CN2919481Y - 765kV electromagnetic standard voltage mutual inductor with single stage structure - Google Patents

Abstract

The utility model relates to a power frequency voltage ratio standard. It is a single-stage structure 765kV electromagnetic standard voltage transformer for laboratories. There is a transformer body in the tank, in which the secondary winding of the transformer adopts a wiring method of varying density, and the primary winding is wound in a tower-shaped structure, and the width gradually shrinks from the innermost layer to the outermost layer, and there are some Glue mylar insulation. The measurement uncertainty of the utility model is better than 3×10 ^-5 , the accuracy level of the secondary winding in the range of 0VA to 1VA can meet the requirement of 0.01 level, and the influence of electromagnetic field interference and ambient temperature change on the error curve is less than 1×10 ^-6 . Has a very high ability to resist electromagnetic field interference. The utility model can be used for the value transmission and value traceability of the power frequency voltage ratio standard, and can also be used as a standard voltage transformer for the factory routine test of the 765kV power voltage transformer and the field test of the substation; it can also be used for the 765kV power frequency voltage division It can be used for detection and calibration of other equipment and devices such as detectors and lightning arresters.

Description

Single-stage structure 765kV electromagnetic standard voltage transformer

technical field

The utility model belongs to high-voltage metering and testing equipment, and relates to a power frequency voltage ratio standard, in particular to a single-stage structure 765kV electromagnetic standard voltage transformer for measuring 750kV voltage level, which is a proportional conversion of power frequency voltage Large and small measuring instruments can be used for value transmission and value traceability of power frequency voltage ratio.

Background technique

With the increase of the voltage level of the power grid, the power frequency voltage ratio standard of higher voltage level related to electricity trade settlement, electric power science and technology research, power equipment manufacturing and testing and other related fields will increase accordingly, and it is necessary to carry out corresponding higher voltage level work. Frequency and voltage value transmission and value traceability. In the 1980s, my country's 500kV power grid began to accelerate construction, and the research work on the 500kV power frequency voltage ratio standard was also carried out simultaneously. After more than 20 years of unremitting efforts by the majority of scientific and technical personnel, in 2002, the National High Voltage Metering Station and Taikai Electric Group Co., Ltd. jointly developed China's first 500kV electromagnetic standard voltage transformer, which has good stability and is easy to use. Reliable, less affected by temperature, measurement uncertainty is less than 2×10 ^-5 , has reached the international advanced level, and solved the power frequency voltage proportional value transmission and value in the field of 500kV AC ultra-high voltage lines in China and related fields of electric power science Problems related to traceability. In 2005, the first 750kV AC ultra-high voltage test line was built in Northwest my country. During the Eleventh Five-Year Plan period, a new 750kV ultra-high voltage line will be added every year. The accuracy of voltage transformers used in 750kV lines is related to the accuracy of energy trade settlement Reliability of loss assessment; the reliability and accuracy of a large amount of scientific research data in the field of electric power science related to 750kV voltage level is also related to the accurate measurement of power frequency voltage. The power frequency voltage proportional value transmission and value traceability of 750kV lines need to be solved urgently. The development of its core equipment - 765kV standard voltage transformer is the material basis for carrying out the power frequency voltage proportional value transmission and value traceability of 750kV lines. However, my country has not yet established a power frequency voltage ratio standard of 750kV voltage level, which cannot meet the needs of power frequency voltage ratio standard value transmission and value traceability for 750kV lines in Northwest China.

Contents of the invention

The purpose of this utility model is to make material preparations for the establishment of the 765kV power frequency voltage ratio standard in my country, so as to carry out the value transmission and value traceability work of the 750kV power grid, lay the foundation for the electric energy measurement and line loss precision measurement of the 750kV power grid in my country, and provide a A single-stage structure 765kV electromagnetic standard voltage transformer for laboratory use.

