GE 750 Instruction Manual page 253

CHAPTER 5: SETPOINTS
5.8.2 Synchrocheck

SYNCHROCHECK
750 FEEDER MANAGEMENT RELAY – INSTRUCTION MANUAL
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PATH: SETPOINTS S7 CONTROL
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If a breaker can be a paralleling point between two generation sources, it is common
practice to automatically perform a check to ensure the sources are within allowable
voltage limits before permitting closing of the breaker. Synchrocheck provides this feature
by checking that the bus and line input voltages are within the programmed differentials of
voltage magnitude, phase angle position, and frequency. If this feature is enabled, the
check will be performed before either manual close or automatic reclose signals can
operate the Close Output Relay. The synchrocheck programming can allow for permitted
closing if either or both of the sources are de-energized. The measured line input voltage
magnitude and frequency are also made available as actual values under
. The frequency is only displayed if the voltage at the relay terminals

SYNCHRO VOLTAGE
is at least 10.0 V. The differential values of angle, magnitude, and frequency are also made
available for display.
With a Delta connected Bus VT, Phase to Neutral voltages cannot be determined. Thus
Synchrocheck cannot be used with a Delta connected Bus VT and a Wye connected Line
VT.
The
DEAD SOURCE PERMISSIVE
that bypass synchrocheck and permit a breaker closure. The voltage levels that determine
whether a source is dead or live are configurable in the four setpoints following this one.
The
DEAD SOURCE PERMISSIVE

SYNCHROCHECK
SYNCHROCHECK
FUNCTION: Disabled
SYNCHROCHECK
RELAYS (3-7): -----
DEAD SOURCE
PERMISSIVE: Off
DEAD BUS MAX
VOLTAGE: 0.20 x VT
DEAD LINE MAX
VOLTAGE: 0.20 x VT
LIVE BUS MIN
VOLTAGE: 0.80 x VT
LIVE LINE MIN
VOLTAGE: 0.80 x VT
MAX VOLTAGE
DIFFERENCE: 2.00 kV
MAX ANGLE
DIFFERENCE: 24°
MAX FREQ
DIFFERENCE: 2.00 Hz
setpoint selects the combination of dead and live sources
range is as follows:
S7 CONTROL
Range: Disabled, Alarm,
Latched Alarm,
Range: Any combination of 3
to 7 Auxiliary relays
Range: Off, DB&DL, LL&DB,
DL&LB, DL|DB,
Range: 0.00 to 1.25 x VT in
steps of 0.01
Range: 0.00 to 1.25 x VT in
steps of 0.01
Range: 0.00 to 1.25 x VT in
steps of 0.01
Range: 0.00 to 1.25 x VT in
steps of 0.01
Range: 0.01 to 100.00 kV in
steps of 0.01
Range: 0 to 100° in steps of 1
Range: 0.00 to 5.00 Hz in
steps of 0.01
A2 METERING
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