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Islanding detection method for grid-connected inverter cluster system for photovoltaic power generation

A cluster system and island detection technology, which is applied in the direction of measuring electrical variables, instruments, and measuring electricity, can solve the problems of reduced effectiveness of the island detection method, achieve the effect of reducing the blind area of ​​island detection and improving the reaction speed

Active Publication Date: 2017-01-04
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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Problems solved by technology

[0008] The purpose of the present invention is to overcome the disadvantage that the effectiveness of the islanding detection method is reduced due to the line impedance when the existing sliding mode frequency drift method is applied to the inverter cluster system, and propose a method suitable for islanding detection of the grid-connected inverter cluster system new method

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  • Islanding detection method for grid-connected inverter cluster system for photovoltaic power generation
  • Islanding detection method for grid-connected inverter cluster system for photovoltaic power generation
  • Islanding detection method for grid-connected inverter cluster system for photovoltaic power generation

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Embodiment Construction

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

[0025] The invention improves the phase angle θ in the traditional mode frequency drift method SMS The expression for:

[0026] θ SMS = θ m sin ( π 2 · f PCC - f 0 f m - f 0 ) ( f PCC > f 0 ) θ m sin ( π 2 · f PCC - f 0 f m - f 0 ) - θ 0 ( f PCC f 0 )

[0027] Where θ m Is the maximum phase shift, f PCC Is the voltage frequency of the inverter grid connection point, f 0 Rated frequency of the power grid 50Hz, f m To produce the maximum phase shift θ m Time frequency. It can be seen that the phase angle θ when the frequency increases after islanding occurs SMS The expression is the same as the traditional mode frequency shift method; if the frequency drops after islanding occurs,...

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Abstract

The invention discloses an island detecting method for a photovoltaic power generation grid-connected inverter trunking system. When the island phenomenon happens in the inverter trunking system and the grid-connected point voltage frequency is reduced, the phase difference between the current and the voltage in a traditional sliding formwork frequency drift method is corrected, the error compensation angle is added, the effect of line impedance on the sliding formwork frequency drift method for detecting the blind area and the response speed is offset, and the reliability of island detecting is improved. If the grid-connected point voltage frequency is increased, the expression of the traditional sliding formwork frequency drift method is adopted, and the system line impedance cannot bring the adverse effect to the validity of island detecting.

Description

Technical field [0001] The invention relates to a detection method suitable for a grid-connected inverter cluster system. Background technique [0002] Islanding refers to a phenomenon in which the grid is out of power due to faults or overhauls in the photovoltaic grid-connected power generation system, and the photovoltaic power generation system does not stop supplying power to the local load, forming a power supply island. The occurrence of islanding will cause huge hidden dangers to the safety of maintenance personnel and the stable operation of the power grid. Therefore, it is of great practical significance to study the islanding detection technology of microgrids. In recent years, photovoltaic power generation systems have gradually developed in the direction of high density and multiple access points. The effectiveness of traditional islanding detection methods, especially active methods, has been challenged. It is suitable for islanding detection technology for photovol...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/00H02J3/38
Inventor 雷鸣宇杨子龙王一波许洪华
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI