| In the power system, bus bars below the 35kV voltage level have not stability problems, so they are not furnished the bus bar protection. The arc produced by middle voltage bus bar in the case of short-circuiting has the tremendous damage to equipment and personnel and even results in chain accidents。The main task of this thesis is as follows:The causes of arc fault in switchgear and the produced damage have been analysed. The arc dynamic model based on arc gap energy balance theory is established in Matlab, in order to research arc in fault and normal situation.Several protection schemes are analysed and compared according to faults of middle voltage bus bar protection in Haibowan Power Plant. The feasibility of using arc protection is determined and arc protection mechanism is discripted in detail.Through analyzing the recent equipment damage accident cause in Haibowan Power Plant, points out that the fundamental reason for accident is arc short-circuit stemming from phase earth fault.According to practical situation of Haibowan Power Plant, it adopts arc protection devices, determines solution approach,calculates protection setting value. The protection devices can eliminate malfunction selectly, ensure normal equipment to continue working. |
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