The Study Of Traveling Wave Protection Of HVDC Transmission Line

With the application of HVDC transmission project in electric power transmission is becoming more and more popular. The requirement of protection performance is also getting higher and higher. Traditional DC tranmission line protection is often affected by the transition resistance and noise. This paper established the simulation model of HVDC transmission system based on the MATLAB/Simulink simulation software. In this simulation model, the normal operation of the HVDC system and its various typical faults is simulated. According to the fault information, a new protection scheme is proposed. It use the wavelet transform as the mathematical means,and combined the single-ended fault traveling wave polarity comparison and the fault location. The main contents are as follows:1) Analysed the traditional traveling wave protection principle based on the transient fault component. In order to solve the problems in the protection scheme which is used in the HVDC system now. Introducing the mathematical method of wavelet transform to the traveling wave protection scheme and analysed its principle.2) A12pulse bipolar HVDC transmission system model is built based on MATLAB/Simulink. This model can adapt to various operating modes and reflect the change of all kinds of faults. On the basis of the HVDC system, the operating mode and various typical fault simulation is carried out.3) Presents a protection scheme which combined with the single-ended fault traveling wave polarity comparison and fault location. The protection scheme operation reliably. It use the single-end fault information to avoid the problem of communication channel. Compared with the protection scheme of ABB and SIEMENS, this kind of protection scheme can efficiently solve the problems in the traditional protection which is poor in identify the high resistance grounding fault and interferenced by the noise. And the polarity comparison and fault location are nested which make the reliable performance stronger.4) Finally, the above researches were summarized and analyzed the HVDC transmission further development.