Oil-immersed inverted current transformer and installation method thereof

Abstract

The invention provides an oil-immersed inverted current transformer and an installation method thereof, and belongs to the technical field of current transformers, the oil-immersed inverted current transformer comprises a base, a straight pipe is installed at the top of the base, a shell is installed at the top of the straight pipe, insulating layers are installed inside the shell and outside the straight pipe, the shell comprises a lower shell, an oil cabinet is installed at the top of the lower shell, and the oil cabinet is installed at the top of the lower shell. The insulating layer is formed by binding domestic cable paper and comprises an annular insulating layer installed in the oil cabinet, and the bottom of the annular insulating layer is connected with a straight rod part insulating layer installed outside the straight pipe; the insulation structure can be optimized to meet the requirements of product dielectric loss factor, local discharge capacity and power frequency withstand voltage, the neck clamping problem is solved on the premise of guaranteeing electrical performance, development of current transformers in China is accelerated, meanwhile, a profiling structure is adopted, the outer surface of the product is smoother, the grading ring is additionally arranged, external electric field distribution is changed, and the insulation performance of the product is improved. The radio interference voltage is reduced, and the influence on communication and automation equipment is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of current transformers, and in particular to an oil-immersed inverted current transformer and a mounting method thereof. Background Art

[0002] Current transformers play a vital role in high-voltage power systems. They are not only used for electric energy metering and current measurement, but also undertake key tasks of automatic control and relay protection. Among the many types of current transformers, oil-immersed current transformers are highly favored due to their excellent performance and are widely used in high-voltage power systems.

[0003] However, the complex and changeable international situation in recent years has brought severe challenges to the production of current transformers, especially the import channel of insulating paper has been seriously affected. The existing domestic manufacturers of inverted oil-immersed current transformers all use imported insulating paper for production. The production of existing current transformers is closely linked to the international situation, which seriously affects the normal production of inverted current transformers. This is undoubtedly a huge blow to current transformer manufacturers who rely on imported insulating paper; what is more serious is that the performance of existing domestic insulating paper cannot fully meet the performance requirements of existing insulation calculations, which means that even if domestic insulating paper can be obtained, it is impossible to guarantee that the quality and performance of the current transformer meet the design requirements, which has a serious impact on the normal production of inverted current transformers and may even threaten the stable operation of the entire power system.

[0004] In summary, oil-immersed current transformers are widely used and important in high-voltage power systems. The current problem of insulation material supply cannot be ignored. We need to take positive and effective measures to meet this challenge and ensure the normal production of current transformers and the stable operation of power systems. Summary of the invention

[0005] The purpose of the present invention is to provide an oil-immersed inverted current transformer and an installation method thereof to overcome the problems existing in the prior art. The present invention can optimize the insulation structure and adopt domestic insulating paper for insulation wrapping to meet the requirements of the product's dielectric loss factor, partial discharge and power frequency withstand voltage, solve the bottleneck problem under the premise of ensuring electrical performance, and accelerate the development of current transformers in my country; due to changes in the shape of the instrument body, the upper and lower oil cabinets and porcelain sleeves are designed, and a contoured structure is adopted to make the outer surface of the product smoother, and a grading ring is added to change the external electric field distribution, reduce the radio interference voltage, and avoid affecting communication and automation equipment.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: An oil-immersed inverted current transformer comprises a base, a straight tube is installed on the top of the base, a shell is installed on the top of the straight tube, and an insulating layer is installed inside the shell and outside the straight tube; The housing comprises a lower housing, an oil tank is installed on the top of the lower housing, and an upper housing is installed on the top of the oil tank; The straight pipe comprises a first straight pipe installed on the top of the base, and a second straight pipe is installed on the top of the first straight pipe; The insulating layer is wrapped with domestic cable paper, including an annular insulating layer installed in the oil tank, the bottom of the annular insulating layer is connected to a straight rod insulating layer installed outside the straight pipe, the straight rod insulating layer includes a first straight rod insulating layer installed outside the first straight pipe, the top of the first straight rod insulating layer is connected to a second straight rod insulating layer installed outside the second straight pipe, and the first straight rod insulating layer is also covered with a porcelain sleeve; Furthermore, the lower housing is installed outside the insulating layer of the second straight rod portion; Furthermore, an expander is installed inside the upper shell, and an oil tank is installed at the bottom of the expander; Furthermore, the oil tank comprises an upper oil tank, the upper oil tank is connected to a lower oil tank via a primary winding, and the bottom of the lower oil tank is connected to the first straight pipe; Further, the primary winding includes a primary conductive rod, both ends of the primary conductive rod are respectively installed with primary terminal boards, and both ends of the primary conductive rod are respectively connected with a grading ring through the primary terminal boards; Furthermore, the annular insulating layer comprises an upper annular insulating layer installed inside the upper oil tank and a lower annular insulating layer installed inside the lower oil tank, and the upper annular insulating layer and the lower annular insulating layer are both sleeved with secondary windings; Furthermore, the base includes a supporting part, a chassis is installed at the bottom of the supporting part, a grounding plate is installed at the rear and side of the chassis, the angle between the two grounding plates is 90°, an outlet box is installed at the front of the chassis, and a nameplate is installed at the front of the outlet box.

