KR101051132B1 - Bushing-type instrument transformers of high-reliability - Google Patents

Abstract

PURPOSE: A bushing type metering outfit is provided to prevent dielectric breakdown by controlling that partial discharge generates in inside of the metering outfit and a seaming part. CONSTITUTION: A semi-conductive paint(22) smears in the outside surface and the inner side of an insulator(21). A semiconducting packing(23) is combined with the semi-conductive paint smearing at the upper part of the inner side of insulator in contact with each other. A shield(27) is inserted into the bottom part of the insulator through an insulation packing(29). An insert(28) is inserted into the end of a tube(24). The insert alleviates the corona discharge at the end of the tube.

Description

Bushing-type Instrument Transformers of high-reliability

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer for a bushing type oil insulated instrument, and more particularly, to a highly reliable bushing type instrument transformer having excellent durability by preventing the occurrence of partial discharge in the bushing part and the winding part of the transformer to prevent insulation breakdown. It is about.

Instrument Transformers can be subdivided into Instrument Transformers (PT), Current Transformers (CT), and Combined Transformers (MOF).

Instrument transformer (PT) is a device that converts a high voltage into a low ratio of a certain ratio and is a kind of transformer used to supply a voltmeter or a relay.

Instrument current transformers (CTs) are devices that convert high currents into a constant proportion of low currents.

The transformer transformer current transformer (MOF) is combined with the maximum demand electricity meter and converts the high voltage into low voltage for accurate calculation and collection of electricity rates according to the measurement of power consumption of industrial consumers and factories and buildings. ) And an instrument current transformer (CT) that accurately converts a large current into a small current, is used as an electronic device for accurately operating a maximum demand power meter.

When the insulation medium is categorized, the gas filled the inside of the tank including the winding body with an insulating gas such as SF6, etc. I can represent you.

As with other electrical appliances, transformers have standard standards for manufacturing and testing. For example, KS, the Korean standard, and International Electrotechnical Commission (IEC), the international standard. Domestic electrical appliances are covered by KS, and most of them are covered by IEC to export internationally.

However, with the development and internationalization of the times, not only KS is naturally changing to the same standard as IEC, but also the IEC standard is gradually upgraded, and corresponding products are competitive in technology, price, and size. The product was forced to be developed.

Particularly, the important factor that distinguishes the durability (life) of the product is the partial discharge measurement.So, the solid insulation type or gas type, which has been pursued in the world since the product development has been developed a lot, there is no problem. Since oil filled type is applied only to 72.5kv class and above, in accordance with the IEC standard, the technology development in the field of partial discharge of relatively low voltage electric products is underdeveloped.

However, it is now applied to instrument transformers of more than 7.2kv, and it is necessary to improve oil tank type except gas type and epoxy mold type, that is, the development of the most economical and bulky products.

Accordingly, an object of the present invention has been made in view of the above-mentioned point, by applying a liquid semiconductive composition (semiconductive composition) in the vicinity of the electric field concentration phenomenon in the bushing in the transformer for the bushing oil insulation instrument of relatively low voltage It is to provide a highly reliable bushing type transformer for reducing electric field and preventing partial discharge.

It is also an object of the present invention to provide a highly reliable bushing by attaching a shield near the occurrence of field concentration in a transformer in a transformer for a relatively low voltage bushing type oil insulated instrument to reduce electric field concentration and to prevent partial discharge. To provide a transformer for the type instrument.

Highly reliable bushing-type instrument transformer according to the present invention for achieving the above object, in the bushing-type oil-insulated instrument transformer, so that the electric field is made only in the insulator of the bushing, the outer surface and the inner surface of the insulator A semiconductive paint to be painted on, a semiconductive packing coupled to abut the semiconductive paint painted on the inner surface of the fraud, a shield inserted through the insulation packing at the lower end of the overlying fraud, and an upper portion of the transformer enclosure And a semiconductive packing coupled between the bracket and the insulator fixing the insulator, wherein the semiconductive paint is applied to the entire inner surface of the insulator, and to the outer surface near the connection to the enclosure where electric field concentration occurs. It improves partial discharge characteristics by relieving concentration of electric field by forming electrical frostbite with enclosure. The.

