CN211930256U - Lightning protection circuit for protecting box type transformer - Google Patents

Lightning protection circuit for protecting box type transformer Download PDF

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Publication number
CN211930256U
CN211930256U CN202020888540.9U CN202020888540U CN211930256U CN 211930256 U CN211930256 U CN 211930256U CN 202020888540 U CN202020888540 U CN 202020888540U CN 211930256 U CN211930256 U CN 211930256U
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output end
input end
box
equipotential
isolator
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CN202020888540.9U
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Chinese (zh)
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熊备
王小芳
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Wuhan Ellen Phoenix Technology Co ltd
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Wuhan Ellen Phoenix Technology Co ltd
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Abstract

The utility model discloses a lightning protection circuit for protecting box transformer, include: the equipotential isolator comprises an equipotential isolator, an input end, an output end and a grounding device; the equipotential isolator is connected in series between an input end and an output end, the input end comprises a first input end and a second input end, the first input end is connected with an outer layer armor layer of the buried cable on the side of the overhead pole tower, and the second input end is connected with an inner layer shield layer of the buried cable on the side of the overhead pole tower; the output end comprises a first output end and a second output end, the first output end is connected with an outer layer armor layer of the buried cable on the box-type transformer side, and the second output end is connected with an inner layer shielding layer of the buried cable on the box-type transformer side. The utility model discloses can prevent or reduce box transformer high-voltage side equipment and damage.

Description

Lightning protection circuit for protecting box type transformer
Technical Field
The utility model belongs to the technical field of the lightning protection, more specifically relates to a lightning protection circuit for protecting box transformer.
Background
Wind power generation is a green energy source which converts kinetic energy of wind into electric energy. The wind energy drives the fan generator set to rotate to generate electric energy, the electric energy is transmitted to a remote boosting transformer substation through the on-site wind power boosting transformer and the power collection circuit, and finally the electric energy is merged into a power grid. On the mountain top or the ridge line that wind turbine generator system and power collection line were usually built, and these regions are for easily suffering the thunderbolt, and the light then causes the circuit tripping operation protection of thunder and lightning accident, and the heavy then causes equipment damage, reduces the utilization ratio of wind-powered electricity generation and increases the maintenance cost, makes wind-powered electricity generation field produce huge economic loss. Therefore, lightning protection of the wind power plant is a problem of great concern of the current wind power plant, a series of standards are specified for construction and overvoltage protection of the current wind power plant, but accidents caused by lightning in actual operation often occur.
The industrial construction standard and the protection technical specification of the power collecting line require that the two ends of the buried cable led out to the tower by the box type transformer of the blower fan need to be grounded, as shown in figure 1, namely, the shielding layer and the armor layer of the buried cable need to be grounded at the terminal tower and the box type transformer.
However, after the power transmission line arranged along the ridge line is struck by lightning, the lightning current is discharged into the ground along the down conductor and is also transmitted to the box-type transformer grounding grid along the shielding layer of the buried cable, so that a high ground potential is formed in the box-type transformer grounding grid to impact the insulator and the high-voltage arrester on the high-voltage side, and the performance of the insulator and the high-voltage arrester is reduced. Therefore, the high-voltage side insulator and the lightning arrester of the box-type transformer are found to be frequently damaged by lightning stroke or even exploded on site in the actual operation of the wind power plant.
SUMMERY OF THE UTILITY MODEL
At least one defect or improvement demand to prior art, the utility model provides a lightning protection circuit for protecting box transformer can restrict or prevent the lightning current to pass to box transformer along burying ground cable shield when suffering the thunderbolt, prevents or reduces box transformer high-pressure side equipment and damages.
In order to achieve the above object, the present invention provides a lightning protection circuit for protecting a box-type transformer, the box-type transformer being connected to an overhead tower via a buried cable, the lightning protection circuit comprising an equipotential isolator, an input terminal, an output terminal, and a grounding device;
the first end of the equipotential isolator is connected with the input end, the second end of the equipotential isolator is connected with the output end, and the first end of the equipotential isolator is also connected with the ground device;
the input end is connected with the outer armor layer and the inner shielding layer of the underground cable on the side of the overhead pole tower, the input end comprises a first input end and a second input end, the first input end is connected with the outer armor layer of the underground cable on the side of the overhead pole tower, and the second input end is connected with the inner shielding layer of the underground cable on the side of the overhead pole tower;
the output end is connected with the outer armor layer and the inner shielding layer of the buried cable on the box-type transformer side, the output end comprises a first output end and a second output end, the first output end is connected with the outer armor layer of the buried cable on the box-type transformer side, and the second output end is connected with the inner shielding layer of the buried cable on the box-type transformer side.
Preferably, the equipotential isolator is a discharge gap device having a breakdown voltage.
Preferably, the breakdown voltage is greater than 2000V.
Generally, through the utility model discloses above technical scheme who conceives compares with prior art, has beneficial effect: increasing the shielding lightning current leakage points of the buried cable, and reducing the lightning current transmitted to the box-type transformer by gradually discharging the lightning current; the earth screen connection between the tower and the box-type transformer can be isolated through the equipotential isolator, so that counterattack is effectively prevented; the circuit is simple and reliable, and the protection effect is obvious.
Drawings
Fig. 1 is a block diagram of a protection circuit of a box type transformer in the prior art;
fig. 2 is a structural diagram of a lightning protection circuit for protecting a box-type transformer according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention. Furthermore, the technical features mentioned in the embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
The utility model provides a lightning protection circuit for protecting box transformer, box transformer bury the cable through ground and are connected with overhead tower. The lightning protection circuit is shown in figure 2 and comprises: an equipotential isolator 00, an input end 10, an output end 20 and an independent grounding device 30;
the connection relation is as follows:
the buried cable has 3 parts, the inlayer transmission cable, transmission cable have the inlayer shielding layer outward, and the inlayer shielding layer still has the outer armor outward, all has the insulator to separate between these three-layer. During installation, after the underground cable of the fan current collection circuit is disconnected, the outer armor layer and the inner shielding layer of the underground cable on the side of the overhead pole tower are connected to the input end 10, wherein the outer armor layer of the underground cable is connected to the input end 11, and the inner shielding layer of the cable is connected to the input end 12; the outer armor layer and the inner shielding layer of the buried cable on the side of the box-type transformer are connected to the output end 20, wherein the outer armor layer of the buried cable is connected to the output end 22, and the inner shielding layer of the cable is connected to the output end 21; the equipotential isolator 00 is connected in series between the input end and the output end; and the independent grounding device 30 is connected to the input end 10 of the equipotential isolator 00. And after the installation is finished, the connection of the transmission cable of the underground cable of the fan current collection line is restored.
The equipotential isolator 00 is connected in series between the input end and the output end, one end of the equipotential isolator 00 is connected with the input end, and the other end is connected with the output end.
Preferably, the equipotential isolator 00 is a discharge gap device with a certain breakdown voltage. Preferably, the gap discharge breakdown voltage is greater than 2000 volts.
When lightning overvoltage exists on the overhead line, part of lightning current is conducted to the fan transformer along the metal shielding layer of the buried cable, and the lightning current is discharged to the ground at the position of the equipotential isolator 00 because the metal shielding layer of the cable is grounded. When the generated overvoltage is not enough to break down the equipotential isolator, the lightning current is not conducted towards the direction of the box-type transformer; even if the equipotential isolator is broken down by overvoltage, the lightning current is partially discharged at the moment, and the current conducted towards the direction of the box-type transformer is small, so that the equipment in the box-type transformer is protected from being damaged.
It will be understood by those skilled in the art that the foregoing is merely a preferred embodiment of the present invention, and is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Claims (3)

