Extra-low voltage (ELV) is an electricity supply voltage in a range which carries a low risk of dangerous electrical shock.
What is the difference between a line voltage and low voltage control system?
What is considered low voltage and high voltage?
What is Extra High Voltage?
Step-down transformer converts high voltage and low current into: (A) How voltage and high current (B) High voltage and low current (C) Low voltage and high current (D) None of the above Last Answer : Step-down transformer converts high voltage and low current into: Low voltage and high current
Which of the following is the least expensive protection for over current in low voltage system? (A) Rewireable fuse (B) Isolator (C) Oil Circuit breaker (D) Air break circuit breaker Last Answer : Which of the following is the least expensive protection for over current in low voltage system? (A) Rewireable fuse (B) Isolator (C) Oil Circuit breaker (D) Air break circuit breaker
What is meant by extra high voltage transmission? Last Answer : HT & LT two types transmission in industrial line
Low voltage cables are meant for use up to (a)l.lkV (b)3.3kV (c)6.6kV (d)llkV
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
Electro-mechanical voltage regulators are generally used in (a) reactors (b) generators (c) transformers (d) all of the above Last Answer : (b) generators
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
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
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
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
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
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
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
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
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
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
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
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 Last Answer : (c) sending end voltage is more
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 Last Answer : (b) 8.8 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 Last Answer : (a) 31.25 percent of copper
Transmitted power remaining the same, if supply voltage of a D.C. 2-wire feeder is increased 100 percent, saving in copper is (a) 25 percent (b) 50 percent (c) 75 percent (d) 100 percent Last Answer : (b) 50 percent
In a D.C. 3-wire distribution system, balancer fields are cross-connected in order to (a) boost the generated voltage (b) balance loads on both sides of the neutral (c) make both machine^ run as unloaded motors (d) equalize voltages on the positive and negative outers
The material generally used for armour of high voltage cables is (a) aluminium (b) steel (c) brass (d) copper Last Answer : (b) steel
The material commonly used for insulation in high voltage cables is (a) lead (b) paper (c) rubber (d) none of the above Last Answer : (b) paper
High voltage transmission lines use (a) suspension insulators (b) pin insulators (c) both (a) and (b) (d) none of the above Last Answer : (a) suspension insulators
Most of the high voltage transmission lines in India are (a) underground (b) overhead (c) either of the above (d) none of the above Last Answer : (b) overhead
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
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
The phenomenon qf rise in voltage at the receiving end of the open-circuited or lightly loaded line is called the (a) Seeback effect (b) Ferranti effect (c) Raman effect (d) none of the above Last Answer : (b) Ferranti effect
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
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
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
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
What is the material used for overhead transmission lines? Last Answer : Answer: ACSR conductors are employed.
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
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
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
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
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
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
Aluminium has a specific gravity of (a) 1.5 (b) 2.7 (c) 4.2 (d) 7.8 Last Answer : (b) 2.7
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
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
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
In a substation the following equipment is not installed (a) exciters (b) series capacitors (c) shunt reactors (d) voltatre transformers Last Answer : (a) exciters
For which of the following equipment current rating is not necessary ? (a) Circuit breakers (b) Isolators (c) Load break switch (d) Circuit breakers and load break switches
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