In order to achieve the object of the present invention, a highly reliable bushing instrument transformer is a bushing type oil insulation instrument transformer in which an instrument transformer composed of a primary coil, a secondary coil, and an iron core is incorporated. An insulating paper inserted between the primary coil and the secondary coil for interlayer insulation, and a shield formed to surround the primary coil to prevent partial discharge, wherein the shield has a mesh or plate structure, and both ends It is rolled up to reduce electric field concentration at the edges of both ends of the primary coil to which high voltage is applied.

Highly reliable bushing-type instrument transformer for achieving the object of the present invention, in a transformer for the oil-type instrument for bushings in which the transformer current transformer for power supply and supply instrument is built, a plurality of bushings, a plurality of instrument current transformers, 1 A plurality of instrument transformers including a secondary coil, a secondary coil and an iron core, and an insulating paper inserted therebetween for interlayer insulation, and a shield formed around the primary coil to prevent partial discharge from occurring; The plurality of instrument current transformers and transformers are built-in, the inner space is composed of an enclosure filled with insulating oil, the shield is a mesh or plate structure, both ends of the rounded edges of both ends of the primary coil applied with high voltage It is characterized by mitigating electric field concentration.

Highly reliable bushing instrument transformer according to the present invention, the semi-conductive paint is applied to the bushing portion in which the electric field concentration phenomenon of the bushing oil insulated instrument transformer occurs, the shield is attached to the winding part to reduce the concentration of the electric field In order to prevent partial discharge from occurring, it is possible to prevent breakdown and to prolong the service life. In addition, products can be developed that are far superior to those set by the IEC standard.

1 is a view schematically showing a transformer for a bushing type oil insulation instrument to which the present invention is applied;
2 is an internal cross-sectional view showing an embodiment of the FIG. 1 bushing;
3 is a view showing the electric field distribution in the bushing of FIG.
4 is an internal cross-sectional view showing another embodiment of the FIG. 1 bushing;
5 is an internal sectional view showing yet another embodiment of the FIG. 1 bushing;
6A-6B are a perspective view and a cross-sectional view showing an embodiment of the instrument transformer of FIG. 1;
7A-7B are perspective views of a sectional view and a shield, showing another embodiment of the instrument transformer of FIG. 1;
Figures 8a-8b is an illustration of the case of applying a highly reliable bushing-type instrument transformer in accordance with the present invention to a transformer transformer current transformer (MOF).

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically showing a transformer for a bushing oil insulation instrument to which the present invention is applied, in particular, when applied to an instrument transformer (PT).

As shown in FIG. 1, the instrument transformer 100 is formed to fix a plurality of tube-like porcelain bushings 20 on an upper portion of the enclosure 10 formed of an iron tank, thereby containing a high voltage to be introduced ( 10 is supplied to the transformer 30 disposed inside the. The interior of the enclosure 10 is filled with insulation oil (OT) to insulate between the conductive parts between phases.

Generally, the partial discharge may occur in the bushing part and the transformer winding part because the inside of the bushing 20 is air insulation, and the transformer 30 maintains insulation with an insulating oil filled in the interior of the enclosure 10, respectively.

Therefore, the present invention newly proposed the structure of the bushing 20 and the transformer 30 to prevent partial discharge generated in the bushing portion and the winding portion.

2 and 3 are views illustrating an internal sectional view and an electric field distribution according to an embodiment of the bushing 20 of FIG. 1.

Referring to FIG. 2, the bushing 20 configured on the upper part of the enclosure 10 of the transformer 100 for oil insulation gauge is a squeezer 21 having an empty inside in the axial direction, and at the inner diameter thereof, air is used to maintain insulation. It is filled with air. The outer and inner surfaces of the insulator 21 are coated with a semiconductive paint 22 formed by mixing a diluent in a proportion to a liquid semiconducting composition in order to alleviate concentration of an electric field. Here, the semiconductive paint is mixed with 50 to 80% of the liquid stock solution containing mainly graphite powder in a proportion of 20 to 50% of the diluent (MEK), and the diluent is methyl, ethyl, or ketone. Is done. Referring to the electric field distribution shown in FIG. 3, since an electric field concentration phenomenon occurs near the connection between the insulator 21 and the enclosure 10, the inner surface of the insulator 21 is coated with the semiconductive paint 22 as a whole. The outer surface is painted with a semiconductive paint 22 only near the connection with the enclosure 10 where the concentration of the electric field occurs. Here, the electric field distribution of FIG. 3 is an analysis of the electric field distribution when applying a withstand voltage of 50 mA.

