Prefault Values - GE 745 TRANSFORMER MANAGEMENT RELAY Instruction Manual

5 SETPOINTS
Table 5–9: SIMULATION MODES
MODE DESCRIPTION
Select Prefault Mode to simulate the normal operating condition of a transformer. In this
Prefault Mode
mode, the normal inputs are replaced with sample values generated based on the
programmed prefault values. Phase currents are balanced (i.e. equal in magnitude and
120° apart), and the phase lag between windings is that which would result under normal
conditions for the transformer type selected. The magnitude of phase currents for each
winding are set to the values programmed in S6 TESTING/SIMULATION/PREFAULT VALUES/W1
(2/3) PHASE ABC CURRENT MAGNITUDE. The magnitude of the voltage is set to the value
programmed in S6 TESTING/SIMULATION/PREFAULT VALUES/VOLTAGE INPUT MAGNITUDE. The
frequency is set to the value programmed in S2 SYSTEM SETUP/TRANSFORMER/NOMINAL
FREQUENCY.
Fault Mode Select Fault Mode to simulate the faulted operating condition of a transformer. In this mode,
the normal inputs are replaced with sample values generated based on the programmed
fault values. The magnitude and angle of each phase current and ground current of the
available windings, the magnitude and angle of the voltage input, and system frequency
are set to the values programmed under S6 TESTING/SIMULATION/FAULT VALUES.
A logic input, programmed to the Simulate Fault function, can be used to trigger the
transition from the Prefault Mode to the Fault Mode , allowing the measurement of element
operating times.
Playback Mode Select Playback Mode to play back a sampled waveform data file which has been pre-loaded
into the relay. In this mode, the normal inputs are replaced with 16-cycles of waveform
samples downloaded into the 745 by the 745PC program (from an oscillographic data file
in the IEEE "Comtrade" file format).
A logic input, programmed to the Simulate Playback function, can be used to trigger the
transition from the Prefault Mode to the Playback Mode , allowing the measurement of
element operating times.
This section contains the settings to configure prefault mode simulation.
S PREFAULT VALUES
S [ENTER] for more
W1 PHASE ABC CURRENT
MAGNITUDE: 1.0 x CT
VOLTAGE INPUT
MAGNITUDE: 1.0 x VT
GE Power Management
This message indicates the start of the PREFAULT VALUES section. To
continue these setpoints press
Range: 0.0 to 40.0 (steps of 0.1)
Enter the winding 1 (2/3) phase current magnitude (in terms of the winding
full load current) while in Prefault Mode.
Range: 0.0 to 2.0 (steps of 0.1)
Enter the voltage magnitude (in terms of the nominal VT secondary voltage)
while in Prefault Mode.
745 Transformer Management Relay
5.8 S6 TESTING

5.8.5 PREFAULT VALUES

or press for the next section.
E N TE R
M E SS AG E
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