[0007] A method for installing an oil-immersed inverted current transformer, based on the above-mentioned oil-immersed inverted current transformer, comprises the following steps: Fix the top of the base and the straight pipe, wrap the straight rod insulation layer outside the first straight pipe and the second straight pipe, sleeve the straight rod insulation layer of the first straight pipe with a porcelain sleeve, then install the shell on the top of the second straight pipe, and then wrap the ring insulation layer inside the shell; Furthermore, wrapping the straight rod portion insulation layer outside the first straight tube and the second straight tube of the straight tube specifically comprises: Domestic cable paper is used to perform insulation wrapping on the outside of the first straight pipe and the second straight pipe of the straight pipe, and the domestic cable paper is heated during the wrapping process to form an insulation layer of the straight rod; Furthermore, the annular insulating layer wrapped inside the shell is specifically: Domestic cable paper is used for insulation wrapping inside the shell, and a capacitor screen is added during the wrapping process for voltage balancing to form an annular insulation layer.

[0008] The above technical solution has the following advantages or beneficial effects: The present invention provides an oil-immersed inverted current transformer. By adopting domestic insulating paper for insulation wrapping, not only the requirements of product dielectric loss factor, partial discharge and power frequency withstand voltage are met, but also the cost is reduced and the localization process is promoted. The design of the insulating layer effectively improves the electrical performance of the transformer and solves the bottleneck problem of traditional transformers in insulation. The change of the appearance of the transformer body prompts the contour design of the oil cabinet and the porcelain sleeve to make the outer surface of the product smoother. By dividing the insulating layer into an annular insulating layer and a straight rod insulating layer, the utilization rate of the domestic insulating paper can be improved to achieve better insulation performance.

[0009] Furthermore, the expander is installed inside the upper shell, and its bottom is closely connected to the oil tank, so that the expander can directly sense and respond to changes in oil temperature and oil volume in the oil tank, which helps prevent the mutual inductor performance degradation or damage caused by excessive pressure.

[0010] Furthermore, by adding a voltage-grading ring, the external electric field distribution is changed, the radio interference voltage is effectively reduced, the potential impact on communication and automation equipment is avoided, and the negative effects caused by electric field inhomogeneity are reduced.

[0011] Furthermore, the layered annular insulation layer helps to better isolate the electric field between the high voltage and the low voltage, reduce electric field coupling and interference, help to improve the insulation strength of the transformer, and reduce the risk of failure caused by insulation breakdown.

[0012] Furthermore, the close integration of the support part and the chassis ensures the stability of the transformer during installation and use, helps to reduce the tilting or shaking of the transformer caused by improper installation or external factors, and improves the operating reliability of the transformer; the setting and layout of the grounding plate meet the requirements of electrical safety, ensure the current dispersion and stability of the transformer during the grounding process, help reduce the risk of electrical failures caused by poor grounding, and improve the safety of the transformer; the design of the outlet box makes wiring work more convenient, and also provides convenience for subsequent maintenance work; the key information marked on the nameplate makes the transformer more convenient in identification and management.

[0013] The present invention also provides an installation method for an oil-immersed inverted current transformer. The wrapping of the insulating layer and the installation of the porcelain sleeve significantly improve the insulation performance of the transformer, help prevent the occurrence of electrical faults such as current leakage and short circuit, and improve the safety and reliability of the transformer.

