Cables & High Voltage Engineering MCQ [Free PDF] – 5 Objective Questions with Answers

Internal/partial-discharge testing is specifically aimed at detecting deterioration, void activity and localized insulation discharge inside a bushing before it develops into complete breakdown.

A — Both core-to-core and core-to-sheath capacitance. In a 3-core cable each core has capacitance to the other cores and to the metallic sheath; together they give the effective capacitance per phase.

For laboratory/factory tests that require a representative cable section while remaining practical to handle, a normal sample length is in the range of about 50 cm to 10 m, matching the keyed option.

In a Cockcroft-Walton multiplier, voltage sag/ripple becomes more severe toward the higher-output stages because charging currents pass through preceding capacitors. Increasing capacitance in the higher stages is one effective grading measure to reduce the voltage sag there, which is the revised final-key choice C.

XLPE is widely used as insulation in modern medium- and high-voltage power cables because cross-linking improves thermal capability, dielectric performance and mechanical stability compared with ordinary polyethylene/PVC.