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Power factor correction brings the power factor of an AC power circuit closer to 1 by supplying or absorbing reactive power, adding capacitors or inductors that act to cancel the inductive or capacitive effects of the load, respectively. In the case of offsetting the inductive effect of motor loads, capacitors can be locally connected.
A valley-fill circuit is a type of passive power-factor correction (PFC) circuit. For purposes of illustration, a basic full-wave diode-bridge rectifier is shown in the first stage, which converts the AC input voltage to a DC voltage.
Using active rectification to implement AC/DC conversion allows a design to undergo further improvements (with more complexity) to achieve an active power factor correction, which forces the current waveform of the AC source to follow the voltage waveform, eliminating reactive currents and allowing the total system to achieve greater efficiency.
An over-excited synchronous motor has a leading power factor. This makes it useful for power-factor correction of industrial loads. Both transformers and induction motors draw lagging (magnetising) currents from the line. On light loads, the power drawn by induction motors has a large reactive component and the power factor has a low value. The ...
Turning off the switch causes the voltage across the inductor to reverse and the current to flow through the freewheeling diodes Da+ and Da-, decreasing linearly. By controlling the switch on-time, the topology is able to control the current in phase with the mains voltage, presenting a resistive load behavior (Power-factor correction capability).
The basis of a STATCOM is a voltage source converter (VSC) connected in series with some type of reactance, either a fixed Inductor or a Power Transformer.This allows a STATCOM to control power flow much like a Transmission Line, albeit without any active (real) power flow. [12]
For instance, a power factor of 0.68 means that only 68 percent of the total current supplied (in magnitude) is actually doing work; the remaining current does no work at the load. Power Factor is very important in Power sector substations. Form the national grid the sub sectors are required to have minimum amount of power factor.
In some uses, power conditioner refers to a voltage regulator with at least one other function to improve power quality (e.g. power factor correction, noise suppression, transient impulse protection, etc.) Conditioners specifically work to smooth the sinusoidal A.C. wave form and maintain a constant voltage over varying loads.