ABB Relion 670 Series Applications Manual page 293

1MRK 511 401-UUS F
VHighBusSynch and VHighLineSynch
The voltage level settings shall be chosen in relation to the bus/line network voltage. The
threshold voltages
the network is expected to be synchronized. A typical value is 80% of the rated voltage.
VDiffSynch
Setting of the voltage difference between the line voltage and the bus voltage. The difference is
set depending on the network configuration and expected voltages in the two networks running
asynchronously. A normal setting is 0.10-0.15 p.u.
FreqDiffMin
The setting
asynchronous. For frequency differences lower than this value, the systems are considered to be in
parallel. A typical value for
synchronizing and synchrocheck functions are provided, and it is better to let the synchronizing
function close, as it will close at exactly the right instance if the networks run with a frequency
difference.
FreqDiffMax
The setting
FreqDiffMax shows the time for the vector to move 360 degrees, one turn on the synchronoscope,
and is called Beat time. A typical value for
4-5 seconds. Higher values should be avoided as the two networks normally are regulated to
nominal frequency independent of each other, so the frequency difference shall be small.
FreqRateChange
The maximum allowed rate of change for the frequency.
CloseAngleMax
The setting
synchronizing is accepted. To minimize the moment stress when synchronizing near a power
station, a narrower limit should be used. A typical value is 15 degrees.
tBreaker
tBreaker shall be set to match the closing time for the circuit breaker and should also include
The
the possible auxiliary relays in the closing circuit. It is important to check that no slow logic
components are used in the configuration of the IED as there then can be big variations in closing
time due to those components. Typical setting is 80-150 ms depending on the breaker closing
time.
tClosePulse
The setting for the duration of the breaker close pulse.
Bay control REC670
Application manual
VHighBusSynch and VHighLineSynch have to be set lower than the value where
FreqDiffMin is the minimum frequency difference where the systems are defined to be
FreqDiffMin is 10 mHz. Generally, the value should be low if both
To avoid overlapping of the synchronizing function and the synchrocheck function
FreqDiffMin must be set to a higher value than used setting FreqDiffM ,
the setting
FreqDiffA used for synchrocheck.
respective
FreqDiffMax is the maximum slip frequency at which synchronizing is accepted. 1/
CloseAngleMax is the maximum closing angle between bus and line at which
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FreqDiffMax is 200-250 mHz, which gives beat times on
Section 14
Control
287