The upper portion of the insulator 21 is coupled to the semi-conductive paint 22 to be in contact with the semi-conductive packing 23, the primary rod 24 is assembled to the primary rod 24 and the inner wall of the insulator 21 Make it electrically frostbite. Instead of applying the semiconductive paint 22 to the lower part of the insulator 21, a high pressure shield 27 is inserted into the lower end thereof, and an insert 28 is inserted into the end of the primary rod 24, respectively. ) Relieve corona discharge at the end. An insulating packing 29 is coupled between the lower end of the insulator 21 and the high pressure shield 27.

The insulator 21 having such a configuration is mounted on the enclosure 10 of the transformer 100 for oil insulation instruments, and then put a semi-conductive packing 26 between the insulator fixing bracket 25 and the insulator 21 and bolted. It is fixed through. In this way, the semiconductive paint 22 and the enclosure 10 painted on the outer surface of the insulator 21 are electrically in phase.

Thus, by painting the semi-conductive paint 22 on the inner and outer surfaces of the insulator 21, the electric field between the high and low pressure is made only inside the insulator 21, the upper and lower borders on the enclosure 10 By forming the insulator (21) wing shape close to the circular shape of the insulator 21 to mitigate the field concentration phenomenon at the end of the outer semiconducting paint (22).

4 is an internal cross-sectional view according to another embodiment of the bushing 20, which is composed of the same structure as the bushing 20 for improving the partial discharge characteristics shown in Figure 2, the outer surface of the lower end of the insulator 21 It is constructed by further inserting the shield 41 to be in contact with the semiconductive paint 22 painted on it.

Referring to FIG. 4, the semiconductivity near the electric field concentration of the outer surface of the insulator 21 of the bushing 20 formed on the upper part of the enclosure 10 of the instrument transformer 100 in which the insulating oil 40 is filled for insulation. Paint 22. As can be seen from the electric field distribution of FIG. 3, since an electric field concentration phenomenon occurs near the connection with the enclosure 10, the outer surface of the insulator 21 is only semiconductive paint 22 near the connection with the enclosure 10. Will be painted. The inside of the fraud 21 is painted with a semiconductive paint 22 as a whole so that an electric field between high and low pressure is made only within the fraud 21.

A shield 41 having a mesh or plate structure is inserted in contact with the semiconductive paint 22 painted on the outer surface of the lower part of the fryer 21. At this time, the shield 41 has a rounded end as shown in the enlarged view. The end of the rounded shield 41 is lowered than the end of the semiconductive paint 22 painted on the outside of the insulator 21, thereby alleviating electric field concentration at the end of the semiconductive paint 22 painted on the outside. Do it. Here, the semi-conductive paint 22 painted on the outer surface of the insulator 21 is rounded at the edge of the lower shield 41 because the upper edge of the insulator itself is rounded around the enclosure 10.

Meanwhile, the semiconductive packing 23 is placed on the insulator 21 so as to be in contact with the painted semiconductive paint 22, and then the primary rod 24 is assembled to assemble the primary rod 24 and the inner wall of the insulator 21. Let this electrically frostbite. Instead of painting the semiconductive paint 22 on the lower surface of the insulator 21, the high pressure shield 27 is inserted at the lower end thereof, and the insert 28 is inserted at the end of the primary rod 24, so that the end of the rod 24 is Alleviates corona discharge at An insulating packing 29 is coupled between the lower end of the insulator 21 and the high pressure shield 27.

The insulator 21 having such a configuration is mounted on the enclosure 10 of the transformer 100 for oil insulation instruments, and then put the anti-conductive packing 26 between the insulator fixing bracket 25 and the insulator 21 and bolted. It will be fixed through. In this way, the semiconductive paint 22 and the enclosure 10 painted on the outer surface of the insulator 21 are electrically in phase. After fixing the insulator 21 to the upper part of the enclosure 10, the insulating oil 40 is injected into the inside of the enclosure 10, where the semiconductive paint 22 and the shield 41 painted on the outer surface of the insulator 21 in the enclosure 10 are provided. Fill the insulating oil 40 so that the end of the) is completely immersed in the insulating oil 40 to relieve the electric field concentrated in the minute air layer between the shield 41 and the insulator 21 surface.

