DGVCL Exam Paper (11-12-2011) If the voltage at the two ends of a line are 132 kV, and its reactance is 40 Ω, the stability limit of the line is 500 MW 435.6 MW 251.5 MW 217.8 MW 500 MW 435.6 MW 251.5 MW 217.8 MW ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Ybus used in power flow studies and Zbus used in short circuit studies Are transpose of each other Are inverse of each other Are the same Have no inter relation Are transpose of each other Are inverse of each other Are the same Have no inter relation ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In carrier current protection, the purpose of the wave trap is for Tripping fault current Trapping power frequency waves Trapping high frequency waves entering into generator/transformer unit. All of these Tripping fault current Trapping power frequency waves Trapping high frequency waves entering into generator/transformer unit. All of these ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Switching over voltages Lightning Unbalanced protection Magnetizing inrush current Switching over voltages Lightning Unbalanced protection Magnetizing inrush current ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Initial inrush of magnetizing currents have high component of even and odd harmonics.2nd - 63%3rd -26.8%4th- 5.1%5th- 4.1%6th- 3.77th-2.4
DGVCL Exam Paper (11-12-2011) Which motor is used to start heavy loads? Differentially compounded motor Series motor Shunt motor Cumulatively compounded motor Differentially compounded motor Series motor Shunt motor Cumulatively compounded 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) Due to skin effect Uniform current flows through the conductor Portion of the conductor near the surface carries less current and the core of the conductor carries more current Portion of the conductor near the surface carries more current and the core of the conductor carries less current Current flows through the half cross section of the conductor Uniform current flows through the conductor Portion of the conductor near the surface carries less current and the core of the conductor carries more current Portion of the conductor near the surface carries more current and the core of the conductor carries less current Current flows through the half cross section of the conductor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Skin Effect:tendency of the current to crowd near the conductor surface.Skin effect is proportional to frequency, conductor diameter and permiability. Skin effect increases effective resistance of conductor.In DC, no skin effect.
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