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Frequency feedback disturbance-based island detection method and apparatus

A technology of island detection and frequency feedback, applied in the fault location and other directions, can solve the problems of easy missed detection, affecting power quality, increasing system harmonics, etc., to shorten the time and reduce the detection blind area.

Active Publication Date: 2014-10-22
河南许继电力电子有限公司 +1
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Problems solved by technology

[0004] The passive detection method detects the abnormal phenomenon of the voltage at the common point between the inverter and the grid (such as over / under voltage, over / under frequency), which is easy to miss
Active detection, such as disturbance detection, can overcome detection blind spots by artificially increasing disturbances, but artificial disturbances will increase system harmonics and affect power quality

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  • Frequency feedback disturbance-based island detection method and apparatus
  • Frequency feedback disturbance-based island detection method and apparatus
  • Frequency feedback disturbance-based island detection method and apparatus

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Embodiment Construction

[0024] The present invention will be further described in detail below in conjunction with the drawings.

[0025] The method of the present invention is suitable for inverter interface grid-connected systems, specifically, such as figure 1 A control block diagram of a photovoltaic inverter based on rotation transformation is given, and the system is taken as an example to introduce the present invention in detail.

[0026] The photovoltaic PV array of the system is connected to the grid-connected point through the output of a three-phase full-bridge inverter. i 1a , I 1b , I 1c Is the three-phase current at the output of the inverter; e a , E b , E c Is the grid-side voltage, used for input to the PLL phase-locked loop output phase θ, used for i 1a , I 1b , I 1c The three-phase current three-phase coordinate system to the two-phase static coordinate system is rotated and transformed to realize the independent control of active current and reactive current, and finally output S a , S...

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Abstract

The invention relates to a frequency feedback disturbance-based island detection method and apparatus. The method comprises the following steps: a preliminary determination step; to be specific, detecting a power grid parameter and determining whether an island state occurs preliminarily; a disturbance step; to be specific, if so, adjusting a frequency difference between a frequency of a phase-locked loop output and a power grid frequency by a PI controller, using the frequency difference as an reactive current input reference value iq*+ and outputting the value to an reactive current control link; and a secondary determination step; to be specific, detecting the power grid parameter again and determining whether an island effect occurs truly. According to the invention, the passive island detection and the active island detection are combined, thereby reducing the detection blind area of the inverter and detecting the island phenomenon occurrence accurately and rapidly. Moreover, manual disturbance of the frequency and phase and the like does not exist in the method and no harmonic waves are introduced in the power grid, thereby reducing the influence on the total harmonic wave content of the inverter output current by the island detection algorithm.

Description

Technical field [0001] The invention relates to a method and device for detecting islanding based on frequency feedback disturbance. Background technique [0002] With the increasing pressure on the global resources and environment, energy conservation, emission reduction and resource conservation have become the trend of world economic development, focusing on the development of a green economy and strengthening energy conservation and emission reduction, and accelerating the construction of a resource-saving and environment-friendly society" On. Electric energy is a widely used energy source, and its application has penetrated into all aspects of industrial production, society and people’s lives. At present, the power generation system composed of new energy is represented by wind and solar grid-connected power generation; if this distribution network exists With the grid-connected power generation system, the distributed power supply will continue to supply power to the distri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
Inventor 陈北海刘刚梁燕孙健芦开平李建伟黄小有郭寅远高志军
Owner 河南许继电力电子有限公司
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