ABB RELION REX640 Technical Manual page 1442

Section 9
Control functions
1436
Table 1371: Typical delays for different output types
Output type
Semiconductor output (SPO)
Mechanical relay output (POSP,
PODP)
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.
f
(
BusA
Frequency slip(s) =
GUID-0F4F8FA8-04EE-443E-8A33-3936FCB5EE7D V1 EN
The measured bus A voltage (U
voltage (U ), bus B frequency (f
BusB
(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
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 phase-
to-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 ) and the set Closing time of CB, the function calculates the necessary lead angle
Bus
(α ) by which the close CB command is shifted forward in time so that the main
Lead
contacts close on phase coincidence.
Recommended value for T
Both Bus side voltage
measurements: Non-Adaptive or
Both Bus side voltage
measurements: Adaptive.
16 ms
23 ms
f
)
−
BusB
f
BusA
), bus A frequency (f
BusA
), and phase angle difference
BusB
1MRS759142 C
PL
Any one of the Bus side voltage
measurement: Adaptive,
The other Bus side voltage
measurement: Non Adaptive
7 ms
13 ms
(Equation 336)
), measured bus B
BusA
Table 1370
Technical Manual
and
REX640