GE D30 Instruction Manual page 253

5 SETTINGS
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The are two identical synchrocheck elements available, numbered 1 and 2.
The synchronism check function is intended for supervising the paralleling of two parts of a system which are to be joined
by the closure of a circuit breaker. The synchrocheck elements are typically used at locations where the two parts of the
system are interconnected through at least one other point in the system.
Synchrocheck verifies that the voltages (V1 and V2) on the two sides of the supervised circuit breaker are within set limits
of magnitude, angle and frequency differences. The time that the two voltages remain within the admissible angle differ-
ence is determined by the setting of the phase angle difference ΔΦ and the frequency difference ΔF (slip frequency). It can
be defined as the time it would take the voltage phasor V1 or V2 to traverse an angle equal to 2 × ΔΦ at a frequency equal
to the frequency difference ΔF. This time can be calculated by:
where: ΔΦ = phase angle difference in degrees; ΔF = frequency difference in Hz.
As an example; for the default values (ΔΦ = 30°, ΔF = 0.1 Hz), the time while the angle between the two voltages will be
less than the set value is:
If one or both sources are de-energized, the synchrocheck programming can allow for closing of the circuit breaker using
undervoltage control to by-pass the synchrocheck measurements (Dead Source function).
• SYNCHK1 V1 SOURCE: This setting selects the source for voltage V1 (see NOTES below).
• SYNCHK1 V2 SOURCE: This setting selects the source for voltage V2, which must not be the same as used for the
V1 (see NOTES below).
• SYNCHK1 MAX VOLT DIFF: This setting selects the maximum primary voltage difference in volts between the two
sources. A primary voltage magnitude difference between the two input voltages below this value is within the permis-
sible limit for synchronism.
• SYNCHK1 MAX ANGLE DIFF: This setting selects the maximum angular difference in degrees between the two
sources. An angular difference between the two input voltage phasors below this value is within the permissible limit
for synchronism.
• SYNCHK1 MAX FREQ DIFF: This setting selects the maximum frequency difference in 'Hz' between the two sources.
A frequency difference between the two input voltage systems below this value is within the permissible limit for syn-
chronism.
• SYNCHK1 MAX FREQ HYSTERESIS: This setting specifies the required hysteresis for the maximum frequency differ-
ence condition. The condition becomes satisfied when the frequency difference becomes lower than
. Once the Synchrocheck element has operated, the frequency difference must increase above the
FREQ DIFF
+
MAX FREQ DIFF SYNCHK1 MAX FREQ HYSTERESIS
angle, remain satisfied).
• SYNCHK1 DEAD SOURCE SELECT: This setting selects the combination of dead and live sources that will by-pass
synchronism check function and permit the breaker to be closed when one or both of the two voltages (V1 or/and V2)
are below the maximum voltage threshold. A dead or live source is declared by monitoring the voltage level. Six
options are available:
GE Multilin
SYNCHK1 LIVE V1
MIN VOLT: 0.70 pu
SYNCHK1 LIVE V2
MIN VOLT: 0.70 pu
SYNCHK1 TARGET:
Self-reset
SYNCHK1 EVENTS:
Disabled
1
T ------------------------------- -
=
360°
----------------- - ×
2 ΔΦ ×
1 1
T ------------------------------- - ------------------------------------------ -
= =
360° 360°
----------------- - × ΔF ------------------ - ×
2 ΔΦ × ×
2 30°
sum to drop out (assuming the other two conditions, voltage and
D30 Line Distance Relay
Range: 0.00 to 1.25 pu in steps of 0.01
Range: 0.00 to 1.25 pu in steps of 0.01
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
ΔF
1.66 sec.
=
0.1 Hz
5.6 CONTROL ELEMENTS
(EQ 5.20)
(EQ 5.21)
SYNCHK1 MAX
SYNCHK1
5-155
5