Test: Power Systems- 3 - Electrical Engineering (EE) MCQ

The string efficiency of a string insulator with the bottom unit having a 50 % of the total voltage is 40%. The number of units in the string insulator is____

An electric train taking of constant current of 800A moves on a section of line between two substations 10 km apart maintained at 600 and 640 V respectively the track resistance is 0.05 Ω/km both go and return. The point of minimum potential along the track is at a distance from 640 V substation is – (in km)

A 50 km long cable has a capacitance of 0.2 μF/km between any two conductors. When the other conductor is connected to sheath. The supply voltage is 22 kV, 50 Hz, 3 – ϕ. The charging current I_Ph is________ (in A)

In a 5 insulator disc, string capacitance between each unit and earth is 1/6^th of the mutual capacitance. The voltage distribution across the middle unit as % of the voltage applied is –

A 3 phase line has conductors 1 cm in diameter spaced equilaterally 2 m apart. The dielectric strength of air is 30 kV (max) per cm. Air density factor is taken as 0.9 and irregularity factor is 0.85. The disruptive critical voltage (rms), for the line is ________ (in kV)

The capacitance of a 3-core lead sheathed cable measured between any two of the conductors with sheath earthed is 0.3 μF per km. Determine the equivalent star connected capacity and the MVA required to keep 20 km of the cable charged when connected to 25 kV, 50 Hz supply

A 3 phase line operating at 150 kV which has a conductor of 1.5 cm diameter arranged in a 4-meter delta. Assume air density factor of 1.2 and the dielectric strength of air to be 21kVcm21kVcm. Calculate the corona loss ____