An online measurement method for generalized short-circuit ratio of multi-infeed new energy grid-connected system

A measurement method and multi-feed technology, applied in the field of electrical information, can solve the problem that generalized short circuit is more complicated than online monitoring, and achieve the effect of resisting noise interference

Active Publication Date: 2021-01-26
ZHEJIANG UNIV +1
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Problems solved by technology

However, due to the time-varying nature of power system operation and protection requirements, the grid structure is constantly changing, which complicates the online monitoring of the generalized short-circuit ratio

Method used

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  • An online measurement method for generalized short-circuit ratio of multi-infeed new energy grid-connected system
  • An online measurement method for generalized short-circuit ratio of multi-infeed new energy grid-connected system
  • An online measurement method for generalized short-circuit ratio of multi-infeed new energy grid-connected system

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Embodiment Construction

[0034] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0035] According to the embodiment and its implementation process of the complete implementation of the inventive method are as follows:

[0036] Consider a wind farm with n wind turbines, such as figure 1 As shown, the current and voltage fed into the port node can be expressed as: and Denotes the i-th current fed into the port node, Indicates the voltage of the i-th feed-in port node, and j represents an imaginary number.

[0037] In this model, nodes 1~n represent n wind turbine feed-in port nodes; nodes n+1~n+m represent nodes in the wind farm that are not directly connected to wind turbines, which are called nodes in the network; the AC power grid is simplified as An infinite grid equivalent node ( figure 1 Infinite Bus).

[0038] According to the electrical network theory, the impedance between node i and node j can be expressed as: Z ij = R...

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Abstract

The invention discloses an online measurement method for the generalized short-circuit ratio of a multi-infeed new energy grid-connected system. The system nodes are divided into three types: feed-in port nodes, network nodes, and infinite power grid equivalent nodes. The discrete time point data of the current and voltage fed into the port nodes are collected in the above-mentioned nodes, and then the current difference matrix and voltage Difference matrix; the current difference matrix and the voltage difference matrix establish a relationship model through the rearranged Crowe reduced-order admittance matrix, and then solve the rearrangement matrix according to the least squares matrix iterative solution, and use the rearrangement matrix to obtain the generalized short-circuit ratio. The generalized short-circuit ratio real-time measurement algorithm of the present invention can realize the real-time on-line measurement of the generalized short-circuit ratio, and at the same time, the matrix iteration algorithm based on the least square method makes the calculation result have strong resistance to measurement noise interference.

Description

technical field [0001] The invention relates to the field of electrical information technology, in particular to an online measurement method for the generalized short-circuit ratio of a multi-infeed new energy grid-connected system. Background technique [0002] With the massive integration of renewable energy generation such as photovoltaics and wind energy into the power system, various studies have been conducted on the grid-connected stability indicators of renewable energy generation at home and abroad. [0003] The generalized short-circuit ratio is one of the indicators that characterizes the relative strength and stability of the AC grid of the power electronics multi-infeed power system. According to the generalized short-circuit ratio theory, the stability margin of wind farms can be obtained only by paying attention to the grid strength and its corresponding boundaries. Therefore, understanding the generalized short-circuit ratio is helpful for the power system ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/00G01R27/02
CPCG01R27/02G01R31/00
Inventor 辛焕海黄林彬王奕鑫鞠平朱承治蒙志全
Owner ZHEJIANG UNIV
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