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What is wattless capacitive power?
I believe you're referring to reactive power. Reactive power is present any time the voltage and current are AC signals and not in phase. Some current simply charges and discharges the load reactance, and therefore does not deliver real power to the load.
Explain the need of power factor correction?
There are two types of power - real power and reactive power. Real power is power that is used, such as the power used to light a light bulb. Reacitve power is power that is held and released by a reactive element (capacitor or inductor), thus is not actually used to do any work. The reactive elements cause a phase shift between voltage and current, which manifests itself as a change in power factor. Power companies must supply both reactive and active power. Total power is equivalent to sqrt( Reactive^2 + active^2). Not only do they need to supply the reactive power, their equipment must be sized to handle a larger total power. Reactive power is generated by installing extra equipment - capacitor banks or inductor banks - or by running generation in such a way that more reactive power is created (this will lower the power plants' real power output). Depending on who the customer is, they may not be billed for the reactive power, thus the oversizing of equipment, and the supplying of reactive power does not generate any revenue (but costs them). If power factor is bad enough, the power company will lose money, and thus require power factor correction, or will bill on both real and reactive power usage. It's simple economics (money)!
What is kilo Var hour meter?
The alternating electric current has two components: one active or effective that moves the fan the refrigerator and lights the house and another one that does not do any useful work, but is necessary to sustain the magnetic fields for the induction devices. Both components load the wiring. The non useful component is called reactive component. The active component is measured by the watt-hour meter and the reactive component is measured by var-hour meters. When the load is high, it might be desirable to measure the reactive component to have an idea of the total load called apparent load. The ratio of the active load and the total or apparent load is called the power factor of the supplied load. The power factor varies between 0 and 1.0. The closer to 1.0, the better used the power is. See Reactive Power Management by R. Barreto in Amazon Kindle version.
How do you control reactive power?
The reactive power depends on the load and not the generator. Reactive power can be detected at the generator, and the load disconnected if there is too much being drawn. A generators's voltage depends on the speed, and the power produced depends on the current in the field winding. An alternator running on a bus bar, as in a grid system, runs synchronously with the grid it is connected to. In this case the power produced depends on the rate that steam is supplied to the turbine, and although the speed stays constant, any increase in power output is accompanied by an advance in the phase angle of the rotor.
What is mean by compensated and uncompensated power transmission line?
Power transmissions lines are inductive by nature. Power in AC systems is transmitted by varying the phase angle between source and receiving end following the below equation: Vsource * Vrecieve * sin (phi) / (Zsource + Zrecieve + Zline) V = the voltage phi = angle between source and receiving end voltage Z = impedance, Zsource = the impedance behind the source end Series compensating lines is accomplished by adding capacitors in series on a line, which reduces the Zline term in the above equation. This allows more power to be transmitted from one end to the other.
What is the importance of reactive power in transmission lines?
Reactive power is the electrical power that oscillate between the magnetic field of an inductor and the electric filed of the capacitor. Reactive Power Cannot Converts to non-electrical power e.g. heat, light & torque. Instantaneous reactive power equal to the multiplication instantaneous current, instantaneous voltage and the sinusoidal of phase difference of current & voltage. It only present in ac power if there is any phase difference between instantaneous current and instantaneous voltage. During complete cycle average reactive power is zero. Active power is the energy supplied to run a motor, heat a home, or illuminate an electric light bulb.Reactive power provides the important function of regulating voltage. If voltage on the system is not high enough, active power cannot be supplied. Reactive power is used to provide the voltage levels necessary for active power to do useful work. Reactive power is essential to move active power through the transmission and distribution system to the customer .Reactive power is required to maintain the voltage to deliver active power (watts) through transmision lines. When there is not enough reactive power, the voltage sags down and it is not possible to push the power demanded by loads through the lines.
The portion of apparent power that doesn t do any work is termed as?
Reactive power is the portion of apparent power that does not do any useful work, but instead oscillates between the source and load causing voltage and current to be out of phase.
What is wattless capacitive power?
I believe you're referring to reactive power. Reactive power is present any time the voltage and current are AC signals and not in phase. Some current simply charges and discharges the load reactance, and therefore does not deliver real power to the load.
Explain the need of power factor correction?