As such, by applying the semi-conductive paint 22 on the inner and outer surfaces of the insulator 21, the electric field between the high pressure and the low pressure is made only in the insulator 21, and the upper side of the insulator 10 is insulated from the insulator 21. (21) Forming the wing formation close to the circle and the lower end inserts the shield 41 to mitigate the field concentration phenomenon at the end of the semi-conductive paint 22 painted on the outer surface. Furthermore, when the insulating oil 40 is filled in the enclosure 10, the ends of the semiconductive paint 22 painted on the outer surface of the insulator 21 and the shield 41 inserted at the ends thereof are completely immersed in the insulating oil 40. (21) The electric field concentrated in the minute air layer between the surfaces is relaxed.

5 is an internal cross-sectional view according to another embodiment of the bushing 20 of FIG. 1, which is configured in the same structure as the bushing 20 structure for improving the partial discharge characteristics shown in FIG. It is further configured to completely wrap the end of the semiconductive paint 22 painted on the side and the end of the shield 41 inserted into the end thereof with the insulator 42 having a high dielectric constant.

Referring to FIG. 5, the semiconductivity near the electric field concentration of the outer surface of the insulator 21 of the bushing 20 formed in the upper part of the enclosure 10 of the instrument transformer 100 in which the insulating oil 40 is filled for insulation. Paint 22. As can be seen from the electric field distribution of FIG. 3, since an electric field concentration phenomenon occurs near the connection with the enclosure 10, the outer surface of the insulator 21 is only semiconductive paint 22 near the connection with the enclosure 10. Paint it. The inside of the fraud 21 is painted with a semiconductive paint 22 as a whole so that an electric field between high and low pressure is made only within the fraud 21.

A shield 41 having a mesh structure is inserted into contact with the semi-conductive paint 22 painted on the outer surface of the lower part of the fryer 21, wherein the shield 41 has a rounded end and a rounded shield 41. End of the lower end of the anti-conductive paint (22) painted on the outside of the insulator (21). In order to mitigate the electric field concentrated in the minute air layer between the shield 41 and the insulator 21 surface, the shield 41 inserted into and in contact with the semiconductive paint 22 painted on the lower outer surface of the insulator 21 as shown in FIG. Instead of allowing the end of) to be completely immersed in the insulating oil, in FIG. 5, the end is completely covered with an insulator 42 such as silicon having a high dielectric constant so that the end is completely wrapped to save the insulating oil.

Meanwhile, the semiconductive packing 23 is placed on the insulator 21 so as to be in contact with the painted semiconductive paint 22, and then the primary rod 24 is assembled to assemble the primary rod 24 and the inner wall of the insulator 21. Let this electrically frostbite. The high pressure shield 27 is inserted into the lower end of the insulator 21, and the insert 28 is inserted into the end of the primary rod 24, respectively, to mitigate corona discharge at the end of the rod 24. An insulating packing 29 is coupled between the lower end of the insulator 21 and the high pressure shield 27.

The insulator 21 having such a configuration is mounted on the enclosure 10 of the transformer 100 for oil insulation instruments, and then put the anti-conductive packing 26 between the insulator fixing bracket 25 and the insulator 21 and bolted. Secure through. In this way, the semiconductive paint 22 and the enclosure 10 painted on the outer surface of the insulator 21 are electrically in phase. After fixing the insulator 21 to the upper part of the enclosure 10, the insulating oil 40 is injected into the inside of the enclosure 10, where the semiconductive paint 22 and the shield 41 painted on the outer surface of the insulator 21 in the enclosure 10 are provided. ) Is completely covered with the insulator 42, so that the insulating oil 40 does not need to be filled so that the ends of the semi-conductive paint 22 and the ends of the shield 41 painted on the outer surface of the insulator 21 in the enclosure 10 are completely locked. do.

