A two-stage multi-ratio standard voltage transformer

Abstract

The application provides a double-stage multi-variable ratio standard voltage transformer in the field of voltage transformer, which comprises an insulating sleeve, an outer shell, an iron core group, a first shielding cover, a second shielding cover, a wire group, a wiring board, a conductive rod, two shielding plates and a junction box; the wire group is wound on the iron core group; the iron core group is arranged in the first shielding cover; the two shielding plates are arranged at two ends of the iron core group respectively; the iron core group, the wire group, the first shielding cover and the shielding plates are arranged in the outer shell; the insulating sleeve is arranged at the upper end of the outer shell and communicates with the outer shell, and the second shielding cover is arranged in the insulating sleeve; the wiring board is connected with the insulating sleeve; the conductive rod is arranged in the second shielding cover and connected with the wiring board and the wire group respectively; and the junction box is arranged outside the outer shell and connected with the wire group. The application has the advantages that the effective voltage range of the voltage transformer measurement is improved, that is, the effective voltage range is increased from the general 20%U n -120%U n to 1%U n -120%U n .

Description

TECHNICAL FIELD

[0001] The present application relates to the field of voltage transformers, in particular to a double-stage multi-ratio standard voltage transformer. BACKGROUND

[0002] Voltage transformers and transformers are similar, both are used to transform the voltage on the line. But the purpose of transformer to transform voltage is to deliver electric energy, and the purpose of voltage transformer to transform voltage is to measure the voltage of the line.

[0003] According to the verification regulation of the voltage transformer for measurement, when considering the error of the voltage transformer, the error of the transformer used on the line is only calibrated at 80%~120% of the rated voltage, and the error of the standard transformer used in the laboratory needs to be calibrated at 20%~120% of the rated voltage, therefore, when calibrating the transformer, the corresponding standard voltage transformer needs to be selected according to the voltage grade of the transformer to be calibrated. For example, the calibration of the transformer with rated voltage grade of 500kV, 330kV, 220kV, 110kV, 66kV, 35kV, 10kV, etc. requires the standard voltage transformer with corresponding rated voltage grade, and it is impossible to achieve it by one standard voltage transformer. Therefore, how to provide a wide-ratio standard voltage transformer with high accuracy grade has become a problem to be solved. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a double-stage multi-ratio standard voltage transformer, to realize the improvement of the accuracy of the voltage transformer measurement, and to have a wide ratio, and the effective voltage is increased from the general 20%U n -120%U n to 1%U n -120%U n .

[0005] The present application is realized as follows: a double-stage multi-ratio standard voltage transformer, comprising an insulating sleeve, an outer shell, a core group, a first shielding cover, a second shielding cover, a wire group, a terminal block, a conductive rod, two shielding plates and a terminal box; the wire group is wound on the core group; the core group is arranged in the first shielding cover; the two shielding plates are arranged at the two ends of the core group respectively; the core group, the wire group, the first shielding cover and the shielding plates are arranged inside the outer shell; the insulating sleeve is arranged at the upper end of the outer shell and communicates with the outer shell, and the second shielding cover is arranged in the insulating sleeve; the lower end of the terminal block is connected with the insulating sleeve; the conductive rod is arranged in the second shielding cover, one end of the conductive rod is connected with the terminal block, and the other end is connected with the wire group; the terminal box is arranged outside the outer shell and is connected with the wire group.

[0006] Further, the iron core group comprises an excitation iron core and a proportional iron core; the wire group comprises an excitation winding, a primary proportional winding and a secondary proportional winding; the excitation winding is wound on the excitation iron core; the primary proportional winding is wound on the excitation iron core and the proportional iron core; the secondary proportional winding is wound on the excitation iron core and the proportional iron core and is connected with the terminal box.

[0007] Further, the excitation iron core is a ring-shaped permalloy iron core and the proportional iron core is a ring-shaped silicon steel sheet iron core.

[0008] Further, the first shielding cover comprises an SF6 density controller and an SF6-filled Mylar film; the Mylar film is provided with an opening; and the SF6 density controller is arranged outside the outer shell.

[0009] Further, the outer shell comprises two cover plates and a cylindrical shell; the two cover plates are connected with the two ends of the cylindrical shell through flanges; the lower ends of the two cover plates are each provided with two universal wheels; and the outer part of the cylindrical shell is provided with a grounding terminal.

[0010] Further, the outer shell comprises two cover plates and a cylindrical shell; the two cover plates are connected with the two ends of the cylindrical shell through flanges; the lower ends of the two cover plates are each provided with two universal wheels; and the outer part of the cylindrical shell is provided with a grounding terminal.

[0011] The present application has the following advantages:

[0012] 1. The insulation sleeve, the first shielding cover, the second shielding cover, the shielding plate and the grounding terminal are arranged to shield the high-voltage power supply, effectively prevent the tester from being electrocuted during testing, and greatly improve the safety of the voltage transformer.

[0013] 2. The SF6-filled Mylar film greatly improves the insulation level because SF6 is a new generation of super-high voltage insulating medium material; and the SF6 density controller is arranged to monitor the pressure of SF6, indirectly monitor the insulation of the voltage transformer, and avoid the tester from using the voltage transformer when the SF6 pressure is too low.

