Island detection method and system

A technology of island detection and power generation system, applied in the direction of measuring electricity, power supply testing, measuring devices, etc., can solve the problems of complex control and reduce the quality of inverter output power, achieve the effect of simple calculation, avoid detection blind spots, and facilitate development

Active Publication Date: 2012-10-10
BOE TECH GRP CO LTD +1
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Problems solved by technology

This method has high detection accuracy and small non-detection area, but the control is more complicated and reduces the quality of inverter output power

Method used

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  • Island detection method and system
  • Island detection method and system
  • Island detection method and system

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Embodiment Construction

[0032] The islanding detection method and system proposed by the present invention are described in detail as follows in conjunction with the accompanying drawings and embodiments.

[0033] The method and system of the present invention adopt a combination of active and passive detection methods for islanding detection of grid-connected inverters, and mainly use the sliding mode frequency shift detection method (Slip-Mode Frequency Shift, SMS) in the active detection method, SMS It is an active island detection method. This method controls the output current of the inverter and introduces a small phase shift disturbance, so that there is a certain phase difference between the inverter and the grid-connected point voltage. When the inverter is connected to the grid, due to the clamping effect of the grid, the inverter The current output by the inverter is in phase with the grid voltage, and the output frequency remains stable and at the same frequency as the grid. When the pow...

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Abstract

The invention discloses an island detection method and system, relating to the technical field of inverter control. The method comprises the following steps of acquiring a voltage signal of a grid-connected point of a generating system, extracting the phase information of the voltage signal; establishing a sliding mode frequency offset island detection curve by adopting a quadratic function; and generating a disturbing signal according to the sliding mode frequency offset island detection curve and sending the disturbing signal to an inverter of the generating system. The method and system provided by the invention can be used for avoiding detection blind spot, and moreover, the control is simple, and the inverter island can be fast and accurately detected.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverter control, in particular to an islanding detection method and system. Background technique [0002] Photovoltaic grid-connected inverter is a key component of the photovoltaic power generation system. Its function is to convert the direct current generated by the solar panels into alternating current with the same frequency and phase as the grid voltage, and feed the alternating current to the grid. When the power grid is interrupted for some reason, the inverter still transmits power to the grid, and it will form a self-sufficient power supply island with the local load that cannot be controlled by the public grid system. This phenomenon is called the island phenomenon. Without any islanding detection or protection techniques, the inverter would continue to supply local loads and partial grid loads. When the photovoltaic grid-connected power generation system is in the island opera...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38G01R31/00
CPCH02J3/38G01R31/00G01R31/40H02J3/388H02J2300/24H02J3/381Y02E10/56
Inventor 郑平崔明赵鹏汪旭洋杨培环
Owner BOE TECH GRP CO LTD
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