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019 1 Pages:3

Power Factor of a 3-@ load of 25kW at 415V, 50Hz is to be improved from 0.6
to 0.9. Calculate the value of the capacitance required in each branch , if the
capacitor bank is in delta configuration.

Explain Ferranti Effect.

Derive an expression for the inductance of an isolated current carrying
conductor.

A 15km long 3 phase line has a resistance of 5.3lohms per phase and inductive
reactance of 5.54ohms per phase. The sending end voltage is 11kV.The receiving
end load is 1200kW at a power factor of 0.8 lagging. Find the receiving end
voltage and line current.(Sending end and receiving end are star connected)

PART C
Answer any twofull questions, each carries 10 marks.

^ two conductor cable 1km long is required to supply a constant current of
200A throughout the year. The cost of cable including installation is Rs.
(20a+20)per metre where a is the area of cross section of the conductor in ला.
The cost of energy is 5P per kWh and interest and depreciation charges amount
to 10%. Calculate the most economical conductor size. Assume resistivity of
conductor material is 1.73 1Qcm.

What is Corona? What are the factors affecting Corona? What are the methods
to reduce Corona.

The capacitances of a 3-phase belted cable are 12.6uF between the three cores
bunched together and the lead sheath and 7.4uF between one core and the other
two connected to sheath. Find the charging current drawn by the cable when
connected to 66kV, 50Hz, star connected supply.

What are the advantages of dc transmission over ac transmission.

Explain the configuration of a TCSC

^ transmission line at ೩ river crossing is supported by two towers 50m and
551118001೮ water level. The horizontal distance between towers is 300m. The
tension in the conductor is 2000kg and weight of conductor is 0.85 kg/m. a) Find
the minimum clearance between conductor and water b) Determine the position

of minimum clearance.

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