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Lightning shielding and counterattack identification method for overhead transmission lines

An overhead transmission line and identification method technology, which is applied in the identification field of lightning shielding and counterattack on transmission lines, can solve the problems of no method for distinguishing, characteristic signal interference annihilation, and criterion failure, etc., to achieve clear and intuitive physical concepts, calculation Simple, easy-to-achieve effects

Inactive Publication Date: 2016-04-20
CHONGQING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the feature quantity used in this method is based on the time-domain characteristics of the wave head. If the sensitivity of the sensor is not high, the feature signal is easily annihilated by interference, resulting in invalidation of the criterion.
There are also literatures that use mathematical morphological spectrum to analyze the waveform characteristics of counterattack and shielding overvoltage from the perspective of geometry, and construct the characteristic quantity of morphological spectrum to identify shielding and counterattack faults. way of distinguishing between the two

Method used

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  • Lightning shielding and counterattack identification method for overhead transmission lines
  • Lightning shielding and counterattack identification method for overhead transmission lines
  • Lightning shielding and counterattack identification method for overhead transmission lines

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Experimental program
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Embodiment 1

[0044] figure 1 Schematic diagram of the lightning monitoring system, figure 2 It is the schematic diagram of the tower-to-earth current measurement system, image 3 The schematic diagram of the non-contact overvoltage sensor, Figure 4 is a 110kV transmission line model, Figure 5 is the tower structure and multi-wave impedance model, where, Figure 5 a is the tower structure, Figure 5 b is the multiwave impedance model, Figure 6 It is a schematic diagram of the non-flashover of the basic tower top insulators struck by lightning, in which, Figure 6 a is the voltage waveform across the insulator, Figure 6 b is the tower current waveform into the ground.

[0045] The present invention introduces the potential difference at both ends of the insulator string and the ground current of the tower as the characteristic signal input quantity, and the required signal passes through figure 1 The lightning monitoring system shown is obtained. Such as figure 2 As shown, a ...

Embodiment 2

[0069] The difference between this embodiment and embodiment 1 is only:

[0070] The identification method provided by the embodiment of the present invention specifies the reference direction: the potential difference Uins of the insulator string is positive from the wire side to the tower side, and the ground current Ig of the tower is positive from the ground to the tower. Transmission line lightning strike simulation model such as Figure 4 As shown, the tower structure and its multi-wave impedance model are as follows Figure 5 as shown, Figure 5 is the tower structure and multi-wave impedance model, where, Figure 5 a is the tower structure, Figure 5 b is the multi-wave impedance model, and the lightning current adopts 2.6 / 50us waveform. The tower on which the signal acquisition device is installed is called the basic tower.

[0071] When the negative polarity lightning strikes the top of the tower or the lightning protection line close to the top of the tower (he...

Embodiment 3

[0088] The difference between this embodiment and embodiment 2 only lies in:

[0089] When a lightning strike occurs on the transmission line, the above method can be used to realize the correct identification of lightning shielding and counterattack. The specific implementation flow chart is as follows Figure 6 shown.

[0090] Specific steps are as follows:

[0091] 1) Normalize the signal. Calculate the D value, if D=+1, the lightning strike point is located on the top of the tower (the lightning protection line is close to the top of the tower), if D=-1, the lightning strike point is located on the wire;

[0092] 2) Calculate U5us, if U5us

[0093] 3) Calculate U1.5ms, if U1.5ms

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Abstract

The invention discloses a lightning shielding failure and back flashover recognizing method of an overhead power transmission line. The method includes the steps of firstly, obtaining the level difference of an insulator string and a buried current signal of a tower; then, judging the position of a lightning strike according to a lightning strike position feature value; finally, judging a lightning shielding failure and a back flashover, wherein when a lightning strike point is located on the top of the tower and a first minimum value is smaller than a threshold, back flashover occurs in the tower, when a second minimum value is smaller than the threshold, back flashover occurs in an adjacent tower, otherwise, no faults exist in the back flashover, when the lightning strike point is located on a wire and the first minimum value is smaller than the threshold, the lightning shielding failure occurs in the tower, if the second minimum value is smaller than the threshold, the lightning shielding failure occurs in the adjacent tower, and otherwise, no faults exist in the lightning shielding failure. The method achieves lightning shielding failure and back flashover recognition on the condition that the lightning strike is faulty or not faulty, the recognition result can detect the lightning-prevention effect of lines, and lightning-prevention design and isolation matching are improved before faults specifically. According to the method, only time domain features are extracted, calculation is simple, physical concepts are clear and visual, and the method is easy to achieve.

Description

technical field [0001] The invention relates to the technical field of on-line monitoring of power systems, in particular to a method for identifying lightning shielding and counterattacks on transmission lines. Background technique [0002] Transmission lines are an important part of the power system. Operation experience shows that line trips caused by lightning strikes account for a large proportion of the total number of line faults. Therefore, strengthening the lightning protection of transmission lines is of great significance to ensure the safe and stable operation of power systems. Identifying the types of lightning strike faults on lines can provide reliable data for lightning protection design, formulate cost-effective lightning protection measures, and provide a basis for improving line insulation coordination. [0003] At present, scholars have carried out relevant research on lightning fault identification and achieved certain results. Some literature proposes...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08
Inventor 杜林王有元姚陈果司马文霞杨庆陈寰姜凯华
Owner CHONGQING UNIV
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