Thankyou everyone,
Alehman, I have been looking through our system impedance data, the great majority of feeders with X0< X1 have oil filled cables, some are older style XLPE cables, and these are all in a geographically similar area. So this may explain why we are seeing this as a problem...
Thankyou Kiribanda,
In our system (500kV, 330kV,132kV,33kV,66kV,11kV) we have, I would estimate, over 40% of sites with 1ph-e or 2ph-e (either Gnd or phase) having the highest fault level. I realize the ground component of the 2ph-e is not relevent to CBs but for our working earths and the...
I have been asked to quote X/R ratios for faults. Historically we have quoted the Z1 X/R but now I am wondering if the Z0 X/R should be quoted as well.
I have also been asked for the X/R for a 2 phase to earth fault.
I am concerned that Z0 X/R could be confused with the single phase to earth...
Hi,
I have been trying to find a reference to help me with calculating the fault duties (limits) of various cables.
I want to include the effect of conductor size and sheath type and size for various operating temperatures and cable construction.
If anyone can give me a reference either on the...
