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ABB Components USA Seismic Considerations & Power Bushings Using IEEE Standards ABB Components USA.

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Presentation on theme: "ABB Components USA Seismic Considerations & Power Bushings Using IEEE Standards ABB Components USA."— Presentation transcript:

1 ABB Components USA Seismic Considerations & Power Bushings Using IEEE Standards ABB Components USA

2 IEEE IEEE Recommended Practice for Seismic Design of Substations

3 ABB Components USA djr 2/00 IEEE Std n Electrical Equipment for Sub Stations n Based on IEEE s Very major revision s Basically a new standard n Three Qualification Levels s Low, Moderate & High n User determines Qualification Levels

4 ABB Components USA European Standards IEC Technical Report 1463

5 ABB Components USA djr 2/00 IEC Technical Report 1463 n Covers seismic qualification of power bushings n Based on static coefficient calculations n Based on cantilever withstand of bushing n Not widely accepted in North America

6 ABB Components USA djr 2/00 IEEE n Performance Levels n Selection of performance Level n Requirements for bushings n Test Methods n Qualification of bushings < 161 kV n Qualification of bushings  161 kV

7 ABB Components USA djr 2/00 Performance Levels (ground acceleration) n Low = 0.1 g, horizontal acceleration peak n Moderate = 0.5 g, horizontal acceleration peak n High = 1.0 g, horizontal acceleration peak n Vertical acceleration = 0.8 x horizontal

8 ABB Components USA djr 2/00 Selection of Performance Level n By User of equipment n Expected ground acceleration by earthquake hazard method or … n … by seismic exposure maps and site conditions n Select Performance Level to match the expected ground acceleration

9 ABB Components USA djr 2/00 General Requirements for Bushings n Bushings as components of larger equipment n Annex D of IEEE Transformers n Requirements depend on system voltage

10 ABB Components USA djr 2/00 Testing for Seismic Performance Levels n Low: 0.1g, horizontal s Equipment testing not required n Moderate: 0.5 g, horizontal s Testing required (when practical with equipment size) n High: 1.0 g, horizontal s Testing required (when practical with equipment size)

11 ABB Components USA djr 2/00 Qualification of Bushings Less than 161 kV s Static Pull Test s Force = 2 x weight s Applied horizontally s at top of bushing s Duration = 2 seconds 161 kV and Higher s Shake Table test s Time history method s Test by design family s Test most seismically vulnerable family member Pass = no damage & no leaking

12 ABB Components USA djr 2/00 Bushing Seismic Considerations n Bushing is not at ground level n Bushing acceleration is amplified by transformer structure n Bushing acceleration = 2x ground acceleration n Transformer tank: s Amplification factor = 2, or s Super Elevation factor (IEC) = 1.5

13 ABB Components USA djr 2/00 Transformer Tank Amplification Factor = g 2.0 g

14 ABB Components USA djr 2/00 Shake Table Testing of Bushings n Method 1 s Test at 1/2 level and s Calculate to demonstrate a 2x safety factor n Method 2 s Test at full level

15 ABB Components USA djr 2/00 Shake Table Testing of Bushings 1/2 Test + Calculation Method n Only practical method for some large equipment n Good when structure behaves in linear fashion and is predictable n Not good for bushings because of the non-linearity of the bushing’s mechanical system, ie, gasket + porcelain + spring clamps

16 ABB Components USA djr 2/00 Shake Table Testing of Bushings Using 1/2 Level Test Method n For large equipment where not practical to test at full level. n Must demonstrate by calculation that equipment can withstand forces 2 times as great as test values

17 ABB Components USA djr 2/00 Example of 1/2 Test Method (Power Transformer) n Purpose of test: demonstrate that transformer is qualified for the High Performance Level where ground acceleration = 1.0 g n Shake Table set-up at 1/2 value = 0.5 g n Use calculations to show that the test results at 0.5 g can be extended to 1.0 g

18 ABB Components USA djr 2/00 Example of 1/2 Test Method (Transformer Bushings) n Purpose of test: s demonstrate qualification at High Performance Level s ground acceleration = 1.0 g n Bushing acceleration is 2 times ground acceleration because of tank effect n Bushing must withstand 2 x 1.0 g = 2.0 g n Shake Table set-up at 1/2 value = 1.0 g n Use calculations to show that the test results at 1.0 g can be extended to 2.0 g

19 ABB Components USA djr 2/00 Shake Table Testing of Bushings Using Full Test Method (Full Performance Level Test) n Purpose of test: s demonstrate qualification at High Performance Level s ground acceleration = 1.0 g n Bushing acceleration is 2 times ground acceleration because of tank effect n Bushing must withstand 2 x 1.0 g = 2.0 g n Shake Table set-up at full value = 2.0 g n Bushing directly qualified by Test n Calculations not required

20 ABB Components USA djr 2/00 Shake Table Testing of Bushings Using Full Test Method (Full Performance Level Test) n Moderate Level (0.5 g) s Bushing tested at 1.0 g n High Level (1.0 g) s Bushing tested at 2.0 g

21 ABB Components USA djr 2/00 2 g Bushing High Level by Direct Testing

22 ABB Components USA djr 2/00 1 g Bushing Moderate Level by Direct Testing

23 ABB Components USA djr 2/00 Shake Table Test Set-up

24 ABB Components USA djr 2/00 ABB Components USA n Qualify bushings based on IEEE n Actual shake table test used for higher voltage bushings n ABB full line of ANSI/IEEE bushings has been tested and qualified according to IEEE

25 ABB Components USA djr 2/00 ABB Bushing Qualification Summary n High - Static Pull Test s Bushings 25 kV through 138 kV n High - Shake Table s Bushings 161 kV through 196 kV u full test of seismically worse bushing in family n Moderate - Shake Table s Bushings 362 kV u full test of seismically worse bushing in family

26 ABB Components USA djr 2/00 ABB Bushing Qualification Summary n 500 kV bushing s not qualified at moderate s passed 0.45 g at flange s equivalent to 0.22 g, ground acceleration u (with tank amplification factor = 2) s failure mode 0.50 g at flange) u slight leak at flange during shake test u re-sealed after test u no worse after second test

27 ABB Components USA djr 2/00 ABB Components USA


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