MCQs of Symmetrical Fault Analysis (Power System - II - 3150911)

Power System - II (3150911) MCQs

MCQs of Symmetrical Fault Analysis

Showing 31 to 40 out of 55 Questions

31.

When a line to ground fault occurs, the current in a faulted phase is 100 A. The zero sequence current in this case will be

(a)	Zero
(b)	33.3 A
(c)	66.6 A
(d)	100 A

32.

The rated breaking capacity (MVA) of a breaker is equal to

(a)	Product of rated voltage (kV) and rated breaking current (kA)
(b)	Product of rated voltage (kV) and rated symmetrical breaking current (kA)
(c)	Product of breaking current (kA) and fault voltage (kV)
(d)	Twice the value of rated voltage (kV) and rated current (kA)

33.

The following sequence currents were recorded in a power system under a fault condition I_positive = j 1.753 pu, I_negative = – j 0.6 pu, I_zero = – j 1.153 pu.The fault is

(a)	Line to ground
(b)	Three-phase
(c)	Line to line to ground
(d)	Line to line

34.

A short circuit current is identified by

(a)	Heavy current flow
(b)	Voltage rise
(c)	Voltage drop
(d)	None of above

35.

Short circuit currents are due to

(a)	Single phase to earth fault
(b)	Phase to phase fault
(c)	All three phase to earth fault
(d)	Any of above

36.

The most serious consequences of a major uncleared short circuit fault can be

(a)	Blowing of a fuse
(b)	Fire
(c)	Heavy voltage drop
(d)	None of above

37.

Which of the following results in a symmetrical fault?

(a)	Single phase to earth
(b)	Phase to phase
(c)	All the three phase to earth
(d)	Two phase to earth

38.

Which portion of the transmission system is more prone to faults?

(a)	Alternator
(b)	Transformer
(c)	Overhead lines
(d)	Underground cables

39.

The magnitude of fault current depends upon

(a)	Total impedance up to faults
(b)	Voltage at the fault
(c)	Load current being supplied before occurrence of fault
(d)	Both (a) and (b)

40.

Which portion of the power system is least prone to faults?

(a)	Alternator
(b)	Switchgears
(c)	Transformer
(d)	Overhead lines

Showing 31 to 40 out of 55 Questions