[0014] Furthermore, by using domestic cable paper to insulate and heat the outside of the straight pipe, it helps to improve the insulation performance of the insulation layer of the straight rod, prevent current leakage through non-conductive paths, and enable the equipment to better meet higher standards of electrical safety requirements.

[0015] Furthermore, by using domestic cable paper for insulation wrapping inside the shell and adding a capacitor screen for voltage balancing, it helps to improve the utilization rate of the insulation paper, achieve better insulation performance, reduce electric field coupling and interference, and improve the measurement accuracy and response speed of the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a front view of an oil-immersed inverted current transformer of the present invention; Figure 2 It is a side view of an oil-immersed inverted current transformer of the present invention; In the figure, 1-shell; 11-upper shell; 12-upper oil cabinet; 13-lower oil cabinet; 14-oil cabinet; 15-lower shell; 16-expander; 2-porcelain sleeve; 21-straight pipe; 22-first straight pipe; 23-second straight pipe; 3-base; 31-support part; 32-chassis; 33-grounding plate; 34-outlet box; 35-nameplate; 4-insulating layer; 41-annular insulating layer; 42-straight rod insulation layer; 43-first straight rod insulation layer; 44-second straight rod insulation layer; 5-primary winding; 51-primary conductive rod; 52-primary terminal board; 53-equalizing ring; 6-secondary winding. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it. In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0018] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0019] Embodiment 1: like Figure 1 and Figure 2 As shown, the present invention provides an oil-immersed inverted current transformer, including a base 3, the base 3 includes a support portion 31, a chassis 32 is installed at the bottom of the support portion 31, a grounding plate 33 is installed at the rear and side of the chassis 32, and the angle between the two grounding plates 33 is 90°, an outlet box 34 is installed at the front of the chassis 32, and a nameplate 35 is installed at the front of the outlet box 34; a straight pipe 21 is installed at the top of the base 3, and the straight pipe 21 includes a first straight pipe 22 installed at the top of the base 3, and the first straight pipe 22 is installed at the top of the base 3. A second straight pipe 23 is installed on the top of the pipe 22; a shell 1 is installed on the top of the straight pipe 21, and the shell 1 includes a lower shell 15, and an oil tank 14 is installed on the top of the lower shell 15. An upper shell 11 is installed on the top of the oil tank 14, and an expander 16 is installed inside the upper shell 11. The oil tank 14 is installed at the bottom of the expander 16. The oil tank 14 includes an upper oil tank 12, and the upper oil tank 12 is connected to the lower oil tank 13 through the primary winding 5. The bottom of the lower oil tank 13 is connected to the first straight pipe 22, and the primary winding 5 includes a primary conductive Rod 51, both ends of the primary conductive rod 51 are respectively installed with a primary terminal board 52, and both ends of the primary conductive rod 51 are respectively connected with a grading ring 53 through the primary terminal board 52; the interior of the shell 1 and the exterior of the straight pipe 21 are both installed with an insulating layer 4, the insulating layer 4 is wrapped with domestic cable paper, and includes an annular insulating layer 41 installed in the oil tank 14, the annular insulating layer 41 includes an upper annular insulating layer installed in the upper oil tank 12 and a lower annular insulating layer installed in the lower oil tank 13, the upper annular insulating layer and The inner parts of the annular insulating layer 41 and the lower annular insulating layer are both sleeved with secondary windings 6, the bottom of the annular insulating layer 41 is connected to the straight rod insulating layer 42 installed on the outside of the straight pipe 21, the straight rod insulating layer 42 includes a first straight rod insulating layer 43 installed on the outside of the first straight pipe 22, the outer part of the first straight rod insulating layer 43 is sleeved with a porcelain sleeve 2, the top of the first straight rod insulating layer 43 is connected to the second straight rod insulating layer 44 installed on the outside of the second straight pipe 23, and the lower shell 15 is installed on the outside of the second straight rod insulating layer 44.

