ABB RELION REX640 Technical Manual page 1569

1MRS759142 C
REX640
Technical Manual
The blocking status can be read from the output BLKD_U_UN.
However, there is no minimum limit for the undervoltage blocking. The blocking is
allowed even if the measured voltage is not connected or it temporarily has a very low
value. There is a minimum limit for the phase angle calculation based on the voltage
phasor magnitude.
Runback raising voltage
The manual raising command is blocked if the overvoltage limit is exceeded
1415). However, in the automatic operation mode, the overvoltage situation triggers
the fast lowering feature. More information can be found in the
regulation chapter. This operation can be adjusted with the setting parameter Runback
raise V.
The blocking status can be read from the output RNBK_U_OV.
High circulating current
The circulating current value is calculated in the operation modes Negative Reactance
Principle (NRP) and Minimizing Circulating Current (MCC). Only the automatic
operation in these modes is blocked when the high circulating current is measured
(Table 1415). This operation can be adjusted with the setting parameter Cir current
limit.
The blocking status can be read from the output BLKD_I_CIR.
LTC_BLOCK – external block input
With the PCM600 tool configuration possibilities, a blocking condition can be built
by connecting an outcome to this input. The blocking status can be read from the
output BLKD_LTCBLK. When activated, this input blocks only the automatic
operation of the regulator by default
signal activation resets the timer, and the output BLKD_LTCBLK is not activated.
Extreme positions
This blocking function supervises the extreme positions of the tap changer. These
extreme positions can be adjusted with the setting parameters Raise block tap and
Lower block tap. When the tap changer reaches one of these two positions, the
commands in the corresponding direction are blocked
comparison between the Raise block tap and Lower block tap settings, which direction
is blocked (Voltage control vs. tap changer moving direction
affects both the automatic and manual operation modes.
However, as shown in Table
automatic modes. Here "Auto follower" is not a fully automatic mode. The
unconnected position information does not cause the total block of OL5ATCC; only
the extreme position blocking does not work.
The blocking status can be seen in the generated events.
(Table 1415). For the fully automatic modes, the
1415, no blocking indication is generated in the fully
Section 9
Control functions
Manual voltage
(Table 1415). It depends on the
section). This blocking
(Table
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