BSI PD IEC/TR 60865-2:2015
$215.11
Short-circuit currents. Calculation of effects – Examples of calculation
| Published By | Publication Date | Number of Pages |
| BSI | 2015 | 88 |
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:
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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.
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The numbers in parentheses at the end of the equations refer to the equations in IEC 60865-1:2011.
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The system voltages are referred to as nominal voltages.
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The results are rounded to three significant digits.
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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.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | CONTENTS |
| 7 | FOREWORD |
| 9 | 1 Scope 2 Normative references 3 Symbols and units |
| 10 | 4 Example 1 – Mechanical effects on a 10 kV arrangement with single rigid conductors 4.1 General Figures Figure 1 – Conductor arrangement |
| 11 | 4.2 Data 4.3 Normal load case: Conductor stress and forces on the supports caused by dead load |
| 12 | 4.4 Exceptional load case: Effects of short-circuit currents 4.4.1 Maximum force on the central main conductor |
| 13 | 4.4.2 Conductor stress and forces on the supports |
| 15 | 4.5 Conclusions |
| 16 | 5 Example 2 – Mechanical effects on a 10 kV arrangement with multiple rigid conductors 5.1 General 5.2 Data (additional to the data of Example 1) Figure 2 – Position of the sub-conductors and connecting pieces |
| 17 | 5.3 Normal load case: Conductor stress and forces on the supports caused by dead load 5.4 Exceptional load case: Effects of short-circuit currents 5.4.1 Maximum forces on the conductors |
| 18 | 5.4.2 Conductor stress and forces on the supports |
| 22 | 5.5 Conclusions 6 Example 3. – Mechanical effects on a high-voltage arrangement with rigid conductors 6.1 General |
| 23 | 6.2 Data Figure 3 – Two-span arrangement with tubular conductors |
| 24 | 6.3 Normal load case: Conductor stress and forces on the supports caused by dead load |
| 25 | 6.4 Exceptional load case: Effects of short-circuit currents 6.4.1 Maximum force on the central main conductor 6.4.2 Conductor stress and forces on the supports |
| 31 | 6.4.3 Conclusions |
| 32 | 7 Example 4. – Mechanical effects on a 110 kV arrangement with slack conductors 7.1 General |
| 33 | 7.2 Data Figure 4 – Arrangement with slack conductors |
| 34 | 7.3 Electromagnetic load and characteristic parameters |
| 36 | 7.4 Tensile force Ft,d during short-circuit caused by swing out |
| 37 | 7.5 Dynamic conductor sag at midspan |
| 38 | 7.6 Tensile force Ff,d after short-circuit caused by drop 7.7 Horizontal span displacement bh and minimum air clearance amin 7.8 Conclusions |
| 39 | 8 Example 5. – Mechanical effects on strained conductors 8.1 General 8.2 Common data Figure 5 – Arrangement with strained conductors |
| 40 | 8.3 Centre-line distance between sub-conductors as 0,1 m 8.3.1 Electromagnetic load and characteristic parameters |
| 43 | 8.3.2 Tensile force Ft,d during short-circuit caused by swing out 8.3.3 Dynamic conductor sag at midspan |
| 44 | 8.3.4 Tensile force Ff,d after short-circuit caused by drop |
| 45 | 8.3.5 Horizontal span displacement bh and minimum air clearance amin 8.3.6 Pinch force Fpi,d 8.3.7 Conclusions |
| 46 | 8.4 Centre-line distance between sub-conductors as 0,4 m 8.4.1 Preliminary remarks 8.4.2 Characteristic dimensions and parameters |
| 47 | 8.4.3 Pinch force Fpi,d |
| 49 | 8.4.4 Conclusions 9 Example 6 – Mechanical effects on strained conductors with dropper in the middle of the span 9.1 General Figure 6 – Arrangement with strained conductors and droppers in midspan. Plane of the droppers parallel to the main conductors |
| 50 | 9.2 Common data 9.3 Plane of the dropper parallel to the main conductors 9.3.1 General |
| 51 | 9.3.2 Current flow along the whole length of the main conductor span |
| 59 | 9.3.3 Current flow along half of the length of the main conductor and along the dropper |
| 66 | 9.4 Plane of the dropper perpendicular to the main conductors 9.4.1 General 9.4.2 Current flow along the whole length of the main conductor span Figure 7 – Possible arrangement of perpendicular droppersin three-phase system and two-line system |
| 71 | 9.4.3 Current flow along half of the length of the main conductor and along the dropper |
| 79 | 10 Example 7 – Mechanical effects on vertical main conductors (droppers) 10.1 General 10.2 Data Figure 8 – Arrangement with strained conductors |
| 80 | 10.3 Short-circuit tensile force and maximum horizontal displacement 10.4 Pinch force 10.4.1 Static tensile force regarding droppers |
| 81 | 10.4.2 Characteristic dimensions and parameters |
| 82 | 10.4.3 Pinch force Fpi,d |
| 83 | 10.5 Conclusions 11 Example 8 – Thermal effect on bare conductors 11.1 General 11.2 Data |
| 84 | 11.3 Calculations 11.4 Conclusion |
| 85 | Bibliography |
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