As such, by applying the semi-conductive paint 22 on the inner and outer surfaces of the insulator 21, the electric field between the high pressure and the low pressure is made only in the insulator 21, and the upper side of the insulator 10 is insulated from the insulator 21. (21) Forming the wing formation close to the circle and the lower end inserts the shield 41 to mitigate the field concentration phenomenon at the end of the semi-conductive paint 22 painted on the outer surface. Furthermore, the ends of the semiconductive paint 22 painted on the outer surface of the insulator 21 and the shield 41 inserted at the ends thereof are completely covered with the dielectric constant 42 having high dielectric constant so that the surfaces of the shield 41 and the insulator 21 are covered. The electric field concentrated in the minute air layer in between is relaxed.

By the above embodiments, it is possible to mitigate the electric field generated in the bushing portion of the oil insulating instrument transformer 100 and to significantly reduce the partial discharge. 6A to 7B illustrate an embodiment for improving the partial discharge characteristics in the winding part of the transformer 100 for oil insulation instruments.

6A and 6B are a perspective view and a cross-sectional view, according to one embodiment of the transformer 30 of FIG. 1.

6A and 6B, the transformer 30 mounted in the enclosure 10 of the transformer 100 for oil insulation instruments includes a primary coil 31, a secondary coil 33, and an iron core 35. do. The primary coil 31 is insulated between layers with diamond epoxy insulating paper or special insulating paper on a primary bobbin made of glass fiber reinforced plastic (FRP) or an insulator, and then uniformly wound, and then dried in a drying furnace for about 10 hours. Diamond epoxy insulating paper is a diamond pattern of epoxy coated on the film, the diamond pattern of epoxy melts to fix the winding. As shown in FIG. 6A, the primary coil 31 is wound in a multi-stage structure. When the impulse voltage waveform is applied to the transformer 30, a large potential difference appears near the end of the line. It is for. That is, the winding width decreases toward the outside during the winding of the primary coil 31 so that the potential distribution is constant. In the present embodiment, the primary coil 31 has two stages.

The primary coil 31 is attached with a shield 32 made of copper or aluminum to prevent partial discharge. The shield 32 is formed to cover the entire surface of the primary coil 31, which alleviates the concentration of the electric field when a high voltage is applied, thereby greatly reducing the occurrence of partial discharge. The shield 32 has a mesh structure or a plate structure and rolls up both ends roundly to alleviate the concentration of the electric field near the edges of both ends of the primary coil 31 to which high voltage is applied.

The secondary coil 33 is uniformly wound while insulating the interlayer with insulating paper on the secondary bobbin (upper core), and then dried in a drying furnace. The secondary coil 33 is installed to penetrate the primary coil 31 so that electric power is transmitted by the electromagnetic induction action (the action of generating electricity under the influence of magnetic field) in the primary coil 31 to which AC power is supplied. .

Here, the iron core 35 is formed to penetrate the secondary coil 33, in which case the iron core 35 is cut-core, so that the iron core 35 is assembled to the band 34 and installed on the support plate 36. The coil lead wire 37 is connected to the shield 32 wrapped around the primary coil 31 by welding, and the secondary lead wire is connected to a terminal block (not shown).

As such, the shield 32 is attached to the entire surface of the primary coil 31 of the transformer 30 to mitigate the concentration of the electric field on the primary coil 31 to which the high voltage is applied, thereby greatly reducing the occurrence of partial discharge. . Therefore, the effect of extending the life of the product is more generated.

7A and 7B are perspective views of a sectional view and a shield according to another embodiment of the transformer 1 of FIG. 1.

7A and 7B, the transformer 30 mounted in the enclosure 10 of the transformer 100 for oil insulation instruments includes a primary coil 71, a secondary coil 73, and an iron core 75. do. The primary coil 71 is insulated evenly by using diamond epoxy insulating paper (120 mm / 100 mm / 80 mm…) having different widths on the primary bobbin made of glass fiber reinforced plastic (FRP) or insulator. Winding. At this time, as the winding height is increased, the insulating paper having a smaller width is used. The wound primary coil 71 is dried in a drying furnace at about 80 to 120 ° C. for about 4 to 10 hours. As shown in FIG. 7A, the primary coil 71 is wound in multiple stages, that is, in the present embodiment, in a two-stage structure in order to make the potential distribution constant.

