WO2013166977A1

WO2013166977A1 - Lightning protection device

Info

Publication number: WO2013166977A1
Application number: PCT/CN2013/075395
Authority: WO
Inventors: 张庭炎; 栾海元
Original assignee: 深圳远征技术有限公司
Priority date: 2012-05-10
Filing date: 2013-05-09
Publication date: 2013-11-14
Also published as: CN103390889A

Abstract

The present invention is applicable to the field of lightning protection, and provides a lightning protection device. The lightning protection device comprises: a lightning current band-stop filter, connected to a front end of a protected device; a first-stage surge protective device, connected in parallel with the lightning current band-stop filter and the protected device; and a second-stage surge protective device, connected in parallel with the protected device, the first-stage surge protective device and the second-stage surge protective device both being connected to a grounding net. The lightning protection device of the present invention discharges the lightning current to the ground twice, which blocks a transmission channel of the lightning current, significantly reduces the lightning-strike probability of the protected device, and greatly lowers the requirement for the grounding resistance, so that a grounding net with a large resistance can be used, the construction cost of the grounding net is greatly reduced, and the construction cycle of the grounding net is greatly shortened.

Description

Lightning protection equipment

The invention belongs to the field of lightning protection, and in particular relates to a lightning protection device.

At present, the general lightning protection method is a Surge Protective device in addition to the lightning rod directly guiding the grounding. Device, SPD) Used in conjunction with a grounding grid with a small grounding resistor to connect the surge protector in parallel between the equipment to be protected and the grounding grid. Since the surge protector device has the characteristic of instantaneous short circuit at overvoltage, the lightning current entering the protected system can be introduced into the grounding net through the surge protector, thereby achieving neutralization and dissipation of the lightning charge, which is equivalent to being protected. The device is short-circuited to protect the load system.

The existing lightning protection method requires a grounding grid having a small grounding resistance value. The smaller the grounding resistance value, the better, preferably 0 Ω. However, the actual ground network construction project is impossible. It takes a very high price to reach a small grounding resistance value. For example, it is necessary to build a large and deep grounding body, consume a lot of steel and copper, and use it. A large number of highly polluting and corrosive drag reducers and so on. Even such a grounding grid may not meet the design requirements, and the geological conditions have a considerable impact on the construction of the grounding grid. The conditions of the mountain, the rock, the gravel, the saline-alkali land, the Gobi, etc. restrict the construction of the grounding project, making the grounding of 0Ω The resistance is almost impossible to achieve.

At present, the grounding resistance value standard of many industries is set to about 10 Ω, and some lightning currents cannot be introduced into the ground, causing damage to the protected equipment.

The embodiment of the invention provides a lightning protection device, which aims to solve the problem that the grounding network of the existing lightning protection equipment cannot achieve a small grounding resistance value, and some lightning current cannot be introduced into the ground, thereby causing damage to the protected equipment.

The embodiment of the present invention is implemented as follows. A lightning protection device includes:

a lightning current band-stop filter connected to the front end of the protected device;

a level 1 surge protector in parallel with a lightning current band stop filter and protected equipment;

a secondary surge protector in parallel with the protected equipment;

The primary surge protector and the secondary surge protector are both connected to the grounding grid.

The lightning protection device in the embodiment of the invention bleeds the lightning current to the ground twice, and blocks the propagation channel of the lightning current. The probability of the lightning protection of the protected equipment is greatly reduced, and the requirement of the grounding resistance value can be greatly reduced, so The use of a grounding grid with a large resistance value greatly reduces the construction cost of the grounding grid and shortens the construction period.

FIG. 1 is a structural diagram of a lightning protection device according to an embodiment of the present invention.

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the embodiment of the present invention, the device for blocking the lightning current is cut off, so that the lightning current is discharged to the earth through the surge protector, and the lightning current is prevented from being introduced through the propagation channel, which is extremely Increases the probability of the device being protected from lightning strikes.

As shown in FIG. 1 , the lightning protection device provided by the embodiment of the present invention includes a lightning current band rejection filter 11 , a first-stage surge protector 12 , and a secondary surge protector 13 .

A lightning current band rejection filter 11 is connected to the front end of the protected device.

The first stage surge protector 12 is connected in parallel with the lightning current band rejection filter 11 and the protected device.

The secondary surge protector 2 is connected in parallel with the protected device.

The primary surge protector 12 and the secondary surge protector 13 are connected to a grounding grid.

Because the lightning current energy spectrum is high frequency, its energy is mainly concentrated in 100Hz~100KHz, accounting for more than 95% of the total energy. Among them, the energy in the frequency range above 1KHz accounts for 76%, while the energy in the vicinity of the power frequency is only 2.3%. %about.

In the embodiment of the present invention, the lightning current band rejection filter 11 is only attenuated for the lightning current energy spectrum band, and the high impedance state is prevented from passing the lightning current in the frequency band of 1 kHz to 100 kHz, and only 0.1 in the 0 to 100 Hz band. With dB ~ 1dB attenuation, all power frequency currents can pass unimpeded. Therefore, the lightning current band rejection filter 11 can realize the "frequency selective attenuation" function only for the lightning current frequency band, and has little influence on the power frequency and the high frequency.

Taking the lightning current into the AC power line as an example, since the lightning current energy spectrum is high frequency, its energy is mainly concentrated at 100 Hz to 100 kHz. When the lightning current is introduced to the near end of the load device through the remote power line, the lightning current will pass through two. Channel propagation:

The first one is to vent to the ground with the turned-on level one surge protector 12 as a channel.

The second channel continues to move to the protected device in accordance with the original route of transmission. At this time, the lightning current band rejection filter 11 generates a high impedance against the current in the lightning current band, thereby preventing the lightning current from continuing to propagate along the propagation path, that is, cutting off the propagation path of the lightning current. The two propagation channels of the lightning current are cut off at this time, so the lightning current can only be discharged to the earth through the preset first-stage surge protector 12, thereby avoiding the uncontrollability of lightning current propagation.

A part of the lightning current close to the power frequency spectrum will still propagate through the lightning current band rejection filter 11, but at this time the energy has been greatly reduced by more than 90%, and the lightning current across the lightning current band rejection filter 11 will encounter two. The surge protector 13 is again vented to the ground.

After two times of venting to the ground, the lightning current has almost no energy to be transferred to the protected equipment, thus completing the lightning protection process blocked by the lightning current channel.

Since the embodiment of the present invention blocks the propagation path of the lightning current, the probability of the protected device being struck by lightning is greatly reduced. Moreover, the lightning current band-stop filter cuts off one of the lightning current propagation branches, forcing the lightning current to propagate through only one branch, and discharges to the earth. Thus, the lightning current is no longer dependent on the grounding resistance value and the characteristic impedance ratio of the protected device, but is 100% vented to the earth, regardless of whether the grounding resistance is large or small.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

A lightning protection device, characterized in that the lightning protection device comprises:

a lightning current band-stop filter connected to the front end of the protected device;

a level 1 surge protector in parallel with a lightning current band stop filter and protected equipment;

a secondary surge protector in parallel with the protected equipment;

The primary surge protector and the secondary surge protector are both connected to the grounding grid.
The lightning protection device according to claim 1, wherein said lightning current band rejection filter has a high impedance state in a frequency band of 1 kHz to 100 kHz and a low attenuation in a power frequency band.