An adaptive protection to single-line-to-ground fault in teed lines with wind power based on measuring impedance characteristic

With the development of wind power and the increase of grid density, it is a common style for wind power to be connected to the grid with T-type. The setting and configuration of protection is very difficult due to fault characteristics of wind power system and teed lines topology. Distance protection is an important research topic in teed lines with wind power. The adaptability of distance protection in teed lines with wind power is firstly analyzed. Then, a mathematical model of teed lines measuring impedance is built and its key influence factors which include wind power teed distance, positive sequence impedance of wind power, fault resistance and the relationship between the three side electromotive forces are extracted. Next, an adaptive pilot distance protection scheme based on measuring impedance characteristic is proposed. Finally, simulation is carried out and the research results verify the reliability and effectiveness of proposed protection scheme.