Figure 150: Phase Selector Timing For Fault Condition; Figure 151: Phase Selector Timing For Fault During A Power Swing - GE MiCOM P40 Agile Technical Manual

Chapter 10 - Power Swing Functions
Fault inception
i (t)
PH1
PH2
: D i exceeds threshold 1 (5%In), so PH1 and PH2 go high
t
1
: Fault current value appears in 2 cycle buffer . This equals present fault current value so D i is reduced to
t
2
zero. PH1 therefore goes low. PH2 remains high because value in PH 2 memory is a stored value .
: Fault is cleared so PH 2 goes low. PH1 stays low even though there is a new D I, because the absolute
t
3
current value is also taken into consideration .
V02770

Figure 150: Phase selector timing for fault condition

Start of
power swing
i (t)
PH1
PH2
t
1
: D i exceeds threshold 1 (5%In), so PH1 and PH2 go high
t
1
t : Threshold 2 invoked (10%In). PH2 goes low on account of threshold being increased (from 5%IN to 10%In).
2
PH1 remains high, because there continues to be a D i
: Fault inception. D i exceeds threshold 2 (10%In), so PH2 goes high
t
3
t : 2 cycles after fault inception , PH1 goes low
4
t : Fault cleared, so PH2 goes low
5
V02771

Figure 151: Phase selector timing for fault during a power swing

274
Fault cleared
t t t
1 2 3
3 cycles
t
2
t t t
3 4 5
P543i/P545i
P54x1i-TM-EN-1