cable impedance
cable impedance
(OP)
I'm trying to compare some impedance values between a table that I've found with values that are modeled through a computer program. The cable that I'm considering is 350 MCM 69 kV (Teck90) 3/C. The software that I'm using models it with the following parameters (this is in p.u., based on a 1000 foot run, Base MVA = 10 MVA, and the systems voltage is 600 V),
Software: R = 2.2929 , X = 0.40317 , B = 1.74E-6,
Ro = 2.2314, Xo = 0.2552, Bo = 1.74E-6
From the table that I've acquired, this specific cable has an impedance of (in ohms - based on 1000 ft run),
Positive/Negative = 0.040+j0.047
Zero Sequence = 0.316+j0.170
If I convert the table value to a p.u. value (base KV = 0.6, base MVA = 10 MVA) my values aren't very close at all.
Why do you suggest the difference is so great ?
Thanks in advance
Software: R = 2.2929 , X = 0.40317 , B = 1.74E-6,
Ro = 2.2314, Xo = 0.2552, Bo = 1.74E-6
From the table that I've acquired, this specific cable has an impedance of (in ohms - based on 1000 ft run),
Positive/Negative = 0.040+j0.047
Zero Sequence = 0.316+j0.170
If I convert the table value to a p.u. value (base KV = 0.6, base MVA = 10 MVA) my values aren't very close at all.
Why do you suggest the difference is so great ?
Thanks in advance






RE: cable impedance
RE: cable impedance
On the other hand, the referred values from the table, [(Ro = 0.316 > R = 0.040) & (Xo = 0.170 > X = 0.047)] Ohm /1000 ft, appear to be more in line with the expected results for positive and zero sequence.
The enclose site will provide an estimate to support the above statement. For exact results, refer to a 600 V table from the cable manufacturer or perform a calculation using realistic data.
http://www.kerite.com/catalog/catalogfiles/impedance_data_power.htm
RE: cable impedance
http://www.kerite.com/catalog/catalogfiles/impedance_data_power.htm