Figure 118: Phase Selector Timing For Power Swing Condition; Figure 119: Phase Selector Timing For Fault Condition - GE MiCOM P40 Technical Manual

P446SV
3.1.1.1 TIMING OF THE PHASE SELECTOR SIGNALS
Start of
power swing
i (t)
PH1
PH2
: D i exceeds threshold 1 (5%In), so PH1 and PH2 go high
t
1
t : Threshold 2 invoked. PH2 goes low on account of threshold being increased . PH1 remains high,
2
because there continues to be a D i
: PH1 goes low as power swing has diminished and D i goes below threshold 1
t
3
V02769

Figure 118: Phase selector timing for power swing condition

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 119: Phase selector timing for fault condition

P446SV-TM-EN-1
3 cycles
t t
1 2
Fault cleared
t t t
1 2 3
Chapter 10 - Power Swing Functions
End of
power swing
t
3
231