CN202134389U

CN202134389U - Dry electromagnetic type voltage transformer with capacitive character

Info

Publication number: CN202134389U
Application number: CN201120236051U
Authority: CN
Inventors: 李承政
Original assignee: ZHEJIANG NANJI TRANSFORMER CO Ltd
Current assignee: ZHEJIANG NANJI TRANSFORMER CO Ltd
Priority date: 2011-07-06
Filing date: 2011-07-06
Publication date: 2012-02-01
Anticipated expiration: 2021-07-06

Abstract

The utility model discloses a dry electromagnetic type voltage transformer with capacitive character, which comprises an iron core, a first winding and a second winding, wherein an outer electrostatic shield and voltage-sharing shield rings are arranged on the high-voltage end of the first winding; and an inner electrostatic shield is arranged on the grounding end of the first winding. The utility model is characterized in that the first winding is of multistep winding displacement structure, the voltage-sharing shield rings are arranged at section winding of each step; a capacitance shield is arranged at each interlayer of the first winding; and all the stacking capacitances of the voltage-sharing shield rings and the capacitance shield are matched with the capacitance required by the anti-resonance of the transformer. In the utility model, the voltage-sharing shield rings are arranged on the section windings of all the steps, the capacitance shield is arranged at each interlayer of the winding, and the stacking capacitances of all the voltage-sharing shield rings and the capacitance shield are matched with the capacitance required by the anti-resonance of the transformer. At 1.2um voltage, the partial discharge amount of the transformer is below 30pc, which is lower than 50pc of the national standard; therefore, the great technical problem of the electromagnetic type voltage transformer manufacturing industry is solved.

Description

Dry type is Capacitive Electromagnetic Voltage Transformer

[technical field]

The utility model belongs to the electrical installation in a kind of power transmission and transformation line, is specifically related to a kind of dry type and is Capacitive Electromagnetic Voltage Transformer.

[background technology]

At present; In China 35kV level and the following distribution network systems; Remain and adopt the isolated neutral mode, in the electromagnetic potential transformer that is adopted, the ubiquity excitation property is poor, be prone to produce defectives such as ferro resonance and partial discharge quantity be bigger than normal; Especially maximum with ferro resonance to operation power harm, receive it to influence that regular meeting occurs that high voltage fuse blows, equipment is impaired and the phenomenon that causes power failure.Be head it off; Brainstrust has been done long-term and unremitting effort; The conclusion of generally acknowledging is: the supposition electromagnetic potential transformer is a load that is capacitive, just can suppress ferro resonance preferably, and wherein between high-pressure side and earth terminal, inserting high-voltage capacitor is comparatively desirable solution.Chinese patent ZL2006200537961 " dry type is Capacitive Electromagnetic Voltage Transformer " improves by this thinking.The structure of this instrument transformer comprises iron core, winding, secondary winding; Electrostatic shielding and grading ring outside on the high-pressure side of a winding, being provided with; On earth terminal, be provided with interior electrostatic shielding; Its crucial improvements are: between high-pressure side and earth terminal, insert high-voltage capacitor, and outside high-pressure side is provided with electrostatic shielding and grading ring.Facts have proved: between high-pressure side and earth terminal, insert after the high-voltage capacitor; Really the overall capacitance amount and increase capacity current of product have been improved; And play a part antiresonance; Outside high-pressure side is provided with behind electrostatic shielding and the grading ring, help improving before the high-tension coil which floor turn-to-turn and interlayer field intensity, the partial discharge of minimizing product has been measured certain function.But there is following problem in this type product in actual motion: the high-voltage capacitor of access was prone to the slow puncture of generation and causes short circuit after operation a period of time between screen board, therefore have potential safety hazard; Electrostatic shielding and grading ring screen outside high-pressure side is provided with, though reduced partial discharge quantity, but still undesirable.Big factory of domestic a few family also can only reach the 50pC requirement of GB regulation reluctantly as this constructed products partial discharge quantity under 1.2Um voltage.

