Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Island detection method for sine low-frequency phase disturbance of three-phase grid-connected photovoltaic inverter

A technology of phase disturbance and islanding detection, applied in the direction of instruments, measuring electricity, measuring devices, etc., can solve problems such as detection blind spots

Inactive Publication Date: 2015-05-20
XI'AN POLYTECHNIC UNIVERSITY
View PDF7 Cites 6 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is characterized by the introduction of disturbances in the grid-connected output current of the inverter, and there is also a detection blind zone under certain conditions

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Island detection method for sine low-frequency phase disturbance of three-phase grid-connected photovoltaic inverter
  • Island detection method for sine low-frequency phase disturbance of three-phase grid-connected photovoltaic inverter
  • Island detection method for sine low-frequency phase disturbance of three-phase grid-connected photovoltaic inverter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0200] take f 2 = 5Hz, θ m =π / 15, the local load parameters are taken as R=15Ω, L=19.108mH, C=530.785μF, at this time, the local load quality factor Q=2.5, assuming the grid-connected voltage peak value is 380V, under the condition of active power matching, the grid will be disconnected When the amplitude of the front and rear load voltage remains unchanged, the amplitude of the inverter output current I m =380V / 15Ω=25.33A;

[0201] The grid-connected current command at this time is:

[0202] i d * = I m cos ( Δθ ) = I m cos ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses an island detection method for sine low-frequency phase disturbance of a three-phase grid-connected photovoltaic inverter. The island detection method comprises the following steps that low-frequency phase disturbance deltatheta which changes according to a sine principle is applied between an inverter output current vector I with phase disturbance and a power grid voltage vector E; during normal grid connection, detected voltage of a public connection point is power grid voltage; after the power grid is switched off, the voltage of the public connection point is determined by inverter output current and a local load commonly; a voltage frequency is changed along with the change of the frequency of the inverter output current so that the frequency exceeds a regulated frequency range and an island phenomenon is detected. According to the island detection method for the sine low-frequency phase disturbance of the three-phase grid-connected photovoltaic inverter, hardware does not need to be additionally arranged; compared with a traditional active type detection method, the island detection method has the advantage of no detection blind region; the applied disturbance is periodically changed, so that the island detection method has the advantage of small grid-connected current distortion when being compared with a traditional fixed disturbance frequency detection method.

Description

technical field [0001] The invention belongs to the technical field of grid-connected inverter control methods, and in particular relates to an island detection method for sinusoidal low-frequency phase disturbance of a three-phase photovoltaic grid-connected inverter. Background technique [0002] With the rapid development of solar power generation technology, more and more photovoltaic systems are connected to the public grid in parallel. When the grid is normal, the photovoltaic system and the public grid supply power to the load; after the grid is disconnected, only the photovoltaic system supplies power to the load. , so higher requirements are put forward for the safe and stable operation of the power grid, and the problem that must be solved is the islanding detection of grid-connected inverters. [0003] Islanding effect may cause serious harm to circuit maintenance personnel and electrical equipment, so it is of great significance to study islanding detection. At ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): G01R31/00
Inventor 陈增禄高洁管瑞欣王宁孟新新
Owner XI'AN POLYTECHNIC UNIVERSITY
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com