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

Frequency acceleration positive feedback island detection method with hysteresis

An island detection and positive feedback technology, which is applied in the direction of measuring electricity, measuring devices, and measuring electrical variables, etc., can solve problems such as relatively few adaptive studies, achieve the effect of speeding up islanding detection and reducing the impact of power quality

Inactive Publication Date: 2017-02-08
YANSHAN UNIV
View PDF5 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For these existing methods, research on reducing blind spots and improving power quality is relatively mature, but there are relatively few studies on their adaptability to multi-machine grid connection.

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
  • Frequency acceleration positive feedback island detection method with hysteresis
  • Frequency acceleration positive feedback island detection method with hysteresis
  • Frequency acceleration positive feedback island detection method with hysteresis

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0027] The present invention will be further described below in conjunction with accompanying drawing:

[0028] The method of the present invention is as figure 2 shown, including the following steps:

[0029] Step 1. In the three-phase inverter grid-connected system, the frequency change is introduced as the positive feedback of reactive power to form a positive feedback loop; the common point voltage frequency is sampled ω, and the angular frequency is subjected to a first-order low-pass filter The difference between the inverter and the grid frequency is multiplied by the feedback coefficient and added to the reactive shaft current in the form of positive feedback, and the frequency obtained by sampling the common point is converted into like figure 1 As shown, namely:

[0030] I q * = I r e f - ( ω ( s )...

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 a frequency acceleration positive feedback island detection method with hysteresis. The method comprises the steps of detecting a common point voltage frequency, and adding a positive / negative feedback disturbance according to magnitude of the common point voltage frequency; determining whether the common point voltage frequency is in an operation frequency range, if the common point voltage frequency exceeds a load operation frequency threshold, determining occurrence of an island, and afterwards, changing a disturbance adding direction for keeping the common point voltage frequency in an allowed frequency range. The frequency acceleration positive feedback island detection method can make an inverter perform loaded operation after connection with a power grid is switched off.

Description

technical field [0001] The invention relates to the field of power grid monitoring, in particular to a method for detecting islands connected in parallel with multiple machines. Background technique [0002] The development of the world is facing the problem of energy depletion, making the development of new energy a hot issue in social development. Solar energy has the characteristics of abundance and cleanliness, and all countries in the world have carried out extensive research on solar energy. [0003] The islanding effect refers to the phenomenon that when the power system stops supplying power due to a fault, the distributed generation system continues to provide active and reactive power to local loads. In the island state, the power company cannot effectively control the line voltage and frequency, which will bring some safety hazards. [0004] The mainstream methods in the existing islanding detection methods include passive islanding detection methods and active ...

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
Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/088
Inventor 王晓寰曹璐张纯江辛岩洁
Owner YANSHAN UNIV
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