ABB RELION REF615R, Technical Manual

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Synchro check
The Synchro check function measures the difference between the line voltage and bus
voltage. The function trips and issues a closing command to the circuit breaker when the
calculated closing angle is equal to the measured phase angle and if the conditions are
simultaneously fulfilled.
• The measured line and bus voltages are higher than the 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
n
.
• The measured voltages for the line and bus are less than the set value of Max
energizing V .
In case Syncro check mode is set to "Syncronous", 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
n
.
• The voltage difference must not exceed the 1 percent of the value of V
n
.
In case Syncro check mode is set to “Asyncronous”, 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 .
1MRS240050-IB C
Section 9
Control functions
REF615R 499
Technical Manual