Submarine cable interconnected sea micro-grid group equivalence modeling method

Abstract

The invention aims to solve the problems that the existing sea micro-grid group external grid equivalence study is insufficient, and provides a submarine cable interconnected sea micro-grid group equivalence modeling method; the method is featured by comprising the following steps: building a sea micro-grid uniform external grid equivalence circuit according to submarine cable parameter change conditions and limited data exchanges, and building an external grid equivalence circuit parameter estimation equation according to a covariance theory; building a weight function according to the distance between a sampling time of a sampling point and the present time, combining the weight function with the equivalent parameter estimation equation, further solving the equivalence circuit equivalence parameters according to voltage and current measurement values of connecting points in a period, wherein the equivalence circuit is the sea micro-grid external grid equivalence circuit. The analysismodel with strict mathematics can realize external grid equivalence under limited data exchange and submarine cable parameter change conditions; the method is strong in adaptation capability on internal grid operation characteristic changes, and good in equivalence effect.

Description

technical field [0001] The invention relates to the technical field of static equivalence of power systems, in particular to an equivalent modeling method of marine micro-grid groups interconnected through submarine cables. Background technique [0002] At present, more and more marine microgrids, such as marine renewable energy fields, all-electric ships, and offshore oil and gas platforms, are interconnected to improve energy efficiency and better control emissions. The interconnection of different types of marine microgrids with “plug and play” functionality is also becoming more popular. Therefore, in order to realize the functional evaluation and the analysis of the operating characteristics of the connected marine microgrid system, it is necessary to establish a complete marine microgrid model. However, because these marine microgrids are far apart and the marine environment is harsh and changeable, it is difficult to collect detailed data of each local microgrid to e...

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Problems solved by technology

[0003] The existing research on equivalent modeling of external networks only focuses on land power grids, and the equivalent modeling of land external networks is more complicated, requiring more measurement points, and land power grids are connected by transmission lines. In the analysis of external network equivalents, it is considered that The parameters of the line are constant, that is, the influence of the change of the parameters of the transmission line on the equivalent effect is not considered

Yan Wei, Li Shiming, Chen Jun, Lu Jiangang, Guo Lin, Li Qin, Zhao Xia. Estimation method of static equivalent parameters of two-port external network based on measured information of internal network[J]. Chinese Journal of Electrical Engineering, 2011,31(13) :101-106; Liu Zhiwen, Liu Mingbo. Multi-area reactive power optimization decomposition coordination algorithm based on Ward equivalent[J]. Electric Power System Automation, 2010,34(14):63-69. When using long-distance submarine cables to transmit power, it will not only consume a certain amount of active power to cause network loss like ordinary land transmission lines, but also cause the reactive power passing through the submarine cables to change in voltage due to the large capacitive effect of the submarine cables. Especially sensitive, but more importantly, the parameters of the submarine cable will change with aging. When the parameters of the submarine cable change, it may affect the performance of the entire offshore system

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