PH
DIFF
MEAS
U
U
Gen
Bus
_
_
Phase shift
= ∠
− ∠
−
(Equation 355)
∠ U
Bus
Measured bus side voltage phase angle
∠ U
Gen
Measured generator side voltage phase angle
Phase shift Setting
Phase shift
The synchronism conditions are checked according to several criteria.
• The measured bus and generator voltages are higher than the set value of
Live
voltage value (ENERG_STATE equals “Both Live”).
• The measured bus and generator frequencies are both within the range of
95...105 percent of the nominal frequency (fn).
• The measured bus and generator voltages are lower than the set value of
Maximum voltage.
If the
Synchrocheck mode parameter under the Setting menu is set
as "Command", then the
SynchroChk Mod Ctl parameter under the
Control menu is used to set values "OFF/Asynchronous". Otherwise, the
Synchrocheck mode parameter under the Setting menu is used to set the
values "Off/Asynchronous".
Some additional conditions must also be fulfilled as per the set
Synchrocheck mode.
Table 1516: Additional conditions for the Synchro check
Measurements
Synchrocheck mode “Asynchronous”
U_DIFF_MEAS
< Voltage Diff Ov Ex and > -Voltage Diff Un Ex
PH_DIFF_MEAS
< Angle Diff positive and > - Angle Diff nega-
tive
FR_DIFF_MEAS
< Freq Diff OV Synch and > -Freq Diff sub
Synch
Closing angle
< Angle Diff positive and >- Angle Diff nega-
tive
Dead voltage value
Live voltage value
Angle Diff negative
U
Bus
U
Gen
Voltage Diff Ov Ex
f
Bus
f
Gen
Frequency[Hz]
∆
f
=
f
Gen
-
f
Bus
∆φ
=
Voltage Diff Un Ex
Angle Diff positive
Freq Diff Ov Synch
Freq Diff sub Synch
∆
U = |
U
Gen
| – |
U
Bu
s
|
∠
U
Gen
-
∠
U
Bus
Rated Frequency
Figure 856: Conditions to be fulfilled when detecting synchronism between systems
When the measured differences in voltage and frequency are within the synchro
check limits, the output
MATCH_OK
is activated. The output
MATCH_INPRO
is active
while the voltage and frequency matching is in progress.
Control functions
1MRS759142 F
1562
REX640
Technical Manual