[0014] 3. The two universal wheels arranged at the lower ends of the two cover plates facilitate the movement of the voltage transformer and further improve the work efficiency of the tester.

[0015] 4. The excitation iron core is arranged as a permalloy iron core and the proportional iron core is arranged as a silicon steel sheet iron core, which balances the magnetic permeance performance and cost of the iron core. BRIEF DESCRIPTION OF DRAWINGS

[0016] The present application will be further described below with reference to the embodiments and the accompanying drawings.

[0017] Fig. 1 is a longitudinal sectional view of a two-stage multi-ratio standard voltage transformer of the present application.

[0018] Fig. 2 is a transverse sectional view of a two-stage multi-ratio standard voltage transformer of the present application.

[0019] Fig. 3 is a front view of a two-stage multi-ratio standard voltage transformer of the present application.

[0020] Fig. 4 is a side view of a two-stage multi-ratio standard voltage transformer of the present application.

[0021] Legend:

[0022] 100 - a two-stage multi-ratio standard voltage transformer, 1 - a voltage equalizing ring, 2 - an insulating sleeve, 3 - an outer shell, 4 - a core set, 5 - a first shielding cover, 6 - a second shielding cover, 7 - a wire set, 8 - a terminal board, 9 - a conducting rod, 10 - a shielding board, 11 - a terminal box, 31 - a cover plate, 32 - a cylindrical shell, 311 - a universal wheel, 321 - a grounding terminal, 41 - an excitation core, 42 - a proportional core, 51 - an SF6 density controller, 52 - a diamond-shaped adhesive polyester film, 71 - an excitation winding, 72 - a primary proportional winding, 73 - a secondary proportional winding. DETAILED DESCRIPTION

[0023] Please refer to Figs. 1 to 4 the preferred embodiment of a two-stage multi-ratio standard voltage transformer 100 of the present application, which comprises a voltage equalizing ring 1, an insulating sleeve 2, an outer shell 3, a core set 4, a first shielding cover 5, a second shielding cover 6, a wire set 7, a terminal board 8, a conducting rod 9, two shielding boards 10, and a terminal box 11; the wire set 7 is wound around the core set 4; the core set 4 is arranged in the first shielding cover 5; the two shielding boards 10 are respectively arranged at the two ends of the core set 4; the core set 4, the wire set 7, the first shielding cover 5, and the shielding boards 10 are all arranged inside the outer shell 3; the insulating sleeve 2 is arranged at the upper end of the outer shell 3 and communicates with the outer shell 3, and the second shielding cover 6 is arranged in the insulating sleeve 2; the lower end of the terminal board 8 is connected with the insulating sleeve 2, and the upper end is connected with the voltage equalizing ring 1; the conducting rod 9 is arranged in the second shielding cover 6, one end of the conducting rod 9 is connected with the terminal board 8, and the other end is connected with the wire set 7; the terminal box 11 is arranged outside the outer shell 3 and is connected with the wire set 7. The voltage equalizing ring 1 can uniformly distribute high voltage around the object, ensure that there is no potential difference between each part of the ring, and thus achieve the effect of voltage equalization, which is used for preventing side lightning strikes; the insulating sleeve 2 is used for protecting the conducting rod 9; the terminal box 11 has terminals for users to connect wires, which is used for selecting the range as needed.

[0024] The iron core group 4 comprises an excitation iron core 41 and a proportional iron core 42; the wire group 7 comprises an excitation winding 71, a primary proportional winding 72 and a secondary proportional winding 73; the excitation winding 71 is wound on the excitation iron core 41; the primary proportional winding 72 is wound on the excitation iron core 41 and the proportional iron core 42; the secondary proportional winding 73 is wound on the excitation iron core 41 and the proportional iron core 42 and is connected with the terminal box 11. The excitation winding 71 and the primary proportional winding 72 are high-voltage input ends, and the secondary proportional winding 73 is a low-voltage output end.

[0025] The excitation iron core 41 is a ring-shaped permalloy iron core, and the proportional iron core 42 is a ring-shaped silicon steel sheet iron core. The permeance performance of permalloy is superior to that of silicon steel sheet, but the cost of permalloy is also higher than that of silicon steel sheet. By setting the excitation iron core 41 as a permalloy iron core and the proportional iron core 42 as a silicon steel sheet iron core, the permeance performance and cost of the iron core are balanced.

[0026] The first shielding cover 5 comprises an SF6 density controller 51 and an SF6-filled diamond-coated polyester film 52; the diamond-coated polyester film 52 is provided with an opening (not shown); the SF6 density controller 51 is arranged outside the outer shell 3 and communicates with the diamond-coated polyester film 52 through the opening. By arranging the SF6-filled diamond-coated polyester film 52, since SF6 is a new generation of ultra-high voltage insulating medium material, the insulation level is greatly improved; by arranging the SF6 density controller 51 to monitor the pressure of SF6, the insulation of the voltage transformer 100 is indirectly monitored, so as to avoid the safety hazard caused by the use of the voltage transformer 100 by the tester without knowing that the pressure of SF6 is too low. The SF6 density controller 51 is used to monitor the SF6 gas density in the diamond-coated polyester film 52, and when gas leakage occurs, a gas supplementing and locking signal is sent to ensure safety. In specific implementation, as long as an SF6 density controller capable of realizing this function is selected from the prior art, it is not limited to a specific model, which can be obtained by the person skilled in the art without creative labor.

