Grid-connected converter sub-synchronous oscillation risk analysis method by considering phase-locked loop influence

A technology of subsynchronous oscillation and risk analysis, applied in the direction of instruments, data processing applications, resources, etc., can solve the problem of inability to accurately analyze the risk of subsynchronous oscillation

Active Publication Date: 2018-06-12
NARI TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These methods are difficult to take into account the influence of the converter control (including phase-locked loop phase-locking error) on the output dynamic impedance characteristics, so they cannot accurately analyze the subsynchronous oscillation risk of the VSC converter connected to the weak grid

Method used

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  • Grid-connected converter sub-synchronous oscillation risk analysis method by considering phase-locked loop influence
  • Grid-connected converter sub-synchronous oscillation risk analysis method by considering phase-locked loop influence
  • Grid-connected converter sub-synchronous oscillation risk analysis method by considering phase-locked loop influence

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Embodiment 1

[0032] An embodiment of the present invention discloses a risk analysis method for subsynchronous oscillation of grid-connected converters considering the influence of phase-locked loops, which is used to evaluate the subsynchronous oscillations that occur when VSC converters are connected to equivalent power grids. It is based on the system Dynamic impedance characteristics identify the risk of subsynchronous oscillation in the system, which is applicable to the risk analysis of subsynchronous oscillation of VSC grid-connected converters, including but not limited to direct drive wind turbines, photovoltaic inverters, flexible DC converters, etc. Specifically, the following steps are included:

[0033] 1) Establish small-disturbance mathematical models of the equivalent power grid, the electrical link of the grid-connected converter, and the control link respectively.

[0034] ①Small disturbance mathematical model of equivalent power grid:

[0035] Δu cd -Δu gd =Δi 2d (L ...

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Abstract

The invention discloses a risk analysis method of sub-synchronous oscillation generated by connection of a converter and an equivalent grid by considering phase-locked loop influence, and belongs to the technical field of electric power systems and automation thereof. The method includes the steps: building an equivalent grid and grid-connected converter electrical appliance link and control linksmall-disturbance mathematical model, and analyzing influence of detection errors of phase-locked loops under small disturbance on grid-connected converter control variables; correcting the grid-connected converter control link small-disturbance mathematical model according to the influence; determining system input voltage variables and output current variables, and getting a system dynamic impedance transfer function under small disturbance; drawing a system frequency impedance curve, and analyzing system sub-synchronous oscillation risks according to characteristics of the curve. A novel stability analysis method of a joint of VSC converter and a grid is provided, and the stability and the oscillating characteristics of the system can be simply and efficiently judged.

Description

technical field [0001] The invention belongs to the technical field of electric power systems and automation thereof, and in particular relates to a subsynchronous oscillation risk analysis method of a grid-connected converter considering the influence of a phase-locked loop. Background technique [0002] my country's wind energy resources and loads are distributed inversely. With the increase in the proportion of power electronic devices and renewable energy connected to the grid, the unique multi-scale control mechanism and low-inertia broadband response characteristics of power electronic conversion technology have significantly changed the dynamic characteristics of the power system. The wind-fired bundled UHV transmission method avoids the risk of subsynchronous oscillations in wind farms caused by series compensation of transmission lines. However, engineering practice in recent years has shown that subsynchronous frequencies also appear in large-scale new energy bases ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06Q10/06G06Q50/06
CPCG06Q10/0635G06Q50/06
Inventor 朱玲侯玉强刘福锁李威李碧君郝鑫杰梁辉郑惠萍宋述勇刘新元张倩赵彦丽陈珏
Owner NARI TECH CO LTD
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