[summary of the invention]

For solving the problems referred to above that prior art exists; The utility model aims to provide a kind of dry type with novel structure and is Capacitive Electromagnetic Voltage Transformer; This instrument transformer can effectively overcome excitation property poor, be prone to produce defectives such as ferro resonance and partial discharge quantity be bigger than normal; Can not cause the slow breakdown accident of CSET again and cause short circuit, thereby help eliminating the potential safety hazard of distribution network systems.

For realizing above-mentioned purpose; The utility model has adopted following technical scheme: this dry type is Capacitive Electromagnetic Voltage Transformer; Comprise iron core, winding, secondary winding, electrostatic shielding and grading ring outside on the high-pressure side of a said winding, being provided with are provided with interior electrostatic shielding on said earth terminal; It is characterized in that: a said winding is the staged bus-bar construction; On the intersegmental winding of each ladder, be provided with all and press the screen ring, be provided with capacitance plate, and all described capacitances of all pressing overlap capacitance amounts that screen ring and capacitance plate produced and this instrument transformer antiresonance to require are complementary at each interlayer of a said winding.

During practical implementation, the line of the copper conductor of a said winding directly is Ф 0.13mm, and at coil outer diameter one regularly can increase umber of turn one time this moment, strengthens D.C. resistance and falls low magnetic density.

During practical implementation, said capacitance plate is composited by the PMP paper of 0.05mm thickness and the aluminium foil of 0.015mm thickness, and the aluminum foil screen edge is smooth shape.

During practical implementation, said centre all presses the screen ring to be composited by the red copper foil of 0.1mm thickness, the PMP paper of 0.1mm thickness and the semiconductive paper of 0.08mm thickness, all presses the edge of the Width both sides of screen ring to be provided with Ф 4 silicon rubber bars at this.

Beneficial effect: compared with prior art; The utility model is according to the thinking of " the supposition electromagnetic potential transformer is a load that is capacitive; with regard to ability better inhibited ferro resonance "; With winding of staged winding displacement mode coiling, on the intersegmental winding of each ladder, be provided with and all press the screen ring, capacitance plate all is set between winding layers, and make all press the screen ring and the overlap capacitance amount of capacitance plate and the capacitance that this instrument transformer antiresonance requires to be complementary.Thereby solved directly shunt capacitor between high pressure screen and ground connection screen well, be prone between screen board produce slowly puncture and the deficiency that causes short circuit accident, can effectively increase capacitance, reached the requirement that makes instrument transformer be the capacitive antiresonance; Even high pressure end field intensity is improved the instrument transformer surge voltage and is distributed again, reduces partial discharge quantity.Through test determination: this instrument transformer is under 1.2Um, and partial discharge quantity is below the 30pC, less than the requirement of national standard 50pC, thereby has solved the manufacturing great technical barrier of electromagnetic type earthed voltage transformer.

[description of drawings]

For deepening understanding, make further detailed description through embodiment below in conjunction with accompanying drawing to the utility model.

Fig. 1 is vertical sectional structure sketch map of an embodiment of the utility model.

Fig. 2 is the B-B cutaway view of Fig. 1.

Fig. 3 is the electrical schematic diagram of present embodiment.

Fig. 4 is the capacitance plate structure for amplifying sketch map among Fig. 1.

Fig. 5 is the grading ring screen structure for amplifying sketch map among Fig. 1.

Among the figure: primary conductive bar 1, outer electrostatic shielding 2 is all pressed screen ring 3, silicon rubber bar 31, PMP paper 32, Copper Foil 33, semiconductive paper 34, interior electrostatic shielding 4, capacitance plate 5, aluminium foil 51,

PMP paper

52,6, inserts A of ground connection inserts, N, unshakable in one's determination 7.