The technical scheme of the utility model is that a single-stage structure 765kV electromagnetic standard voltage transformer adopts a sulfur hexafluoride gas insulation structure, and is composed of an outer pressure equalizing ring 1, a high-voltage bushing 16, and a metal tank body 18. The metal tank There is a transformer body 10 in the body 18 and is fixed on the bottom plate in the metal tank body 18. The upper end of the high-voltage bushing 16 has a primary terminal board 2, and the outer pressure equalizing ring 1 is fixed on the primary terminal board 2. The high-voltage bushing 16 The upper part of the high-voltage bushing 16 is sealed and connected with the primary terminal board 2 through the O-ring 3, and the lower part of the high-voltage bushing 16 is sealed and fixed on the metal tank 18 through the flange 8 and the O-ring 3, and the metal tank 18 is equipped with a lifting ring for hoisting. 17 is also equipped with a sulfur hexafluoride gas pressure vacuum gauge 19, which is characterized in that: the diameter range of the outer pressure equalizing ring 1 is 160-260mm, the diameter range is 1400-1800mm, the height of the high-voltage casing 16 is 4800±5mm, The inner diameter is 600±5mm, the metal tank body 18 is a pressure vessel, and its thickness range is 6-8mm; the transformer body 10 is composed of a clamp bracket 11, a primary winding 20, a secondary winding 21, an iron core 12 and a high-voltage shielding cover 14, The primary winding 20 is wound outside the secondary winding 21 and co-wound on the iron core 12, and the high-voltage shield 14 is covered outside the primary winding 20; The width gradually shrinks from the innermost layer to the outermost layer, and the polyester film insulating layer 22 is glued between the layers. There is an electrostatic shielding layer 23 made of thin copper plate between the primary winding 20 and the secondary winding 21. After debugging, fix the relative positions of the primary and secondary windings 20, 21 and the iron core 12 with epoxy glue; the high-voltage terminals of the primary winding 20 are softly connected with the high-voltage lead wires of the high-voltage bushing 16, and the lead wires of the secondary winding 21 pass through the metal tank 18 is introduced into the secondary junction box 13, and there are terminals for user wiring in the secondary junction box 13.

From the single-stage structure 765kV electromagnetic standard voltage transformer mentioned above, the high-voltage bushing 16 is composed of a shielding tube 4, a basin insulator 5, an intermediate shielding cylinder 6, a ground electrode shielding cylinder 7 and a silicone rubber composite insulating sleeve 15 , there is a primary high-voltage lead in the shielding tube 4, and the basin insulator 5 is connected to the intermediate shielding tube 6 and the shielding tube 7. The shielding tube 4, the intermediate shielding tube 5 and the grounding electrode shielding tube 7 form a three-layer coaxial shielding tube, and their lengths are respectively 4800±5mm, 1900±5mm, 750±5mm, the diameters are 90±5mm, 320±5mm, 540±5mm respectively.

From the above-mentioned single-stage structure 765kV electromagnetic standard voltage transformer, the high-voltage terminal of the primary winding 20 is softly connected to the high-voltage lead wire of the high-voltage bushing 16 by using the high-voltage connection spring 9 to connect.

The iron core 12 of the utility model is to select the high-quality silicon steel sheet with high magnetic density saturation point and small unit iron loss, and the iron core silicon steel sheet adopts the oblique cut seam connection mode of about 45°.

The utility model is a single-stage structure 765kV electromagnetic standard voltage transformer for laboratories, with high insulation level, and the short-time power frequency withstand voltage of 1 minute reaches 1.7 times of the rated voltage of the 765kV standard voltage transformer, 20% to 120% of the rated voltage Good linearity, the measurement uncertainty is better than 3×10 ^-5 , the upper limit measurement range can reach 150% of the rated voltage, and can meet the measurement of the winding error of the protection level of the power voltage transformer with a transformation ratio of 765/√3kV/100/√3V; the error The long-term stability of the curve is good; the accuracy level of the secondary winding in the range of 0VA to 1VA can meet the requirements of a 0.01-level standard voltage transformer; when used in a 750kV substation, the influence of electromagnetic field interference and ambient temperature changes on the error curve is less than 1×10 ^{- 6.} It has a very high ability to resist electromagnetic field interference.

Description of drawings

Fig. 1 structural diagram of the utility model

Fig. 2 Schematic diagram of winding and iron core structure of transformer body 4 of the utility model

Fig. 3 schematic diagram of circuit of the utility model

1 Outer equalizing ring, 2 Primary wiring board, 3O-type sealing ring, 4 Shielding tube, 5 Basin insulator, 6 Intermediate shielding cylinder, 7 Grounding electrode shielding cylinder, 8 Flange, 9 High voltage connection spring, 10 Transformer body, 11 clip bracket, 12 iron core, 13 secondary junction box, 14 high voltage shielding cover, 15 silicone rubber composite insulating bushing, 16 high voltage bushing, 17 lifting ring, 18 metal tank body, 19 gas pressure vacuum gauge, 20 Primary winding, 21 secondary winding, 22 glued polyester film insulation layer, 23 electrostatic shielding layer

