- If the frequency difference reaches the target value "± Smax/2" with the
hysteresis band specified by the settings
Freq Diff Ov Synch and Freq Diff
sub Synch, the raise and lower commands are reset.
• During matching of network CB synchronization
- If any of the governor limit alarms
GOV_ALM_HI
or
GOV_ALM_LO
is TRUE, the
raise and lower commands are reset.
- When the generator is selected for fine tuning, if the frequency difference
reaches to target value "± Smax/2" with the hysteresis band specified by the
settings
Freq Diff Ov Synch and Freq Diff sub Synch, the raise and lower
commands are reset.
- When the generator is selected for coarse tuning, if the frequency difference
reaches within the limits of
Coarse Freq Diff Ov and Coarse Freq Diff sub, the
raise and lower commands are reset.
When the matching is done for its own CB synchronization, the output
MATCH_OK
is activated if the measured voltage and frequency differences are within the set
synchro check limits. The
MATCH_INPRO
output is active while the matching is in
progress.
When the matching is done for network CB synchronization, the monitored data
NTWMATCH_OK
is activated if the network breaker voltage and frequency differences
are within the set match limits.
NTWMATCH_PRO
is active while the matching is in
progress.
NTWMATCH_OK
and
NTWMATCH_PRO
are available in the Monitored data
view.
Frequency rate of change tuning
When the control command parameter
Tune V and F match is set to "Freq match
rate", the function calculates the generator frequency matching rate (dF/dt). The
calculated frequency matching rate is stored to the nonvolatile memory output
FREQ_CHG_RTE
and is available in the Monitored data view. Once stored, the value
from
FREQ_CHG_RTE
can be used to set the setting
Freq rate of change.
This tune frequency matching rate proceeds as follows:
1. The slip is adjusted until this lies in the range of +1...+3 %, then the adjusting
pulse is discontinued.
2. Ten seconds after the first adjusting pulse, the slip s0 is measured, then a
frequency raise command
RAISE_F
lasting 3 s is given. Ten seconds after the
end of the pulse, the slip s is measured and df/dt is calculated according to the
formula
df
dt
s
s
=
−
0
3
(Equation 365)
3. With this df/dt value, the slip is brought back to approxi2 %.
Ten seconds later, the slip is brought to 0 % with the same df/dt value. After
ten seconds, df/dt is calculated again and shown as monitored data output
FREQ_CHG_RTE
.
The binary input
BLOCK
can be used to block the function. The activation of the
BLOCK
input deactivates all binary outputs, binary monitored data and resets the
internal timers.
Control functions
1MRS759142 F
1578
REX640
Technical Manual