| Summary: | 碩士 === 中原大學 === 電機工程研究所 === 90 ===
ABSTRACT
The metropolitan rapid transit system（MRTS）passes through urban area with thick people distribution. The first consideration to MRTS is safety, i.e., the MRTS must be safe for people and equipments. Many factors affect the safety of MRTS, in which the high voltage ground fault occurred on the traction power substation is very critical to people and system. This is because of that the ground fault will not only cause the traction power system to tript out of service but also cause the grounding system to produce ground potential rise（GPR）which will be transferred to other places by some interconnected conductors to form transferred voltages to damage personnel and equipments, especially, the damage of transferred voltage may occurred on rail way, passenger stations, control center, maintenance/repair depot, etc. At present, the domestic MRTS are still in the initial stage with lack of experience in ground faults. In the problem of ground fault, although the grounding resistance had been considered in the design of each substation grounding system, the damage of transferred voltage can not be full characterized by grounding resistance without analysis of grounding potential distribution of the whole MRTS. The proposal is aimed to study the ground potential distribution when a ground fault occurred on the traction power substation of an operated MRTS.
In this paper, the ground potential distribution due to the ground fault on the traction power substation of metropolitan rapid transit systems (MRTS) and its affections are studied. The circuit model is called "the cross-bonding ladder circuit model". The circuit model represents the interconnected ground system of MRTS is first constructed, in which all the grounding systems of traction power substation and various interconnects conductors are considered. The ground potential rise (GPR) and the associated transfer voltages at the critical positions are analyzed by using the circuit model. Finally, the affections of GPR and the transfer voltages on the personnel and equipments are assessed.
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