GETCO Exam Paper (22-07-2015) HVDC transmission is preferred to EHV AC because Harmonic problem is avoided System stability can be improved VAR compensation is not required in it Its terminal equipment are inexpensive Harmonic problem is avoided System stability can be improved VAR compensation is not required in it Its terminal equipment are inexpensive ANSWER DOWNLOAD EXAMIANS APP
GETCO Exam Paper (22-07-2015) Which of the following breaking method save energy? plugging resistor breaking dynamic breaking regenerative breaking plugging resistor breaking dynamic breaking regenerative breaking ANSWER EXPLANATION DOWNLOAD EXAMIANS APP three types of electric breaking:Regenerative breaking( leads to economic and energy consevation)pugging (more efficient method of breaking)rheostatic breaking
GETCO Exam Paper (22-07-2015) For eliminating 7th harmonics from generated EMF in alternator the fractional pitch must be 7\8 2\3 6\7 5\6 7\8 2\3 6\7 5\6 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP fractional pitch = Cos( α/2)α is obtain from: (nα/2)=90˚ where n is harmonicα=25.7143˚fractional pitch=6/7
GETCO Exam Paper (22-07-2015) The Z matrix of 2 port network is given by [0.9 0.2 : 0.2 0.6]. The element Y22 of the corresponding Y matrix of the same network is given by 0.4 1.2 1.8 -0.4 0.4 1.2 1.8 -0.4 ANSWER DOWNLOAD EXAMIANS APP
GETCO Exam Paper (22-07-2015) A transformer has negative voltage regulation when its load PF is zero lagging leading unity zero lagging leading unity ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Voltage regulation = ((no load voltage)-(full load voltage)/(no load voltage))VR at leading PF = ((I*R*cosφ)-(I*X*sinφ))/VVR at lagging PF = ((I*R*cosφ)+(I*X*sinφ))/V
GETCO Exam Paper (22-07-2015) Critical clearing time of a fault in a power system is related to Short circuit limit Reactive power limit Steady state limit Transient stability limit Short circuit limit Reactive power limit Steady state limit Transient stability limit ANSWER DOWNLOAD EXAMIANS APP
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