[0020] Embodiment 2: like Figure 1 and Figure 2 As shown, the present invention provides an installation method of an oil-immersed inverted current transformer, comprising a housing 1, a straight tube 21, a porcelain sleeve 2, a base 3 and an insulating layer 4; the housing 1 comprises an upper housing 11, an oil tank 14 and a lower housing 15, the upper housing 11 comprises an expander 16, the oil tank 14 comprises an upper oil tank 12, a primary winding 5 and a lower oil tank 13, the primary winding 5 comprises a primary conductive rod 51, a primary terminal board 52 and a grading ring 53; The lower oil tank 13 is installed on the top of the lower shell 15, and the lower oil tank 13 is connected to the upper oil tank 12 through a primary conductive rod 51. The lower oil tank 13 and the upper oil tank 12 are welded by an argon arc welding structure. The primary conductive rod 51 and the upper oil tank 12 are sealed and isolated by an insulating pad and a sealing ring. The two ends of the primary conductive rod 51 are respectively installed with a primary terminal board 52, and the two ends of the primary conductive rod 51 are respectively connected to the grading ring 53 through the primary terminal board 52. The top of the upper oil tank 12 is connected and installed with an expander 16 by bolt connection, and is sealed with an O-ring, and the upper shell 11 is installed on the outside of the expander 16; The straight pipe 21 includes a first straight pipe 22 and a second straight pipe 23. The base 3 is installed at the bottom of the first straight pipe 22, the second straight pipe 23 is installed at the top of the first straight pipe 22, and the lower oil tank 13 is installed at the top of the second straight pipe 23. The base 3 includes a support portion 31, a chassis 32, a grounding plate 33, an outlet box 34 and a nameplate 35. The bottom of the support portion 31 is installed with the chassis 32, and a grounding plate 33 is installed at the rear and side of the chassis 32 respectively, and the angle between the two grounding plates 33 is 90°. The front of the chassis 32 is installed with the outlet box 34, and the nameplate 35 is installed at the front of the outlet box 34; the porcelain sleeve 2 and the lower oil cabinet 13 and the base 3 are bonded with cement, and a concave-convex structure is used at the casting part of the lower oil cabinet 13 and the base 3 to avoid the problem of separation between the porcelain sleeve 2 and the lower oil cabinet 13 and the base 3 due to thermal expansion and contraction; The insulating layer 4 includes an annular insulating layer 41 and a straight rod insulating layer 42. The annular insulating layer 41 includes an upper annular insulating layer and a lower annular insulating layer. The straight rod insulating layer 42 includes a first straight rod insulating layer 43 and a second straight rod insulating layer 44. The insulating layer 4 is installed inside the shell 1 and outside the straight pipe 21. The insulating layer 4 is wrapped with domestic cable paper. The upper annular insulating layer is installed inside the upper oil cabinet 12, and the lower annular insulating layer is installed inside the lower oil cabinet 13. The upper annular insulating layer and the lower annular insulating layer are both sleeved with secondary windings 6. The bottom of the annular insulating layer 41 is connected to the straight rod insulating layer 42. The first straight rod insulating layer 43 is installed on the outside of the first straight pipe 22. The outside of the first straight rod insulating layer 43 is sleeved with a porcelain sleeve 2. The top of the first straight rod insulating layer 43 is connected to the second straight rod insulating layer 44 installed on the outside of the second straight pipe 23. The lower shell 15 is installed on the outside of the second straight rod insulating layer 44.

[0021] Embodiment 3: The present invention also provides an installation method of an oil-immersed inverted current transformer, based on the above-mentioned oil-immersed inverted current transformer, comprising the following steps: The top of the base 3 and the straight tube 21 are fixed, and the first straight tube 22 and the second straight tube 23 of the straight tube 21 are wrapped with domestic cable paper for insulation, and the domestic cable paper is heated during the wrapping process to improve the insulation performance, forming a straight rod insulation layer 42, and the porcelain sleeve 2 is sleeved on the outside of the first straight tube 22, and then the top of the second straight tube 23 is threadedly connected to the shell 1 using a joint, and then the inside of the shell 1 is wrapped with domestic cable paper for insulation, and a capacitor screen is added during the wrapping process for voltage balancing to achieve better insulation performance, improve the utilization rate of the insulation paper, and form an annular insulation layer 41; Preferably, the heating temperature is 90-105°C.

