Control method for primary frequency modulation of wind power generation system

Abstract

The invention discloses a control method for primary frequency modulation of a wind power generation system. The method comprises the following steps: step 1, obtaining frequency and voltage deviation and obtaining the deviation between the alternating-current side frequency of the wind generating set and a rated value and the direct-current side voltage deviation of the grid-side converter; 2, setting a conduction signal and setting a conduction signal according to the deviation between the AC side frequency of the wind generating set and the rated value and the DC side voltage deviation of the grid-side converter; 3, adjusting the output active power of the AC side of the wind turbine generator grid-side converter, performing logic or operation on the conduction signal to generate a comprehensive conduction signal, and automatically sending a trigger conduction signal to a power electronic switch of an unloading branch where the unloading resistor is located according to the value of the comprehensive conduction signal so as to conduct the unloading resistor and skipping to the step 1. The method has the advantages that the capacity of quickly reducing the output power of the wind turbine generator is improved, and the primary frequency modulation performance of the wind turbine generator is improved.

Description

technical field [0001] The invention relates to the technical field of electric power system transmission, more specifically, it is a control method for primary frequency regulation of a wind power generation system, and more specifically, it is a scheme for using an unloading resistance to assist a wind turbine primary frequency regulation and its coordinated control. Background technique [0002] With the gradual increase of the penetration rate in the power system, wind turbines have a greater impact on the stability of the power system. Due to the weak support and low immunity of wind turbine power generation, with the large-scale connection of wind turbines, the moment of inertia and frequency and voltage regulation capabilities of the power system continue to decrease, and the risk of large-scale faults in the power grid continues to accumulate. In particular, the insufficient active power regulation capability of wind turbines has led to a continuous decline in the fr...

AI Technical Summary

Problems solved by technology

It can be seen that if the new energy stations cannot meet the grid guidelines under the current standards, the new energy stations will be subject to strict assessment, and even cannot be connected to the grid, which will greatly reduce economic benefits

[0004] At present, the conventional technical solution for wind turbines to realize the primary frequency regulation function is to reserve active output or configure energy storage equipment: the way of reserving active output will seriously weaken the power generation efficiency of wind farms and waste wind power resources; configuring energy storage will increase additional Investment and construction costs of wind farms

The academic community has proposed strategies such as wind turbine pitch control, virtual inertia control, and rotor overspeed control. However, the wind turbine pitch control is adjusted through mechanical devices, and the response speed cannot meet the requirements of primary frequency modulation, and frequent adjustments of the pitch angle will also cause problems. Affect the life of the unit; rotor overspeed control may cause a secondary drop in frequency, further deteriorating frequency characteristics; virtual inertia control has a fast response time, mainly by adjusting the kinetic energy of the fan rotor, but the adjustment range is limited

[0005] And in the primary frequency regulation scheme of wind turbines, the scheme of additional devices (such as energy storage) will increase the investment cost, and the improvement of control strategy (such as virtual inertia control, overspeed control) will not increase additional hardware costs, but due to the lack of A physical hardware device that buffers power or energy, so control strategies alone have limited control over power and energy

[0006] At present, in order to realize low-voltage ride-through during AC faults, wind turbines are generally equipped with an unloading resistor on the DC side of the wind turbine grid-side converter to dissipate the surplus power generated by the wind turbine during the low-voltage ride-through process; The role of the resistor is limited to dissipating the surplus power during the fault ride-through process of the fan, and no other additional functions can be tapped

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