DGVCL Exam Paper (11-12-2011) Bulk power transmission over long HVDC lines are preferred on account of No harmonic problems Simple protection Low cost of HVDC terminals Minimum line power losses No harmonic problems Simple protection Low cost of HVDC terminals Minimum line power losses ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Lagging power factor Leading power factor Depends on nature of load Unity power factor Lagging power factor Leading power factor Depends on nature of load Unity 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) Which type of back up protection is widely used for the protection of transmission lines? Relay backup Breaker backup Control backup Remote backup Relay backup Breaker backup Control backup Remote backup ANSWER DOWNLOAD EXAMIANS APP
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) DC series motors are best suited for traction work because Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Torque and speed are proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is directional proporational to torque Torque and speed are inversely proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Torque and speed are proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is directional proporational to torque Torque and speed are inversely proportional to the square of the armature current ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²N α 1/φN α 1/T
DGVCL Exam Paper (11-12-2011) A Mho relay is a Voltage restrained directional relay Voltage controlled over current relay Directional restrained over voltage relay Directional restrained over current relay Voltage restrained directional relay Voltage controlled over current relay Directional restrained over voltage relay Directional restrained over current relay ANSWER DOWNLOAD EXAMIANS APP
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