Engineering :: Energy Conversion

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221.

Alternating current power is transmitted at high voltages

A.	to safeguard against pilferage	B.	to minimise transmission losses
C.	to reduce cost of generation	D.	to make the system reliable

222.

Standed conductors are used for transmitting power at high voltages because of

A.	increased tensile strength	B.	low cost
C.	case in handling	D.	low wind resistance

223.

The function of steel wire in a ACSR conductor is

A.	to take care of voltage surges	B.	to prevent corona
C.	to reduce inductance and hence improve power factor	D.	to provide additional mechanical strength

224.

In high voltage transmission lines the top most conductor is

A.	R-phase conductor	B.	Y-phase conductor
C.	B-phase conductor	D.	Earth conductor

225.

If 3 MW power is to be transmitted over a distance of 30 km, the desirable transmission voltage will be

A.	11 kV	B.	33 kV
C.	66 kV	D.	132 kV

226.

The most economic voltage for transmitting given power over a known distance by overhead transmission lines is approximately

A.	0.6 kV/km	B.	1.6 kV/km
C.	2.6 kV/km	D.	3.6 kV/km

227.

For a 66 kV transmission line having span of 200 metres between towers, the approximate sag will be

A.	0.02 m	B.	0.2 m
C.	2 m	D.	20 m

228.

During storm the live conductor of public electric supply breaks of down and touches the earth. The consequence will be

A.	supply voltage will drop	B.	supply voltage will increase
C.	current will flow to earth	D.	no current will flow in the conductor

229.

In transmission system a feeder feeds power to

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

230.

For transmission lines the standing wave ratio is the ratio of

A.	maximum foltage to minimum voltage	B.	maximum current to minimum voltage
C.	peak voltage to rms voltage	D.	maximum reactance to minimum reactance