power factor

Unity is the maximum possible limit for power factor.

Power factor is defined as the cosine of the phase angle between current and voltage, and therefore cannot exceed unity.

Industrial loads are typically inductive which explains the large banks of capacitors seen in the substations that feed these installations. The added capacitance counters the inductive reactance of the industrial load.

Power factors less than unity cost power companies money. Even though a portion of the load's power is returned to the grid (due to the reactance of the load), resistive losses in the grid itself dissipate real power and the returned power thus results in a net loss to the power company. This is why power companies charge extra for non-unity power factors. Consequently it is economically prudent for both parties that the power factor be maintained as close to unity as possible.

I think by `more than unity'.. he meant `Leading' power factor.

Ah. Were you planning to explain it to him/her?

Boss.....I just tried to calrify the question to other friend who said power factor cannot be more than unity... however, I feel handicapped to comment on the impact of having `Leading Power Factor'... somehow I feel it should be better to have 0.95 leading pf rather than having 0.95 lagging pf... what do u say?

Rgds

Sanjeev

Hi to all

One cannot achieve ideal power factor (unity). Neither lagging nor leading power factor is good for a system. Leading power factor (some people call it more than unity) is achieved only when capacitive load connected to the system is higher than the inductive (inductive is usually the case). Thus it might be that the capacitor bank installed is of higher capacity or APFC relay is malfuctioning if installed.

One has to pay same amount of electricity bill for 0.95 lag / 0.95 lead power factor if supply board is charging on KVAH. But lead power factor is still not recommended as it is achieved by additional capacitors being switched ON....... Further to add if the p.f. is fluctuating from lag to unity to lead it is harmful for system

feel free to comment

Well said, ashuashi.

Nice answer.

I'll add that running continuously in a leading PF will increase the liklihood of setting up ressonance roblems with other capacitve devices and can end up with severe voltage spikes that will damage sensitive equipment, such as power supplies in computes and instrumentation. It can also cause added heating in some peices of equipment such as transformers, shortening their life expectancy. That is why a utility will punish you for leading as well as lagging PF.

PF is meant to be optimal, not unity.

Hai

Thanks a lot for sharing your idia with me.

Regards

Now that's a clever technique.

Welcome to The Asylum, fb. Hope you enjoy your stay!

Power Factor above unity will add capacitive volatge VC to the Supply Voltage VS thus Received Voltage VR = VS+VC, hence received voltage is greater than Supply voltage & will draw higer excitation currents from sysytem & additional losses.

I don't think this is correct.

Rgds

Sanjeev