Analysis method of the influence of wind farm connection on the fault limit cut-off time of multi-machine system

Abstract

The invention relates to an analysis method for the influence of wind farm access on the fault limit removal time of a multi-machine system. Based on the transient energy function theory, starting from the original multi-machine system, the first integration method is used to construct a temporary multi-machine system including a wind farm. On this basis, the relationship between the critical energy value of the system and the transient output power of the wind farm is derived, and the changes in the critical energy that the system can withstand due to changes in the network topology due to the DFIG access are quantitatively analyzed. , from the perspective of critical energy, it reflects the influence of wind farm access on the system stability margin; according to the influence of DFIG on the system equivalent electromagnetic power during the fault period, the changes of system state variables and the energy accumulation process are analyzed, and the impact of wind farm access on the system is given. The influence mode of the transient energy accumulation speed; the fault limit clearing time is calculated by the accumulation time from the transient energy to the critical energy of the system.

Description

technical field [0001] The field of the invention is the analysis of the influence of new energy access on the transient stability of the power system, especially for the power multi-machine system including wind farms, starting from the transient energy function to analyze the failure limit removal of the power multi-machine system from the wind farm access The influence of time, and then reflects the influence on the transient stability of the power multi-machine system. Background technique [0002] The continuous expansion of the demand for clean energy and the increasing maturity of wind power generation technology have made wind power generation vigorously developed and applied all over the world. However, the access of large-scale wind farms also brings many unfavorable factors while providing more energy supply to the grid. For example, the access of a large proportion of wind power often changes the power flow distribution and topological structure of the system, t...

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Problems solved by technology

[0004] At present, the research related to this invention is mainly aimed at single-machine infinite system or equivalent double-machine system [2-3] , seldom analyze the impact of wind farm connection on system power angle transient stability directly from the actual power multi-machine system, and it is difficult to consider the influence of wind farm connection in multi-machine system on system transient stability ; Many related studies have given general laws through simulation analysis [5-7] , the conclusion is not convincing due to the lack of theoretical support

Currently in research [2,9-10] , most of them fail to comprehensively consider the mechanism of wind farm access to system critical energy and energy accumulation process to comprehensively affect the transient power angle stability of power system, and only analyze its impact from a single perspective, and the conclusion is one-sided; in addition, some studies believe that After the wind farm is connected to the power multi-machine system, the change of the energy margin of the whole system is to increase the energy limit that the wind turbines can withstand in the transient process on the basis of the energy margin of the original system [4] , without considering the impact of wind turbine access on the network topology, the conclusion has limitations

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