The primary coil 71 is attached with a shield 72 made of copper or aluminum as shown in FIG. 7B to prevent partial discharge. The shield 72 is formed to cover the entire surface of the primary coil 71, which alleviates the concentration of the electric field when high voltage is applied, thereby greatly reducing the occurrence of partial discharge. As shown in FIG. 7B, the shield 72 has a mesh or plate structure and rolls up both ends to alleviate concentration of electric fields at both ends of the primary coil 71 to which high voltage is applied.

The secondary coil 73 insulates the interlayer with insulating paper on the secondary bobbin (upper core) and winds it uniformly, and then removes moisture by drying in a drying furnace. The secondary coil 73 is installed to penetrate the primary coil 71.

The iron core 75 is formed to penetrate the secondary coil 73. At this time, the iron core 75 is formed by using the channel 74 as the hematite core and the primary and secondary coils 71 and 73. After the combination is fixed using the channel (74). The shield 76 is inserted into the lower end of the iron core 75 to block discharge to the sharp surfaces of the iron core 75 and the channel 74.

In the above embodiment has been described by applying to the instrument transformer (PT), it can be equally applied to the transformer transformer current transformer (MOF). This is illustrated in Figures 8a and 8b.

8A and 8B show a case of applying a highly reliable bushing instrument transformer according to the present invention to a transformer transformer current transformer (MOF) for power supply and supply, which shows internal structures in front and side surfaces, respectively.

8A and 8B, the upper part of the transformer current transformer for the power supply instrument consists of three insulator bushings (20A, 20B, 20C) and one ground bushing (20D), the lower part of the enclosure 10 made of steel tanks The current transformer winding body 50 and the transformer winding body 30 of the same number as the number of insulator bushings formed in the upper portion are arranged. In particular, the transformer winding 30 is provided with a transformer having a structure as described in Figures 6a to 7b for improving the partial discharge characteristics.

That is, the transformer winding 30 is composed of a primary coil 81 to apply a high voltage, a secondary coil 83 to induce a low voltage, and an iron core 85, the iron core 85 is cut core as shown in Figure 6a Equation or hematite like FIG. 7A may be used. In addition, the primary coil 81 is surrounded by a shield 82 as shown in FIG. 7B to mitigate an electric field and to reduce durability of partial discharge generated in the transformer current transformer, thereby improving durability. In this embodiment, in order to reduce the volume, as shown in Fig. 8A, three transformer windings are fixed using one channel 84.

By the above embodiments, it is possible to mitigate the electric field generated in the winding portion of the transformer 100 for oil insulation instrument and to significantly reduce the partial discharge.

As described above, the results of the performance test measurement of the high reliability bushing type transformer according to the embodiment of the present invention are shown in the following chart.

Test Methods Test voltage Allowable partial discharge Test result The partial discharge test is carried out after the withstand voltage test. The applied voltage rises to 80% (40 mA) of the induced withstand voltage held for 60 seconds or less. Then, the specified partial discharge test voltage is reduced without interruption.
The measured partial discharges shall not exceed the limits specified in the test voltage.
(Um = 25.8㎸)
1.2 × Um
10pC
2pC

5pC
1pC * Test frequency: 400㎐
* Background noise: 1pC
Atmospheric conditions: 23 ℃, 38%

Looking at the above diagram, a partial discharge test (partial discharge test) was performed to measure the performance of the high reliability bushing type transformer according to the embodiment of the present invention. Here, the partial discharge amount is represented by pC (pico coulomb) which is a unit of charge amount.

)에서 5pC 이하여야 하는데 시험결과 1pC의 값을 나타내었다. 주변잡음이 1pC인 경우를 고려하면 30.96㎸와 17.8㎸에서 모두 거의 부분방전이 발생되지 않음을 알 수 있다.As indicated by the above performance test measurement value, the partial discharge amount should be 10pC or less at the test voltage (1.2 × Um) of 30.96㎸, and the test result was 2pC, and the test voltage was 17.8㎸ (1.2 × Um /

) Should be less than 5pC, and the test result shows 1pC. Considering the case where the ambient noise is 1pC, almost no partial discharge occurs at 30.96㎸ and 17.8㎸.

