The mechanical effects of short-circuit currents in - Montefiore

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Case *11 (EDF 1990) This is the 102-m-span in Case *11 but with dropper in midspan. The short-circuit current flows through the complete span, path B is with dropper and path A the reference without dropper, see also [Ref 3]. The calculation is also done using the method described in paragraph 3.3. Figure 8.20 gives the results. a) b) 40 4,0 0 % kN 35 +25 % m 30 3,0 25 -25 % 2,5 F c 20 15 10 5 0 0 5 10 15 20 25 30 35 kN 40 F m current path: A B Figure 8.20: Case *11 (5 tests) a) Maximum of Ft and Ff 12 10 8 6 F c / F st 4 2 0 b) Horizontal displacement bh +25 % 0 % -25% 0 2 4 6 8 10 12 F m /F st b c 126 8.3.3. Bundle pinch effect In cases 7 (University of Erlangen-Nürnberg 1985) and *16 (Furukawa 1966), only bundle pinch effect is measured. In case 7, a special test arrangement had been used with short span length and low static tensile forces, whereas in case *16 a 35-m-span with high static tensile force. For these very different test structures, sufficient accuracy is obtained in most tests, Figure 8.21 and Figure 8.22. 2,0 1,5 1,0 0,5 0,0 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 m 4,0 6 5 4 3 F c/ F st 2 1 0 b m +25 % current path: A B +25 % -25 % 0 % 0 % -25% 0 1 2 3 4 5 6 F m / F st Figure 8.21: Case 7: Pinch force F pi (73 tests) Figure 8.22: Case *16: Pinch force F pi (29 tests)
8.3.4. Conclusions For flexible conductors, the calculations according to the IEC Publication 60865-1 [Ref 2] and the European Standard EN 60865-1 [Ref 3] are compared with tests done in different laboratories. Most results lie in the range of ±25 % and show a good agreement with the tests. Higher values evaluated by the standard can be traced back to effects which cannot be taken into account in the method, or that are not measured, whereas the worst case is calculated, or due to safety factors considered. Also, the extension on spans with droppers in midspan in paragraph 3.3 and on three phase automatic reclosing in paragraph 3.7.1 gives good results. Furthermore, the limitation of the method to span lengths ≤60 m is no longer necessary. The confrontation confirms the validity of the simplified method stated in the standard for design purposes in substations. 127
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THE MECHANICAL EFFECTS OF SHORT-CIR
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3.7. Special problems .............
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1. INTRODUCTION 1.1. GENERAL PRESEN
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The pinch (first maximum) can be ve
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1.3.3.2 Supporting structures Simil
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This method allows to state the sho
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and becomes the static force in equ
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(2.26) M el-pl ⎡ y d/ 2 y = 2⎢
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V σ 3 2,5 2 1,5 1 mechanical reson
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V F 3 2,5 2 1,5 1 mechanical resona
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1. eigenmode 2. eigenmode 3. eigenm
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(2.43) U E max max = 1 2 1 = 2 l
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m (2.47) M = σm = Z mσ m dm 2 J w
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profiles in Figure 2.14 it follows
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(2.71) 2 tube tube 4 tube U ∂U
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2.3.2. Influence of two busbars a)
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Asymmetrical associated-phase layou
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d)Methods used IEC 60865 method : -
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Section 3.4 deals with the effects
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In Figure 3.5 to Figure 3.8, the ma
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Figure 3.17 Comparison calculated a
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movement of the dropper (swing out
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This value has to be compared with
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EN 60865-1 [Ref 3] with the assumpt
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a) b) c) 3 m 2 1 0 -1 δ m δ 1 Mov
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Droppers with fixed upper ends Duri
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Manuzio developed a simplified meth
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From prior tests the stiffness valu
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Force / kN Force / kN 100mm 200mm 4
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1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 ESL F
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3.7. SPECIAL PROBLEMS 3.7.1. Auto-r
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for the maximum outswing and the ma
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Zug-/Druck-Kraft in kN Z eit in s F
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The numerical resolution of these e
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4. GUIDELINES FOR DESIGN AND UPRATI
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standards and tested under specifie
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5. PROBABILISTIC APPROACH TO SHORT-
Page 75: f G f(L) Lt Ls 75 G(L) ∞ R = ∫
Page 78 and 79: Only the lowest break values are im
Page 80 and 81: 5.2.2. A global Approach For analyz
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Page 84 and 85: 5.2.3.1.7. Proposed Approach The st
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Page 88 and 89: centers are normally balanced by ba
Page 90 and 91: Remark: The risk integral (5.3) can
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Page 94 and 95: The histograms below for the instan
Page 96 and 97: 5.2.3.8.2. Reliability based design
Page 98 and 99: power converter in a three phase br
Page 100 and 101: The time functions of the currents
Page 102 and 103: a) Determination of the linear mome
Page 104 and 105: Figure 6.11 Coefficients mJs1 and m
Page 106 and 107: 7. REFERENCES Ref 1. IEC TC 73/CIGR
Page 108 and 109: Ref 42. Stein, N.; Miri, A.M.; Meye
Page 110 and 111: Ref 80. Fiabilité des structures d
Page 112 and 113: 8. ANNEX 8.1. THE EQUIVALENT STATIC
Page 114 and 115: Figure 8.2 What is ESL in this case
Page 116 and 117: As the eigenfrequency of the portal
Page 118 and 119: Figure 8.9 Case 3 (third eigenfrequ
Page 120 and 121: Both cases have the same 200-kV-arr
Page 122 and 123: a) c) 5 +25 % 0 % 4 3 F c / F st 2
Page 124 and 125: a) b) 24 kN 20 +25 % 0 % 2,0 m F c
Page 128 and 129: 8.4. INFLUENCE OF THE RECLOSURE The
Page 130 and 131: ( ( δ ) ( δ ) ) T = Mg08 . b r .
Page 132 and 133: IEC 60865 Calculations If the clear
Page 134 and 135: 8.6.1.1 With calculation of the rel
Page 136 and 137: f) Calculation of the stresses due
Page 138 and 139: d) Determination of the forces at t
Page 140 and 141: 8.7. ERRATA TO BROCHURE NO 105 In V
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