ABB RELION REX640 - Page 454

OPERATE
START
t
Timer
t
Level
detector
ENA_MULT
Directional
calculation
BLOCK
RCA_CTL
I
2
U
2
I3P
U3P
URES
Blocking
logic
IRES
Uo
DIRECTION
FAULT_DIR
Io
Figure 255: Functional module diagram
Level detector
The magnitude of the operating quantity is compared to the set Start value and
the magnitude of the polarizing quantity is compared to the set Voltage start value .
If both the limits are exceeded, the level detector sends an enabling signal to the
timer module. When the Enable voltage limit setting is set to "False", Voltage start
value has no effect and the level detection is purely based on the operating quantity.
If the ENA_MULT input is active, the Start value setting is multiplied by the Start
value Mult
setting.
If the
Enable voltage limit setting is set to "True", the magnitude of the
polarizing quantity is checked even if the Directional mode was set to
"Non-directional" or Allow Non Dir to "True". The protection relay does
not accept the Start value or Start value Mult setting if the product of
these settings exceeds the Start value setting range.
Typically, the ENA_MULT input is connected to the inrush detection function
INRHPAR. In case of inrush, INRPHAR activates the ENA_MULT input, which multiplies
Start value by the Start value Mult setting.
Directional calculation
The directional calculation module monitors the angle between the polarizing
quantity and operating quantity. Depending on the Pol quantity setting, the
polarizing quantity can be the residual voltage (measured or calculated) or the
negative sequence voltage. When the angle is in the operation sector, the module
sends the enabling signal to the timer module.
The minimum signal level which allows the directional operation can be set with the
Min operate current and Min operate voltage settings.
If Pol quantity is set to "Zero. seq. volt", the residual current and residual voltage are
used for directional calculation.
If Pol quantity is set to "Neg. seq. volt", the negative sequence current and negative
sequence voltage are used for directional calculation.
Protection functions
1MRS759142 F
454 REX640
Technical Manual