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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.
