DGVCL Exam Paper (11-12-2011) Which type of back up protection is widely used for the protection of transmission lines? Remote backup Control backup Breaker backup Relay backup Remote backup Control backup Breaker backup Relay backup ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) If the excitation of a synchronous generator fails, it acts as a Induction motor Induction generator Synchronous generator Synchronous motor Induction motor Induction generator Synchronous generator Synchronous motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP if excitation of synchronous generator fails, operate as induction motor
DGVCL Exam Paper (11-12-2011) The positive and negative sequence impedance of a transmission line are Infinite Zero Equal Different Infinite Zero Equal Different ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) A 3 phase, 6 pole induction motor operates on 440 V, 50 Hz, supply. If the actual speed of the motor is 960 rpm the slip will be 4 % 5 % 0.4 % 6 % 4 % 5 % 0.4 % 6 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ns = 120f/PSlip=(Ns-Nr)/NsNs = 1000 and Nr = 960 from equation of slip, S = (1000-960)/1000S = 0.04 or 4%
DGVCL Exam Paper (11-12-2011) If the percentage reactance of the system upto the point of fault is 20% and the base kVA is 10,000 the short ciruit kVA is 50 MVA 10 MVA 60 MVA 20 MVA 50 MVA 10 MVA 60 MVA 20 MVA ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Short circuit kVA = Base kVA/%X
DGVCL Exam Paper (11-12-2011) Ybus used in power flow studies and Zbus used in short circuit studies Have no inter relation Are the same Are transpose of each other Are inverse of each other Have no inter relation Are the same Are transpose of each other Are inverse of each other ANSWER DOWNLOAD EXAMIANS APP
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