An Equivalent Modeling Method of Wind Farm Based on the Probabilistic Coherence of Wind Turbines

Abstract

The invention relates to a wind power plant equivalent modeling method based on the probability coherence of wind power units. Based on the probability of various short circuit faults in the actual operation of an electric system and statistical result of wind resource state in a wind power plant, the dynamic change of the rotating speed of a wind-driven generator in a transient process under the conditions of combinations of various short circuit faults and wind speeds is collected through time-domain simulation, and the wind power units are aggregated and classified by a two-step classification method according to the information. Based on collecting the clustering results of all wind power units, the wind power plant equivalent model is determined according to the probability of appearance of unit group classifying result, and the parameters of the wind-driven generator, current collection system and the like are equalized. The wind power plant equivalent modeling method provided by the invention fully considers the influence of different short circuit faults and unit operation conditions on the classifying result of the coherent unit group, the step of real-time monitoring the change of the coherent unit group in engineering application is effectively avoided, and the engineering application value of the wind power plant equivalent model is improved.

Description

technical field [0001] The invention relates to a wind farm equivalence modeling method for the grid-connected characteristics of the wind farm. Background technique [0002] At present, most wind farm equivalent models suitable for off-line transient stability analysis are established based on the idea of ​​coherent equivalent of power system. In the dynamic equivalence of traditional power systems, the coherence between generating units can be judged based on the information provided by the generator rotor swing curve in the transient process, and studies have pointed out that the coherence of the unit is mainly related to three factors: 1) Fault disturbance type; 2) operating conditions of generator sets; 3) network topology. Literature [1] considers the influence of operating conditions on coherence, and divides the wind turbine fleet according to the input wind speed of the wind turbine. However, the wind speed is random and fluctuating, and the grouping result based ...

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Problems solved by technology

Literature [3] divides the fleet based on the active power, terminal voltage and wind speed before the fault reflecting the action of the pitch angle, and literature [4] divides the fleet according to the speed at the initial moment of the wind turbine failure, but does not consider the fault disturbance factor. The influence of unit coherence

Literature [5] based on the assumption that the short-circuit voltage of all wind turbines in the wind farm is zero, the fixed-speed wind turbines are grouped only by the rotational speed at the sampling point of the wind turbine fault removal time obtained by approximate calculation , it is difficult to accurately and comprehensively reflect the voltage drop difference and dynamic operating characteristics of wind turbines in the transient process

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