CN215267585U - Protection device for preventing earth fault counterattack - Google Patents
Protection device for preventing earth fault counterattack Download PDFInfo
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- CN215267585U CN215267585U CN202121127384.5U CN202121127384U CN215267585U CN 215267585 U CN215267585 U CN 215267585U CN 202121127384 U CN202121127384 U CN 202121127384U CN 215267585 U CN215267585 U CN 215267585U
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Abstract
The utility model discloses a protection device for preventing earth fault counterattack, which comprises an arrester, a post insulator, a first adjustable metal rod, a second adjustable metal rod and a fixed base, wherein the arrester and the post insulator are arranged on the fixed base side by side, the first adjustable metal rod is transversely arranged at the top end of the arrester, and the second adjustable metal rod is transversely arranged at the top end of the post insulator and is connected with a main grounding net; the length of the first adjustable metal rod and the length of the second adjustable metal rod can be adjusted, so that a discharge gap generated between the first adjustable metal rod and the second adjustable metal rod can be adjusted. The utility model discloses can make the power frequency energy discharge through air gap promptly discharge gap before the arrester is punctured by the power frequency overvoltage, avoid it to lead to the arrester explosion through the arrester, can take precautions against earth potential rising effectively and lead to the counterattack to equipment.
Description
Technical Field
The utility model relates to an excessive pressure arrester technical field, especially a device for preventing that high soil resistivity area transformer substation's grounding grid potential from rising to constitute counterattack to equipment.
Background
The grounding system of the transformer substation is the fundamental guarantee for maintaining the reliable operation of the power system and ensuring the safety of operators and electrical equipment, when a grounding fault occurs in the transformer substation, the short-circuit electricity flows into the ground to cause safety problems such as ground potential rise, mesh potential difference, step voltage, contact voltage, secondary interference and the like, thus threatening the safety of primary equipment, secondary equipment and workers in the substation, and many accidents or expansion of accidents caused by the failure of the grounding system in China occur. As such, the design of grounding systems has been a significant concern for designers in substation electrical design work.
In the design of a transformer substation grounding system in a conventional area, the ground potential rise of a grounding network is generally limited by reducing the power frequency grounding resistance of the grounding network in a single-phase grounding fault, so that the purpose of reducing the step voltage, the contact voltage and the counterattack voltage is achieved, but for the transformer substation in a high-soil resistivity area, the reduction of the power frequency grounding resistance of the grounding network is very difficult, and the investment of the grounding system is greatly increased by adopting a large number of resistance reduction measures. Therefore, in most high soil resistivity area substations, in consideration of engineering economy, resistance is often not greatly reduced, and the step voltage, the contact voltage and the counterattack voltage caused by the ground fault are controlled within a safe range by taking appropriate measures.
However, generally, the control of the step voltage and the contact voltage is relatively simple, and the step voltage and the contact voltage can be controlled below a safe value only by laying gravels or increasing a voltage equalizing belt, but the control of the counterattack voltage caused by the ground potential rise is difficult. This is mainly because the counterattack voltage is mainly determined by the ground potential rise, which is directly determined by the ground resistance, so that the problem of suppressing the counterattack voltage is finally converted into the problem of reducing the resistance, which finally leads to the increase of the engineering investment.
Therefore, in practical engineering, how to effectively prevent the counterattack problem caused by the ground potential rise becomes a key for controlling the investment of the grounding system in the high-soil resistivity area.
SUMMERY OF THE UTILITY MODEL
To the equipment counterattack problem that the earth potential risees and leads to, the utility model provides a protection device who prevents earth fault counterattack for prevent that high soil resistivity area transformer substation's ground net electric potential from rising the counterattack that constitutes to equipment.
The utility model adopts the technical scheme as follows:
a protection device for preventing earth fault counterattack comprises an arrester, a post insulator, a first adjustable metal rod, a second adjustable metal rod and a fixed base, wherein the arrester and the post insulator are arranged on the fixed base side by side, the first adjustable metal rod is transversely arranged at the top end of the arrester, and the second adjustable metal rod is transversely arranged at the top end of the post insulator and is connected with a main grounding grid; the length of the first adjustable metal rod and the length of the second adjustable metal rod can be adjusted, so that a discharge gap generated between the first adjustable metal rod and the second adjustable metal rod can be adjusted. The protection device can make power frequency energy pass through the air gap, namely the discharge gap discharges before the arrester is punctured by power frequency overvoltage, so that the arrester is prevented from exploding due to the fact that the arrester passes through the arrester, and counterattack to equipment caused by ground potential rising can be effectively prevented.
