Q51. Murray loop test is performed on a faulty cable 300 m long. At balance, the resistance connected to the faulty core was set at \(R=15\:\Omega\) and the resistance of the resistor connected to the sound core was \(R=45\:\Omega\). Calculate the distance of the fault point from the test end.

Q52. The voltage conversion for the transformer in the one-line diagram is achieved by:

Q53. If the percentage reactance of the system up to the fault point is 20 % and base kVA is 10000, then short circuit kVA is

Q54. A 3-phase, 20 MVA, 11 KV alternator has 10% sub-transient reactance. Find short circuit MVA and current, if a symmetrical fault occurs at its terminals.

Q55. The fault current limiters
(i) insert zero impedance in the system when there is no fault
(ii) insert large impedance when fault occur in the system
(iii) reduce the short-circuit current of the system
Select the correct statement.

Q56. A negative sequence relay is commonly used to protect

Q57. If the severity of single line-to-ground fault at the terminals of an unloaded synchronous generator is lesser than that of 3-phase faults, then __________ where, \(X_1\) is the positive sequence reactance of the generator,\(X_{g0}\) is the zero sequence reactance of the generator and\(X_n\) is the neutral reactance.

Q58. Which of the following statements is false ?

Q59. Which of the following equipment is not installed in a substaion?

Q60. The disadvantage offered by ungrounded systems is