ABB 615 series Technical Manual page 985

1MAC059074-MB A
615 series ANSI
Technical Manual
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
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.
Difference angle
V_Bus
GUID-72527DBF-2FC1-4E3B-BE9D-E5978DB3BDA4 V2 EN
Figure 493: 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 Synchro check function compensates for the measured slip frequency and the circuit
= -
V_Bus V_Line
Difference voltage
V_Line
Live line or bus value
Dead line or bus value
Frequency deviation
Section 9
Control functions
.
n
Difference frequency
f f f
= -
V_Bus V_Line
f
f
V_Line
V_Bus
Frequency[Hz]
Rated frequency
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