PD IEC/TR 60865-2:2015

This standard PD IEC/TR 60865-2:2015 Short-circuit currents. Calculation of effects is classified in these ICS categories:

• 29.020 Electrical engineering in general
• 17.220.01 Electricity. Magnetism. General aspects
• 29.240.20 Power transmission and distribution lines

The object of this part of IEC 60865, which is a Technical Report, is to show the application of procedures for the calculation of mechanical and thermal effects due to short circuits as presented in IEC 60865-1. Thus, this technical report is an addition to IEC 60865-1. It does not, however, change the basis for standardized procedures given in that publication.

The following points should particularly be noted:

1. The examples in this Technical Report illustrate how to make the calculations according to IEC 60865-1 in a simplified and easy-to-follow manner. They are not intended as a check for computer programs.

2. The numbers in parentheses at the end of the equations refer to the equations in IEC 60865-1:2011.

3. The system voltages are referred to as nominal voltages.

4. The results are rounded to three significant digits.

5. Short-circuit effects appear as exceptional load in addition to the mechanical loads of the normal operation of a switchgear. In the following examples with rigid conductors, a possible static preloading is therefore calculated too. Depending on whether it concerns the load of the normal operation or the load during the short-circuit different safety factors come to use. The height of these factors has been chosen typically and is recommended for the use. However, other safety factors may be necessary depending on the safety concept.