ABB RELION REX640 Technical Manual page 373

1MRS759142 F
If ENA U MULT isTRUE
Effective start value Start value low
If ENA U MULT is FALSE
Effective start value Start value
Voltage and input control mode
Control mode is set to "Voltage and input Ctrl", both the "Voltage control"
If
and "Input control" modes are used. However, the "Input control" functionality is
dominant over the "Voltage control" mode when ENA_LOW_LIM is active.
No voltage dependency mode
When
voltage dependency and the function acts as a normal time overcurrent function
with effective start value being equal to the
Level detector
The measured phase currents are compared phasewise to the calculated effective
start value. If the measured value exceeds the calculated effective start value, the
Level detector reports the exceeding value to the phase selection logic. If the
ENA_MULT input is active, the effective start value is multiplied by the
Mult setting.
The start value multiplication is normally done when the inrush detection function
INRPHAR is connected to the ENA_MULT input.
Phase selection logic
If the fault criteria are fulfilled in the level detector, the phase selection logic detects
the phase or phases in which the measured current exceeds the setting. If the phase
information matches the
activates the Timer module.
Timer
Once activated, the Timer module activates the START output.
Depending on the value of the
are according to DT or IDMT. When the operation timer has reached the value of
Operate delay time in the DT mode or the maximum value defined by the inverse
time curve, the OPERATE output is activated.
When the user programmable IDMT curve is selected, the operation time
characteristics are defined by the settings
Curve parameter C , Curve parameter D and Curve parameter E .
REX640
Technical Manual
_ _ :
=
_ _ :
=
Control mode is set to "No Volt dependency", the effective start value has no
Do not set the multiplier
the value is too high, the function may not operate at all during an inrush
followed by a fault, no matter how severe the fault is.
Num of start phases setting, the phase selection logic
Start value setting.
Start value Mult setting higher than necessary. If
Operating curve type setting, the time characteristics
Curve parameter A , Curve parameter B ,
Protection functions
(Equation 29)
(Equation 30)
Start value
373