大型科技廠特高壓及高壓配電系統之地電流特性分析

A Study on the Ground Current Characteristic of Very High Voltage and High Voltage Distribution Systems in the Large High-tech Plants

邱森福(Sen-Fu Chiu)

指導教授 ： 周至如

中原大學/工學院/電機工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400196

摘要

摘要
本研究以典型的高科技工廠之特高壓及高壓配電系統為對象，探討其地電流之特性，其中考慮對地電流的三個主要成分包括感應環流、絕緣劣化洩漏電流及電容性充電電流，這些電流注入工廠接地系統在接地系統上產生的地電位昇(GPR)及導體電流，以及在地表面上產生的磁場、電位、步間電壓及接觸電壓等之分佈都加以分析，以評估對人員、設備及系統的影響。所有的分析將分別針對正常供電模式及緊急供電模式來進行，且將考慮不同的接地條件包括電力公司接地線、工廠內各地網的連接狀況、電纜接地架構、電纜架之接地阻抗、負載準位及不平衡狀況。分析方法是採用解耦法以計算電纜架及其它並行導體之感應環流及應用一分析軟體CDEGS來計算各項電磁特性分佈。研究結果顯示，對地電流所引起的GPR、步間電壓及接觸電壓尚不足以威脅人員的安全，也不致於破壞設備的絕緣，但接地系統之GPR及其導體電流，及地面磁場分佈及電位分佈對敏感設備的系統及設備可能造成干擾，本文由不同接地條件所分析的結果進行比較相關的改善措施亦據以提出以供參考。

關鍵字

地電位昇 ； 地電流 ； 接觸電壓

並列摘要

Abstract
The ground current characteristics of very high voltage (VHV) and high voltage (HV) distribution systems in the large high-tech plants are studied with considering three main components of ground currents including induction current, insulation degradation leakage current and capacitive charging current. The ground potential rise (GPR) and conductor currents of grounding system and the distributions of magnetic fields, potentials, touch voltage and step voltage on the ground surface due to the ground currents are analyze for investigating their affections on personal, equipments and systems. Two different power modes of distribution system in the plant namely normal power mode and emergency power modes are considered for the study. Furthermore, various grounding conditions including the utility ground wires, the connections between ground grids, the grounding scheme of power cable and the grounding impedances of cable tray, and the load levels and unbalances are also considered in the analysis. A decoupled method is used to calculate the induction currents of cable tray and other parallel conductors. A software package” CDEGS” is used to analyzed the distribution of each electromagnetic characteristic item. The study results show that the ground currents will not produce significant GPR and touch and step voltages to damage equipments and personal, but the GPR and conductor currents of grounding system and the distributions of magnetic field and potential on the ground surface may interfere the sensitive equipments and systems. The related mitigating methods based on the comparisons between the analysis results with different grounding conditions are proposed.

並列關鍵字

Ground Current ； GPR ； Touch Voltage

參考文獻

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