[embodiment]

Referring to Fig. 1, and combine Fig. 2.This dry type is the structure of Capacitive Electromagnetic Voltage Transformer, comprises 7, windings unshakable in one's determination, secondary winding, and the high-pressure side of a winding is provided with outer electrostatic shielding 2 and all presses screen ring 3, electrostatic shielding 4 on earth terminal, being provided with.One time winding adopts the coiling of stairstepping bus-bar construction to form, and has four sections.The laminated core that the permeability magnetic material of 7 employing high-qualitys unshakable in one's determination is processed, the anti-stress of laminated core is strong.One time winding adopts self-binding enamel wire m/3 winding method, and the line of its copper conductor directly is Ф 0.13mm, and at coil outer diameter one regularly can increase umber of turn one time this moment, helps strengthening D.C. resistance and falls low magnetic density.

On the intersegmental winding of each ladder, be provided with all and press screen ring 3, be equipped with capacitance plate 5, and all described capacitances of all pressing overlap capacitance amount that screen ring 3 and capacitance plate 5 produced and the anti-ferro resonance of this instrument transformer to require are complementary at the interlayer of said winding.Calculating through the overlap capacitance amount can reach the coupling requirement, and for example JZWX-35 requirement matching capacitance amount is more than 500pF reaches.

Referring to Fig. 3.Can know from electrical schematic diagram; After adopting many groups all to press the measure of screen ring 3, capacitance plate 5; Greatly increase turn-to-turn, interlayer, intersegmental electric capacity and the direct-to-ground capacitance of instrument transformer, promptly reduced capacitor value and increased capacitance current, can well play the effect that suppresses ferro resonance; Through these major measure, make this type instrument transformer become a brand-new product.On the other hand, evenly the end field intensity is improved surge voltage and is distributed, and has reduced partial discharge quantity, has solved the difficult problem that the local discharging level of 10～35kV electric pressure ground connection electromagnetic potential transformer under 1.2Um voltage is up to state standards.

Referring to Fig. 4.Capacitance plate 5 adopts the aluminium foil 51 of 0.015mm to be composited with 0.05PMP paper 52.Before compound, the equal folding 15mm along the cross direction both sides with aluminium foil 51 makes the edge smooth.When being provided with, be placed on the interlayer of a winding, therebetween or a layer line or two layer lines or multilayer line, the size of looking the required value of its anti-ferro resonance capacitance decides, and plays electric field and the effect that increases the layer capacitance value of being uniformly distributed with.

Referring to Fig. 5.Make and all pressed the screen ring at 3 o'clock; Earlier that the red copper foil 33 of 0.1mm thickness is compound with the PMP paper 32 of 0.1mm thickness; Compound with the semiconductive paper 34 of 0.08mm thickness more afterwards; Placing all pressure screen rings 3 of Φ 4 silicon rubber bars 31 (on the semiconductive paper bag) formation on the edge of its cross direction, in the coiling process, need primary line is welded on the red copper foil 33.

Claims

1. a dry type is Capacitive Electromagnetic Voltage Transformer; Comprise iron core (8), winding, secondary winding; Electrostatic shielding (2) and all press screen ring (3) outside on the high-pressure side of a said winding, being provided with; On said earth terminal, be provided with interior electrostatic shielding (4), it is characterized in that: a said winding is the staged bus-bar construction, on the intersegmental winding of each ladder, is equipped with all to press screen ring (3); Interlayer at a said winding is equipped with capacitance plate (5), and all the described overlap capacitance amount of screen ring (3) and capacitance plate (5) and capacitances of this instrument transformer antiresonance requirement of all pressing are complementary.

2. electromagnetic potential transformer as claimed in claim 1 is characterized in that: the line of the copper conductor of a said winding directly is φ 0.13mm.

3. electromagnetic potential transformer as claimed in claim 1 is characterized in that: said capacitance plate (5) is composited by the PMP paper (52) of 0.05mm thickness and the aluminium foil (51) of 0.015 thickness, and the aluminum foil screen edge is smooth shape.

4. electromagnetic potential transformer as claimed in claim 1; It is characterized in that: said grading ring screen (3) is composited by the red copper foil (33) of 0.1mm thickness, the PMP paper (32) of 0.1mm thickness and the semiconductive paper of 0.08mm thickness, all presses the edge of the Width both sides of screen ring (3) to be provided with φ 4 silicon rubber bars (31) at this.