The surge impedance for over head line is taken as 100-200 ohms
Description : A 50Ω transmission line is terminated in an impedance of 20-j50. What will be the reflection coefficient? A) 0.69 B) 1.69 C) 6.9 D) 16.9
Last Answer : A 50Ω transmission line is terminated in an impedance of 20-j50. What will be the reflection coefficient? A) 0.69 B) 1.69 C) 6.9 D) 16.9
Description : A transmission line has 1 P.0 impedance on a base of 11 KV, 100 MVA. On a base of 55 KV. it will have a P.0 impedance of
Last Answer : A transmission line has 1 P.0 impedance on a base of 11 KV, 100 MVA. On a base of 55 KV. it will have a P.0 impedance of 0.02 P.U
Description : Surge absorbers are used for protection against
Last Answer : Surge absorbers are used for protection against low voltage high frequency oscillations
Description : State the purpose of surge tank and spill way in hydroelectric power station.
Last Answer : Surge tank :- A surge tank is the small reservoir or tank. It is open at the top. It is installed near Vale house of turbine. It avoids water hammer effect when load on turbine reduces. (It ... ; during floods etc. In this way spill way avoids damage of dam due to excess pressure of water.
Description : State the function of following with respect to hydro power plant : I) Storage reservoir II) Surge tank II) Spillways IV) Trash rack
Last Answer : I) Storage reservoir: It is the basic requirement of hydroelectric plant. Its purpose is to store water which may be utilized to run the prime mover to produce electrical power. A reservoir stores during ... of nozzles of impulse turbines. It is made of steel bars and is placed across the intake.
Description : The function of a surge tank is to (1) produce surge in the pipeline (2) relieve water hammer pressure in the penstock (3) supply water at constant pressure (4) none of above
Last Answer : The function of a surge tank is to relieve water hammer pressure in the penstock
Description : What would cause a power surge in a house?
Last Answer : If your neibour / other flat owners / your maintainer staff switch on any type of inductive load that can cause power surge / dip
Description : In the induction type directional over current relay, when a short-circuit occurs in the circuit (A) power flows in reverse direction (B) power flows in normal direction (C) directional power element does not operate (D) over current element is not energized
Last Answer : In the induction type directional over current relay, when a short-circuit occurs in the circuit power flows in reverse direction
Last Answer : Over voltage protection is recommended for hydro-electric generators, steam turbine generators, gas turbine generators.
Last Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.
Description : Define impedance diagram and reactance diagram.
Last Answer : Impedance diagram: Impedance diagram is the simplified equivalent circuits of single line or one line diagrams of power system in which all components are represented by their equivalent circuit. ... machines are neglected and is used only for fault current calculation is called reactance diagram.
Description : A linear network has a current input 4cos(ω t + 20º)A and a voltage output 10 cos(ωt +110º) V. Determine the associated impedance.
Last Answer : Solution
Description : Give the effect of source impedance on converter operation.
Last Answer : Effect of source impedance on converter operation: For single-phase fully controlled bridge converter, the SCRs are triggered in pairs alternately. During positive half-cycle of input, SCRs T1 and T2 are triggered ... increases and as a consequence, the output dc voltage decreases.
Description : Impedance ratio
Last Answer : Impedance ratio
Description : How to find total impedance Z, current I and Impedance angle ?
Last Answer : How to find total impedance Z, current I and Impedance angle ?
Description : An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when A) ZL = R B) ZL = jXS C) ZL = R-jXS D) ZL = R+jXS
Last Answer : An independent voltage source in series with an impedance ZS=R+jXS delivers a maximum average power to a load impedance ZL when ZL = R-jXS
Description : The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be
Last Answer : The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be 0.5 Ohm
Description : Which of the following is true for a bus impedance matrix ? (A) It is sparse (B) It has diagonally dominant elements (C) It is the inverse of the bus admittance matrix (D) Each element of it is the reciprocal of the corresponding element in admittance matrix
Last Answer : Which of the following is true for a bus impedance matrix ? (A) It is sparse (B) It has diagonally dominant elements (C) It is the inverse of the bus admittance matrix (D) Each element of it is the reciprocal of the corresponding element in admittance matrix
Description : In a series resonant circuit, the impedance of the circuit is?
Last Answer : In a series resonant circuit, the impedance of the circuit is minimum.
Description : Is the input impedance of MOSFET more than BJT and FET?
Last Answer : Yes, the input impedance of MOSFET more than BJT and FET.
Description : The reactive power transfer over a line mainly depends on
Last Answer : The reactive power transfer over a line mainly depends on lVsl- lVRl
Description : Carvin V3 head switches channels on it's own. Any ideas?
Last Answer : Poltergeist?
Description : Anyone here ever hit their head so hard that you felt your brain bump?
Last Answer : I've done it once, when I hit my head directly in the center of my temple. I could have sworn, like you, that I could feel my brain hit the opposite side of my head. That reminds me that I hit my ... closest thing to me, which happened to be my bed, out of pure instinct. It hurt like a mother*@#*&#!
Description : Does nodding your head up and down universally mean "yes"?
Last Answer : answer:“In many cultures, it is most commonly, but not universally, used to indicate agreement, acceptance, or acknowledgment.” http://en.wikipedia.org/wiki/Nod_(gesture)
Description : How to Get Rid of Head Lice
Last Answer : How to Get Rid of Head Lice You have probably heard of lice, but have you heard of a louse? Lice are simply a group of tiny bugs that often get into people's hair. A louse is a tiny, ... bedding in the washer's hottest setting. Shave, wash, and comb out any areas that pubic lice have affected.
