Table 1531: Typical delays for different output types
Output type Recommended value for T
PL
Both Bus side
voltage measurements: Non-
Adaptive or
Both Bus side voltage
measurements: Adaptive
Any one of the Bus
side voltage measurement:
Adaptive,
The other Bus side voltage
measurement: Non Adaptive
Semiconductor output (SPO) 16 ms 7 ms
Mechanical relay output
(POSP, PODP)
23 ms 13 ms
The
Minimum Syn time
setting defines the minimum time for which synchro check
conditions must be simultaneously fulfilled.
The frequency slip acceleration (ds/dt) SLIP_ACCL is the average value of frequency
slip difference (Δs) calculated over a time period of 0.5 s.
Frequency slip(s) =
−
( )
f f
f
BusA BusB
BusA
(Equation 371)
The measured bus A voltage (U
BusA
), bus A frequency (f
BusA
), measured bus B
voltage (U
BusB
), bus B frequency (f
BusB
) and phase angle difference (PH_DIFF_MEAS)
values between the two sides of the CB are available as monitored data values.
If the measured U_DIFF_MEAS does not fulfill the condition given in
Table
1530
and thus synchronism is prevented, the monitored data U_DIFF_SYNC is
activated. Similarly PH_DIF_SYNC and FR_DIFF_SYNC are activated based on the
measurements PH_DIFF_MEAS and FR_DIFF_MEAS, respectively. These monitored
data values are updated only when the setting
Synchrocheck mode
is set to either
"Synchronous" or "Asynchronous" and the measured ENERG_STATE is "Both Live".
The outputs U_DIFF and FR_DIFF_MEAS give the calculated phaseto- phase voltage
difference and the frequency difference values, respectively. These U_DIFF and
FR_DIFF_MEAS outputs are sent to ASCGAPC.
The monitored data ACT_ASC_CB indicates the ASCGAPC CB number. The CB
number of the protection relay's ASCGAPC is received via ASC1_NS_DAT signal.
Close CB condition
If
Synchrocheck mode
is set to "Asynchronous", the CB close command is generated
as explained below.
From the frequency slip s, the acceleration ds/dt, the bus frequency FR_BUS_MEAS
(f
Bus
) and the set
Closing time of CB
, the function calculates the necessary lead
angle (α
Lead
) by which the close CB command is shifted forward in time so that the
main contacts close on phase coincidence.
Control functions
1MRS759142 F
1594 REX640
Technical Manual
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