ABB RELION REX640 Technical Manual page 1039

1MRS759142 F
Table 970: Analog Inputs
Input
I3P
U3P
Table 971: Special conditions
Condition
U3P connected real measurements
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings.
4.7.5.5 Operation principle
The
the function is enabled and respectively "Off" means function is disabled.
The operation of DNZPDIS can be described by using a module diagram ( see
578
Figure 578: Functional module diagram
Low level blocking
This module receives positive sequence current (I
(I ). Both are calculated from fundamental frequency three phase currents.
2
Low level blocking is used to block the Impedance calculation if negative sequence
current does not satisfy minimum level criteria. If negative sequence current
exceeds setting
forward direction. Alternatively, if negative sequence current is exceeds setting
Ng Seq current Rv value, impedance calculation is allowed in reverse direction.
The negative sequence current to positive sequence current ratio (I
exceed the setting
REX640
Technical Manual
Operation setting is used to enable or disable the function. When selected "On"
below). All the modules in the diagram are explained in the next sections.
U
U3P 2
I
2
I3P
I
1
BLOCK
Min Ng Seq current Fw value, impedance calculation is allowed in
Restrain factor to enable impedance calculation.
Description
Three phase currents
Three phase voltages
Description
The function requires that at least two volt-
age channels are connected
Fault
Impedance
direction
calculation
detector
Low Level
blocking
Blocking
logic
) and negative sequence current
1
Protection functions
Timer
OPERATE
t
START
FAULT_DIR
DIRECTION
/I ) should also
2 1
Figure
Min
1039