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Calculation method and system of distance protection fault impedance based on high frequency transient

A technology of distance protection and fault impedance, applied in the electric power field, can solve problems such as affecting the performance of distance protection, measuring impedance that cannot truly reflect the fault location, etc., achieving good engineering practical value and improving the effect of operating time.

Active Publication Date: 2022-07-22
STATE GRID ZHEJIANG ELECTRIC POWER CO LTD HANGZHOU POWER SUPPLY CO +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the existence of transition resistance when a single phase is grounded makes the measured impedance unable to truly reflect the fault location, which seriously affects the action performance of the distance protection

Method used

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  • Calculation method and system of distance protection fault impedance based on high frequency transient
  • Calculation method and system of distance protection fault impedance based on high frequency transient
  • Calculation method and system of distance protection fault impedance based on high frequency transient

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Embodiment 1

[0053] The embodiment of the present application proposes a distance protection fault impedance calculation method based on high-frequency transients, such as figure 1 shown, including:

[0054] Step 1: collect cable data, the cable data includes the current at the distance protection installation place, the high-frequency harmonics in the voltage, and the line unit resistance and inductance in the cable data;

[0055] Step 2: Calculate the percentage of the distance from the fault point to the protection installation according to the current at the distance protection installation and the high-frequency harmonics in the voltage in the cable data;

[0056] Step 3: Based on the obtained distance percentage, combined with the line unit resistance and inductance in the cable data, calculate the true fault impedance of the distance protection.

[0057] Specifically, with figure 2 Taking the dual power supply system shown as an example, the working principle of the distance prot...

Embodiment 2

[0094] The distance protection fault impedance calculation system 2 based on high-frequency transients provided by the present invention, such as Figure 7 As shown, the system includes a data read-in module 21, a distance percentage calculation module 22 and a fault impedance calculation module 23;

[0095] The data read-in module 21 is respectively connected with the fault distance percentage calculation module 22 and the fault impedance calculation module 23;

[0096] The distance percentage calculation module 22 is connected with the fault impedance calculation module 23;

[0097] The data read-in module 21 is used to obtain the line length, line unit inductance, line unit resistance, phase current and voltage at the protection installation, and send the collected data to the distance percentage calculation module;

[0098] The distance percentage calculation module 22 is used to extract high-frequency harmonics in the current and voltage at the protection installation, c...

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Abstract

The present application proposes a method and system for calculating distance protection fault impedance based on high-frequency transients, including: collecting cable data, where the cable data includes the current at the distance protection installation location, high-frequency harmonics in voltage, and high-frequency harmonics in cable data. Line unit resistance and inductance; Calculate the percentage of distance from the fault point to the protection installation according to the current and high-frequency harmonics in the voltage at the distance protection installation in the cable data; Based on the obtained distance percentage, combine the line units in the cable data Resistance and inductance, calculate the true fault impedance of the distance protection. By extracting the high-frequency harmonic components in the voltage and current after the fault, it is not affected by the transition resistance and the fault location, and the calculation error is better than the traditional scheme; the richer the harmonic components, the closer the calculation results are to the actual value; The length of the sampling window required by the frequency and harmonics is helpful to improve the action time of the distance protection, and has good engineering practical value.

Description

technical field [0001] The invention belongs to the field of electric power, and in particular relates to a method and system for calculating fault impedance of distance protection based on high-frequency transients. Background technique [0002] According to the requirements of the national standard, line protection devices in high-voltage and above power systems must be equipped with staged distance protection and fast distance protection functions as an effective supplement to differential protection (longitudinal protection). However, the existence of transition resistance when single-phase grounding causes the measurement impedance to fail to truly reflect the fault location, which seriously affects the performance of the distance protection. SUMMARY OF THE INVENTION [0003] In order to solve the shortcomings and deficiencies in the prior art, the present invention proposes a distance protection fault impedance calculation method and system based on high-frequency tr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R27/02G01R27/16G01R31/08
CPCG01R27/16G01R27/02G01R31/088
Inventor 马伟黄晓波罗少杰尤敏吴靖侯伟宏陈嘉宁丁冬林森章玮明陈聪王明昶金公羽张魁
Owner STATE GRID ZHEJIANG ELECTRIC POWER CO LTD HANGZHOU POWER SUPPLY CO