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Fig. 1 is a structural diagram of the utility model, a single-stage structure 765kV electromagnetic standard voltage transformer, which adopts a sulfur hexafluoride gas insulation structure to improve the insulation level, and consists of an outer pressure equalizing ring 1, a high-voltage bushing 16, and a metal tank body 18, the metal tank body 18 has a transformer body 10 and is firmly installed on the bottom plate in the metal tank body 18, so that the primary winding, secondary winding and iron core of the standard voltage transformer are in the process of transportation and moving. The relative position between them remains unchanged to ensure that its characteristic parameters remain unchanged, and the error characteristics can remain unchanged for a long time; the upper end of the high-voltage bushing 16 has a terminal board 2, and the outer equalizing ring 1 is used to increase the corona voltage and has a voltage equalizing effect. It is fixed on the primary terminal board 2, the upper part of the high-voltage bushing 16 is sealed and connected with the primary terminal board 2 through the O-ring 3, and the lower part of the high-voltage bushing 16 is sealed and fixed on the metal tank body through the flange 8 and the O-ring 3 18, the metal tank body 18 is equipped with a hoisting ring 17 and a sulfur hexafluoride gas pressure vacuum gauge 19, the outer equalizing ring 1 has a pipe diameter of 260mm and a diameter of 1800mm; the height of the high-voltage bushing 16 is 4800mm , the inner diameter is 600mm, the metal tank body 18 is a pressure vessel with a thickness of 8mm, and the interior is filled with an insulating medium with excellent insulation performance - SF ₆ gas. In the tank, to ensure that the influence of external electromagnetic field penetration is less than one-twentieth of the error limit of the 0.01-level standard voltage transformer.

Transformer body 10 is made up of clip bracket 11, primary winding 20, secondary winding 21, iron core 12 and high-voltage shielding cover 14. Fig. 2 is a schematic view of the winding and iron core structure of transformer body 10 of the present invention. Fig. 3 is The circuit principle diagram of the utility model, in Fig. 2 and Fig. 3, the primary winding 20 is wound outside the secondary winding 21 and co-wound on the iron core 12, and the outer side of the primary winding 20 is equipped with a voltage equalizing high-voltage shielding cover 14, and the design of the shielding curvature The structure is determined according to the electric field calculation, and at the same time, it is formed by spinning processing to ensure that the surface roughness meets the requirements and improve the work function of the electrode shielding surface; the utility model adopts changing the relative position of the primary winding and the secondary winding, and the secondary winding 21 adopts sparse The wiring method of varying density is mainly to change the width and narrow layout of the secondary winding and the sparseness of the wiring of the secondary winding, and make full use of the capacitive current compensation effect of the stray capacitance between the layers of the primary winding to achieve the effect of adjusting the phase angle of the standard voltage transformer ; Adjust the ratio of the standard voltage transformer by adjusting the number of turns of the primary winding. The primary high-voltage winding 20 is wound in a tower-shaped structure to evenly distribute the voltage between the coil and its surroundings. The width gradually shrinks from the innermost layer to the outermost layer. ) to improve the use efficiency of interlayer insulation materials, the use of interlayer insulation and the tower-shaped distribution of the primary winding can reduce the height of the primary winding, effectively use the space, and minimize the material used for the core material, thereby reducing the overall size of the standard voltage transformer Active power loss, reducing the leakage reactance between the primary winding and the secondary winding, can reduce the compensation amount of the phase angle difference of the standard voltage transformer, and improve the linearity and load capacity of the error curve; the use of dispensing polyester film as the interlayer insulation of the primary winding, After high-temperature treatment and curing, the stability of the error characteristics of the standard voltage transformer is ensured; between the primary winding 20 and the secondary winding 21, there is an electrostatic shielding layer 23 rolled with a thin copper plate but not short-circuited, which is used to prevent the gap between the two windings. Mutual coupling is generated by distributed capacitance to improve the linearity of the error curve of the utility model; after the error debugging is completed, the relative positions of the primary and secondary windings 20, 21 and the iron core 12 are fixed with epoxy glue.

The high-voltage bushing 16 is composed of a shielding tube 4, a pot insulator 5, an intermediate shielding cylinder 6, a grounding electrode shielding cylinder 7 and a silicone rubber composite insulating sleeve 15. The silicone rubber composite insulating sleeve 15 plays the role of external insulation and support. The rubber sleeve 15 is supported by a high-strength fiberglass cylinder inside, and the outside is integrally injection-molded with a silicone rubber umbrella group, which has excellent anti-pollution flashover performance, water-repellent performance and excellent electrical corrosion resistance. The high-voltage lead wire is in the pure SF ₆ gas-insulated structure shielding tube 4, and the basin-type insulator 5 is connected to the intermediate shielding tube 6 and the shielding tube 4. A three-layer coaxial shielding tube is used. The selection principle of the edge flange curvature is to ensure that the surface field strength is uniform everywhere, and the electric field distribution inside and outside the bushing should also be balanced. Here we choose the shielding tube 4, the middle shielding cylinder 6 and the grounding electrode shielding cylinder 7 Three layers of coaxial shielding tubes are formed and the lengths are 4800mm, 1900mm, 750mm respectively, and the diameters are 90mm, 320mm, 540mm respectively.

