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.
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...
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...
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...
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??
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...
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...
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
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?
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.
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...
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...
