高導電性混凝土之電磁及接地特性分析

Analysis of Electromagnetic and Grounding Characteristics of Conductive Concrete

王湘仁(Siang-Ren Wang)

指導教授 ： 李俊耀

中原大學/工學院/電機工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000407

摘要

本文旨針對大型科技產業或科學園區之超高壓(345kV)或特高壓(161kV)供電系統，以斷路器或開關動作切換時在接地系統所造成的突波為問題研究重點，利用高導電性混凝土取代接地網周圍土壤，改善開關突波於接地網所產生之電磁暫態現象，有效降低開關突波對設備及人員安全之危害。
本論文首先針對自製之導電混凝土性質作研究，包括電阻係數與導磁係數的模擬與量測，電阻係數部分運用壓片法及四極法，針對兩種量測方式作穩定性之測試，且探討溫度及溼度對於導電混凝土電阻係數之影響，並討論及比較兩者間之優劣；導磁係數部分則利用簡單磁路模型，使用有限元素分析軟體(ANSYS)模擬整體產生之磁場強度與磁通密度以推估其導磁係數，且以實際量測之方式求證。
其次，應用電磁暫態分析軟體(EMTP/ATP)建立超高壓變電所模型，分析變電所一、二次側輸電線路及匯流排因開關操作所產生注入於接地系統的突波電流，並根據突波電流注入變電所地網之數據，進一步應用接地系統分析軟體(CDEGS)分析各項電磁暫態特性。
最後，針對接地網所處之不同土壤層型態進行模擬分析，以瞭解開關突波電流於接地系統之電磁特性對變電所內外人員、系統及設備影響之程度。研究結果顯示，在數種假設土壤層型態中，採用接地網設置於地面下1(m)處，且從地面開始往下至1.25(m)處皆為添加導電混凝土型態，可有效降低開關突波所造成之電磁暫態現象，並提升接地系統之保護特性。

關鍵字

開關突波 ； 導磁係數 ； 電阻係數 ； 接地系統 ； 導電混凝土

並列摘要

The purpose of this thesis is to improve the electromagnetic characteristics of grounding grid with the conductive concrete for an extra high voltage (EHV, 345kV) and very high voltage (VHV, 161kV) system, located in a high-tech industry or science-based industrial park. The Study focuses the switching surge is injected to grounding grid caused by operations of breakers or switches. Instead of traditional soil around grounding grid, the conductive concrete can reduce equipment damage and the body damage, caused by switching surges.
First, the properties of the conductive concrete, including resistivity and permeability, are studied. The resistivity is measured by both using four-electrode method and stress-electrode method. Test their stability and considering the influence of temperature and humidity. Then, we discuss and compare what the differences between four-electrode method and stress-electrode method. The permeability is simulated and measured based on simple magnetic circuit model. Finite Element Method Analysis (ANSYS) is employed to simulate the magnetic intensity and the magnetic flux density for estimating relative permeability. Subsequently, the conductive concrete is measured partically.
Second, the circuit model is used to analyze surge currents constructed by the electromagnetic transient program (EMTP/ATP), and the injection currents to grounding system since the switching action on the primary and secondary transmission lines and buses are analyzed. Furthermore, based on the analysis results of switching surge current which is injected into the ground grid of substation, various electromagnetic characteristics of grounding system are analyzed by a software package (CDEGS).
Finally, the variations of different soil materials around the grounding grid are analyzed. The influences of electromagnetic characteristics of grounding system on the personal, equipments and systems are evaluated. Comparing to several soil material styles, the study results have shown that the conductive concrete can effectively reduce the negative damage, caused by electromagnetic transient, and obviously improve the protection of grounding system under the condition that the grounding gird is located 1.0(m) underground, and the conductive concrete is applied from the ground surface to 1.25(m) underground.

並列關鍵字

resistivity ； grounding system ； conductive concrete ； switch surge ； permeability

參考文獻

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