
MESSAGE
FREQUENCY TRACKING:
Enabled
Range: Enabled, Disabled
MESSAGE
PHASE SEQUENCE:
ABC
Range: ABC, ACB
MESSAGE
TRANSFORMER TYPE:
Y/d30°
Range: Refer to Transformer types on
page 5–13
MESSAGE
LOAD LOSS AT RATED
LOAD: 1250 kW
Range: 0 to 20000 kW in steps of 1
(Auto-ranging; see table below)
MESSAGE
LOW VOLTAGE WINDING
RATING: Above 5 kV
Range: Above 5 kV, 1 kV to 5 kV, Below
1 kV
MESSAGE
RATED WINDING TEMP
RISE: 65°C (oil)
Range: 65°C (oil), 55°C (oil), 80°C (dry),
115°C (dry), 150°C (dry)
MESSAGE
NO-LOAD LOSS:
125.0 kW
Range: 0.1 to 2000.0 kW in steps of 0.1
(see description below)
MESSAGE
TYPE OF COOLING:
OA
Range: FA, OA, Directed FOA/FOW,
Non-Directed FOA/FOW
MESSAGE
RATED TOP OIL RISE
OVER AMBIENT: 10°C
Range: 1 to 200°C in steps of 1
MESSAGE
XFMR THRML CAPACITY:
1.00 kWh/°C
Range: 0.00 to 200.00 kWh/°C in steps
of 0.01
MESSAGE
WINDING TIME CONST:
2.00 min.
Range: 0.25 to 15.00 min. in steps of
0.01
MESSAGE
SET ACCUMULATED LOSS
OF LIFE: 0 x 10h
Range: 0 to 20000 x 10h in steps of 1