Power System 23

LL, LG

LLL,LG

LG, LLL

LLG,LLLG

Fault is highly lagging phenomenon

Fault is high current, low pf phenomenon

Fault is low voltage, low frequency phenomenon

Fault current is only limited by reactance of a machine

Both are correct and St2 is correct explanation of St1

Both are correct but St2 is correct explanation of St1

St1 is correct, St2 is wrong

St2 is correct, St1 is wrong

0.01, 1, 0.1

1, 0.1, 1.1

0.01, 0.1, 0

0.01, 0.1, 1

Fault Current in pu

Fault MVA

Short Circuit capacity

C, B

3 phase fault

LG fault

LG fault cleared by Opening CB

None

be represented as ideal voltage source

send and receive unlimited amount of active and reactive power

be denoted by an alternator with short circuited series reactance

All of the above

Momentory Current Rating is more than subtransient current rating passing through a CB

To interrupt an arc below 3 cycles, ratings of CB should be 1.5 times of the rating of a CB needed to interrupt the arc below 2 cycles

DC offset effect changes with requirement of arc extinguishement cycles

None