Principles of Symmetrical Components Part 2

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Principles of symmetrical components part two.

In this part, we're going to get into a decomposition or the breakdown of symmetrical components. And this more of an overview so we won't go into too much detail here, but this is to serve as a visual example of what we can do with symmetrical component. I have this example already set up. You see, this is an unbalanced set of three phasors or it's an unsymmetrical set of three phasors.

We're gonna call this phasor here IA, this phasor IV, and this phasor IC. Now these three sets of phasors here, these are called the symmetrical components of the unbalanced set. This is the unbalanced set and these three are the symmetrical components. This is positive sequence component, this is negative sequence component, and this right here is zero sequence component. So let's just describe a few things about our system.

So our system, first of all, the phasors in our systems are rotating in the counter clockwise direction. Remember, this is the direction that a lot of the standards and a lot of the papers out there always assume for any system. And then our sequence. So in our system, our sequence, we have an A, B, C phase sequence. These two informations are very important. So as these unbalanced set, as they rotate in the counter clockwise direction, we can assume it has an A, B, C phase sequence.

So now let's zoom in to our positive sequence component. Remember, this positive sequence component is just a breakdown of our unbalanced set. So in our positive sequence component, this phase here is a breakdown of our IA. And then we're gonna give it a super script of one to indicate that this is a positive sequence component. This here is IB and we're gonna give it a super script of one to indicate positive sequence component. And this phase here is IC super script one. Now the cool thing about this positive sequence component is that if we rotate in the counter clockwise direction, remember this is the direction that we always rotate, then the sequence of our phasors is going to be A, B, C.

Now earlier we said that our system has an A, B, C sequence. And as we can see in our positive sequence component, the positive sequence component also has an A, B, C phase sequence. So the phase sequence of our positive sequence component in our phase sequence of our system should be the same, which means that if you have an A, B, C system, then our positive sequence component is going to be A, C, B. So just keep that in mind.

Now for a negative sequence component, let's define some of these phasors. So I'm gonna zoom in a little bit. So this phasor here we're gonna call this IA and we're gonna have a super script of two to indicate that it's a negative sequence component, this right here is IC and we're going to have a super script of two, and this right here is IB and we're going to have a super script of two. Now if you haven't caught on already, look at the phase sequence of the negative sequence component.

So if we place a stationary mark there, and if we assume that the phasors were rotating in the counter clockwise direction, we get a phase sequence of A, C, B. Interesting. So we know for a negative sequence component our phase sequence is going to be the opposite of our positive sequence component. For positive sequence component, it was A, B, C and it was the same as our system phase sequence. For a negative sequence component, the phasors are also rotating in the counter clockwise direction, but the phase sequence is A, C, B.

Now we get to our zero sequence components. Well let's zoom in here. Now for our zero sequence component, that is IA super script of zero, this right here is IC super script of zero, and this phase here is IB super script of zero. Now the zero sequence component, that is also rotating in the counter clockwise direction. But in terms of our phase sequence or phase rotation, it has no phase sequence. Which mean it's neither A, B, C or A, C, B.

In reality though, the zero sequence component, they actually overlap each other. But to make the zero sequence easier to see, we've kind of displaced it like that. So our native sequence component has no phase sequence. So let's back up. We know that we have this unbalanced set of phasors and our system is rotating in a counter clockwise direction and it's an A, B, C phase sequence system. Our positive sequence component is also rotating counter clockwise direction. It's phase sequence is A, B, C, which is the same as our system sequence.

The negative sequence component, it's rotating in the counter clockwise direction, but it's phase sequence is A, C, B, which is the opposite of our system sequence. And the zero sequence component, it also rotating in the counter clockwise direction, but it has no phase sequence. At this point, we're going to conclude this video. But in part two, be able to continue where we left off. Now if you haven't subscribed already, please go ahead by clicking on the bottom right corner of the screen.

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