Relay protection for AT traction networks is the key to maintaining safe and reliable operation of high-speed railways. Existing relay protection in the electrical supply network of high-speed railways often ensures its reliability at the expense of its selectivity. The current reliability-first relay protection scheme no longer meets the current safety requirements for high-speed railway operations, so the need to select a more optimised relay protection scheme is crucial. The fully parallel AT power supply method used in high-speed railways has the Feeding Section as the basic unit. Optimising the relay protection mode of the Feeding Section is of great help in optimising the AT traction network relay protection system. In this paper, the IED model for the protection of the entire Feeding Section is established by building a model based on the relevant rules of the IEC 61850 communication protocol and configuring the parameters of each logical node, starting from the actual project of the high-speed railway. The OPNET software was used to carry out simulations to prove that the IED model for line protection based on the supply arm can effectively balance the reliability and selectivity of relay protection.

Energy is the foundation of economic development and technological development. Facing the present situation of non-renewable energy decline, wind power generation has been developed rapidly. However, the problem of unstable output voltage of wind power generation due to unstable wind speed needs to be solved, and traditional solutions cannot make the generated electric energy meet the national standards for grid-connected and off-grid operation. In this paper, the electric energy generated by wind turbine is rectified by bridge rectifier circuit and using large capacity capacitor filtering to generate DC with flat waveform. Then, using SPWM inversion technology, the normal rotation wave with the same frequency as the power grid is used as the modulation wave and according to the required voltage amplitude, and the triangle wave with appropriate duty ratio is calculated by SPWM smoothing control theory as carrier wave. Subsequently, accurate filtering is carried out and grid-connected and off-grid operation is carried out through the self-aligning device. Finally, with the help of MATLAB simulation platform, the wind turbine is simulated to work under different wind conditions, and whether the generated electric energy meets the grid-connected and off-grid operation standards is judged, which further determines the reliability and authenticity of the theory.

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