Waveform distortion:

Status
Not open for further replies.
Hameedulla-Ekhlas

Hameedulla-Ekhlas

Senior Member
Location
AFG
greeting all,

Waveform Distortion: What things cause the waveform distortion in Power quality and how we can prevent it.

Is it due to harmonic or something else causes it.
 
100309-0736 EST

Ham:

Any periodic waveform can be represented by the sum of sine waves of the fundamental frequency and its harmonics.

What causes waveform distortion?

First consider an ideal sine wave voltage source, then any non-linear load on this source will have a non-sinusoidal current waveform. One example of a non-linear load is a diode and resistor in series. The resulting current is a half sine wave.

Second, consider an ideal sine wave voltage source with an internal series resistance of R ohms. If we consider the output voltage at the terminals of this source with a non-linear, then there will be distortion of both the current and the terminal voltage.

.
 
Have a look at this page (which is just a random google hit) which illustrates the current draw vs voltage of several things. Note that some of these waveforms the current flow is almost a spike. This sudden flow of current for a short time causes additional voltage drop across the supply conductors, and creates a notch in the supply voltage waveform that matches the time of the current pulse.

If you really want to see this, any of the modern generation of strobe lights (eg Martin Atomic) are truly ugly loads. They plug into a normal recepticle, and when they flash they draw a current of about 80A for a several milliseconds. As the wiring to the recepticle is designed for a 15A or 20A load, when the 80A is flowing you get lots of voltage drop and on the scope you see a big dip in the supply voltage.
 
Status
Not open for further replies.
Top