Home › Electrical Engineering Forum › General Discussion › EXCEL FILE FOR Setting of instant short circuit tripping of C.B/ selection of circuit fuse › Re: EXCEL FILE FOR Setting of instant short circuit tripping of C.B/ selection of circuit fuse
help in Calculation of instant short circuit tripping of circuit breaker is based on following inputs:
• Instantaneous Short-Circuit Triping Set
• Cable Size
• Cable Material
• Actual Length of Cable
And according to what you select or choose, result of maximum length of cable for your tripping setting is calculated. Selection of fuse is based on circuit wire size input (1,5mm2 – 70mm2).
First, I can’t download the mentioned file.
The calculation of any Short Circuit Fault current value is simple by using the “ Ohm’s Law ”, where we should know, as mentioned in the Topic, the Voltage’s value and the Fault Impedance loop value, but refer to the inquiry information mentioned in the Topic I have the following comments :
A- The impedance loop value is composed of :
1- The impedance of the source “ MV & Transformer ” or “ Generator ”.
2- The impedance of all cables from the source to the point of fault, not only the final cable supplying the fault’s point.
B- In you don’t take into consideration all these impedances, the short circuit value will be certainly not correct, and you can’t adjust the protection’s setting.