Hve Unit Test-ii.docx

BALAJI INSTITUTE OF TECHNOLOGY & SCIENCE COURSE: IVYR I-SEM SUB: HVE

MAX MARKS:10

Answer any two questions 1. 2. 3. 4.

Explain different theories of charge formation in clouds? What is capacitance grading and how it is used to improve string efficiency? Derive the expression for insulation resistance and capacitance of a single core cable? Determine a) Critical Disruptive voltage. B) Visual critical voltage c) Corona loss under foul weather conditions for a 3-phase line 160KM long, conductor diameter 1.036cm,;2.44m delta spacing. Air temperature 26.6°C corresponding to an approximate barometric pressure of 73.15cm of mercury, operating voltage 110KV at 50Hz,surface irregularity factor 0.85.Assume a value of mv =0.72