Description : A feeder, in a transmission system, feeds power to (a) distributors (b) generating stations (c) service mains (d) all of the above
Last Answer : (a) distributors
Description : The loads on distributors systems are generally (a) balanced (b) unbalanced (c) either of the above (d) none of the above
Last Answer : (b) unbalanced
Description : The distributors for residential areas are (a) single phase (b) three-phase three wire (c) three-phase four wire (d) none of the above
Last Answer : (c) three-phase four wire
Description : Which of the following is the demerit of a 'constant voltage transmission system' ? (a) Increase of short-circuit current of the system (b) Availability of steady voltage at all loads at ... of carrying increased power for a given conductor size in case of long-distance heavy power transmission
Last Answer : (a) Increase of short-circuit current of the system
Description : The use of strain type insulators is made where the conductors are (a) dead ended (b) at intermediate anchor towers (c) any of the above (d) none of the above
Last Answer : (c) any of the above
Description : In aluminium conductors, steel core is provided to (a) compensate for skin effect (b) neutralise proximity effect (c) reduce line inductance (d) increase the tensile strength
Last Answer : (d) increase the tensile strength
Description : In AC.S.R. conductors, the insulation between aluminium and steel conductors is (a) insulin (b) bitumen (c) varnish (d) no insulation is required
Last Answer : (d) no insulation is required
Description : The steel used in steel cored conductors is usually (a) alloy steel (b) stainless steel (c) mild steel (d) high speed steel (e) all of the above
Last Answer : (c) mild steel
Description : The spacing between phase conductors of a 220 kV line is approximately equal to (a) 2 m (b) 3.5 m (c) 6 m (d) 8.5 m
Last Answer : (c) 6 m
Description : Large industrial consumers are supplied electrical energy at (a) 400 V (b) 11 kV (c) 66 kV (d) 400 kV
Last Answer : (c) 66 kV
Description : The voltage of the single phase supply to residential consumers is (a) 110 V (b) 210 V (c) 230 V (d) 400 V
Last Answer : (c) 230 V
Description : Which of the following equipment, for regulating the voltage in distribution feeder, will be most economical ? (a) Static condenser (b) Synchronous condenser (c) Tap changing transformer (d) Booster transformer
Last Answer : (d) Booster transformer
Description : Which of the following distribution systems is more reliable ? (a) Radial system (b) Tree system (c) Ring main system (d) All are equally reliable
Last Answer : (c) Ring main system
Description : A 3-phase 4 wire system is commonly used on (a) primary transmission (b) secondary transmission (c) primary distribution (d) secondary distribution
Last Answer : (d) secondary distribution
Description : Distribution lines in India generally use (a) wooden poles (b) R.C.C. poles (c) steel towers (d) none of the above
Last Answer : (b) R.C.C. poles
Description : Which of the following D.C. distribution system is the simplest and lowest in first cost ? (a) Radial system (b) Ring system (c) Inter-connected system (d) None of the above
Last Answer : (a) Radial system
Description : Which of the following materials is not used for transmission and distribution of electrical power ? (a) Copper (b) Aluminium (c) Steel (d) Tungsten
Last Answer : (d) Tungsten
Description : Explain some of the methods to improve the strength of transmission system?
Last Answer : Introducing or adding of new transmission lines in to the system to avoid the overloading of the existing lines Application of devices such as series capacitors in the right location of ... system Adoption of multi-voltage levels an multi-circuits in the existing ac transmission system
Description : What are the factors that limit the maximum power transfer capability in a transmission line?
Last Answer : Answer: Some of the factors which limits the maximum power transfer are: 1. Electrical phase shift 2. Voltage drop 3. Thermal effects in the line
Description : Why does surge impedance loading (SIL) increase with increase in voltage level?
Last Answer : Answer: SIL varies as the square of the operating voltage, so SIL increases with increase in voltage level
Description : What are the problems associated with EHV transmission?
Last Answer : Answer: The problems associated with EHV transmission are corona loss and radio interference, requirement of heavy supporting structures and insulation requirments
Description : What is the material used for overhead transmission lines?
Last Answer : Answer: ACSR conductors are employed.
Description : What for series and shunt compensation provided in EHV transmission lines?
