Abstract
This paper presents a strain analysis in transmission line cables caused by mechanical vibrations induced mainly by the wind action that can cause the fatigue rupture of the cable. The tests were performed on a test bench that consists of two spans of 9 and 12 m, respectively, and it was built using elements of transmission lines (suspension clamps, insulators, anchoring towers, etc.). The vibrations were generated by an electrodynamics shaker. Strains were measured by means of micro-electric strain gauges set in 04 wires of the cross-section of the cable at the vicinity of the suspension clamp, which presents severe levels of dynamic stresses. The cable bending amplitude was measured with two laser transducers. The bending amplitude was converted in strain with the Poffenberger-Swart equation. The comparison between the measured strain and that predicted theoretically showed RMS errors of 31 and 48 % for axial load levels of 20 and 30 % UTS, respectively.
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Abbreviations
- a :
-
Horizontal distance of L1 laser transducer to the clamps’s centre of rotation, m
- A :
-
Standarized distance of 89 mm from the last point of contact between the cable and the clamp
- b :
-
Constant of integration
- d :
-
Wire diameter, m
- E :
-
Young modulus, N/m2
- EI:
-
Bending stiffness, N m2
- f :
-
Frequency, Hz
- I :
-
Area moment of inertia, m4
- j :
-
Stiffness parameter, m
- k :
-
Bending curvature, 1/m
- L :
-
Loop length, m
- m :
-
Mass per unit length, kg/m
- M :
-
Bending moment, N.m
- M 0 :
-
Couple, N.m
- n :
-
Sample size
- n L :
-
Number of loops
- S :
-
Span length, m
- T :
-
Traction load, N
- V t :
-
Travel wave velocity, m/s
- V T :
-
Accurate travelling wave velocity, m/s
- x :
-
Horizontal axis
- y :
-
Deflection, m
- y a :
-
Bending amplitude (peak to peak), m
- y′′ :
-
Second derivatives of y, 1/m
- w :
-
Ransverse load, N/m
- Δβ :
-
Rotation angle, rad
- Δ L1 :
-
Displacement measured with L1 laser transducer
- Δ L2 :
-
Displacement measured with L2 laser transducer
- ε:
-
Strain amplitude (zero to peak), m/m
- λ:
-
Dimensionless parameter of Poffenberger-Swart equation
- θ :
-
Rotation angle, rad
- ϕ :
-
Dimensionless parameter of Poffenberger-Swart equation
- a :
-
Relative to distance
- L:
-
Relative to loop
- t :
-
Relative to the travel wave velocity
- T :
-
Relative to the accurate travelling wave velocity
- 0:
-
Relative to the maximum amplitude (w) or to a couple (M)
- max:
-
Relative to maximum
- min:
-
Relative to minimum
- slip:
-
Relative to maximum friction stress which act on each wire
- stick:
-
Relative to the situation when all wires stick together as a solid body
References
Cigré (1979) Recommendations for the evaluation of the lifetime of transmission line conductors. Electra 63 WG 04 SC 22–02
Edwards AT, Boyd JM (1963) Ontario hydro live-line vibration recorder for transmission conductors. IEEE Trans Power Ap Syst 82:269–270
EPRI (1979) Wind induced conductor motion, Electrical Power Research Institute. Transmission Line Reference Book, Palo Alto
IEEE Committee Report (1966) Standardization of conductor vibration measurements. IEEE PAS-85 85(1):10–22
Fadel AA, Rosa D, Murça JLA, Ferreira JLA, Araújo JA (2011) Effect of high mean tensile stress on the fretting fatigue life of an Ibis steel reinforced aluminium conductor. Int J Fatigue. doi:10.1016/j.ijfatigue.2011.03.007
Goudreau S, Lévesque F, Cardou A, Cloutier L (2010) Strain measurements on ACSR conductors during fatigue tests II—stress fatigue indicators. IEEE Trans Power Deliv 25(4):2997–3006
Goudreau S, Lévesque F, Cardou A, Cloutier L (2010) Strain measurements on ACSR conductors during fatigue tests III—strain related to support geometry. IEEE Trans Power Deliv 25(4):3007–3016
Lévesque F, Goudreau S, Cardou A, Cloutier L (2010) Strain measurements on ACSR conductors during fatigue tests I—experimental method and data. IEEE Trans Power Deliv 25(4):2825–2834
NBR-7270 (1988) Aluminum cables, stell-reinforced for overhead lines. Brazilian Code—ABNT, Rio de Janeiro, Brazil
Papailiou KO (1997) On the bending stiffness of transmission line conductors. IEEE Trans Power Deliv 12(4):1576–1588
Poffenberger JC, Swart RL (1965) Differential displacement and dynamic conductor strain. IEEE Trans, vol. PAS-84. p 281–289
Rawlins CB (1997) Transactions on power delivery, some effects of mill practice on the stress behavior of ACSR. IEEE
Rolim AL (2009) Contribution for the study of mechanical stresses due to aeolian vibrations in transmission line cables, (in Portuguese). MSc Dissertation, Civil Engineering College, Federal University of Pará, Pará, Brazil
Tebo GB (1941) Measurement and control of conductor vibration. Trans AIEE 60:1188–1193
Acknowledgments
The authors would like to thank CNPq—“Conselho Nacional de Desenvolvimento Científico e Tecnológico”, of the Brazilian Ministry for Science and Technology and ELETRONORTE—“Centrais Elétricas do Norte do Brasil” for the financial support provided.
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Technical Editor: Paulo Varoto.
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Rolim, A.L., Moreira, J.L.R., Veloso, L.A.C.M. et al. Differential displacement and strain analysis of transmission line cables. J Braz. Soc. Mech. Sci. Eng. 35, 327–336 (2013). https://doi.org/10.1007/s40430-013-0026-x
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DOI: https://doi.org/10.1007/s40430-013-0026-x