Reliable virtual synchronous machine multi-machine parallel synchronous grid connection method and system

A virtual synchronous machine and reliable technology, applied in the direction of single-network parallel feeding arrangement, etc., can solve the problems of uneven output, failure, and long synchronization time of multiple virtual synchronous machines, so as to achieve uniform output, ensure effectiveness, and improve Concurrent success rate effect

Active Publication Date: 2020-05-15
NARI TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the deficiencies in the prior art, the present invention provides a reliable multi-machine parallel synchronous grid connection method and system of virtual synchronous machines, which solves the problem of uneven output between multiple virtual synchronous machines and synchronous failure caused by too long multi-machine synchronous time The problem

Method used

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  • Reliable virtual synchronous machine multi-machine parallel synchronous grid connection method and system
  • Reliable virtual synchronous machine multi-machine parallel synchronous grid connection method and system
  • Reliable virtual synchronous machine multi-machine parallel synchronous grid connection method and system

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Experimental program
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Effect test

Embodiment 1

[0047] A reliable virtual synchronous machine multi-machine parallel synchronous grid connection method, including steps:

[0048] Step 1: After the synchronous device receives the synchronous grid-connected command, it sets the synchronous adjustment flag, and starts synchronous timing, reads the voltage and frequency on both sides of the grid-connected switch, and according to the voltage difference and frequency difference between the two sides and the set voltage difference The relationship between the frequency difference threshold and the broadcast information content is obtained, and the communication broadcast is performed to multiple virtual synchronous machines participating in the same period;

[0049] The broadcast information includes synchronous adjustment signs, increase / decrease / maintain frequency commands, increase / decrease / maintain voltage commands, frequency increase times, frequency decrease times, boost times, voltage drop times, adjustment times (including...

Embodiment 2

[0085] The present invention will be described by taking the synchronous grid connection of multiple virtual synchronous machine parallel microgrid systems as an example.

[0086] The synchronization system consists of a synchronization device installed near the grid-connected switch and multiple virtual synchronization machines scattered in the microgrid. The synchronization device and virtual synchronization machines are connected through communication lines.

[0087] Step 1: The synchronous device receives the synchronous grid-connected closing command from the background, first sets the synchronous adjustment flag, starts the synchronous timing, and reads the grid voltage Ug, grid frequency Fg, and micro-grid voltage Um on both sides of the grid-connected switch. Micro-grid frequency Fg, and judge the frequency difference of pressure difference on both sides, the judgment is: Um-Ug<-Uset1, then set the voltage boost command, and add 1 to the voltage boost times; Fm-Fg<-Fset...

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Abstract

The invention discloses a reliable virtual synchronous machine multi-machine parallel synchronous grid connection method and system, and the method comprises the steps: enabling a synchronous device to read the voltage and frequency at two sides of a grid connection switch, obtaining the broadcast information content according to the relation between the voltage difference and frequency differenceat two sides and the set voltage difference and frequency difference threshold values, and carrying out the communication broadcast of a virtual synchronous machine; allowing each virtual synchronousmachine to analyze the broadcast information, if the broadcast information is set, comprehensively judging a voltage and frequency target needing to be adjusted according to the broadcast information, and adjusting the voltage and frequency according to the target; then after the synchronization device waits for a specified time, judging whether the current synchronization period is overtime or not, ending the synchronization period if the current synchronization period is overtime, detecting a synchronization point and ending switching-on if the absolute values of the voltage difference andthe frequency difference are both smaller than set voltage difference and frequency difference thresholds, otherwise, carrying out adjustment effect verification, and executing single-machine pollingor repeating the previous broadcasting or repeating the process according to a verification result. Uniform output of each virtual synchronous machine can be ensured, and the success rate of synchronization is improved.

Description

technical field [0001] The invention relates to the technical field of new energy power generation and smart micro-grid, in particular to a method and system for reliable multi-machine parallel connection and synchronous grid connection of virtual synchronous machines. Background technique [0002] The power electronic converter device using virtual synchronous machine technology (hereinafter referred to as virtual synchronous machine) has been widely used in application scenarios such as new energy generation side, power distribution side, and smart microgrid. Usually, the above application scenarios require virtual The synchronous machine can operate in both grid-connected mode and off-grid mode, and can realize online seamless switching of these two modes. Generally speaking, the transition from off-grid mode to grid-connected mode requires synchronous adjustment of the virtual synchronous machine, and the off-grid bus can be integrated into the grid only after it meets t...

Claims

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Application Information

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IPC IPC(8): H02J3/42
CPCH02J3/42
Inventor 王俊辉王腾飞宋飞孙海洋曹鹏刘良尹航王小红侯凯杨合民
Owner NARI TECH CO LTD
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