In Fig. 1, the high-voltage terminal of the primary winding 20 and the high-voltage lead wire of the high-voltage bushing 16 are softly connected by a high-voltage connection spring 9, and the lead wire of the secondary winding 21 is introduced into the secondary junction box 13 through the metal tank body 18, and the secondary wiring There are terminals for user wiring in the box 13 . The iron core 12 of the utility model is made of a high-quality silicon steel sheet with a high magnetic density saturation point, that is, a high inflection point of the hysteresis curve, and a small unit iron loss. In the selection of the magnetic density of the iron core, the 765kV standard voltage transformer is selected in the range of 20% to 120% of the rated voltage. The linearity of the error within the requirements, make full use of the linear segment of the hysteresis curve; the silicon steel sheet of the core adopts the oblique cut seam connection method of about 45°.

The utility model can be used for the value transmission and value traceability of the power frequency voltage ratio standard, and can also be used as a standard voltage transformer for the factory routine test of the 765kV power voltage transformer and the field test of the substation; it can also be used for the 765kV power frequency It is used for testing and calibration of other equipment and devices such as voltage divider and lightning arrester.

Claims (4)

1, a kind of single step arrangement 765kV electromagnetic type standard potential transformer, adopt the sulfur hexafluoride gas-insulating structure, by outer grading ring (1), bushing (16), metal can (18) is formed, instrument transformer device body (10) is arranged in the metal can (18) and be fixed on the base plate in the metal can (18), bushing (16) upper end is terminal block (2) once, outer grading ring (1) is fixed on the primary connection plate (2), the top of bushing (16) is tightly connected by O RunddichtringO (3) and primary connection plate (2), bushing (16) bottom by flange (8) and O RunddichtringO (3) sealing and fixing on metal can (18), metal can (18) is outer to be equipped with lifting with hoisting ring (17) and be provided with sulfur hexafluoride gas pressure vacuum meter (19), it is characterized in that: the caliber scope of outer grading ring (1) is 160～260mm, diameter range is 1400～1800mm, the height of bushing (16) is 4800 ± 5mm, internal diameter is 600 ± 5mm, and metal can (18) is 6～8mm for its thickness range of pressure vessel; Instrument transformer device body (10) is made up of folder support (11), a winding (20), secondary winding (21), (12) unshakable in one's determination and high-tension shielding cover (14), outside secondary winding (21) and altogether on (12) unshakable in one's determination, high-tension shielding cover (14) covers on outside the winding (20) winding (20); The wire laying mode that secondary winding (21) adopts density not wait, a winding (20) is the pyramidal structure coiling, shrink gradually to the outermost layer width from innermost layer, and interlayer has a glue polyester film insulating barrier (22), the electrostatic screen layer (23) that useful sheet copper rolls between a winding (20) and the secondary winding (21) is debugged first and second winding (20,21) and (12) unshakable in one's determination are fixed in the back that finishes with epoxide-resin glue relative position in error; The high-voltage connection of winding (20) HV Terminal and bushing (16) is flexible coupling, and secondary winding (21) lead-out wire has the terminal for terminal block in the secondary connection box (13) in metal can (18) is introduced secondary connection box (13).

2, single step arrangement 765kV electromagnetic type standard potential transformer as claimed in claim 1, it is characterized in that: bushing (16) is by shielded-plate tube (4), disc insulator (5), intershield tube (6), grounding electrode shielding tube (7) and silicon rubber compound insulating sleeve (15) are formed, high-voltage connection once in the shielded-plate tube (4), disc insulator (5) connects intershield tube (6) and shielded-plate tube (4), shielded-plate tube (4), three layers of coaxial shielding tube formed by intershield tube (6) and grounding electrode shielding tube (7) and its length is respectively 4800 ± 5mm, 1900 ± 5mm, 750 ± 5mm, its diameter is respectively 90 ± 5mm, 320 ± 5mm, 540 ± 5mm.

3, single step arrangement 765kV electromagnetic type standard potential transformer as claimed in claim 2 is characterized in that: the high-voltage connection of winding (20) HV Terminal and bushing (16) is flexible coupling, and is to adopt high pressure line spring (9) to connect.

4, as claim 1 or 2 or 3 described single step arrangement 765kV electromagnetic type standard potential transformers, it is characterized in that: unshakable in one's determination (12) are to select the close saturation point height of magnetic, high-quality silicon steel sheet that iron-loss per unit weight is little for use, and the electrical steel sheet adopts about 45 ° the seam connected mode of cutting sth. askew.

Images