Q5. U = 220 kV voltage is applied to the conductor cable with cross sectional area 350 mm². The geometric characteristic of the cable is p = 2.5 . For the isolation of the cable, oil is used as an insulator. The dielectric constant of the oil is 2.2. a) Calculate maximum field strength across the oil. b) In order to decrease the maximum field strength across the oil, the surface of the conductor cable is covered with a solid insulator with thickness 0.5 cm and relative dielectric constant of 82 = 5. Under this condition find voltage and maximum field strength across the oil. (Note: total thickness of the isolation remains constant, i.e. the outer radii is same as part (a)). c) What must be the minimum electric field strength of the solid insulator (i.e. minimum value of Ebi) in order not to breakdown?

Q5. U = 220 kV voltage is applied to the conductor cable with cross sectional area 350 mm². The geometric characteristic of the cable is p = 2.5 . For the isolation of the cable, oil is used as an insulator. The dielectric constant of the oil is 2.2. a) Calculate maximum field strength across the oil. b) In order to decrease the maximum field strength across the oil, the surface of the conductor cable is covered with a solid insulator with thickness 0.5 cm and relative dielectric constant of 82 = 5. Under this condition find voltage and maximum field strength across the oil. (Note: total thickness of the isolation remains constant, i.e. the outer radii is same as part (a)). c) What must be the minimum electric field strength of the solid insulator (i.e. minimum value of Ebi) in order not to breakdown?

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.9MCQ: Match the following: (i) Hysteresis loss (a) Can be redud by constructing the core with laminated...

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