CN202058572U

CN202058572U - Small local discharge outdoor dry-type voltage transformer

Info

Publication number: CN202058572U
Application number: CN2011201478614U
Authority: CN
Inventors: 李承政; 黎倩
Original assignee: ZHEJIANG NANJI TRANSFORMER CO Ltd
Current assignee: ZHEJIANG NANJI TRANSFORMER CO Ltd
Priority date: 2011-05-11
Filing date: 2011-05-11
Publication date: 2011-11-30
Anticipated expiration: 2021-05-11

Abstract

A small local discharge outdoor dry-type voltage transformer comprises an iron core and a primary winding, which is characterized in that the iron core is in a shape of a trapezoid, the primary winding is wound around the upper bottom of the iron core in the shape of the trapezoid, and an angle in turning portion of a magnetic circuit of the iron core in the shape of the trapezoid is an obtuse angle. An inner grading ring capacitive screen is arranged on the primary winding in a specific implementation process. The dry-type voltage transformer replaces an iron core in a shape of a rectangle by the iron core in the shape of the trapezoid, a distance between the primary winding and the iron core is relatively increased, so that an insulation distance of a high 'electric field' portion is increased, and local discharge capacity is reduced. The turning portion of the magnetic circuit of the iron core is changed from a right angle to the obtuse angle, so that the dry-type voltage transformer is not only favorable to package a periphery insulating layer and arrange a shielding layer, but also favorable to improve strength of the insulating layer. The inner grading ring capacitive screen is arranged in the primary winding, so that end field strength is further even, surge voltage distribution is improved and the local discharge capacity is reduced.

Description

The outdoor dry type voltage transformer is put in little office

[technical field]

The utility model belongs to a kind of electrical installation that uses in transmission line, relate in particular to a kind of little office and put the outdoor dry type voltage transformer.

[background technology]

Voltage transformer generally is used in the power network line, as the equipment of voltage measurement and protection.Existing voltage transformer structure is made of primary winding that is wound on the rectangle iron core periphery and secondary coil; the periphery of exposed iron core is surrounded by insulating barrier; primary winding is connected with the high-pressure side; secondary coil is connected with measuring instrument or protection equipment; rectangle iron core is reeled by cold-reduced silicon sheet and is formed, and is commonly called as " R " shape iron core.During work, first and second coil is converted into the low pressure that can be convenient for measuring by iron core coupling realization with high pressure or is used to drive the low pressure of relay protection device.There are the following problems in actual applications for this voltage transformer: the distance on high pressure and ground evenly is set, not have the just insulation distance difference at " electric field " position, therefore, have partial discharge quantity height, defective that dielectric strength is low; In addition, the magnetic circuit turning of iron core bag rolls buffering and the shielding difficulty is set.

[summary of the invention]

For solve existing voltage transformer partial discharge quantity height, dielectric strength is low, and iron circuit turning bag rolls buffering and the difficult problem of shielding is set, the utility model aims to provide a kind of little office and puts the outdoor dry type voltage transformer, this voltage transformer is because the insulation distance at high " electric field " position is big, therefore have the advantage that partial discharge quantity is low, dielectric strength is high, and bag rolls buffering and shielding is set conveniently.

For achieving the above object, the utility model has adopted following technical scheme: the outdoor dry type voltage transformer is put in this little office, comprises iron core, primary winding, and it is characterized in that: the shape of described iron core is trapezoidal, and described primary winding is wound on the upper base of trapezoidal iron core; The magnetic circuit turning angle of this trapezoidal iron core is the obtuse angle.

During concrete enforcement, on primary winding, be provided with internal layer grading ring capacitance plate.

Beneficial effect: compared with prior art, after the utility model changes cabinet shape iron core into trapezoidal iron core, drawn back the spacing of primary winding and iron core relatively, promptly strengthened the insulation distance at high " electric field " position, helped reducing partial discharge quantity like this.Moreover the magnetic circuit turning of trapezoidal iron core has become the obtuse angle by original right angle, so both has been beneficial to the wrapping of peripheral insulating barrier and the setting of screen, also helps improving isolation layer intensity.On primary winding, after portion sets up internal layer grading ring capacitance plate, can play further even end field intensity within it, improve the effect that surge voltage distributes and reduces partial discharge quantity.

For deepening that understanding of the present utility model is described in further detail by embodiment below in conjunction with accompanying drawing.

[description of drawings]

The broken section structural representation of an embodiment of Fig. 1 the utility model.

Among the figure: primary winding lead-in

wire

1,2, primary winding 3, outer grading

ring capacitance plate

4,5 and 11, internal layer grading ring capacitance plate 6, brace 7, iron core 8, insulating barrier 9, ground wire 10, secondary coil lead-in wire 12.

[embodiment]

Referring to Fig. 1.This iron core 8 that is formed by the cold-reduced silicon sheet coiling is trapezoidal, and up-small and down-big, therefore, the silicon steel sheet angle at the magnetic circuit turning of iron core 8 is the obtuse angle, has so both helped the wrapping of peripheral insulating barrier 9 and the setting of screen, also helps improving isolation layer intensity.Primary winding 3 and secondary coil are wound on the upper base of trapezoidal iron core 8 respectively and go to the bottom, because primary winding 3 is in height " electric field ", with iron core 8 be designed to trapezoidal after, drawn back the spacing of coil and iron core relatively, promptly strengthen the insulation distance at high " electric field " position, helped reducing partial discharge quantity like this.

In addition, on primary winding, except that being provided with outer grading

ring capacitance plate

4,5 and 11, portion also is provided with internal layer grading ring capacitance plate 6 within it, inside and outside the grading ring capacitance plate is set after, can play further evenly the end field intensity, improve the effect that surge voltage distributes and reduces partial discharge quantity.

Claims

1. the outdoor dry type voltage transformer is put in one kind little office, comprises iron core (8), primary winding (3), and it is characterized in that: the shape of described iron core (8) is trapezoidal, and described primary winding (3) is wound on the upper base of trapezoidal iron core; The magnetic circuit turning angle of this trapezoidal iron core (8) is the obtuse angle.

2. voltage transformer as claimed in claim 1 is characterized in that: be provided with internal layer grading ring capacitance plate (6) on primary winding (3).