DGVCL Exam Paper (11-12-2011) First zone distance relay protects the transmission line section upto 50 % of its full length 80 % of its full length Its full length 25 % of its full length 50 % of its full length 80 % of its full length Its full length 25 % of its full length ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The transient stability of a power system can be improved by Phase shifting transformer Excitation control Single pole switching of circuit breakers Increasing the turbine valve opening Phase shifting transformer Excitation control Single pole switching of circuit breakers Increasing the turbine valve opening 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 6 % 4 % 5 % 0.4 % 6 % 4 % 5 % 0.4 % 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) An IDMT relay provides A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current A definite time cuttent characteristic An inverse time current characteristic An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current A definite time cuttent characteristic An inverse time current characteristic An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Unity power factor Lagging power factor Depends on nature of load Leading power factor Unity power factor Lagging power factor Depends on nature of load Leading power factor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Over excitation : leading currentUnder excitation : lagging currentNormal excitation : current with unity PF (in phase current)
DGVCL Exam Paper (11-12-2011) The corona effect can be minimized by increasing Spacing between the conductors The length of the conductor Diameter of the conductor Both spacing between the conductors and diameter of the conductor Spacing between the conductors The length of the conductor Diameter of the conductor Both spacing between the conductors and diameter of the conductor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Corona can be reduced by using large size of conductor, bundle conductor and hollow conductor.
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