Transmission and Distribution

A 3-phase 4 wire system is commonly used on________________?

A. primary transmission
B. secondary transmission
C. primary distribution
D. secondary distribution

There is a greater possibility of occurence of corona during______________?

A. dry weather
B. winter
C. summer heat
D. humid weather
E. none of the above

Which of the following is not a constituent for making porcelain insulators ?

A. Quartz
B. Kaolin
C. Felspar
D. Silica

Which of the following materials is used for overhead transmission lines ?

A. Steel cored aluminium
B. Galvanised steel
C. Cadmium copper
D. Any of the above

The power transmitted will be maximum when____________?

A. corona losses are minimum
B. reactance is high
C. sending end voltage is more
D. receiving end voltage is more

A feeder, in a transmission system, feeds power to________________?

A. distributors
B. generating stations
C. service mains
D. all of the above

The presence of ozone due to corona is harmful because it________________?

A. reduces power factor
B. corrodes the material
C. gives odour
D. transfer energy to the ground
E. none of the above

For an overhead line, the surge impedance is taken as________________?

A. 20-30 ohms
B. 70—80 ohms
C. 100—200 ohms
D. 500—1000 ohms
E. none of the above

Which of the following is usually not the generating voltage ?

A. 6.6 kV
B. 8.8 kV
C. 11 kV
D. 13.2 kV

As compared to a 2-wire D.C. distributor, a 3-wire distributor with same maximum voltage to earth uses only__________________?

A. 31.25 percent of copper
B. 33.3 percent of copper
C. 66.7 percent of copper
D. 125 percent of copper