ABB RER620 Technical Manual page 332

Section 5
Control functions
326
• The measured line and bus voltages are higher than set values of Live bus value and
Live line value (ENERG_STATE equals to "Both Live").
• The measured bus and line frequency are both within the range of 95 to 105 percent
of the value of f .
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• The measured voltages for the line and bus are less than set value of Max energizing
V.
In case Synch check mode is set to "Synchronous", the additional conditions must be
fulfilled:
• In the synchronous mode, the closing is attempted so that the phase difference at
closing is close to zero.
• The synchronous mode is only possible when the frequency slip is below 0.1 percent
of the value of f .
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• The voltage difference must not exceed the 1 percent of the value of VV
In case Synch check mode is set to "Asynchronous", the additional conditions must be
fulfilled:
• The measured difference of the voltages is less than the set value of Difference
voltage.
• The measured difference of the phase angles is less than the set value of Difference
angle.
• The measured difference in frequency is less than the set value of Frequency
difference.
• The estimated breaker closing angle is decided to be less than the set value of
Difference angle.
Figure 168: Conditions to be fulfilled when detecting synchronism between systems
When the frequency, phase angle and voltage conditions are fulfilled, the duration of the
synchronism conditions is checked so as to ensure that they are still met when the
condition is determined on the basis of the measured frequency and phase difference.
Depending on the circuit breaker and the closing system, the delay from the moment the
closing signal is given until the circuit breaker finally closes is about 50 - 250 ms. The
selected Closing time of CB informs the function how long, the conditions have to persist.
The synch-check function compensates for the measured slip frequency and the circuit
1MAC309294-MB F
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RER620
Technical Manual