Analysis and Calculation of Seismic Performance for UHV Equipment of HGIS

Abstract:

In order to analyze and understand the seismic performance of UHV HGIS, and further improve it, the analysis of dynamic characteristics and seismic response spectra for 1100kV HGIS was carried out in four kinds of seismic waves, and then acquired structural frequencies and mode features. The situation that the natural frequency of UHV equipment and the main frequency of seismic wave were so similar that quasi resonance occurred was considered in the process of analysis. The calculation is conducted by the string of modulated wave that includes three sinusoidal-resonant waves and five sinusoidal-resonant modulated waves to analyze mechanical strength and seismic performance of integral structure. The results show that 1100kV HGIS under those seismic waves has certain safety margin, provide effective data for analysis of seismic performance of UHV equipment.

• Periodical: Applied Mechanics and Materials (Volumes 256-259)
• Pages: 2136-2141
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.256-259.2136
• Online since: December 2012
• Authors: Ke Jian Shi, Bo Wen Xu, Ling Hui Zhou, Xin Lin
• Keywords: Dynamic Characteristic, Five Sinusoidal-Resonant Modulated Waves, HGIS, Mechanical Strength, Quasi Resonance, Response Spectra, Seismic Performance, Three Sinusoidal-Resonant Waves, UHV

References

[12] (6) While " and ", represent viscous damping coefficient and the coefficient of elastic restitution respectively. The particular solution of equation (6) can be derived by Duhami integral: (7) Whileis the volume ratio of the system, represent the circular frequencies with damping and without damping respectively. The product of the mess of particle and absolute acceleration is the inertial force acting on it [13]: (8) By using equation (7) and (8): (9) In the response spectrum analysis, the loads acting on the system is the maximum value of inertial force. Assuming thatis the maximum value of the seismic loads, then [14]: (10) Assuming that，, then: (11) Note that, represent the seismic coefficient, the dynamic magnification factor and the mess of particle. The dynamic magnification factoris the ratio of the maximum response acceleration and the maximum ground acceleration. After the calculation of the seismic loads on the structure, apply the seismic loads as the static loads acting on the structure. Then we can derive the seismic performance of the system through the system analysis [15]and the results are shown in Table2. Under the action of three sinusoidal-resonant waves and five sinusoidal-resonant modulated waves, the deformations and displacements of the structure are shown in Fig. 5(a) and Fig. 5(b) while the maximum displacement is DMX. Fig. 6(a) and 6(b) show the stress distributions of stress under the actions of EI-Centro seismic wave and T-JIN wave while the maximum values are 38. 74MP and 36. 87MPa respectively. Tab. 2 The amplitude of seismic response Modes of waves and reactions Wiring terminal Bottom of pipe Conjunction Three sinusoidal-resonant waves Displacements[mm] Stress[Mpa].

[26] 33.

[7] 23.

[6] 32.

[9] 73.

[26] 36.

[68] 76 Five sinusoidal-resonant modulated waves Displacements[mm].

[22] 35.

[6] 86.

[5] 93 stress [Mpa].

[9] 12.

[23] 78.

[58] 96 EI-Centro seismic waves displacements [mm].

[14] 65.

[4] 12.

[3] 31 stress [Mpa].

[5] 12.

[15] 43.

[38] 74 T-JIN wave displacements [mm].

[13] 41.

[3] 88.

[3] 29 Stress[Mpa].

[4] 86.

[13] 85.

