# Recent content by OliskaP

1. ### Ampere's law to calculate the B field from a balanced three-phase system

Thanks again. I played around a little, and tried to calculate the magnitude of the resultant \vec{B} at point P and got the figure below. What do you guys think, looks reasonable? I might have done some errors, I did this in a rush. The interesting point is that the magnitude of B is zero some...
2. ### Ampere's law to calculate the B field from a balanced three-phase system

Thanks, both of you, I really appreciate the help. Things are much clearer now.
3. ### Ampere's law to calculate the B field from a balanced three-phase system

By the way, lets say I never saw that table stating that the value of B is different from zero at point P. So without knowing about thetable, I would apply Ampere's law as shown in the picture from post #1, and concluded that the value of B to be zero for every point in space that lies on the...
4. ### Ampere's law to calculate the B field from a balanced three-phase system

Thanks Jim, and after reading the pdf you linked in post #6, it became clear. First we consider one conductor and calculate the value of B at point P, then we consider the other two conductors individually and add the values of B from the three conductors to get the value of B at point P.
5. ### Ampere's law to calculate the B field from a balanced three-phase system

I will have a look at the pdf from the UK utility company later when I am home. The table is in a compendium written in Norwegian by a professor at the Norwegian university of science and technology, and his source is the Norwegian radiation protection authority, this one is also in Norwegian...
6. ### Ampere's law to calculate the B field from a balanced three-phase system

Thanks for the replies. I looked at a table which showed typical values of B at a distance x from a 420 kV transmission line, and they were not zero. So if I would want to calculate the value of B below the transmission line at ground level, I would have to use Biot-Savart equation on each...
7. ### Ampere's law to calculate the B field from a balanced three-phase system

I am a little confused when I try to use Ampere's law to calculate the B field from a balanced three-phase system. Consider the following, shown in the picture below: Lets say I want to calculate the value of B at a distance r (radius of my Amperian loop), the value of r is big enough so that...
8. ### Suggestions for a Power System Analysis book?

Thanks all. I ordered used copies of the books suggested by jim hardy and Dr.D. I dont expect good conditions, but they were so cheap so I'll wait and see. If I like them I can buy them in better condition later. The book suggested by Electrical also seems like a good choice, I will take a...
9. ### Suggestions for a Power System Analysis book?

Hi, I want a book about power system analysis that I can have laying around and read from time to time. I have taken a course in power system analysis some time ago, where I was taught simple fault analysis including unbalanced faults, frequency and voltage control. So to maintain this...
10. ### Phase Locked Loop

Thank you @jim hardy , i'll read what you suggested tomorrow morning.
11. ### Phase Locked Loop

I have some trouble fully understanding the PLL block diagram shown below in the figure. The PLL circuit is used to generate currents (i alpha and i beta) which are in phase with the positive fundamental sequence of the voltage. I am using the book "Instantaneous Power Theory and Applications...

Bump.
13. ### Positive Sequence Detector

Hi, I am studying a positive sequence detector and have some trouble understanding it. I understand most of it, but the author in the book "Instantaneous Power Theory and Applications to Power Conditioning" writes: For extracting the fundamental positive-sequence voltage with the dual method...
14. ### Harmonic sources, flowing from load, why?

Thanks for the explainations @anorlunda and @Windadct , but I am still abit confused when a passive shunt filter is connected in parallel, see figure. So if a nonlinear load causes flow of fundamental + harmonics, but the filter is implemented in such a way that the source only has to supply...
15. ### Harmonic sources, flowing from load, why?

I have been thinking of this and can not seem to understand why nonlinear loads can be tought of harmonic current sources injecting current back into the grid? For example if you connect a passive filter in parallel to attenuate the 5th harmonic, the 5th harmonic would flow between the filter...