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  1. strongone

    Power flow methods

    I want to get detailed information on there different types of power flow methods. Are there any sources of this information on the web??
  2. strongone

    Zero Sequence Impedance for 3 phase Cable

    I'm trying to calculate the zero sequence impedance of the following types of cables: NYY-J, NYFGbF and XLPE-SWA. The only information I presently have on the cablye are its length, resistance, reactance and conductor size. Any help is greatly appreciated. Thanks.
  3. strongone

    Proper Sizing of Power Factor Capacitors

    I'm currently performing a power factor correction on a plant, and I've calculated that I need to install 2400 kVAR reactive power correction. I have decided that I would install 5 banks of 500kVAR capacitors. The problem I now face is that I have received quotes on 150kVAR single phase...
  4. strongone

    simple btu conversion problem

    I would like to know the conversion of: $/litre to $/million Btu for diesel
  5. strongone

    calculating step potentials

    c i | i a - x - b i | i d a,b,c,d and i are all 1m from x I think the reason why Heppe did this was to take into account , the voltage at the diagonals Vstep = sqrt[(dv/dx)^2+(dv/dy)^2]. However is there anywrong with Vstep = max(abs(Va-Vx) and abs(Vb-Vx) and...
  6. strongone

    calculating step potentials

    a,b,c,d are all 1m from x the true step potential at x VmaxX = max(abs(Va-Vx) and abs(Vb-Vx)) VmaxY = max(abs(Vc-Vx) and abs(Vd-Vx)) Vstep at x = sqrt(VmaxY^2 + VmaxX^2) where Va is the potential at a etc. Is this correct??? c | a - x - b | d...
  7. strongone

    calculating step potentials

    Vo = 0 volts, that doesnt make sense to me, how would you calcuate the step voltage through, supposing that you knew the potentail at each point of the grid??
  8. strongone

    calculating step potentials

    Well it seems that i have interpreted Heppe completely wrong. Could you give me a demonstration of Heppe's method, for some reason i just cant visualize it. i would like to determine step potentials throughout a grid. the potentials at every 1m is know. how do i go about calculating the step...
  9. strongone

    calculating step potentials

    Heppe R.J., 1979, Computation of potential at surface above an energized grid or other electrode, allowing for non-uniform current distribution", IEEE Trans. on Power App. and Sys., 98, 1978-88. Heppe gives the step voltage as Vstep = sqrt((dV/dx)^2 + (dV/dy)^2) where Vstep is also known as...
  10. strongone

    calculating step potentials

    ab - parallel to x-axis ab = 1m cd - parallel to y-axis cd = 1m Now if i want to determine the step potential at x Vstep^2 = (Va-Vb)^2 + (Vc-Vd)^2 where Va is the potential at a etc. Is this correct??? c | a - x - b | d
  11. strongone

    Limitations of IEEE std 80 2000

    I am wondering why these limitations werent given. Thanks for point them out. What about grid size?? The guide also states that irregularity factors were added/adjusted to accomadte ground rods and produced favourable results. From you experience to what extent these corrections can be used?
  12. strongone

    Limitations of IEEE std 80 2000

    Limitations i am referring to are those such as grid geometery, grid size. Annex D lists a variety of grid shapes that can be accomodated. What i really want to know is in what situations would the equations for calculating maximum step and touch voltages and grid resistance fail.
  13. strongone

    Limitations of IEEE std 80 2000

    Besides the fact that the guide is somewhat limited to homogenous soil conditions (approx multi-layer to uniform), what are the other limitations.
  14. strongone

    Images of rods in two layer soil

    i am quite familiar with the method in [1], i have even implemented it, not for two-layer though. my problem is the theory , the appendix of [1] gives the location of the images when the field segment/point is in the soil. I understand that situation. ok this is the question Is the system of...
  15. strongone

    Images of rods in two layer soil

    no i am not using any software, i just need to know the location of the images, when the field point is above the earth's surface. for exapmle if a horizontal rod is buried at a depth D, and the surface layer thickness is H. Where are the location of the images of the rod segment when it is in...
  16. strongone

    Images of rods in two layer soil

    i am having a little difficulty tracking images in two layer soil, when the field point is above the earths surface and the source segment is either in the top or lower layer of the two layer soil model. i am trying to calcuate the potential on the earth's surface due to a rod(horizontal or...
  17. strongone

    Program for grounding analysis

    Alex68: I am having problems determining the mutual resitance between two perpendicular conductors. Your third reference states that one integral can be determined analytically and the other by Gaussian quadrature of third order. Could i send you my solution and correct me where i am wrong...
  18. strongone

    Program for grounding analysis

    I was shying away from this algorithim not because it deals with self and mutual resistances but it seems that it cannot calculate the mutual resistance bewteen angled (other than 90 and 0 degrees) conductor segments. Currently I am using the Neuman Integral to calculate self and mutual...
  19. strongone

    Program for grounding analysis

    I am currently working on a prg to perform grounding analysis of earthing grids. I am using the work by R.J Heppe “Computation of potential at surface above an energized grid or other electrode, allowing for non-uniform current distribution”, IEEE Trans. on Power App. and Sys., 98, 1978-88...

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