[36] 87 Fig. 5. Displacement of structure Fig. 6. Distribution of stress As is shown in the consequences, the peak value of the displacement occurs on the top of the wiring terminal of the drive pipe which reaches 26. 33mm (Fig. 5). Since the height of high pressure pipe and the mess of its top is are quite high and the bottom is fixed with the transition pipe while the top is totally released, when intensive loads act on the top section, the stress would be totally released which will lead to great displacements. The maximum stress occurs at the conjunction between transition tank and other equipments, as is shown in Fig. 6. This is mainly because of the large displacement of the top of the insulator which causes intensive moment at the bottom and caused large deformation. It will cause great acting force on the equipments linked with it. However, the discordant deformation may intensify the force even causes breaks between them. By comparing the different performances of the 4 types of seismic waves, it is easy to know that 1100kV HGIS shows the greatest seismic reaction under the action of three sinusoidal-resonant waves that twice its counterpart of EI-Centro wave while the reaction is quite similar when being input the five sinusoidal-resonant modulated waves. Since the high pressure pipe of HGIS has big length ratio, the stress would concentrate at the bottom of the pipe, which may cause serious fault such as cracks on the bottom. Conclusion This article chooses 1100kV HGIS as the target to analyze its seismic performance and draw the conclusions as follows: (1) Since the natural frequency of high voltage switchgear is similar to the principle frequency of the seismic wave and the quasi resonance phenomenon, the amplitude wave train of three sinusoidal-resonant waves and five sinusoidal-resonant modulated waves is used in calculation. The results indicate that the reaction conducted by three sinusoidal-resonant waves varies most, reaching 68. 76Mpa, which is slightly larger than its counterpart of five sinusoidal-resonant modulated waves reaching 58. 96Mpa. Meanwhile, both of the two reactions are greater than the one conducted by inputting the real seismic wave. (2) Under the action of three sinusoidal-resonant waves, the maximum stress on the root of the drive pipe is 26. 36Mpa as is shown in Form2. It is mainly because of the large length ratio and stress concentration there. The allowable stress of the drive pipe is 45Mpa, so 1100kV HGIS possesses an adequate security margin. (3) It is suggested that the analysis of HGIS high voltage switchgear should base on the vibration table experiments and analyzed according to the analog of computers in order to fully understand its weak points and improve its seismic performance finally. Referances.

[1] M.F. Li, G.F. Jin, Y. Yang et all: Journal of Shenyang University of Technology, Vol. 33 (2011) No. 4, pp.456-461.

[2] H. Wei, H.Z. Du, Y.Z. Pu et all: Journal of Shenyang University of Technology, Vol. 30 (2008) No. 2, pp.223-227.

[3] Y.F. Cheng, Q.J. Zhu, Z.C. Lu: Power System Technology, Vol. 32 (2008) No. 22, pp.84-89.

[4] Y.X. Hu: Earthquake Engineering. ( Seismological Press, China 2004).

[5] X.Q. Li, H. Wei, Y.F. Feng. Journal of Shenyang University of Technology, Vol. 27 (2005) No. 6, pp.682-685.

[6] H.R. Lin: Friend of Science Amateurs, Vol. 38 (2007) No. 10, pp.38-39.

[7] M.J. Johnston and A.T. Linde: International Handbook of Earthquake and Engineering Seismology, Vol. 81 (2002) No. A, p.589 – 605.

[8] X.X. Ren: Acta Seismologica Sinica, Vol. 19 (2006) No. 1, pp.87-92.

[9] Y.J. Hu: Finite element analysis and applications. (Tsinghua University Press, China 2009).

[10] Y.Z. Zhang: Elastic mechanics and finite element method. (China Railway Publishing House, China 1983).

[11] B.F. Zhu: The finite element method theory and applications. (China Waterpower Press, China 1998 ).

[12] Y.Q. Li: Seismic analysis of the porcelain high-voltage equipments system. (China Institute of Geophysics, China 2002) pp.27-36.

[13] B.Y. Zhang, X.L. Du: Earthquake Resistant Engineering, Vol. 6 (1999) No. 2, pp.34-37.

[14] M.L. Lou, C.Q. Li: Structural Engineers, Vol. 24 (2008) No. 4, pp.80-84.

[15] T. Li, J. Li, Z.Y. Shen: Earthquake Engineering and Engineering Vibration, Vol. 20 (2000) No. 3, pp.43-49.