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ANSI09000636 V1 EN
Figure 32: Directional characteristic of the phase overcurrent protection
1
RCA = Relay characteristic angle 55°
2 ROA = Relay operating angle 80°
3 Reverse
4 Forward
If no blockings are given the pickup signals will start the timers of the step. The time
characteristic for step 1 and 4 can be chosen as definite time delay or inverse time
characteristic. Step 2 and 3 are always definite time delayed. A wide range of standardized
inverse time characteristics is available. The possibilities for inverse time characteristics
are described in section
"Inverse time characteristics".
All four steps in OC4PTOC (51/67) can be blocked from the binary input BLOCK. The
binary input BLKx (x=1, 2, 3 or 4) blocks the operation of respective step.
1MRK 511 287-UUS A Section 6
Current protection
93
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