A method for detecting a short-circuit capacity at a grid connection point of a wind turbine, comprising: modulating, when a converter is in a grid-side no-load modulation state and a power grid is in a short-circuited state with respect to the converter, a reactive power reference value and a braking power reference value of the converter, and collecting a modulated three-phase voltage signal and a modulated three-phase current signal at the grid connection point of the wind turbine; and obtaining, according to the modulated three-phase voltage signal and the modulated three-phase current signal at the grid connection point of the wind turbine as well as a rated line voltage at the grid connection point of the wind turbine, the short-circuit capacity at the grid connection point of the wind turbine, wherein when the power grid is in a short-circuited state with respect to the converter, a power system between the grid connection point and the converter is equivalent to a low-voltage side power supply, an internal resistance (Rs) and a line impedance in series, and characterized in that said modulating the reactive power reference value and the braking power reference value of the converter comprise: performing, when a difference between the line impedance and the internal resistance (Rs) is greater than a first predetermined threshold and a difference between an inductive reactance (Lc) in the line impedance and a resistance (Rc) in the line impedance is greater than a second predetermined threshold, a first no-load modulation operation on the converter in which the reactive power reference value is set to any power value between 0 and a rated apparent power of an inverter in the converter and the braking power reference value is set to zero. modulating, when a converter is in a grid-side no-load modulation state and a power grid is in a short-circuited state with respect to the converter, a reactive power reference value and a braking power reference value of the converter, and collecting a modulated three-phase voltage signal and a modulated three-phase current signal at the grid connection point of the wind turbine; and obtaining, according to the modulated three-phase voltage signal and the modulated three-phase current signal at the grid connection point of the wind turbine as well as a rated line voltage at the grid connection point of the wind turbine, the short-circuit capacity at the grid connection point of the wind turbine, wherein when the power grid is in a short-circuited state with respect to the converter, a power system between the grid connection point and the converter is equivalent to a low-voltage side power supply, an internal resistance (Rs) and a line impedance in series, and characterized in that said modulating the reactive power reference value and the braking power reference value of the converter comprise: performing, when a difference between the line impedance and the internal resistance (Rs) is greater than a first predetermined threshold and a difference between an inductive reactance (Lc) in the line impedance and a resistance (Rc) in the line impedance is greater than a second predetermined threshold, a first no-load modulation operation on the converter in which the reactive power reference value is set to any power value between 0 and a rated apparent power of an inverter in the converter and the braking power reference value is set to zero.