Permissive Over-Reach Scheme; Figure 71: Aided Distance Pur Scheme - GE MiCOM P40 Technical Manual

Chapter 8 - Carrier Aided Schemes
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Figure 71: Aided Distance PUR scheme

4.2

PERMISSIVE OVER-REACH SCHEME

Permissive Over-reach schemes are variously referred to as POR, POP, POTT. We normally use the term POR.
In a Permissive Overreach scheme the channel is keyed (that means that the aiding signal is asserted) by the
pickup of an over-reaching Zone 2 element.
To use this scheme, you need to set the relevant setting (Aid. 1 Selection or Aid. 2 Selection) in the SCHEME LOGIC
column to POR.
If a remote protection element detects a forward fault and receives a POR signal, the protection operates without
further delay. Faults in the last 20% of the protected line are therefore cleared with minimal time delay.
Note:
This assumes a 20% typical end-zone when Zone 1 is set to 80% of the protected line.
172
Zone 3
Zone 2
&
Z1
TZ1
Zp
TZp
Z2
TZ2
Z3
TZ3
Z4
TZ4
Zone 1
A
B
Z
Z
Zone 1
CRx
CRx
CTx
CTx
Trip A Trip B
1
1
Optional features of scheme
Zone 2
Zone 3
&
Z1
TZ1
Zp
TZp
Z2
TZ2
Z3
TZ3
Z4
TZ4
P446SV-TM-EN-1
P446SV