Mechanism analysis of power fluctuation of wind power AC transmission channel caused by DC commutation failure

China's west-east power transmission strategy will continue to advance for a long time, and large-scale wind power transmission through AC-DC parallel channels will become the norm. For the current mechanism of DC commutation failure triggering AC tie-line power fluctuation has not taken into account the current situation of a large-scale wind power centralized access to the grid, the impact of large-scale wind power centralized access on both is analyzed from the relationship between system rotational inertia and AC grid damping characteristics. Secondly, the mechanism of the AC tie line power fluctuation after the DC commutation failure in the large-scale wind power AC-DC parallel transmission channel is studied, and the calculation formula of the peak value and peak time of the fluctuation is proposed for the first time. The correctness of the proposed mechanism and calculation formula is proved by the simulation analysis of AC-DC transmission in Jiuquan Wind power base in Gansu Province.