ABB RELION REX640 Technical Manual page 315

1MRS759142 C
REX640
Technical Manual
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.
The start value multiplication is normally done when the inrush detection function
(INRPHAR) is connected to the ENA_MULT input.
GUID-B69BD6DB-6322-4FB1-AE76-F72161751599 V1 EN
Figure 176: Start value behavior with ENA_MULT input activated
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 Num of start phases setting, the phase selection logic
activates the timer module.
Timer
Once activated, the timer activates the START output. Depending on the value of the
Operating curve type setting, the time characteristics 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 parameters Curve parameter A, Curve parameter B,
Curve parameter C, Curve parameter D and Curve parameter E.
Section 4
Protection functions
309