As such, the highly reliable bushing-type instrument transformer according to the embodiment of the present invention hardly generates partial discharge, and is much superior to the IEC standard.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below but also by the equivalents of the claims.

100: instrument transformer 10: enclosure
20: bushing 30: instrument transformer
40: insulating oil 50: current transformer for instrument
21: Scammer 22: Semiconductive Paint
23,26: Semi-conductor packing 24: 1st rod
25: insulator bracket 27,32,41,72,76: shield
28: insert 29: insulation packing
42: insulator

Claims (10)

In the transformer for the bushing type oil insulation instrument,
Semiconductive paint painted on the outer and inner surfaces of the insulator so that the electric field is made only within the fraud of the bushing;
A semiconductive packing coupled to abut the semiconductive paint painted on the inner surface of the fraud insulator;
A shield inserted through the insulation packing at the lower end of the fraud insulator; And
A semiconductive packing coupled between the bracket and the insulator fixing the insulator on the transformer enclosure,
The semi-conductive paint is painted on the entire inner surface of the insulator, and the outer surface is painted near the connection with the enclosure where the electric field concentration phenomenon occurs, so as to form an electrical phase with the enclosure to reduce the concentration of the electric field to improve the partial discharge characteristics. High reliability bushing instrument transformer characterized in that the. The method of claim 1, wherein the semi-conductive paint is formed of a mixture of 50 to 80% of the liquid liquid containing graphite powder as a main raw material, 20 to 50% of a diluent (MEK) consisting of methyl, ethyl, and ketones. Bushing instrument transformers. 2. The semiconductive paint tip painted on the outer surface of at least one of at least one of the upper and lower borders of the enclosure top along the rounded shape of the insulator blades to concentrate the electric field at the semiconductive paint tip. Highly reliable bushing instrument transformer characterized by easing. 4. A rounding treatment as set forth in claim 3, wherein the ends are rounded in contact with the semiconductive paint painted on the outer surface of the insulator to mitigate field concentration at the ends of the semiconductive paint painted on the outer surface of the insulator on the lower side of the enclosure top plate. Insert the shield,
Highly reliable bushing instrument transformer characterized in that the semi-conductive paint end and the shield end are completely immersed in the insulating oil filled in the enclosure for the relaxation of the electric field concentrated in the fine air layer between the shield and the insulator surface. . 5. The highly reliable bushing instrument transformer according to claim 4, further comprising an insulator completely covering the tip of the semiconductive paint painted on the outer surface of the insulator and the end of the shield inserted to contact the insulator. In the transformer for the bushing type oil insulation instrument in which an instrument transformer composed of a primary coil, a secondary coil and an iron core is embedded,
Insulating paper for interlayer insulation between the primary coil and the secondary coil of the instrument transformer; And
It is formed to surround the primary coil includes a shield to prevent partial discharge,
The shield is a mesh or plate structure, both ends of the round rolled up high-voltage, high reliability Bushing type instrument transformer characterized in that to reduce the electric field concentration at both ends of the primary coil. In the transformer for the oil-type instrument for bushing type with a transformer current transformer for power supply and supply instrument,
A plurality of bushings;
A plurality of instrument current transformers;
A plurality of instrument transformers comprising a primary coil, a secondary coil, and an iron core, including an insulating paper inserted between the layers for insulation between the primary coils, and a shield formed around the primary coils to prevent partial discharge; And
The plurality of instrument current transformers and transformers are built, the inner space is composed of an enclosure filled with insulating oil,
The shield is a mesh or plate structure, the both ends of the round rolled high-reliability bushing type instrument transformer, characterized in that to reduce the electric field concentration of the edges of both ends of the primary coil is applied with a high voltage. The method of claim 6 or 7, wherein the primary coil is wound in multiple stages on a bobbin made of glass fiber reinforced plastic (FPR) or insulator, and the electric potential distribution is constant by reducing the winding width toward the outside. Highly reliable bushing instrument transformers. 8. The highly reliable bushing instrument transformer according to claim 6 or 7, wherein the iron core is a cut-core. 8. The highly reliable bushing instrument transformer according to claim 6 or 7, wherein the iron core is a hematite core.

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