CN2244247Y

CN2244247Y - Resonance eliminating and anti-earthing voltage mutural inductor

Info

Publication number: CN2244247Y
Application number: CN 95210112
Authority: CN
Inventors: 王建民; 王进杰
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-05-15
Filing date: 1995-05-15
Publication date: 1997-01-01
Anticipated expiration: 2005-05-15

Abstract

The utility model discloses a resonance eliminating and anti-earthing voltage mutual inductor, composed of an iron core, a zero sequence coil, and a three-phase coil. The tail end of a zero order primary coil is connected with the tail end of a three-phase primary coil. The head end of the zero order primary coil which is led out from a protective box is connected with the earth. The tail end of a zero sequence secondary coil is connected with the tail end of a three-phase secondary coil. The head end and the rear end of the zero sequence secondary coil lead out the protective box and connect with a monitoring relay. A three-phase auxiliary coil is in closed delta connection. The iron core is composed of three phase columns which provided with the three-phase coils, a zero sequence column which is provided with the zero sequence coils, and three magnetic yokes which connect the zero sequence column and the three phase columns into integration. The utility model can avoid the over-voltage and over-current damage of the voltage mutual inductor and can continuously operate in long term with anti-earthing performance.

Description

The anti-earthed voltage transformer of harmonic elimination

The utility model relates to a kind of voltage transformer, belongs to the transformer technology field.

Common voltage instrument transformer that neutral nondirect earthing network uses, when electrical network generation single-phase earthing, the terminal voltage of non-fault phase coil can be elevated to line voltage by normal phase voltage, and magnetic flux density also increases to regime values Doubly, follow and recurrent resonance in addition, make voltage transformer because of overvoltage, overcurrent, the overheated accident that frequently is damaged.Can remedy above-mentioned defective though install zero sequential potential transformer additional, must increase the table of equipment number like that, make that taking up room greatly, influence the equipment routine arranges, invests high.In recent years (" transformer " 1995 310-11), do not installed the three-phase equilibrium coil to the antiresonance voltage transformer of Sheng Chaning, adopts two magnetic circuits iron core independently separately.Because its three-limb core do not have the zero sequence flux circuit, the zero sequence magnetic flux need that produce because of electrical network is asymmetric are through non-magnetizing mediums and iron-clad closure, so exciting curent is big, electric energy loss is high, easily overheated.

The purpose of this utility model is a kind of voltage transformer with harmonic elimination and anti-grounding function that is applied to the neutral point indirect earthing power network of design, and it can avoid overvoltage, overcurrent damage, can anti-ground connection long-time running.

The purpose of this utility model be achieved in that the anti-earthed voltage transformer of harmonic elimination by protective housing, iron core, zero sequence coil and comprise once, the three-phase coil of secondary and ancillary coil constitutes.Each coil is contained on the iron core, iron core is contained in the protective housing, three-phase coil once all draw outside the protective housing with the head end of secondary coil, zero sequence coil and three-phase coil are around to identical, the tail end of zero sequence primary winding connects the tail end of three-phase primary winding, and its head end is drawn the protective housing external ground, and the tail end of zero sequence secondary coil connects the tail end of three-phase secondary coil, its head end and tail end are all drawn protective housing and are connected in series the supervision relay outward, and the three-phase ancillary coil becomes closed triangle to connect.Iron core by three phase posts that three-phase coil is installed, install the zero sequence coil the zero sequence post, and with the zero sequence post with three mutually post connect the all-in-one-piece yoke and constitute.

When producing the zero sequence magnetic flux, the zero sequence iron core column provides close access for the zero sequence magnetic flux in that three-phase voltage is asymmetric, so the zero sequence coil produces voltage, the supervision actuating of relay is reported to the police.

During the electrical network single-phase earthing, zero sequence iron core column and ground connection iron core column parallel connection mutually, the zero sequence coil is also in parallel with the grounded phase wire circle simultaneously, zero sequence coil and three-phase coil bear three-phase voltage jointly like this, make each coil-end voltage can not be elevated to line voltage, magnetic flux density can not increase naturally, thereby avoids voltage transformer overvoltage, overcurrent damage, can resist the long-term continuous service of ground connection.

In this voltage transformer, the existing three-phase magnetic circuit of its iron core, the zero sequence flux circuit is arranged again, its three-phase ancillary coil is equivalent to connect a low resistance between the asterism of power supply neutral point and voltage transformer, so can eliminate electrical network resonance (its theoretical foundation can referring to Chen Weixian " internal overvoltage basis " hydraulic and electric engineering publishing house) effectively.

Below in conjunction with drawings and Examples the utility model is described in detail.

Fig. 1 is an electrical schematic diagram of the present utility model;

Fig. 2～4th, three kinds of core structure figure of the present utility model.

