| With the persistent increasing of our country's economy, the traffic jam of the city is nervous day by day. The best way to solve the problem is the subway. With fast development of the subway, DC traction supply system is widely applied, so research of the highly capability and reliable DC protection is very urgent.Because permanent fault and transient fault can't be distinguished by the present protection mode, transmission line protection is compelled to deal with reclosure blindly, which bring unnecessary secondly damage to the power equipment and fault line. To solve the problem, a protection project based on fault traveling waves is brought forward in this paper, which can correctly identify the fault qualities and give a pulse signal to reclosure device, this ensure the reclosure's efficient action.There are some attributions: first, apply traveling wave method and virtual instrument technology to acquire the fault signal, with the help of NI-5112 DAD card, signal adjustment circuit and the tool of LabVIEW7, the writer developed the signal analysis's software and realized high and real-time data sampling. Next based on the wavelet analysis theory, this paper presents a... |
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