Does anyone know the meaning of index “k” in many of the short-circuit related parameters, for example, Ik (short-circuit current), Uk (short-circuit voltage), Sk (short-circuit power)?
This index is used many books and standards in many languages. I suspect it comes from German “kurzschluss”...
I'd like to ask if anyone knows how to form an equation shown in the attached figure (from US4559491 patent).
In the image there is an expression for a phase R current at a point A for a phase-to-phase fault:
IR = (a^2 * I1R + a * I2R + a^2 * Ipre-fault) * a (1)
I can't figure out why (1) is...
There are different ways to estimate current imbalance. The most recent and easiest to manage is given in [1, 2, and 3]. Earlier approach from [4, 5] can also be mentioned.
All these methodologies employ simple reactance formulas (ohms per 1000 feet at 60Hz):
Xii = 0.023*(K’+ln(1/rc)) (1)
Xij =...
Hello
IEC 60287-1-1 standard includes a table with coefficients for skin and proximity effects (ks and kp) for different conductors (round, stranded, hollow etc.). These coefficients are influenced also by the condition “Whether dried and impregnated or not”.
Can anyone help me with the...
Hello.
I’d like to ask if anyone knows why no-load loss of multi-winding power transformers is not referenced to the winding with the highest rated power as it is done with no-load current?
In IEC 60076-1 it is mentioned that no-load current, load-loss, and short circuit impedance can be...
Hello!
I’m trying to calculate impedances of a buried single-circuit cable system.
In the handbook of electric power calculations (H. Wayne Beaty, 2001) I found a very useful chapter written by R. A. Rivas. It says:
“...The method and the formulae proposed in Wedepohl and Wilcox (1973) and...
If it’s possible I’d like to ask advice. We have three XLPE cables in trefoil formation laid in the steel pipe (the pipe was previously a part of high-pressure fluid-filled pipe-type cable system). The pipe and cable screens are directly earthed at both ends of the cable (see attached image).
I...
