Wind power generator set electric network voltage oscillation identification method and system

Abstract

The invention discloses a wind power generator set electric network voltage oscillation identification method. The method mainly aims at a single-machine accessed grid connection point of a fan, and whether the electric network oscillation occurs or not is judged by analyzing second-stage and millisecond-stage transient data generated by a wind power generator set by a feature analysis method. The invention also provides a wind power generator set electric network voltage oscillation identification system adopting the method. When the method and the system provided by the invention are used for carrying out grid connection voltage oscillation judgment identification, the required data requirement is low, the goal can be achieved through the existing data collecting means of the fan, and the additional arrangement of high-calculation-frequency test and control devices is not needed. In addition, the goal of discovering the voltage oscillation in an early oscillation stage can be achieved, and the early detection and fast anti-accident measure adoption can be favorably realized.

Description

technical field [0001] The invention relates to the technical field of wind power, in particular to a method and system for identifying voltage oscillation of a power grid of a wind turbine. Background technique [0002] By the end of 2013, the cumulative installed capacity of wind power generation in the world has reached 318 million kilowatts, and wind power generation has become an industry with a considerable scale. As the proportion of wind power generation capacity in the regional power grid is increasing, it brings development opportunities to the power system, but also brings new challenges to its safe and stable operation, dispatching control and many other aspects. Most of the access points of large wind farms are at the end of the grid, and the regional grid is a weak grid with poor voltage stability. A large number of research results have shown that the worse the voltage stability of the power grid, the more sensitive the changes in the active and reactive powe...

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Problems solved by technology

[0005] However, the above method has the following disadvantages: it needs to use high-sampling frequency measurement and control acquisition equipment, the data requires microsecond-level data, the minimum sampling frequency needs to be 4.8kHz, and the fast Fourier transform is used to extract relevant oscillation trigger signals

Using this method, the calculation frequency of measurement and control equipment is relatively high, and special secondary measurement and control equipment needs to be added in the wind farm to meet the sampling calculation requirements, which will increase the equipment procurement cost in the wind farm

And using the fast Fourier transform algorithm to determine whether oscillation occurs by setting the threshold value also makes it impossible to identify the grid voltage oscillation phenomenon in the early stage of oscillation

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