Simulation Research On Distance Protection Of Wind Farm Outgoing Line And Experiment Platform Design

When the wind farm outgoing line is in fault, because of the wind speed fluctuation and weak feed characteristics of wind power grid side, the capacity to identify internal fault in protection range of distance protection algorithm and phase selection is influenced, so it is necessary to use simulation to study impacts of wind farm on it. An open, easy and practical computer protection experimental platform is designed. By simulating the characteristics of wind speed fluctuation and weak feed,distance protection algorithm and phase selection used in computer protection are tested, and the action characteristics of computer distance protection are tested. It is helpful to the understanding, experiment and teaching of computer distance protection.In this thesis, the simulation model of double-fed wind farm integration into power grid is established by using the software PSCAD. The fault characteristics of wind speed fluctuation and the impact on Fourier algorithm and solving differential equation algorithm measuring impedance are simulated, and the influence of week feed on error of power frequency extraction and measuring impedance of matrix pencil algorithm is simulated. The fault characteristics of week fed and the impact on phase selection are simulated. The phase selection method based on steady state voltage sequence component is presented, which is suitable for weak power, and simulation and verification of different type short circuit is carried out. At the same time, the computer distance protection experimental platform based on DSP is designed. By simulating the frequency offset characteristics of wind farm, the Fourier algorithm, solving differential equation algorithm and matrix pencil algorithm applied to the experimental platform is tested. By simulating the week fed of wind farm,phase selection of steady state voltage sequence component applied to the experimental platform is tested. By combining the protection algorithm and software and using the computer relay protection tester, the action characteristics are tested with specific items when the line is in fault, so as to validating the four requirements of experimental platform and realizing three section distance protection.