Referring to Fig. 1, the utility model is made of protective housing 1 and the iron core 2, three-phase coil and the zero sequence coil that are contained in the protective housing 1.Ancillary coil 3 in the three-phase coil is connected into closed triangle, three-phase coil once, secondary coil all is connected into star, head end a, the b of head end A, B, C and the secondary coil of its primary winding, c draw outside the protective housing 1 through the insulation sleeve pipe respectively.Zero sequence coil and three-phase coil around to identical, the tail end of its primary winding connects the tail end of three-phase primary winding, be asterism OH, its head end N draws protective housing 1 external ground through the insulation sleeve pipe, the tail end of its secondary coil connects the tail end of three-phase secondary coil, be asterism Od, its head end n and tail end Od all draw outside the protective housing 1 through the insulation sleeve pipe, and serial connection supervision relay YJ.The three-phase secondary coil adopts the n earthing mode, also can adopt b phase earthing mode, when adopting b phase earthing mode, should install additional to puncture at the n point and insure.

Under the normal condition, no-voltage, no current in the zero sequence coil, the asterism of voltage transformer is equivalent to direct ground connection.When producing the zero sequence magnetic flux, the zero sequence iron core column provides close access for the zero sequence magnetic flux, makes the zero sequence coil produce voltage, so relay YJ action is reported to the police in that three-phase voltage is asymmetric.Produce balanced balanced current in the three-phase ancillary coil 3, can limit and eliminate the triple-frequency harmonics electromotive force, improve voltage waveform, and make insulation avoid the triple-frequency harmonics infringement.

When electrical network generation single-phase earthing, A phase ground connection for example, then A is connected with N, the a point is identical with n point current potential, zero sequence iron core column and A iron core column parallel connection mutually, the zero sequence coil is also in parallel with the A phase coil simultaneously, and zero sequence coil and three-phase coil bear three-phase voltage jointly like this, make each coil can not bear line voltage.

This voltage transformer is identical with common voltage instrument transformer lead wire insulation sleeve pipe number, can make the product of the various electric pressures of dry type or oil immersed type.

Fig. 2 is four volume four-column type core structures, and it is made of the yoke that center pillar, three mutual deviation 120 degree are distributed in side column, connection center pillar and side column around the center pillar, and the zero sequence coil is contained on the center pillar, and three-phase coil is contained on the side column.This kind structure manufacturing process is complicated, but its three-phase magnetic circuit symmetry, iron core materials are few, circuit and magnetic circuit are the most reasonable, are applicable to the place that accuracy requirement is high.

Five volume pentastyle iron cores shown in Figure 3 are made of five posts and yoke side by side, adorn three-phase coil on middle three posts, and zero sequence once all is divided into two sections with secondary coil and is installed in respectively on two side columns, make the zero sequence coil under normal circumstances total voltage be zero.Five posts of this kind structure all at grade, manufacturing process is simple, but middle phase magnetic resistance is mutually different with both sides, the three-phase exciting curent does not wait, accuracy is easy to control not as four volume four-column types.

In Fig. 4, three-limb core 4 and twin columns rectangle iron core 5 usefulness yokes 6 are coupled to four volume pentastyles side by side, and three-phase coil is contained on the three-limb core, and the zero sequence coil is contained in the twin columns iron core on that post away from three-limb core.Common three-core five-post type voltage transformer only damages a coil mostly when electrical network ground connection, will load onto the zero sequence coil after its reasonable cutting, changes and has decreased coil, just constitutes the anti-earthed voltage transformer of four volume pentastyle harmonic eliminations.This kind structure manufacturing process is simple, and for the voltage transformer that utilizes a large amount of damages provides good approach, but three-phase magnetic circuit is asymmetric, the difficult control of accuracy.

Claims

1. the anti-earthed voltage transformer of harmonic elimination is by protective housing, iron core, the zero sequence coil, and comprise once, the three-phase coil of secondary and ancillary coil constitutes, each coil is contained on the iron core, iron core is contained in the protective housing, three-phase coil once all draw outside the protective housing with the head end of secondary coil, zero sequence coil and three-phase coil are around to identical, the tail end of zero sequence primary winding connects the tail end of three-phase primary winding, its head end is drawn the protective housing external ground, the tail end of zero sequence secondary coil connects the tail end of three-phase secondary coil, its head end and tail end are all drawn protective housing and be connected in series the supervision relay outward, it is characterized in that: said iron core is by three phase posts that three-phase coil is installed, the zero sequence post of zero sequence coil is installed, and with the zero sequence post with three mutually post connect the all-in-one-piece yoke and constitute; Said three-phase ancillary coil becomes closed triangle to connect.

2. the anti-earthed voltage transformer of harmonic elimination according to claim 1, it is characterized in that: said iron core is made of yoke, center pillar, three side columns that are evenly distributed in around the center pillar, said zero sequence coil is contained on the center pillar, and said three-phase coil is contained on three side columns.

3. the anti-earthed voltage transformer of harmonic elimination according to claim 1 is characterized in that: said iron core is made of five posts and yoke side by side, and said three-phase coil is contained on middle three posts, and said zero sequence coil is divided into two sections and is contained in respectively on two side columns.

4. the anti-earthed voltage transformer of harmonic elimination according to claim 1, it is characterized in that: said iron core is made of side by side a three-limb core, twin columns iron core and yoke, said three-phase coil is contained on the three-limb core, and said zero sequence coil is contained in the twin columns iron core on that post away from three-limb core.