Offshore wind plant grid-connected system small interference stability determination method

The invention provides a small-interference stability determination method for an offshore wind plant grid-connected system, and the method comprises the steps: building a small-signal model of the offshore wind plant grid-connected system, and obtaining a transfer function model of the offshore wind plant grid-connected system; drawing a Nyquist curve to obtain a small interference critical stable point of the offshore wind plant grid-connected system; and judging the small-interference critical stability of the grid-connected system of the offshore wind power plant under different access alternating-current power grid strengths. According to the method for judging the small interference stability of the offshore wind plant grid-connected system, the impedance or admittance model of the offshore wind plant or the wind turbine generator is obtained through measurement, so that under the condition that the actual model and parameters of the offshore wind plant are unknown, the critical stability of the offshor