The mechanical effects of short-circuit currents in - Montefiore

CONTENTS
1. INTRODUCTION ............................................................................................... 5
1.1. General presentation of the book content ............................................................................................... 5
1.2. General presentation of the main problem ............................................................................................. 6
1.3. Substations mechanical characteristics................................................................................................... 7
1.3.1. Insulator support dynamic behaviour.................................................................................................. 7
1.3.2. Typical apparatus dynamic behaviour................................................................................................. 7
1.3.3. Rough evaluation of the basic frequency of insulators apparatus and supporting structures. ............. 8
1.3.4. Main busbars frequencies.................................................................................................................... 9
2. RIGID BUSBARS............................................................................................ 10
2.1. Introduction............................................................................................................................................. 10
2.2. Short-circuit Strength according to IEC 60865-1 and EN 60865-1 .................................................... 10
2.2.1. Method .............................................................................................................................................. 10
2.2.2. Short-circuit current forces................................................................................................................ 11
2.2.3. Bending stresses in the conductors taking into account plastic effects and forces on the substructures
13
2.2.4. Relevant natural frequencies of main- and sub-conductors............................................................... 20
2.2.5. Section moduli of main and sub-conductors ..................................................................................... 24
2.2.6. Superposition of stresses in conductors............................................................................................. 27
2.3. Special Configurations............................................................................................................................ 28
2.3.1. Associated phase structures busbar on a common support................................................................ 28
2.3.2. Influence of two busbars ................................................................................................................... 31
3. FLEXIBLE BUSBARS..................................................................................... 36
3.1. Introduction............................................................................................................................................. 36
3.2. Typical Oscillograms and Calculations................................................................................................. 37
3.2.1. Typical oscillograms of forces in the bus.......................................................................................... 37
3.2.2. Application of advanced method on high voltage busbar system ..................................................... 39
3.3. The dropper behaviour........................................................................................................................... 42
3.3.1. Introduction....................................................................................................................................... 42
3.3.2. Typical oscillograms ......................................................................................................................... 42
3.3.3. Advanced computation results .......................................................................................................... 44
3.3.4. Simplified methods ........................................................................................................................... 46
3.4. The bundle pinch..................................................................................................................................... 52
3.4.1. Introduction....................................................................................................................................... 52
3.4.2. Advanced computation results .......................................................................................................... 53
3.4.3. Dynamic behaviour of close and various degrees of wide bundling................................................. 54
3.5. Load on Portals, apparatus terminals and equivalent static load....................................................... 58
3.5.1. Introduction....................................................................................................................................... 58
3.5.2. Maximum instantaneous load and equivalent static load for dropper stretch.................................... 58
3.5.3. Maximum instantaneous load and equivalent static load for bundle pinch....................................... 58
3.5.4. Maximum instantaneous load and equivalent static load for Ft, Ff................................................... 59
3.6. ESL factors from numerical simulations. ............................................................................................. 60
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