1. A lightning protection circuit for protecting a box transformer connected to an overhead tower by a buried cable, the lightning protection circuit comprising: the equipotential isolator comprises an equipotential isolator, an input end, an output end and a grounding device;
the first end of the equipotential isolator is connected with the input end, the second end of the equipotential isolator is connected with the output end, and the first end of the equipotential isolator is also connected with the grounding device;
the input end is connected with the outer armor layer and the inner shielding layer of the underground cable on the side of the overhead pole tower, the input end comprises a first input end and a second input end, the first input end is connected with the outer armor layer of the underground cable on the side of the overhead pole tower, and the second input end is connected with the inner shielding layer of the underground cable on the side of the overhead pole tower;
the output end is connected with the outer armor layer and the inner shielding layer of the buried cable on the box-type transformer side, the output end comprises a first output end and a second output end, the first output end is connected with the outer armor layer of the buried cable on the box-type transformer side, and the second output end is connected with the inner shielding layer of the buried cable on the box-type transformer side.
2. The lightning protection circuit for protecting a box transformer according to claim 1, wherein the equipotential isolators are discharge gap devices having a breakdown voltage.
3. The lightning protection circuit for protecting a box transformer according to claim 2, wherein the breakdown voltage is greater than 2000V.
CN202020888540.9U 2020-05-22 2020-05-22 Lightning protection circuit for protecting box type transformer Active CN211930256U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202020888540.9U CN211930256U (en) 2020-05-22 2020-05-22 Lightning protection circuit for protecting box type transformer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202020888540.9U CN211930256U (en) 2020-05-22 2020-05-22 Lightning protection circuit for protecting box type transformer

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CN211930256U true CN211930256U (en) 2020-11-13

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CN202020888540.9U Active CN211930256U (en) 2020-05-22 2020-05-22 Lightning protection circuit for protecting box type transformer

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CN (1) CN211930256U (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113541114A (en) * 2021-06-30 2021-10-22 国网河南省电力公司电力科学研究院 Underground barrier-based ground current protection method for buried pipe network

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113541114A (en) * 2021-06-30 2021-10-22 国网河南省电力公司电力科学研究院 Underground barrier-based ground current protection method for buried pipe network
CN113541114B (en) * 2021-06-30 2023-03-07 国网河南省电力公司电力科学研究院 Underground barrier-based ground current protection method for buried pipe network

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