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 (AC), an internal resistance (Rs) and a line impedance (Z1) 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 (Z1) and the internal resistance (Rs) is greater than a first predetermined threshold and a difference between an inductive reactance (Lc) in the line impedance (Z1) and a resistance (Rc) in the line impedance (Z1) 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 (AC), an internal resistance (Rs) and a line impedance (Z1) 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 (Z1) and the internal resistance (Rs) is greater than a first predetermined threshold and a difference between an inductive reactance (Lc) in the line impedance (Z1) and a resistance (Rc) in the line impedance (Z1) 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. <EOS>