DGVCL Exam Paper (11-12-2011) Bulk power transmission over long HVDC lines are preferred on account of Simple protection Minimum line power losses Low cost of HVDC terminals No harmonic problems Simple protection Minimum line power losses Low cost of HVDC terminals No harmonic problems ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which motor is used to start heavy loads? Differentially compounded motor Shunt motor Cumulatively compounded motor Series motor Differentially compounded motor Shunt motor Cumulatively compounded motor Series motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²starting torque of dc series motor is high
DGVCL Exam Paper (11-12-2011) The transient stability of a power system can be improved by Increasing the turbine valve opening Single pole switching of circuit breakers Excitation control Phase shifting transformer Increasing the turbine valve opening Single pole switching of circuit breakers Excitation control Phase shifting transformer 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 % 0.4 % 5 % 6 % 4 % 0.4 % 5 % 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) Buchholz relay causes Tripping for both major and minor faults Tripping for minor faults and alarm for major faults Alarm for both major and minor faults Tripping for major faults and alarm for minor faults Tripping for both major and minor faults Tripping for minor faults and alarm for major faults Alarm for both major and minor faults Tripping for major faults and alarm for minor faults ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The best location of the power factor correction equipment to be installed in the transmission line is at The sending end Middle of the line The receiving end Any place The sending end Middle of the line The receiving end Any place ANSWER DOWNLOAD EXAMIANS APP
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