| Summary: | 碩士 === 中原大學 === 電機工程研究所 === 86 === The performance of grounding system is very important to the safetyof human and equipments. A grounding system is conventionallycharacterized by its grounding resistance , but more and more damagesoccurred on grounding system due to switching surge can not be evaluatedonly by using grounding resistance. The thesis analyzes the switchingsurge characteristics of grounding system directly form the view pointof electromagnetic principles , i.e. analyzes the electromagneticcharacteristics of grounding system with respect to the injection ofswitching surge current.The analysis items included the potential and electromagnetic fields dueto switching surge , and next , based on the analysis results , the stepvoltage and touch voltage related to human safety , and the groundpotential rise(GPR) and ground potential difference(GPD) related toequipment protection are analyzed ; from which , we can assess thedamages of personnel and equipment on a grounding system.The analysis result have shown that the critical touch voltage and GPDwill produced during single pole switching operation to energize ultrahigh voltage transmission line or bus connected with capacitor banks.This will threaten the safety of personnel and low voltage equipments.For solving this problem , the improved methods based on equipotentialand insulation measures are proposed to enhance the protectionperformance of a grounding system , and this will contribute to upgradethe power quality.
|
|---|
