Thanks jim.
Hmm, should it not be: Has a higher zero sequence impedance, as there is a low reluctance path in the transformer core as impedance is proportional to 1/reluctance.
I have not been an active poster on pf, but I have been a member for almost a year. And I have learned a lot from...
@jim hardy , quick follow-up questions if you don't mind? When you said:
This could be a three-limb transformer core, as shown in the picture below. And the reason for it to act as a "ghost tertiary" is because of the high reluctance path of zero sequence flux (through the transformer case...
Thanks, I think it finally "clicked" for me.
I appreciate your patience, and I will look at this closely tommorow. Now I need to rest my brain and maybe open a beer, before I take a look at it again.
Thanks!
Thanks, I will have to study this thread carefully and see if I can understand it, what is confusing me is this statement from the IEEE greenbok:
Based on that quote, and how I interpret it, primary is not needed at all if we have a tertiary delta winding for supplying zero-sequence currents...
Thanks jim, I have encountered zigzag windings and I understand its basics, but I still do not get my initial question, sorry if I am annoying and not understanding what you are saying.
Imagine the following (might not be possible in the real world, I don't know): Imagine you have a power...
Thanks, still I find it somewhat difficult to understand. Since the zero sequence currents can not flow in the primary i.e. there is no closed loop between load and source, why is the zero sequence current "allowed" to flow in the secondary in the first place if it can not get back to the source...
"Current must return to the source", I find it hard to understand that it is sufficient for the zero sequence currents to only flow from the load to secondary and get amp-turns balanced in the tertiary connection, why do they not go back to the source, i.e. primary and then back to a generator?
Hi again, another question.
Please see the schematic below. It shows a wye-wye(n) with a delta tertiary winding. So this delta winding is inserted here so that we can achieve amp-turn balance with the zero sequence currents flowing on the secondary side.
I know that zero sequence currents...
Hi
Got some questions regarding grounding transformers (wye-delta), or maybe I should write, I need someone to tell me if my understanding is correct.
First, under no fault operation:
Only a small current will flow in the wye side of the grounding transformer, aka magnetizing current...
Hi
Take a look at the picture below, I am curious of what transformer connections are used at each step up/step down transformer. I am sure that there are several way of connecting them and each have their pros and cons, but what are the most usual connections?
Lets start at the consumer and...
Nice post @jim hardy , so from that post if I understand correctly, you can use a zig zag connection as secondary in a transformer to prevent triplen harmonics from coupling magnetically back to the primary.
But I am still alittle confused about the sentence in the PDF: "For this to work, the...
Hi again,
Can/are zig zag connections used on the secondary side to avoid triplen harmonics flowing further up the power system? Let's say 3rd harmonics are flowing up the power system from some loads connected to phases a,b,c and the neutral. Since 3rd harmonic are all in phase, the...
Hi, thank you all for replying, I have had internet troubles.
If you look at my drawing, the wye side of the transformer is connected to 3 balanced loads each injecting 3rd harmonic current. When this current (3rd harmonics)
reaches the transformer, it gets magnetically coupled over to the...