KW-KVA-KVAR-PF

How does it work, and why?

How does it work

The system has a current sensor and compares the angle of the current signal to the voltage signal to determine the KVA. Then they select the closest cap to cancel the PF of the load and place it in parallel with the load.

They cancel the reactive portion of the load. A pure inductor would have a +90° phase angle and a pure capacitor would have a -90° phase angle. That is the direction of the angle. The magnitude of the vector is determined by the size of the capacitor.

why?

This will only work with inductive loads, Don't bother with this type of device on your computer or electronic load as those look captive to the power system.

Theoretically speaking, it would be possible to have excessive leading (capacitive) power factor that would benefit from power factor correction inductors. This is not particularly common, as far as I know.

Theoretically you are correct. Electronic loads use diodes to charge capacitors which is why they look some what like a captive load. These devices mostly cause 3rd harmonic distortion. So an inductor will not fix that. Now almost all new devices use what is called Power Factor Correction (PFC) that makes them look more like a resistive load on the power system.

APCPDCL changed KWH billing to KVAH billing since April 2011; hence it will be wise to maintain optimum PF instead of high PF;

The best answer and also the best description I've ever seen.. May I use it please?

Thanks to every one...I hit the books and my doubt is clear...let me put this in this way...when combination of capacitors connected across the circuit it will affect PF,KVA,KVAR but not KW because (consider 1 figure) this is power triangle shows some active power(KW) consumption which is fixed irrespective of PF, KVA and KVAR.

now (Consider figure 2) in this figure due to capacitors combination PF will improves which further reduce KVA and KVAR for the same active power(KW). Amplitude of both KVA and KVAR reduce as pf reduce.

correct me if I am wrong.

The only possible saving of true power with PF correction is the reduced heating of supply cables which is the resistive part of the equation. This could be a problem if you had a PF of 0.5, but at 0.9 PF any further improvement becomes very expensive.

Most of the plug-in devices of this type are consumer frauds. Capacitors can be used to correct power factor and you will benefit by paying a lower penalty for a high power factor (usually levied on higher power 3 phase loads - never on residential - yet you describe a residential plug in unit).

You will not benefit by lower KW hours. The power company rewards those with a PF of unity with zero penalty because it reduces losses caused by the added lag/lead currents making wires hotter - they bear those losses - a reward you for alleviating them.

There are numerous people selling these fraud units, since they cost little to make = very profitable - all they need are fools to buy them. They are often sold by people on commission who try to cheat their friends for a fee - now you know.

For a regular residential consumer, installing power factor correcting device is not going to decrease their power consumption and lower their billing since the installed residential watt meters are designed to measure only the real power (in kw-hr) used. In this respect, in order for the utility companies not to be on the losing end due to reflected kvars on their power lines, they are strategically installing PF correcting devices on their poles.

In contrast, industries running big motors, it is mandatory or required to have their PF corrected else will be penalized and billed accordingly.

I agree with the comments made!

There are a lot of deceptive (Junk) devices that create mistrust for new emerging technologies that have proven to perform. However, most of the points made are valid for single-phase applications only. Because the homeowner often "Feels" the hurt of high utilities; while industry just factors this in as a production cost! Fraudulent companies prey on this need by homeowners to reduce utility costs…

However, IF you utilize 3-phase motors, and your process does not require full-speed operation to perform, reducing the motor cycles will dramatically reduce energy consumption and costs. VFD technology is nothing new, but an accurate method of optimizing these VFDs has always been lacking. New Smart Controller technologies that decrease, align, clean, and balance the power signal, actually reduce and improve kW, kVAR, kVA, and PF.

This is nothing more than "Cruise Control" technology for motors; allowing you to save on "Fuel" (Electricity) by taking advantage of these new "Demand-Response" technologies…