Method for judging influence of power factor on small-interference stability of converter grid-connected system

A power factor and converter technology, applied in AC network circuits, reactive power adjustment/elimination/compensation, reactive power compensation, etc., can solve problems such as complex judgment process, and achieve the effect of avoiding instability

Active Publication Date: 2020-04-24
STATE GRID JILIN ELECTRIC POWER COMPANY LIMITED +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patented technology helps determine if an AC voltage has enough energy at its terminals when connected into another electrical circuit without causing damage or affecting other parts that it'll be used with later. It also prevents malfunctions from overloading certain components within the device due to insufficiently high voltages during operation.

Problems solved by technology

This patented technical solution describes how large amounts of solar or wind may cause instability on an electricity network due to factors like changes caused by weather patterns that change over time (such as rain) or other environmental variables such as temperature fluctuations causing variations in load). To address this issue, there are two main methods: passive stabilization systems and automatic control techniques. Passively stable connections between generators and grids have been developed but they still require significant effort from researchers working at laboratories around them. Automatic control devices use feedback signals obtained during operation to adjust their settings based upon these issues.

Method used

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  • Method for judging influence of power factor on small-interference stability of converter grid-connected system
  • Method for judging influence of power factor on small-interference stability of converter grid-connected system
  • Method for judging influence of power factor on small-interference stability of converter grid-connected system

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specific Embodiment

[0041] The specific embodiment that implements according to the complete method of content of the present invention is as follows:

[0042] Established in Matlab / Simulink software such as figure 1 The grid-connected model of the converter shown is used for simulation experiments, and the converter controller considers phase-locked loop and current inner loop control. Among them, the control parameters of the converter and the main parameters of the system parameters are shown in Table 1:

[0043] Table 1 Main parameters of photovoltaic inverter

[0044] Filter inductance L f / p.u.

0.15 Current inner loop ratio, integral coefficient 0.25、20 Phase-locked loop ratio, integral parameters 2.5、2500

[0045] figure 1 The converter grid-connected system shown is divided into the converter side and the grid side, and the converter admittance model and the grid admittance model can be established respectively.

[0046] figure 2 It is a schematic diag...

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Abstract

The invention discloses a method for judging the influence of a power factor on the small-interference stability of a converter grid-connected system. The method comprises the following steps: establishing a converter admittance model and a power grid admittance model by linearly processing a dynamic equation of the converter grid-connected system; forming a single-input single-output closed-loopsystem model by combining the converter admittance model and the power grid admittance model to obtain a closed-loop transfer function of the closed-loop system model; and judging by using a Nyquist curve according to the closed-loop transfer function to obtain a result whether the current running power factor of the converter can enable the converter to run stably or not. The influence of the power factor of the converter on the stability of the grid-connected system can be effectively judged, and the instability problem caused by improper setting of the power factor of the converter is avoided.

Description

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Claims

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Application Information

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Owner STATE GRID JILIN ELECTRIC POWER COMPANY LIMITED
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