Impacts of Diverting Potential Difference on Armored Cables in Substations

Abstract:

To reduce the interference on communication equipments caused by transient electromagnetic field of switching operation, the shields of cables are connected to grounding grid on both sides in the substations grounding designs. However, when the substation is stroke by lightning or shorted, the huge potential difference called diverting potential difference between the cable core and the shield is generated, which can easily destroy insulation of cables, even producing electrical tree or dielectric breakdown in insulation material. Moreover, the large current flowing through the shield of cables will cause personnel accidents and equipment damages. In this paper, the electric model of cables is established using grounding grid simulation software—CEDGS. The way diverting potential difference changes influenced by grounding grids, soil and other parameters is analyzed. Measures to reduce diverting potential difference are proposed for providing a theoretical basis of construction in practice.

• Periodical: Advanced Materials Research (Volumes 986-987)
• Pages: 931-935
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.986-987.931
• Online since: July 2014
• Authors: Li Chen*
• Keywords: Armored Cable, CDEGS, Diverting Potential Difference, Ground Resistance, Grounding Grid

References

[1] DL/T 620-1999 Over-voltage protection and insulation coordination for AC electrical installations [S]. Electric power industry ministry of the People's Republic of China, (1999).

[2] Qi Lei and so on. Measurement of distributed parameters and transient analysis of shielded cable [J]. Proceedings of the CSEE, 2005, 25(6): 119-123.

[3] Wu Maolin and so on. Analysis of electromagnetic interference in shielded cables caused by ground potential difference in substations [J]. High Voltage Engineering, 2005, 31(3): 53-55.

[4] Wang Zhongren and so on. Hydropower station grounding design [M]. China WaterPower Press, (2008).

[5] Hu Yi. The analyses of substation grounding systems and improving measures [J]. High Voltage Engineering, 1987(1): 59-62.

[6] Lu Zhiwei and so on. Potential difference within grounding net for large substations [J]. electric power construction, 2004, 25(9): 39-40.

[7] Li Shenglin and so on. Study of influence factors of dual-layered soil on vertical grounding rod performance [J]. Insulators And Surge Arresters, 2007, (5).

[8] Otero A F. Frequency-dependent grounding system calculation by means of a conventional nodal analysis technique　[J]. IEEE Transaction on Power Delivery, 1999, 14(3): 873-878.

DOI: 10.1109/61.772327

[9] R D Southey, F P Dawalibi, W Vukonich. Recent Advances in the Mitigation of AC Voltages Occurring in Pipelines Located Close to Electric Transmission Lines　[J]. IEEE Transactions on Power Delivery, 1994, 9(2): 1090-1097.

DOI: 10.1109/61.296294