Method for rapidly identifying sub-synchronous oscillation in wind power integrated system

Abstract

The invention relates to a method for rapidly identifying sub-synchronous oscillation in a wind power integrated system, and is applicable to detection and control on sub-synchronous oscillation of a wind power system, belonging to the control technical field of electrical power system. On the basis of the rotate speed of a wind turbine generator and a Mallet arithmetic, the rotate speeds of multiple sub-synchronous oscillation frequencies in real time are calculated, the condition that the wind turbine generator has the sub-synchronous oscillation phenomena or does not have is judged according to a fixed off-line value of sub-synchronous oscillation, and depending on the sub-synchronous oscillation degree, the wind turbine generator is given an alarm or the operation parameter of the wind turbine generator is adjusted and even the control measures of cutting-off the wind turbine generator is adopted. The Mallet arithmetic on the basis of the wavelet overcomes the deficiencies that the traditional Fourier transform lacks the spatial locality and is difficult to endure the location and distribution of a singular point. The Mallet arithmetic makes use of the good localization feature in time domain and frequency domain, resolves the rotate speed signals of the wind turbine generator through different scale observing signals with and different resolution ratios, and further realizes the precise detection and control on multiple sub-synchronous oscillation frequencies of the wind power system.

Description

technical field [0001] The invention belongs to the technical field of electric power systems and automation thereof. More precisely, the invention relates to a method for quickly identifying subsynchronous oscillations in a wind power system based on a wavelet algorithm (Mallet algorithm). Background technique [0002] Wind farms are generally far away from the load center, and often need to transmit wind power through the transmission network with series compensation capacitors to reduce the electrical distance and increase the transmission capacity. However, due to the basic characteristics of wind turbines commonly used at present, when large-scale wind power passes through the transmission network with series compensation capacitors, some disturbances will also cause special voltage and current subsynchronous oscillations, which may cause serious damage to wind turbines and the system . [0003] In 2009, such a failure occurred in the North American power grid. The fol...

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Problems solved by technology

[0004] At present, the general criteria for detecting power system oscillations are all proposed for conventional types of oscillations, and the special subsynchronous oscillations that may be caused by the connection of wind turbines to the power grid cannot be judged.

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