Harmonics Case Study

now what I was going to do here is this case study I wanted to show the load profiles of three common devices that we see in our lives not only at the industrial and commercial stage but also in our homes the CFL bulb the LED bulb ending incandescent bulb I had planned to set up a live demo but we're not going to have time for that so I'll just kind of talk about it and then to some charts I want to show you CF bulbs but a few years ago there was a boom you know utilities were saying okay take out all the incandescent bulbs put in CF bulbs you'll save energy you'll do all those things but now the kind of backtracking for that because now we're seeing some of the negatives of CF bolts number one they don't last as long as as they were originally rated as and there's a reason why that occurs and I think I have a slide that shows that number two and probably more importantly when they fail how do you get rid of them the mercury content and things of that nature so you just can't take them and throw them in the trash I'm sure people still do that but you're not supposed to do that LEDs that they're the newcomer the problem with LEDs are is that they cost probably on the average ten times more than a CF bulb incandescent bulb probably next year you probably won't be able to get them the government the government is really fighting hard to pull them off the shelves so we're going to be we're still going to be dealing with CF balls but eventually once manufacturing costs decrease then these bulbs will become cheaper and they'll be the way to go now I did some comparisons where I took a 60 watt CFL 60 watt LED bulb and 60 watt compact fluorescent bulb and yes these two devices here use about a quarter less of the power required for an incandescent bulb so yes there's your energy savings however the so nonlinear loads they generate high third order harmonics their little harmonica generators so the next time you look up and you see a CF bobbing your lamp or your light fixture that's a little home otic generator now again the fortunate thing that we have for us is that the utility grid is low impedance so it probably won't this you probably have to put a thousand of them in your place if you can before the wave form is going to react the voltage wave one's going to react to it so that's kind of like our saving grace but they both exhibit the same harmonic pattern this generates no harmonic at all it's a nonlinear but it's linear so it generates no harmonics at all the failure of the CF bulbs has a lot to do with the startup because the stressing of turning them on and off they get this startup they get this in rush that stresses them and cause them to fail prematurely if you have a CF bulb and you left it on you're probably better off believe it or not you're probably better off leaving your CFL bulb on and not cycle it on and off then it will probably last close to the the rated lifetime spec associated with it and then of course as Ana Gil you're only running at one quarter of the usage of a incandescent bulb so there's there is an energy savings there but here's a start-up of an incandescent bulb we could tell that the load is linear because look at our current waveform its sinusoidal that tells us it's a linear load it's not going to distort the voltage but here we see just to kind of give you a point of reference this is seven amps this is about seven amps the bulb will typically run at 1 amps what 1 amp once you start it up so you can see that the end rush when I initially turn on that Bob it flipped the switch on it's going to draw seven times more of its normal running current but it only cars for like a half a cycle and then it finally settles down this is the CF ball now with the CF bulb the normal running current is less than a nap so here you see the benefit of lower running current lower energy usage and so forth but look at the startup associated with this when this bulb comes on it draws almost as high as 12 amps ok the bubbler is normally running at less than a nap maybe a quarter of an amp but initial startup it's running high as 12 amps it's that repetitive on and off that stresses the ball belt that causes the premature failure you can even see that once I when I started up the bulb I caused the both this transient right at this point here so the inrush was high enough to basically cause a little niche in the voltage waveform and then obviously we can tell that it's nonlinear because here's your normal running current it has no sinusoidal characteristics at all so we know that it's a this is the LED bulb you can see that the LED bulb is not as severe or as far as the startup here's before it is the actual startup you can see actually it kind of takes a while for it to start up so it gradually comes up but again it's nonlinear look at the waveforms because they the waveforms are or distort it okay and it's all about having the right tool for the job and I'll be here past lunchtime so if there are any questions you guys want to chat about anything in particular you can seek me out I'll now open the floor to any questions you

Channel: DranetzTech

Views: 7,063

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Keywords: Dranetz, Electrical Harmonics, PX5, PowerXplorer, EP1, PowerVisa, Power Quality, PQ, Electricity, Energy

Id: zWG-Uzu2IGU

Length: 6min 50sec (410 seconds)

Published: Wed May 11 2011