There are two types of power - real power and reactive power. Real power is power that is used, such as the power used to light a light bulb. Reacitve power is power that is held and released by a reactive element (capacitor or inductor), thus is not actually used to do any work. The reactive elements cause a phase shift between voltage and current, which manifests itself as a change in power factor. Power companies must supply both reactive and active power. Total power is equivalent to sqrt( Reactive^2 + active^2). Not only do they need to supply the reactive power, their equipment must be sized to handle a larger total power. Reactive power is generated by installing extra equipment - capacitor banks or inductor banks - or by running generation in such a way that more reactive power is created (this will lower the power plants' real power output). Depending on who the customer is, they may not be billed for the reactive power, thus the oversizing of equipment, and the supplying of reactive power does not generate any revenue (but costs them). If power factor is bad enough, the power company will lose money, and thus require power factor correction, or will bill on both real and reactive power usage. It's simple economics (money)!
What is the effect if the reactive power is larger than the real power?
With a large reactive power in a load, the cables supplying it have to carry a larger current than they otherwise would have to do, for that amount of power. If the reactive power equals the real power, the power factor is 0.7 and the power loss in the supply cables is double what it needs to be. That is disliked by the supply company because they have to provide big enough cables to carry the extra current without receiving any revenue for it.
Do reactive component of impedance dissipate power?
The reactive part dissipates no power because in a reactor the current is 90 degrees out of phase with the voltage. The effect of this is that any power that leaves the generator on one quarter-cycle comes back to the generator on the next. The net power is zero.
What is kilo Var hour meter?
The alternating electric current has two components: one active or effective that moves the fan the refrigerator and lights the house and another one that does not do any useful work, but is necessary to sustain the magnetic fields for the induction devices. Both components load the wiring. The non useful component is called reactive component. The active component is measured by the watt-hour meter and the reactive component is measured by var-hour meters. When the load is high, it might be desirable to measure the reactive component to have an idea of the total load called apparent load. The ratio of the active load and the total or apparent load is called the power factor of the supplied load. The power factor varies between 0 and 1.0. The closer to 1.0, the better used the power is. See Reactive Power Management by R. Barreto in Amazon Kindle version.
What is reactive volt amps?
volt ampere reactive is the unit of reactive power.It is the power which does no useful work but is required to assist in performing work,such as setting up magnetic fields in motors and transformers.It is also called as imaginary power.It occurs in purely reactive circuit i.e. purely inductive or capacitive.The inductance absorbs the reactive power and capacitance injects the reactive power.In inductance,reactive power is utilised to develop the flux while in the capacitance,the reactive power's function is to store the charge.
How do you find the power factor with true and apparent power?
to put out the power fector you have to divided apparent power with true power.AnswerYou can determine the true power of any load using a wattmeter. To find the apparent power, you use a voltmeter to measure the supply voltage and an ammeter to measure the load current, and multiply the two readings together.If you then want to go on to find the power factor, then you divide the true power by the apparent power. If you want to find the reactive power you use the following equation:(reactive power)2 = (true power)2 x (apparent power)2
Why VAR meter does not measure real and apparent power?
A VAr meter only measures the reactive (imaginary) power. Apparent power is a combination of real and reactive power; thus having a VAr meter will not suffice to measure apparent power. Likewise, because the VAr meter only measures reactive power, it does not provide any information on real power.
Why diode is active device when all other active devices require external power supply?
A Device is said to be active if... (i) It is a source of Power in the circuit... (ii) It amplifies any voltage or current in a circuit... (iii) It acts as a switch ie., has modes equivalent to ON and OFF... e.g., transistor amplifies and can also act as a switch...
Why you are using capacitor banks to improve power factor?
A poor power factor is caused by inductive loads or electronic devices. These loads cause excess current to flow in the circuit reducing the efficiency. Inductive devices are considered to be a "load" for reactive power. Reactive power does not actually do any real work by is required to develop magnetic fields. Capacitors are considered to be "sources" of reactive power. So these capacitors will supply the reactive power to the inductive loads instead of the utility supplying this power. This is why capacitors are used to improve a poor or low power factor. This is just a very brief description on this topic. Power factor correction is becoming a very complex topic with more and more poor power factor loads being used every day.
