SF6 gas insulation closed transformer neutral point combined electric appliance

Abstract

The utility model relates to an SF6 (sulfur hexafluoride) gas insulated enclosed transformer neutral point combined electrical apparatus, which comprises a three-position isolating switch, a protective current transformer, a lightning arrester and a gap current transformer connected in series on a neutral point gap grounding loop, and is characterized in that the input end of the three-position isolating switch is connected with a transformer; the lightning arrester is connected in series with a closing loop of the three-station isolation switch, and the protection current transformer is connected in series with a grounding loop of the three-station isolation switch. The problems of difficulty in parallel protection and insulation matching of the gap and the lightning arrester and possible system protection maloperation are solved, the stability and safety of the system are greatly improved, the device has very important application prospects in a transformer neutral point protection system, frequent actions of the lightning arrester are avoided, the service life of the lightning arrester is greatly prolonged, and the safety of the transformer neutral point protection system is improved. And meanwhile, the switching operation of the transformer becomes simple and safe.

Description

Technical Field

[0001] The utility model relates to the technical field of high-voltage switches, in particular to an SF6 gas-insulated enclosed transformer neutral point combination electrical appliance. Background Art

[0002] In 110kV and 220kV neutral point effective grounding systems, in order to meet the setting configuration requirements of relay protection, some transformer neutral points are often operated in an ungrounded mode. During operation, the transformer neutral point may be subjected to lightning, power frequency and resonance overvoltages, which may damage the insulation of the transformer neutral point.

[0003] At present, the main neutral point protection methods for ungrounded transformers in my country are: single rod-rod gap protection; single zinc oxide arrester protection; gapless zinc oxide arrester and rod-rod gap parallel protection. None of the above three methods can solve the problem of transformer neutral point protection and system protection coordination. It is necessary to develop a set of devices to solve this problem. Utility Model Content

[0004] The utility model aims at the deficiencies of the prior art and provides a SF6 gas insulated enclosed transformer neutral point combined electrical appliance.

[0005] The utility model is realized through the following technical scheme, providing a SF6 gas insulated enclosed transformer neutral point combination electrical appliance, comprising a three-position disconnector, a protective current transformer, a lightning arrester and a gap current transformer connected in series to a neutral point gap grounding loop, wherein the input end of the three-position disconnector is connected to the transformer, the lightning arrester is connected in series to a closing loop of the three-position disconnector, and the protective current transformer is connected in series to a grounding loop of the three-position disconnector.

[0006] In this scheme, under lightning overvoltage, the three-position disconnector is adjusted to connect with the arrester, and the arrester is activated; when single-phase grounding and loss of ground or non-full-phase operating power frequency overvoltage occurs, the neutral point gap is adjusted; when the switching transformer requires neutral point grounding, the three-position disconnector is adjusted to grounding, thereby switching to the grounding state, the gap current transformer is used to monitor the gap current, and the protection current transformer is used to monitor the grounding current.

[0007] As an optimization, an aluminum housing is also included, and the three-position disconnector, the protection current transformer, the lightning arrester and the gap current transformer are all enclosed in the aluminum housing. In this solution, the enclosure is achieved by the aluminum housing, and protection can be provided by insulating gas.

[0008] As an optimization, the neutral point gap and the input end of the three-position disconnector are connected to the transformer through the transformer oil and gas bushing. In this solution, the oil and gas bushing is connected to the neutral point of the transformer.

[0009] As an optimization, the three-position disconnector, the protection current transformer, the arrester and the gap current transformer are fixed on the ground by brackets respectively. The brackets in this solution realize the support and fixation of each component.

[0010] As an optimization, the three-position disconnector is installed on the upper end of the arrester, and the protective current transformer is installed on the upper end of the three-position disconnector, so that the structure is compact.

[0011] The beneficial effects of the utility model are as follows: the utility model is an SF6 gas insulated enclosed transformer neutral point combination electrical appliance, which effectively solves the problems of the arrester being prone to explosion under power frequency overvoltage, the gap being unable to extinguish arcs under lightning and power frequency overvoltage shocks, the difficulty in matching the insulation of the parallel protection between the gap and the arrester, and the possible malfunction of the system protection, greatly improves the stability and safety of the system, has a very important application prospect in the transformer neutral point protection system, avoids frequent action of the arrester, greatly prolongs its service life, and makes the transformer switching operation simple and safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the front view of the utility model;

[0013] Figure 2 It is the left view of the utility model;

[0014] Figure 3 For this utility model Figure 1 Middle A-direction view;

[0015] Figure 4 This is the wiring schematic diagram of the utility model;

[0016] As shown in the figure:

[0017] 1. Three-position isolating switch, 2. Protective current transformer, 3. Lightning arrester, 4. Gap current transformer, 5. Transformer oil and gas bushing, 6. Neutral point gap, 7. Transformer, 8. Protective current transformer grounding bar, 9. Lightning arrester grounding bar, 10. Gap current transformer grounding bar. DETAILED DESCRIPTION

[0018] In order to clearly illustrate the technical features of this solution, this solution is described below through a specific implementation method.