Further, the length of the first adjustable metal rod and the length of the second adjustable metal rod are set as follows: and enabling the power frequency action voltage of the discharge gap to be smaller than the direct current 1mA reference voltage of the lightning arrester, and enabling the lightning impulse action gap to be smaller than the lightning arrester protection level. Furthermore, for 10kV equipment in the transformer substation, the power frequency operating voltage of the discharge gap is set to be 20kV, the lightning impulse operating voltage is set to be 54kV, and the corresponding gap is 55 mm-60 mm. For 35kV equipment in a transformer substation, the power frequency action voltage of the discharge gap is set to be 68kV, the lightning impulse action voltage is set to be 142kV, and the corresponding gap is 140 mm-170 mm.
Further, the first adjustable metal rod and the second adjustable metal rod are arranged to match the heat capacity borne during counterattack. Furthermore, for 10kV equipment in a transformer substation, the cross section of the first adjustable metal rod and the cross section of the second adjustable metal rod are set to be not less than 100mm2(ii) a For 35kV equipment in a transformer substation, the cross sections of the first adjustable metal rod and the second adjustable metal rod are set to be not less than 150mm2。
Further, the post insulators are configured to match the insulation level of the protected equipment. Further, for 10kV equipment in a transformer substation, the voltage grade of the post insulator is set to be 24kV, the bending strength is set to be 6 kN-10 kN, and the torsion resistance is set to be 6 kN.m-10 kN.m. For 35kV equipment in a transformer substation, the voltage grade of the post insulator is set to be 40.5kV, the bending strength is set to be 8 kN-12 kN, and the torsion resistance is set to be 10 kN.m-12 kN.m.
Further, the arrester is configured to match the voltage class of the protected device.
The beneficial effects of the utility model reside in that:
(1) the utility model discloses can make the power frequency energy discharge through air gap promptly discharge gap before the arrester is punctured by the power frequency overvoltage, avoid it to lead to the arrester explosion through the arrester, can take precautions against earth potential rising effectively and lead to the counterattack to equipment.
(2) The utility model discloses an adjustable metal pole of first transversely sets up in the arrester top, and the adjustable metal pole of second transversely sets up in the post insulator top, has directly utilized arrester and post insulator as clearance bearing structure.
(3) The utility model discloses a length of first adjustable metal pole and the adjustable metal pole of second can be adjusted, makes the discharge gap who produces between the two adjustable.
Drawings
Fig. 1 is a schematic structural diagram of a protection device for preventing earth fault counterattack according to an embodiment of the present invention;
reference numerals: 1-lightning arrester, 2-post insulator, 3-first adjustable metal rod, 4-second adjustable metal rod and 5-fixed base.
Detailed Description
In order to clearly understand the technical features, objects, and effects of the present invention, the embodiments of the present invention will be described. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention, i.e., the described embodiments are only some, but not all embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by the person skilled in the art without creative work belong to the protection scope of the present invention.
Normally, the lightning arrester is used to protect the lightning and operating overvoltage in the system, and can limit the lightning and operating overvoltage to the level that the equipment can bear. However, when a single-phase ground fault occurs in the transformer substation, the power frequency ground potential of the grounding network in the transformer substation rises at the moment, so that the lightning arrester can bear higher power frequency overvoltage, but the lightning arrester generally cannot bear the power frequency overvoltage, the energy is too large, and explosion is possible.
In view of the above problems, the present embodiment provides a protection device for preventing ground fault counterattack, as shown in fig. 1, which includes a lightning arrester, a post insulator, a first adjustable metal rod, a second adjustable metal rod, and a fixed base, where the lightning arrester and the post insulator are arranged side by side on the fixed base, the first adjustable metal rod is transversely arranged at the top end of the lightning arrester, and the second adjustable metal rod is transversely arranged at the top end of the post insulator and connected to a main grounding grid; the length of the first adjustable metal rod and the second adjustable metal rod can be adjusted, so that a discharge gap generated between the first adjustable metal rod and the second adjustable metal rod is adjustable.
Based on above-mentioned structure, the protection device of this embodiment can make the power frequency energy discharge through the air gap promptly discharge the clearance before the arrester is punctured by the power frequency overvoltage, avoids it to lead to the arrester explosion through the arrester, can prevent effectively that the ground potential rising leads to the counterattack to equipment.
The length of first adjustable metal pole and the adjustable metal pole of second sets up to: the power frequency action voltage of the discharge gap is smaller than the direct current 1mA reference voltage of the lightning arrester, and the lightning impulse action gap is smaller than the protection level of the lightning arrester. Preferably, for 10kV equipment in a transformer substation, the power frequency operating voltage of a discharge gap is set to be 20kV, the lightning impulse operating voltage is set to be 54kV, and the corresponding gap is 55 mm-60 mm. For 35kV equipment in a transformer substation, the power frequency action voltage of a discharge gap is set to be 68kV, the lightning impulse action voltage is set to be 142kV, and the corresponding gap is 140-170 mm.
