ASNSCSYN
(NSCB2)
ASGCSYN
(SCB2)
Synchronize
ASGCSYN
(SCB1)
∆
U,
∆
F
∆
U,
∆
F
Start Matching
ASCGAPC
ASNSCSYN
(NSCB3)
ASCGAPC
ASNSCSYN
(NSCB1)
ASCGAPC
ASCGAPC
ASCGAPC
Source
2
Source
1
NS_ASC_DAT
Figure 881: NSCB3 synchronization
This function supports manual, semi-automatic and automatic synchronizing, which
adds flexibility in the user operation. In the manual synchronization, the matching
is done manually and the closing command is released from the function on user
request. In the semi-automatic synchronization, the matching is done automatically
with coordination from ASCGAPC and the closing command is released from
the function on user request. In the automatic synchronization, the matching is
done automatically with coordination from ASCGAPC and the subsequent closing
command is released from the function without user intervention.
This function output can be used to block the other functions in the power network
to ensure that only one CB is synchronized at a time. This logic has to be developed
outside the function block.
Voltage angle difference adjustment
In applications where the power transformer is located between the voltage
measurement and the CB, the vector group connection gives phase difference to
the voltages between the high- and low-voltage sides. The angle adjustment can be
used to meet synchronism.
The vector group of the power transformer is defined with clock numbers, where
the value of the hour pointer defines the low-voltage-side phasor and the high-
voltage-side phasor is always fixed to the clock number 12, which is the same
as zero. The angle between clock numbers is 30°. When comparing phase angles,
the U_BUS_A input is always the reference. This means that when the Yd11 power
transformer is used, the low-voltage-side voltage phasor leads the high-voltage-
side phasor by 30º or lags by 330º. The rotation of the phasors is counterclockwise.
The generic rule is that a low-voltage-side phasor lags the high-voltage-side phasor
by clock number · 30º. This is called angle difference adjustment and can be set for
ASNSCSYN with the
Phase shift setting.
9.7.7
Signals
1MRS759142 F
Control functions
REX640
Technical Manual
1601