Last Answer : Answer: Series capacitance is provided in EHV lines to artificially reduce the series reactance of the line so as to improve stability, voltage regulation and transmission efficiency Shunt compensation ... reduce the line susceptance so as to improve the voltage regulation under light load condition
Description : Series capacitors on transmission lines are of little use when the load VAR requirement is (a) large (b) small (b) fluctuating (d) any of the above
Last Answer : (b) small
Description : Electro-mechanical voltage regulators are generally used in (a) reactors (b) generators (c) transformers (d) all of the above
Last Answer : (b) generators
Description : The angular displacement between two interconnected stations is mainly due to (a) armature reactance of both alternators (b) reactance of the interconnector (c) synchronous reactance of both the alternators (d) all of the above
Last Answer : (a) armature reactance of both alternators
Description : When an alternator connected to the bus-bar is shut down the bus-bar voltage will (a) fall (b) rise (c) remain unchanged (d) none of the above
Last Answer : (c) remain unchanged
Description : The frequency of voltage generated, in case of generators, can be increased by (a) using reactors (b) increasing the load (c) adjusting the governor (d) reducing the terminal voltage (e) none of the above
Last Answer : (c) adjusting the governor
Description : When the interconnector between two stations has large reactance (a) the transfer of power will take place with voltage fluctuation and noise (b) the transfer of power will take place with least loss ... out of step be¬cause of large angular displacement between the stations (d) none of the above
Last Answer : (c) the stations will fall out of step be¬cause of large angular displacement between the stations
Description : In the analysis of which of the following lines shunt capacitance is neglected ? (a) Short transmission lines (b) Medium transmission lines (c) Long transmission lines (d) Medium as well as long transmission lines
Last Answer : (a) Short transmission lines
Description : For transmission of power over a distance of 500 km, the transmission voltage should be in the range (a) 150 to 220 kV (b) 100 to 120 kV (c) 60 to 100 kV (d) 20 to 50 kV
Last Answer : (a) 150 to 220 kV
Description : The effect of corona can be detected by (a) presence of ozone detected by odour (b) hissing sound (c) faint luminous glow of bluish colour (d) all of the above
Last Answer : (d) all of the above
Description : Constant voltage transmission entails the following disadvantage (a) large conductor area is required for same power transmission (b) short-circuit current of the system is increased (c) either of the above (d) none of the above
Last Answer : (b) short-circuit current of the system is increased
Description : In a tap changing transformer, the tappings are provided on (a) primary winding (b) secondary winding (c) high voltage winding (d) any of the above
Last Answer : (b) secondary winding
Description : For aluminium, as compared to copper, all the following factors have higher values except (a) specific volume (6) electrical conductivity (c) co-efficient of linear expansion (d) resistance per unit length for same cross-section
Last Answer : (6) electrical conductivity
Description : For transmission of power over a distance of 200 km, the transmission voltage should be (a) 132 kV (b) 66 kV (c) 33 kV (d) 11 kV
Last Answer : (a) 132 kV
Description : Aluminium has a specific gravity of (a) 1.5 (b) 2.7 (c) 4.2 (d) 7.8
Last Answer : (b) 2.7
Description : Pin type insulators are generally not used for voltages beyond (a) 1 kV (b) 11 kV (c) 22 kV (d) 33 kV
Last Answer : (d) 33 kV
Description : The current drawn by the line due to corona losses is (a) non-sinusoidal (b) sinusoidal (c) triangular (d) square
Last Answer : (a) non-sinusoidal
Description : The voltage drop, for constant voltage transmission is compensated by installing (a) inductors (b) capacitors (c) synchronous motors (d) all of above (e) none of the above
Last Answer : (c) synchronous motors
Description : In a substation the following equipment is not installed (a) exciters (b) series capacitors (c) shunt reactors (d) voltatre transformers
Last Answer : (a) exciters
Description : A circuit is disconnected by isolators when (a) line is energized (b) there is no current in the line (c) line is on full load (d) circuit breaker is not open
Last Answer : (b) there is no current in the line
Description : By which of the following a bus-bar is rated ? (a) Current only (b) Current and voltage (c) Current, voltage and frequency (d) Current, voltage, frequency and short time current
Last Answer : (d) Current, voltage, frequency and short time current
Description : By which of the following methods string efficiency can be improved ? (a) Using a guard ring (b) Grading the insulator (c) Using long cross arm (d) Any of the above (e) None of the above
Last Answer : (d) Any of the above
Description : Owing to skin effect (a) current flows through the half cross-section of the conductor (b) portion of the conductor near the surface carries more current and core of the conductor carries less current (c) ... core of the conductor carries more cur¬rent (d) any of the above (e) none of the above
Last Answer : (b) portion of the conductor near the surface carries more current and core of the conductor carries less current
Description : Which of the following bus-bar schemes has the lowest cost ? (a) Ring bus-bar scheme (b) Single bus-bar scheme (c) Breaker and a half scheme (d) Main and transfer scheme
Last Answer : (b) Single bus-bar scheme
Description : A conductor, due to sag between two supports, takes the form of (a) semi-circle (b) triangle (c) ellipse (d) catenary
Last Answer : (d) catenary
Description : Which of the following regulations is considered best? (a) 50% (b) 20% (c) 10% (d) 2%
Last Answer : (d) 2%
Description : Transmission voltage of ll kV is normally used for distances upto (a) 20—25 km (b) 40—50 km (c) 60—70 km (d) 80—100 km
Last Answer : (a) 20—25 km
Description : Which of the following characteristics should the line supports for transmission lines possess ? (a) Low cost (b) High mechanical strength (c) Longer life (d) All of the above
Last Answer : (d) All of the above