The first adjustable metal rod and the second adjustable metal rod are arranged to match the heat capacity experienced during counterattack. Preferably, for 10kV equipment in a substation, the cross sections of the first adjustable metal rod and the second adjustable metal rod are set to be notLess than 100mm2(ii) a For 35kV equipment in a transformer substation, the cross sections of the first adjustable metal rod and the second adjustable metal rod are set to be not less than 150mm2。
The post insulators are arranged to match the insulation level of the protected equipment. Preferably, for a 10kV installation in a substation, the voltage class of the post insulator is set to 24kV, the bending strength is set to 6 kN-10 kN, and the torsion resistance is set to 6 kn.m-10 kn.m. For 35kV equipment in a transformer substation, the voltage grade of a post insulator is set to be 40.5kV, the bending strength is set to be 8 kN-12 kN, and the torsion resistance is set to be 10 kN.m-12 kN.m.
The arrester is set to match the voltage class of the protected equipment. Preferably, for 10kV equipment in a transformer substation, the lightning arrester can be a YH5W-17/45 type zinc oxide lightning arrester; YH5W-51/134 type zinc oxide arresters can be selected for 35kV equipment arresters in the transformer substation.
The foregoing is illustrative of the preferred embodiments of the present invention, and it is to be understood that the invention is not limited to the precise forms disclosed herein, and that various other combinations, modifications, and environments may be resorted to, falling within the scope of the invention as defined by the appended claims. But that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention, which is to be limited only by the claims appended hereto.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "inner", "outer", and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the present invention is used, and are only for convenience of description and simplification of the description, but do not indicate or imply that the device or element to which the present invention is directed must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; either a wired or wireless connection.
Claims (10)
1. A protection device for preventing earth fault counterattack is characterized by comprising an arrester, a post insulator, a first adjustable metal rod, a second adjustable metal rod and a fixed base, wherein the arrester and the post insulator are arranged on the fixed base side by side, the first adjustable metal rod is transversely arranged at the top end of the arrester, and the second adjustable metal rod is transversely arranged at the top end of the post insulator and is connected with a main grounding grid; the length of the first adjustable metal rod and the length of the second adjustable metal rod can be adjusted, so that a discharge gap generated between the first adjustable metal rod and the second adjustable metal rod can be adjusted.
2. The ground fault counterattack protection device of claim 1, wherein the first and second adjustable metal rods are of a length set to: and enabling the power frequency action voltage of the discharge gap to be smaller than the direct current 1mA reference voltage of the lightning arrester, and enabling the lightning impulse action gap to be smaller than the lightning arrester protection level.
3. The protection device against ground fault counterattack according to claim 2, characterized in that for 10kV equipment in a substation, the power frequency operating voltage of the discharge gap is set to 20kV, the lightning impulse operating voltage is set to 54kV, and the corresponding gap is 55mm to 60 mm.
4. The protection device against ground fault counterattack as claimed in claim 2, wherein for a 35kV device in a substation, the power frequency operating voltage of the discharge gap is set to 68kV, the lightning impulse operating voltage is set to 142kV, and the corresponding gap is 140mm to 170 mm.
5. A ground fault counterattack protection device according to any one of claims 1 to 4, wherein the first and second adjustable metal rods are arranged to match the thermal capacity experienced during counterattack.
6. The ground fault counterattack protection device of claim 5, wherein the cross-section of the first and second adjustable metal bars is set to be not less than 100mm for 10kV equipment in a substation2(ii) a For 35kV equipment in a transformer substation, the cross sections of the first adjustable metal rod and the second adjustable metal rod are set to be not less than 150mm2。
7. A ground fault counterattack protection device according to any one of claims 1 to 4, wherein the post insulators are arranged to match the insulation level of the equipment to be protected.
8. The protection device against earth fault counterattack according to claim 7, characterized in that for 10kV equipment in a substation, the post insulator is set to 24kV in voltage class, 6 kN-10 kN in bending strength and 6 kn.m-10 kn.m in torsion resistance.
9. The earth-fault counterattack protection device of claim 7, wherein the post insulators are set to a voltage rating of 40.5kV, a bending strength of 8 kN-12 kN and a twisting resistance of 10 kn.m-12 kn.m for 35kV equipment in a substation.
10. A protection arrangement against earth fault counterattack according to any one of claims 1 to 4, characterised in that the lightning arrester is arranged to match the voltage class of the equipment to be protected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121127384.5U CN215267585U (en) | 2021-05-25 | 2021-05-25 | Protection device for preventing earth fault counterattack |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121127384.5U CN215267585U (en) | 2021-05-25 | 2021-05-25 | Protection device for preventing earth fault counterattack |
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| Publication Number | Publication Date |
|---|---|
| CN215267585U true CN215267585U (en) | 2021-12-21 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202121127384.5U Active CN215267585U (en) | 2021-05-25 | 2021-05-25 | Protection device for preventing earth fault counterattack |
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| CN (1) | CN215267585U (en) |
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2021
- 2021-05-25 CN CN202121127384.5U patent/CN215267585U/en active Active
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