Improved additional frequency control method suitable for double-fed wind-driven generator set to participate in system frequency adjustment in short-circuit fault

Abstract

The invention discloses an improved additional frequency control method suitable for a double-fed wind-driven generator set to participate in system frequency adjustment in a short-circuit fault in the field of new energy technology. In view of the conventional additional frequency control of a DFIG unit is only suitable for frequency fluctuation caused by a sudden load change and makes it difficult to satisfy the frequency adjustment in the whole process from the occurrence of the short-circuit fault to the elimination of the fault, the wind-driven generator set uses MPPT control when the power grid is in normal operation, and uses the conventional additional frequency control in response to a system frequency change, and improves the transient stability of the system frequency when the system has a load fluctuation. When a transmission line has a fault, according to the change law of the system frequency in the whole process from the occurrence of the short-circuit fault to the elimination of the fault, the parameters in the conventional additional frequency control of the DFIG unit are corrected, so that the output of the DFIG unit is quickly adjusted according to the system frequency change, thereby maintaining the effective inertia damping characteristics of the DFIG unit in the whole process and improving the dynamic response characteristics of the system frequency.

Description

technical field [0001] The invention belongs to the technical field of new energy power systems and microgrids, and in particular relates to an improved additional frequency control method suitable for a doubly-fed wind turbine to participate in system frequency regulation under a short-circuit fault. Background technique [0002] The northwest region of my country is rich in wind power resources. Large-scale wind farms are centrally connected to the grid for power generation and long-distance transmission to the load center through high-voltage transmission lines has become the current development trend. The continuous increase in wind power penetration has brought new challenges to the safe and stable operation of the system. Doubly-fed induction generator (DFIG) has excellent characteristics such as high power generation efficiency, small inverter capacity, and can realize active and reactive power decoupling control, and has become the main model of large-scale wind farms...

AI Technical Summary

Problems solved by technology

Among them, the response speed of the pitch change method is slow and there is mechanical wear, which limits its engineering application, making the overspeed method the first choice under the condition of satisfying the load reduction level

However, reserved reserve capacity limits the active output of wind turbines in normal operation, affecting their economy and practicability

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