ABB RELION 620 Series Technical Manual page 810

Section 5
Protection related functions
804
The operation of INRPHAR can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
A070694 V2 EN
Figure 409: Functional module diagram
I_2H/I_1H
This module calculates the ratio of the second harmonic (I_2H) and fundamental
frequency (I_1H) phase currents. The calculated value is compared to the set Start
value. If the calculated value exceeds the set Start value, the module output is
activated.
Level detector
The output of the phase specific level detector is activated when the fundamental
frequency current I_1H exceeds five percent of the nominal current.
Timer
Once activated, the timer runs until the set Operate delay time value. The time
characteristic is according to DT. When the operation timer has reached the Operate
delay time value, the BLK2H output is activated. After the timer has elapsed and the
inrush situation still exists, the BLK2H signal remains active until the I_2H/I_1H ratio
drops below the value set for the ratio in all phases, that is, until the inrush situation is
over. If the drop-off situation occurs within the operate time up counting, the reset
timer is activated. If the drop-off time exceeds Reset delay time, the operate timer is
reset.
The BLOCK input can be controlled with a binary input, a horizontal communication
input or an internal signal of the relay program. The activation of the BLOCK input
prevents the BLK2H output from being activated.
1MRS757644 F
620 series
Technical Manual