Effect of static reactive power generators on high frequency oscillations in doubly-fed wind farms

Doubly-fed wind turbine is a kind of wind turbine that is widely used nowadays, which has the advantages of high efficiency, low cost and better dynamic response. However, doubly-fed wind farms may encounter some high-frequency oscillation problems during operation, which can be effectively solved by the static reactive power generator.

Firstly, let us understand the high frequency oscillation problem of doubly-fed wind farms. Doubly-fed wind turbines in doubly-fed wind farms usually consist of a grid-side inverter and a generator-side inverter. When there is a phase or frequency difference between the grid-side and generator-side inverters, high-frequency oscillations will be triggered, which will lead to distortions in the waveforms of the grid voltages and currents, and even cause certain disturbances to the entire grid.

A static reactive power generator (STATCOM) is a device for reactive power compensation and power quality control. It achieves the control of reactive power in the grid by adjusting the phase and amplitude of voltage and current. In doubly-fed wind farms, the static reactive power generator can suppress the occurrence of high-frequency oscillations by adjusting the phase of voltage and current.

The static reactive power generator keeps the phase difference and frequency difference between the grid side and generator side within a reasonable range by regulating the inverter on both sides. In this way, the doubly-fed wind turbine can maintain stable operation and avoid the occurrence of high-frequency oscillation. At the same time, the static reactive power generator can also achieve the regulation of reactive power by changing the amplitude of voltage and current.

The effects of the static reactive power generator on the high frequency oscillation of doubly-fed wind farms are mainly reflected in the following aspects:

1. Suppressing high-frequency oscillations: the static reactive power generator suppresses the occurrence of high-frequency oscillations by adjusting the frequency converter on the grid side and generator side, so that the phase difference and frequency difference between the two can be kept within a reasonable range.

2. Improve the stability of the power grid: high-frequency oscillation will lead to the distortion of the waveforms of the grid voltage and current, thus affecting the stability of the power grid. The static reactive power generator controls the phase and amplitude of voltage and current to achieve the control of reactive power of the grid, thus improving the stability of the grid.

3. Improvement of power quality: High-frequency oscillations cause voltage and current waveforms to be distorted, thus affecting power quality. The static reactive power generator can keep the voltage and current in a reasonable waveform range through the regulation of voltage and current, so as to improve the power quality.

In summary, the static reactive power generator has an important influence on the high-frequency oscillation of doubly-fed wind farms. It suppresses the occurrence of high-frequency oscillations, improves the stability of the power grid and improves the power quality by regulating the phase and amplitude of the voltage and current. The application of static reactive generator can effectively solve the problem of high frequency oscillation in doubly-fed wind farms and improve the operation efficiency and stability of doubly-fed wind turbines.

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