DGVCL Exam Paper (11-12-2011) Buchholz relay causes Alarm for both major and minor faults Tripping for minor faults and alarm for major faults Tripping for major faults and alarm for minor faults Tripping for both major and minor faults Alarm for both major and minor faults Tripping for minor faults and alarm for major faults Tripping for major faults and alarm for minor faults Tripping for both major and minor faults ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The efficiency of a transformer at full load, 0.8 p.f. lag is 90%. Its efficiency at full load, 0.8 p.f. lead will be 90 % 80 % Less than 90% More than 90% 90 % 80 % Less than 90% More than 90% ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Efficiency= output power/input powerefficiency = (v*i*cosφ)/((v*i*cosφ)+(x² Pc)+(Pi)) x=fractional part of full load
DGVCL Exam Paper (11-12-2011) The insulation coordination for UHV lines (above 500 kV) is done based on Lightning and switching surges Switching surges Voltage level of the line Lightning surges Lightning and switching surges Switching surges Voltage level of the line Lightning surges ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which lightning stroke is most dangerous? Direct stroke on line conductor Direct stoke on tower top Indirect stroke on conductor Direct stroke on ground wire Direct stroke on line conductor Direct stoke on tower top Indirect stroke on conductor Direct stroke on ground wire ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) It is difficult interrupt a capacitive current because It has a leading power factor Current magnitude is very small The restriking voltage can be high Stored energy in the capacitor is very high It has a leading power factor Current magnitude is very small The restriking voltage can be high Stored energy in the capacitor is very high ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The corona effect can be minimized by increasing Spacing between the conductors The length of the conductor Both spacing between the conductors and diameter of the conductor Diameter of the conductor Spacing between the conductors The length of the conductor Both spacing between the conductors and diameter of the conductor 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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