256 REPORT ON CURRENT PRACTICES REGARDING FREQUENCIES AND MAGNITUDE OF HIGH INTENSITY WINDS Working Group B2.16 October 2004 REPORT ON CURRENT PRACTICES REGARDING FREQUENCIES AND MAGNITUDE OF HIGH INTENSITY WINDS Working Group B2.16 October 2004 Copyright © 2004 “Ownership of a CIGRE publication, whether in paper form or on electronic support only infers right of use for personal purposes. Are prohibited, except if explicitly agreed by CIGRE, total or partial reproduction of the publication for use other than personal and transfer to a third party; hence circulation on any intranet or other company network is forbidden”. Disclaimer notice “CIGRE gives no warranty or assurance about the contents of this publication, nor does it accept any responsibility, as to the accuracy or exhaustiveness of the information. All implied warranties and conditions are excluded to the maximum extent permitted by law”. B2-04(WG16)21) CIGRE WGB2.16 - METEOROLOGY FOR OVERHEAD LINES REPORT ON CURRENT PRACTICES REGARDING FREQUENCIES AND MAGNITUDE OF HIGH INTENSITY WINDS 1/46 B2-04(WG16)21) CIGRE WGB2.16 - METEOROLOGY FOR OVERHEAD LINES 1.LIST OF CONTENT 1.List of content....................................................................................................................................2 2.Abstract..............................................................................................................................................4 3.Introduction........................................................................................................................................5 4.Characteristics of Severe Wind Storm Events..................................................................................5 4.1Subtropical Thunderstorms .........................................................................................................5 4.2Thunderstorm Formation, Classification and Organisation......................................................... 8 4.3Severe Winds.............................................................................................................................10 4.4Tropical Cyclones, Typhoons and Hurricanes...........................................................................15 4.5Extratropical Storms / Winter Storm Events..............................................................................19 4.6Other Effects..............................................................................................................................20 4.6.1Instability depressions in cold air.........................................................................................20 4.6.2Katabatic or Downslope Winds...........................................................................................21 4.6.3Jet Streaks ..........................................................................................................................22 4.6.4Rotor Effects........................................................................................................................22 4.7Impact of Severe wind gusts on Overhead Lines......................................................................22 4.7.1Subtropical Thunderstorms –Downbursts, Microbursts, and Tornadoes............................22 4.7.2Tropical Cyclones, Hurricanes, and Typhoons....................................................................24 4.7.3Katabatic or Downslope Winds ..........................................................................................24 5.Current International Design Standard Provision for High Intensity Winds.....................................25 5.1Australia.....................................................................................................................................25 5.2Brazil..........................................................................................................................................26 5.3Argentina....................................................................................................................................26 5.4Venezuala..................................................................................................................................26 5.5USA............................................................................................................................................26 5.6Japan..........................................................................................................................................27 5.7Netherlands................................................................................................................................28 5.8New Zealand..............................................................................................................................28 5.9Belgium......................................................................................................................................28 5.10Finland......................................................................................................................................28 5.11Norway ....................................................................................................................................28 5.12Italy...........................................................................................................................................29 5.13Canada.....................................................................................................................................29 5.14United Kingdom........................................................................................................................30 5.15South Africa..............................................................................................................................30 5.16France......................................................................................................................................30 5.17Iceland .....................................................................................................................................31 5.18Spain........................................................................................................................................31 5.19China and Hong Kong..............................................................................................................31 5.20India..........................................................................................................................................32 5.21Philippines................................................................................................................................32 5.22Ukraine.....................................................................................................................................32 6.Current Design Practices relating to High Intensity Wind Loads.....................................................33 6.1Australia ....................................................................................................................................33 6.2Brazil..........................................................................................................................................33 6.3Argentina....................................................................................................................................34 6.4Venezuela..................................................................................................................................34 6.5USA............................................................................................................................................35 6.6Japan..........................................................................................................................................35 6.7Netherlands................................................................................................................................36 6.8New Zealand..............................................................................................................................36 6.9Belgium......................................................................................................................................37 6.10Finland......................................................................................................................................37 6.11Norway.....................................................................................................................................37 6.12Italy...........................................................................................................................................38 6.13Canada.....................................................................................................................................38 6.14United Kingdom........................................................................................................................38 6.15South Africa..............................................................................................................................39 6.16France......................................................................................................................................39 6.17Iceland......................................................................................................................................39 6.18Spain........................................................................................................................................40