Description : How to Fix a Leaky Shower Head
Last Answer : How to Fix a Leaky Shower Head It's annoying when your shower head leaks, disrupting your bath time regimen. It can be a pain in the neck, but instead of buying a new one, there's ... repair a leaking shower head. You'll soon find yourself bathing comfortably under a well-functional shower fixture.
Description : How to Clean a Shower Head
Last Answer : How to Clean a Shower Head We take showers to remove dirt from our bodies, but what if the dirt itself comes from the shower? If not cleaned and maintained properly, mineral deposits can build ... out of the bathroom squeaky clean every time. Try these simple steps and solve this problem with ease.
Description : Compare variable head flow meter with variable area flow meter.
Last Answer : Parameter Variable head flowmeter Variable area flowmeter Working principle Restriction or obstacle is placed in the path of flow to create a differential Pressure. The pressure ... viscous fluid slurries and dirty fluids. In laboratories and testing and production lines.
Description : With a neat diagram explain medium head hydro-electric power plants.
Last Answer : Diagram of medium head hydro-electric power plants: Explanation:- If head of water is between 30 and 100 m, the plant is called a medium-head plant. Potential energy of ... Francis turbines are normally used. Alternator required in these plants is of low speed and large in diameter.
Last Answer : Turbine used for low head is Kaplan turbine.
Description : A lightening arrester connected between the line and earth in a power system (1) protects the terminal equipment against travelling surges (2) protects the transmission line against direct ... suppresses high frequency oscillations in the line (4) reflects back the travelling wave approaching it
Last Answer : A lightening arrester connected between the line and earth in a power system protects the terminal equipment against travelling surges
Description : lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is
Last Answer : lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is terminated into a resistance equal to surge impedance of the line
Description : Transmission efficiency of a transmission line increases with the
Last Answer : Transmission efficiency of a transmission line increases with the increase in power factor and voltage
Last Answer : The inductive interference between power and communication line can be minimized by transposition of the power line, transposition of the communication line.
Last Answer : Reactance relay is preferred for phase fault on short transmission line.
Last Answer : Impedance relays are used for phase faults on long line.
Last Answer : When a wave propagates on a transmission line, it suffers reflection several times at sending and other end.
Last Answer : The interaction between a transmission line and communication line is minimized by transposing transmission as well as communication lines, increasing the height of the transmission line tower, increasing the distance between the two lines.
Last Answer : When a transmission line is energized, the wave that propagates on it is current wave and voltage wave.
Last Answer : A transmission line is protected by distance protection, time graded and current graded overcurrent protection.
Description : Select insulating materials for following parts : (i) Insulation between heating element and base plate of electric iron. (ii) Insulation used over copper or aluminium conductor used for making coils. (iii) Transformer bushings. (iv) Insulation between transmission line and pole.
Last Answer : Parts Insulating Materials Insulation between heating element and base plate of electric iron. Mica Insulation used over copper or aluminium conductor used for making coils. ... Transformer bushings Porcelain Insulation between transmission line and pole. Porcelain
Description : State any two advantages of MCB over Fuse. State the standard specifications of MCB available in the market.
Last Answer : Following advantages of MCB over Fuse: 1. No need of replacement of fuse wire. 2. Manually restore of supply is simple. 3. Fault understanding by visual inspection 4. More safe than fuse The standard specifications of ... 6A, 10A,16A,20A, 25A, 30A, 32A, 40A, 50A, 60A and 63A 6. 250V and 450 v
Description : State advantages of short pitch winding over full pitch winding in alternators.
Last Answer : Advantages of Short Pitch Winding over Full Pitch Winding in Alternators: 1) Short pitching reduces the amount of copper needed for end connection when compared with full pitched coil. 2) They ... reduced, thereby increasing the efficiency. 4) The power quality of generated emf is improved.
Description : What do you mean by active filter? State its advantages over passive filter . Define pass band & stop band with respect to filter.
Last Answer : Active Filter: Active Filter is formed by using active element along with the passive components. Advantages of Active filter over Passive filter: High value of pass band gain can be obtained. It is ... pass band. Stop Band Filter: The frequency range which is attenuated is known as stop band.
Description : State two advantages of digital system over analog system.
Last Answer : 1. They are less susceptible to noise. 2. The effect of fluctuation in the characteristic of the components, ageing of components etc. is very small in digital circuits. 3. Digital circuits have capability of memory which makes them suitable for computers. 4. More accurate.
Description : Thyristor can be protected from over voltages by using
Last Answer : Thyristor can be protected from over voltages by using Voltage clamping device
Description : The main advantage of AC over DC is: (A) Conversion flexibility from one voltage level to other (B) AC can be easily converted into DC by using a rectifier (C) AC is easy to maintain & can be easily distributed at long distances (D) All of the above
Last Answer : Ac is easy to maintain and ac can be easily converted to dc by rectifier .There is no commutator for conversion in ac that's why ac machines are weight less and more efficiency.ac machines occupy less space than dc .
Description : 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
Last Answer : In over compounded generator, full load terminal voltage is more than no load terminal voltage.
Last Answer : An over excited synchronous motor on noload is known as synchronous condenser.