BSI PD IEC/TS 61463:2016
$167.15
Bushings. Seismic qualification
| Published By | Publication Date | Number of Pages |
| BSI | 2016 | 44 |
IEC TS 61463 , which is a Technical Specification, is applicable to alternating current and direct current bushings for highest voltages above 52 kV (or with resonance frequencies placed inside the seismic response spectrum), mounted on transformers, other apparatus or buildings. For bushings with highest voltages less than or equal to 52 kV (or with resonance frequencies placed outside from the seismic response spectrum), due to their characteristics, seismic qualification is not used as far as construction practice and seismic construction practice comply with the state of the art.
This document presents acceptable seismic qualification methods and requirements to demonstrate that a bushing can maintain its mechanical properties, insulate and carry current during and after an earthquake.
The seismic qualification of a bushing is only performed upon request.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | CONTENTS |
| 6 | FOREWORD |
| 8 | INTRODUCTION |
| 9 | 1 Scope 2 Normative references 3 Terms and definitions |
| 10 | 4 Symbols and abbreviated terms |
| 11 | 5 Methods of seismic qualification |
| 12 | 6 Severities 6.1 At the ground 6.2 At the bushing flange Tables Table 1 – Ground acceleration levels |
| 13 | 7 Qualification by static calculation |
| 14 | Table 2 – Dynamic parameters obtained from experience on bushings with porcelain insulators (f0 = natural frequency, d = damping) Table 3 – Dynamic parameters obtained from experience on bushings with composite insulators (f0= natural frequency, d = damping) |
| 15 | 8 Qualification by dynamic analysis 8.1 General |
| 16 | 8.2 Modal analysis using the time-history method 8.3 Modal analysis using the RRS 9 Qualification by vibration test 9.1 General 9.1.1 General Figures Figure 1 – Example of model of the transformer system |
| 17 | 9.1.2 Mounting 9.1.3 External load 9.1.4 Measurements 9.1.5 Standard frequency range 9.1.6 Test methods |
| 19 | 9.1.7 Testing Figure 2 – RRS for ground mounted equipment – ZPA = 0,5 g [1] [2] Table 4 – Example of qualification level: AG5: ZPA = 0,5 g |
| 20 | 9.2 Test on complete apparatus 9.3 Test on the bushing mounted on a simulating support 9.4 Test on the bushing alone 10 Evaluation of the seismic qualification 10.1 Combination of stresses |
| 21 | 10.2 Cantilever test 10.3 Acceptance criteria |
| 22 | 11 Necessary exchange of information 11.1 Information supplied by the apparatus manufacturer 11.2 Information supplied by the bushing manufacturer |
| 23 | Figure 3 – Response factor R Table 5 – Response factor R |
| 24 | Figure 4 – Test with simulating support according to 9.3 Figure 5 – Determination of the severity |
| 25 | Annexes Annex A (informative) Flow chart for seismic qualification Figure A.1 – Flow chart for seismic qualification |
| 26 | Annex B (informative) Natural frequency and damping determination: Free oscillation test B.1 Free oscillation test Figure B.1 – Typical case of free oscillations |
| 27 | Figure B.2 – Case of free oscillations with beats |
| 28 | Annex C (informative) Static calculation method – Additional considerations C.1 General C.2 Effect of the first bending mode C.3 Determination of Sc C.4 Value of abg |
| 29 | C.5 Typical seismic response of cantilever type structures Figure C.1 – Single degree of freedom system |
| 30 | Figure C.2 – Structure at the flange of a bushing with cemented porcelain [5] [7] |
| 31 | C.6 Superelevation factor K Figure C.3 – Spring stiffness C in function of cemented part geometry [5] [7] |
| 32 | Figure C.4 – Superelevation factor due to the existenceof transformer body and foundation [5] |
| 33 | Table C.1 – Examples of typical seismic responses |
| 35 | Annex D (informative) Qualification by static calculation – Example on transformer bushing D.1 Seismic ground motion D.2 Critical part of the bushing D.3 Static calculation D.3.1 General Figure D.1 – Critical part of the bushing |
| 36 | D.3.2 Seismic load Figure D.2 – Forces affecting the bushing |
| 37 | D.3.3 Wind load D.3.4 Terminal load Figure D.3 – Porcelain diameters |
| 38 | D.4 Guaranteed bending strength |
| 39 | Annex E (informative) Center clamped bushings Figure E.1 – Failure process [6] |
| 40 | Figure E.2 – Failure process, flow chart [5] [6] Figure E.3 – Stress profile during the opening process [6] |
| 41 | Figure E.4 – Relation between compression and tensile stress in the bottom edge of the porcelain due to the opening process [6] |
| 42 | Bibliography |
