Permissive Underreach Protection Tripping Via Forward Start (Pup Fwd) - GE MiCOM P40 Agile Technical Manual

Application Notes
MiCOM P40 Agile P442, P444
Figure 25: PUP Z2 permissive underreach scheme
Trip logic:
IEC Standard
448.15.13 PUR or AUP
3.2.1.2.2

Permissive Underreach Protection Tripping via Forward Start (PUP Fwd)

This scheme allows an instantaneous Z2 or Z3 trip on receipt of the signal from the remote
end protection. Figure 26 shows the simplified scheme logic.
If the remote relay has picked up in a forward zone and the underimpedance element has
started, then it will trip after the transmission time delay ('Distance schemes / Aid Dist Delay'
setting) upon reception of the permissive signal from the other end of the line.
Send logic:
Permissive trip logic: Underimpedance Start within any Forward Distance Zone, plus
Carrier
Trip Logic
Send
Z2.CR.'Aid Dist Delay' + Z1.T1 + Z2.T2
Z1
+ Z3.T3...
Zone 1
Channel Received.
P44x/EN AP/Hb6
(AP) 5-49
User
Application
setting
Z1 = 80% ZL PUP Z2