[0027] The insulating sleeve 2 is a silicon rubber composite insulating sleeve, and silicon rubber has excellent insulation performance, corona resistance and arc resistance.

[0028] The outer casing 3 includes two cover plates 31 and a cylindrical shell 32. The two cover plates 31 are connected to both ends of the cylindrical shell 32 via flanges. Each of the two cover plates 31 has two casters 311 at its lower end. A grounding terminal 321 is provided on the outside of the cylindrical shell 32. By setting up the insulating sleeve 2, the first shielding cover 5, the second shielding cover 6, the shielding plate 10, and the grounding terminal 321, the high-voltage power supply is shielded, effectively preventing the risk of electric shock to test personnel from contacting high voltage during testing, and greatly improving the safety of the voltage transformer. The two casters 311 at the lower end of each of the two cover plates 31 facilitate the movement of the voltage transformer 100, thereby improving the work efficiency of the test personnel. The grounding terminal 321 is used to ground the voltage transformer 100.

[0029] It also includes a bracket (not shown); the iron core assembly 4 is bolted to the bracket; the bracket is bolted to the inside of the outer casing 3. By setting the bracket, the iron core assembly 4 is fixed inside the outer casing 3, preventing shaking when the voltage transformer 100 is moved.

[0030] Working principle of this invention:

[0031] The terminal block 8 is connected to a high-voltage power supply. The high-voltage power supply is transmitted to the excitation winding 71 and the primary proportional winding 72 through the conductive rod 9, and coupled to the secondary proportional winding 73 to output a low-voltage power supply to the junction box 11. The tester calculates the voltage of the high-voltage power supply by testing the voltage of the low-voltage power supply in the junction box 11.

[0032] In summary, the advantages of this invention are:

[0033] 1. By setting up the insulating sleeve, the first shielding cover, the second shielding cover, the shielding plate and the grounding terminal, the high voltage power supply is shielded, effectively preventing the risk of electric shock to the test personnel from contacting the high voltage during the test, and greatly improving the safety of the voltage transformer.

[0034] 2. By setting the SF6-filled diamond-patterned polyester film, the insulation level is greatly improved because SF6 is a new generation of ultra-high voltage insulating medium material; by setting the SF6 density controller to monitor the SF6 pressure, the insulation of the voltage transformer is indirectly monitored, avoiding the safety hazards caused by the test personnel using the voltage transformer when the SF6 pressure is too low.

[0035] 3. Two casters are provided at the lower end of each of the two cover plates to facilitate the movement of the voltage transformer, thereby improving the work efficiency of the testers.

[0036] 4. By setting the excitation magnet core as a permalloy iron core and the proportional iron core as a silicon steel sheet iron core, the magnetic permeability performance and cost of the iron core are balanced.

[0037] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A two-stage multi-ratio potential transformer, characterized by: The utility model relates to a transformer, which comprises an insulating sleeve, an outer shell, a core set, a first shielding cover, a second shielding cover, a wire set, a terminal board, a conductive rod, two shielding plates, a terminal box and a support; the wire set is wound on the core set; the core set is arranged in the first shielding cover; the two shielding plates are arranged at the two ends of the core set respectively; the core set, the wire set, the first shielding cover and the shielding plates are arranged inside the outer shell; the insulating sleeve is arranged at the upper end of the outer shell and communicates with the outer shell, and the second shielding cover is arranged in the insulating sleeve; the lower end of the terminal board is connected with the insulating sleeve; the conductive rod is arranged in the second shielding cover, one end of the conductive rod is connected with the terminal board, and the other end is connected with the wire set; the terminal box is arranged outside the outer shell and is connected with the wire set; the core set is mounted on the support through bolts; the support is mounted inside the outer shell through bolts; the core set comprises an excitation core and a proportional core; the wire set comprises an excitation winding, a primary proportional winding and a secondary proportional winding; the excitation winding is wound on the excitation core; the primary proportional winding is wound on the excitation core and the proportional core; the secondary proportional winding is wound on the excitation core and the proportional core and is connected with the terminal box; the excitation core is a ring-shaped permalloy core, and the proportional core is a ring-shaped silicon steel sheet core; the first shielding cover comprises an SF6 density controller and a SF6-filled diamond-coated polyester film; the diamond-coated polyester film is provided with an opening; the SF6 density controller is arranged outside the outer shell; the outer shell comprises two cover plates and a columnar shell; the two cover plates are connected with the two ends of the columnar shell through flanges; the lower ends of the two cover plates are each provided with two universal wheels; the outer part of the columnar shell is provided with a grounding terminal.

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