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Lightning stroke fault recognition method for EHV (extra-high voltage) DC transmission line based energy spectrum similarity

A technology for ultra-high voltage direct current and lightning strike faults, which is applied in the directions of measuring electrical variables, pulse characteristics, and measuring current/voltage, etc. Intrinsic transient characteristics need to be further studied and other issues

Active Publication Date: 2017-10-17
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this criterion does not take into account the situation that the lightning fault is weak, which will cause the malfunction of the component, and there is a possibility of misjudgment
However, for the analysis of lightning interference, traveling wave of lightning strike faults and traveling wave waveform characteristics of short-circuit faults on UHVDC lines, the proposed method is still difficult to identify lightning strike faults and common short-circuit faults on UHVDC transmission lines. The inherent transient characteristics of the line under lightning strike still need further research

Method used

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  • Lightning stroke fault recognition method for EHV (extra-high voltage) DC transmission line based energy spectrum similarity
  • Lightning stroke fault recognition method for EHV (extra-high voltage) DC transmission line based energy spectrum similarity
  • Lightning stroke fault recognition method for EHV (extra-high voltage) DC transmission line based energy spectrum similarity

Examples

Experimental program
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Effect test

Embodiment 1

[0065] Example 1: A lightning strike fault identification method for UHVDC transmission lines based on energy spectrum similarity. When the voltage of UHVDC transmission lines fluctuates, the positive time-domain waveform and the area enclosed by its zero axis during stable operation and any The ratio of the positive time-domain waveform of a fault type to the area surrounded by the zero axis is used to identify the fault and lightning strike interference according to the ratio; if it is a fault, it is transferred to the identification of fault classification, and the additional component is identified by wavelet decomposition using wavelet, and it is judged to be grounding The fault is still a lightning strike fault; if it is a lightning strike fault, turn to the identification of shielding fault and counterattack fault.

[0066] The specific steps of the method are:

[0067] (1) Take the voltage sampling data within 5ms of the initial traveling wave for analysis, first take ...

Embodiment 2

[0093] Example 2: Simulation model such as figure 2 As shown, the parameters of the Yunguang ±800kV DC transmission system are adopted, the transmission capacity of the bipolar line is 5000MW, the reactive power compensation capacities of the rectification side and the inverter side are 3000 and 4000Mvar respectively, and the commutation units of each pole are two 12-pulse converters streamer composition. The DC filter is a 12 / 24 / 36 three-tuned filter.

[0094] (1) Take the voltage sampling data within 5 ms of the initial traveling wave for analysis, and compare the area enclosed by the positive time domain waveform of stable operation and its zero axis with the area enclosed by the positive time domain waveform of any fault type and its zero axis, k, Use this ratio to identify faults and lightning interference.

[0095]

[0096] In the formula, U + (t) is the positive electrode voltage during stable operation; u + (t) is the positive pole voltage at the time of fault. ...

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Abstract

The invention relates to a lightning stroke fault recognition method for an EHV (extra-high voltage) DC transmission line based energy spectrum similarity, and belongs to the technical field of power system relay protection. The method comprises the steps: extracting the ratio of a positive time domain waveform to an area formed by the enclosing of the zero axis of the positive time domain waveform and the ratio of a positive time domain waveform of any fault type to the area formed by the enclosing of the zero axis of the positive time domain waveform during stable operation when the voltage of the EHV DC transmission line fluctuates, and recognizing the fault and lightning stroke interference according to the ratios; switching to fault classification recognition if the interference is a fault, carrying out the wavelet decomposition recognition of an additional component through wavelet, and judging whether the fault is a grounding fault or a lightning stroke fault; and switching to a shielding failure and back flashover fault recognition if the fault is the lightning stroke fault. The method achieves the time frequency analysis of the simulation data, achieves the extraction of data in a short time period, and integrates area ratios, energy spectrum similarity and modular maximum value. The method achieves the extraction of a set of criteria for thunder interference, grounding faults, back flashover faults and shielding failures, and can achieve the accurate, quick and effective recognition of various types of conditions.

Description

technical field [0001] The invention relates to a lightning strike fault identification method for UHV DC transmission lines based on energy spectrum similarity, and belongs to the technical field of electric power system relay protection. Background technique [0002] Lightning strikes are the main cause of UHV transmission line tripping, and direct lightning strikes are more serious. In addition, my country's UHV DC transmission lines have long distances, wide distribution and complex and harsh natural conditions, which pose a major challenge to the protection of transmission lines. Lightning strike faults and ordinary faults have their own characteristics. How to use their characteristics as the basis for transient protection to accurately and quickly identify various types of faults is a very important issue. [0003] At present, many scholars at home and abroad have done a lot of research on this. Some scholars have proposed identification criteria for the transient c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R19/00G01R29/04G01R29/02G01R23/16
CPCG01R19/0084G01R23/16G01R29/02G01R29/04
Inventor 刘可真束洪春周帆吴尉民骆逍张凌跃张灿袁宝辉杜峥卢佳杨浩
Owner KUNMING UNIV OF SCI & TECH
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