[0022] The explanations of relevant terms in the present invention are as follows: Instrument transformer - a transformer designed to transmit information signals to measuring instruments, meters and protection or control devices or similar electrical appliances; Oil-immersed type - an insulation method of the transformer, using insulating oil as the insulating medium; Inverted type: Compared with traditional transformers, the secondary winding is located at the top of the product; Insulation paper - used as product insulation material; Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An oil-immersed inverted current transformer, characterized in that: It comprises a base (3), a straight tube (21) is installed on the top of the base (3), a shell (1) is installed on the top of the straight tube (21), and an insulating layer (4) is installed inside the shell (1) and outside the straight tube (21); The housing (1) comprises a lower housing (15), an oil tank (14) is mounted on the top of the lower housing (15), and an upper housing (11) is mounted on the top of the oil tank (14); The straight tube (21) comprises a first straight tube (22) installed on the top of the base (3), and a second straight tube (23) is installed on the top of the first straight tube (22); The insulating layer (4) is wrapped with domestic cable paper and comprises an annular insulating layer (41) installed in the oil tank (14); the bottom of the annular insulating layer (41) is connected to a straight rod insulating layer (42) installed outside the straight pipe (21); the straight rod insulating layer (42) comprises a first straight rod insulating layer (43) installed outside the first straight pipe (22); the top of the first straight rod insulating layer (43) is connected to a second straight rod insulating layer (44) installed outside the second straight pipe (23); and the first straight rod insulating layer (43) is further sheathed with a porcelain sleeve (2).

2. The oil-immersed inverted current transformer according to claim 1, characterized in that: The lower housing (15) is installed outside the second straight rod portion insulating layer (44).

3. The oil-immersed inverted current transformer according to claim 1, characterized in that: An expander (16) is installed inside the upper shell (11), and an oil tank (14) is installed at the bottom of the expander (16).

4. The oil-immersed inverted current transformer according to claim 1, characterized in that: The oil tank (14) comprises an upper oil tank (12), the upper oil tank (12) being connected to a lower oil tank (13) via a primary winding (5), and the bottom of the lower oil tank (13) being connected to a first straight pipe (22).

5. The oil-immersed inverted current transformer according to claim 4, characterized in that: The primary winding (5) comprises a primary conductive rod (51), primary terminal plates (52) are respectively installed at both ends of the primary conductive rod (51), and voltage grading rings (53) are respectively connected to both ends of the primary conductive rod (51) via the primary terminal plates (52).

6. The oil-immersed inverted current transformer according to claim 4, characterized in that: The annular insulating layer (41) comprises an upper annular insulating layer installed inside the upper oil tank (12) and a lower annular insulating layer installed inside the lower oil tank (13), and the upper annular insulating layer and the lower annular insulating layer are both sleeved with secondary windings (6).

7. The oil-immersed inverted current transformer according to claim 1, characterized in that: The base (3) comprises a support portion (31), a chassis (32) is mounted on the bottom of the support portion (31), a grounding plate (33) is mounted on the rear and side of the chassis (32), the angle between the two grounding plates (33) is 90°, an outlet box (34) is mounted on the front of the chassis (32), and a nameplate (35) is mounted on the front of the outlet box (34).

8. A method for installing an oil-immersed inverted current transformer, based on the oil-immersed inverted current transformer according to any one of claims 1 to 7, characterized in that: The following steps are involved: The top of the base (3) and the straight tube (21) are fixed, and a straight rod insulation layer (42) is wrapped around the outside of the first straight tube (22) and the second straight tube (23) of the straight tube (21), and a porcelain sleeve (2) is sleeved around the outside of the straight rod insulation layer (42) of the first straight tube (22), and then a shell (1) is installed on the top of the second straight tube (23), and then a ring-shaped insulation layer (41) is wrapped around the inside of the shell (1).

9. The installation method of an oil-immersed inverted current transformer according to claim 8, characterized in that: The method of wrapping the straight rod portion insulation layer (42) outside the first straight tube (22) and the second straight tube (23) of the straight tube (21) is specifically as follows: Domestic cable paper is used to perform insulation wrapping on the outside of the first straight tube (22) and the second straight tube (23) of the straight tube (21), and the domestic cable paper is heated during the wrapping process to form a straight rod insulation layer (42).

10. The installation method of an oil-immersed inverted current transformer according to claim 8, characterized in that: The step of wrapping the annular insulating layer (41) inside the housing (1) specifically comprises: Domestic cable paper is used to perform insulation wrapping inside the housing (1), and a capacitive screen is added during the wrapping process to perform voltage balancing, thereby forming an annular insulation layer (41).

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