U
ref
I
dir
RCA
ROA
Forward
Reverse
ROA
en05000745.vsd
IEC05000745 V1 EN
Figure 159: Directional characteristic of the phase overcurrent protection
The default value of AngleRCA is –65°. The parameters AngleROA gives the angle
sector from AngleRCA for directional borders.
A minimum current for directional phase start current signal can be set:
IminOpPhSel.
If no blockings are given the start signals will start the timers of the step. The time
characteristic for each step can be chosen as definite time delay or inverse time
characteristic. A wide range of standardized inverse time characteristics is available.
It is also possible to create a tailor made time characteristic. The possibilities for
inverse time characteristics are described in section
"Inverse characteristics".
All four steps in OC4PTOC can be blocked from the binary input BLOCK. The binary
input BLKSTx (x=1, 2, 3 or 4) blocks the operation of respective step.
Section 8 1MRK502052-UEN B
Current protection
348
Technical manual
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