GE 745 - 5.4.7 Voltage Input; 5.4.8 Ambient Temperature

CHAPTER 5: SETPOINTS S2 SYSTEM SETUP
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL 5–39
custom FlexCurve™ has setpoints for entering the times-to-trip at various levels of pickup.
The levels are as follows: 1.03, 1.05, 1.1 to 6.0 × pu in steps of 0.1, and 6.5 to 20.0 × pu in
steps of 0.5.
• FLEXCURVE A DELAY AT n × PU: Enter the trip time for n = 1.03. 1.05,..., 20.0 × pu for
FlexCurve™ A(C). The messages that follow sequentially correspond to the trip times
for the various pickup levels as indicated above.
5.4.7 Voltage Input
PATH: SETPOINTS  S2 SYSTEM SETUP  VOLTAGE INPUT
The 745 provides a voltage input for the purposes of energization detection (for the
energization inhibit feature of the percent differential element), overexcitation protection
(the volts-per-hertz 1 and 2 functions), and frequency protection (the underfrequency,
frequency decay, and overfrequency functions). Note that the frequency elements will use
the winding 1 phase A current input if voltage is not available.
• VOLTAGE INPUT PARAMETER: Enter the winding and phase of the voltage connected
to the voltage input.
• NOMINAL VT SECONDARY VOLTAGE: Enter the nominal secondary voltage (in volts) of
the voltage transformer.
• VT RATIO: Enter the ratio of the voltage transformer.
5.4.8 Ambient Temperature
PATH: SETPOINTS  S2 SYSTEM SETUP  AMBIENT TEMP
• AMBIENT RTD SENSING: Select “Enabled” to use an RTD to monitor ambient
temperature.
 VOLTAGE INPUT [] VOLTAGE SENSING:
Disabled
Range: Enabled, Disabled
MESSAGE
VOLTAGE INPUT
PARAMETER: W1 Van
Range: W1, W2, W3;
Van, Vbn, Vcn, Vab, Vbc, Vca
MESSAGE
NOMINAL VT SECONDARY
VOLTAGE: 120.0 V
Range: 60.0 to 120.0 in steps of 0.1
MESSAGE
VT RATIO:
1000:1
Range: 1 to 5000:1 in steps of 1
 AMBIENT TEMP [] AMBIENT TEMPERATURE
SENSING: Disabled
Range: Enabled, Disabled
MESSAGE
AMBIENT RTD TYPE:
100 Ω Platinum
Range: 100 Ω Platinum, 120 Ω Nickel,
100 Ω Nickel, By Monthly
Average
MESSAGE
AVERAGE AMBIENT TEMP
FOR JANUARY: 20°C
Range: –50 to 125°C in steps of 1
↓
MESSAGE
AVERAGE AMBIENT TEMP
FOR DECEMBER: 20°C
Range: –50 to 125°C in steps of 1