[0019] like Figures 1 to 4 As shown, the utility model is an SF6 gas insulated enclosed transformer neutral point combination appliance, including a three-position isolating switch 1, a protective current transformer 2, a lightning arrester 3 and a gap current transformer 4 connected in series to the neutral point gap 6 grounding loop, and the gap current transformer 4 is used to monitor the gap current.

[0020] The discharge gap of the neutral point gap 6 adopts a stainless steel ball gap electrode, which has a uniform electric field, a stable discharge voltage, small dispersion and good protection performance.

[0021] It also includes an aluminum shell, in which the three-position disconnector 1, the protective current transformer 2, the lightning arrester 3 and the gap current transformer 4 are all enclosed, and SF6 gas is used as an insulating medium.

[0022] The protection current transformer 2 is grounded through the protection current transformer grounding bar 8 , the lightning arrester 3 is grounded through the lightning arrester grounding bar 9 , and the gap current transformer 4 is grounded through the gap current transformer grounding bar 10 .

[0023] The three-position disconnector 1 is installed on the upper end of the lightning arrester 3 , and the protective current transformer 2 is installed on the upper end of the three-position disconnector 1 .

[0024] The input end of the three-position disconnector 1 is connected to the transformer 7 through the oil and gas casing 5, the lightning arrester 3 is connected in series to the closing circuit of the three-position disconnector 1, and the protection current transformer 2 is connected in series to the grounding circuit of the three-position disconnector 1.

[0025] The neutral point gap 6 and the input end of the three-position disconnector 1 are both connected to the transformer 7 through the transformer oil-gas bushing 5. In this embodiment, the oil-SF6 bushing is used.

[0026] The neutral point gap 6 is connected between the transformer oil and gas bushing 5 and the three-position disconnector 1 .

[0027] The three-position disconnector 1, protective current transformer 2, lightning arrester 3 and gap current transformer 4 are fixed on the ground through brackets. The brackets are supported by cylinders and fixed by anchor bolts; the secondary control, measurement and monitoring devices are centrally installed in the local control box, the control box is installed on the device bracket, and the CT secondary cable, disconnector control line and close controller line are led into the control box.

[0028] The use of the utility model:

[0029] The utility model can realize the following functions by adjusting the neutral point gap distance and operating the three-position isolating switch:

[0030] Under lightning overvoltage, the three-position disconnector is adjusted to connect with the arrester, and the arrester is activated; when single-phase grounding and loss of ground or non-full-phase operation power frequency overvoltage occurs, the neutral point gap is adjusted; when the switching transformer requires neutral point grounding, the three-position disconnector is adjusted to grounding, thereby switching to the grounding state. The gap current transformer is used to monitor the gap current, and the protection current transformer is used to monitor the grounding current.

[0031] Of course, the above description is not limited to the above examples. The technical features not described in the present invention can be achieved by or by adopting the existing technology, which will not be repeated here. The above embodiments and drawings are only used to illustrate the technical scheme of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that the changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not deviate from the purpose of the present invention and should also fall within the scope of protection of the claims of the present invention.

Claims

1. A SF6 gas insulated enclosed transformer neutral point combination device, characterized in that: The invention comprises a three-position isolating switch (1), a protective current transformer (2), a lightning arrester (3), and a gap current transformer (4) connected in series to a grounding circuit of a neutral point gap (6); the input end of the three-position isolating switch (1) is connected to a transformer (7); the lightning arrester (3) is connected in series to a closing circuit of the three-position isolating switch (1); and the protective current transformer (2) is connected in series to a grounding circuit of the three-position isolating switch (1).

2. The SF6 gas insulated enclosed transformer neutral point combination device according to claim 1, characterized in that: It also comprises an aluminum shell, in which the three-position isolating switch (1), the protective current transformer (2), the lightning arrester (3) and the gap current transformer (4) are all enclosed.

3. The SF6 gas insulated enclosed transformer neutral point combination device according to claim 1, characterized in that: The neutral point gap (6) and the input end of the three-position disconnector (1) are both connected to the transformer (7) via the transformer oil and gas bushing (5).

4. The SF6 gas insulated enclosed transformer neutral point combination device according to claim 1, characterized in that: The three-position isolating switch (1), the protective current transformer (2), the lightning arrester (3) and the gap current transformer (4) are respectively fixed on the ground via brackets.

5. The SF6 gas insulated enclosed transformer neutral point combination device according to claim 1, characterized in that: The three-position disconnector (1) is mounted on the upper end of the lightning arrester (3), and the protective current transformer (2) is mounted on the upper end of the three-position disconnector (1).

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