New energy grid-connected system oscillation coupling frequency determination method and device

Abstract

The invention provides a new energy grid-connected system oscillation coupling frequency determination method and device. Firstly the power frequency domain harmonic component of a new energy grid-connected system is determined according to the three-phase current frequency domain value and the three-phase voltage frequency domain steady state value of the new energy grid-connected system; then the relationship between the power disturbance component and the oscillation coupling frequency of the new energy grid-connected system is determined according to the three-phase current frequency domain steady state value and the three-phase voltage frequency domain value; and finally the oscillation coupling frequency is determined according to the power frequency domain harmonic component and thepower disturbance component so that the cost of oscillation frequency suppression measures can be reduced and the suppression effect is obvious. The power frequency domain value of the new energy grid-connected system is obtained based on the power coupling effect mechanism through convolution processing of the three-phase voltage frequency domain value and the three-phase frequency domain valueof the new energy grid-connected system, and the new energy grid-connected system oscillation coupling frequency can be rapidly obtained under the condition that the oscillation frequency of the new energy grid-connected system is known so as to provide the favorable theoretical basis for analysis and suppression measure formulation of the new energy grid-connected system.

Description

technical field [0001] The invention relates to the technical field of new energy grid connection, in particular to a method and device for determining the oscillation coupling frequency of a new energy grid connection system. Background technique [0002] At present, in the face of increasingly serious global problems such as energy shortage, environmental pollution and climate warming, large-scale development and utilization of renewable energy such as wind and light has become an important choice for energy strategies of countries around the world. However, with the sharp increase in the proportion of renewable energy installed capacity and the gradual weakening of access to the synchronous grid, the stability characteristics of the power system are undergoing profound changes. Safe and stable operation of the power grid. [0003] Since 2015, the power grid at the sending end of the Hami wind power base in Xinjiang, China has repeatedly experienced sub / supersynchronous o...

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Problems solved by technology

[0006] In order to overcome the shortcomings of the lack of oscillation coupling frequency of new energy grid-connected systems in the above-mentioned prior art and the large investment and poor suppression effect of oscillation frequency suppression measures, the present invention provides a method and device for determining the oscillation coupling frequency of new energy grid-connected systems , first determine the power frequency domain harmonic components of the new energy grid-connected system according to the three-phase current frequency domain value and the three-phase voltage frequency domain steady-state value of the new energy grid-connected system; then according to the three-phase current frequency-domain steady-state value and the three-phase voltage The phase voltage frequency domain value determines the relationship between the power disturbance component and the oscillation coupling frequency of the new energy grid-connected system; finally, the oscillation coupling frequency is determined according to the power frequency domain harmonic component and the power disturbance component, and the invention provides a new energy grid-connected system The specific determination process of oscillation coupling frequency reduces the cost of oscillation frequency suppression measures, and the suppression effect is obvious

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