WO2007140675A1

WO2007140675A1 - Non-excited tap-changer with shielding device

Info

Publication number: WO2007140675A1
Application number: PCT/CN2007/000515
Authority: WO
Inventors: Gang Liu
Original assignee: Wuhan Taipu Transformer Changer Co., Ltd.
Priority date: 2006-06-02
Filing date: 2007-02-14
Publication date: 2007-12-13
Also published as: DE112007001277B4; CN100442410C; CN1866441A; DE112007001277T5

Abstract

A non-excited tap-changer with shielding device for a transformer includes an upper and a lower bearing (1,2). A rotating shaft (3) passes through the upper and the lower bearing (1,2) and is connected to an insulator (5). One end of the rotating shaft is connected to an operating mechanism (4). Moving contacts (7) are mounted on the rotating shaft and fixed contacts (6) are mounted correspondingly around the moving contacts. A cylindrical shielding housing (8) is covering the circumference of the fixed contacts. Also, an insulating drum is installed inside and /or outside of the shielding housing. A shielding coil is mounted on the one end or both ends of the cylindrical shielding housing. The non-excited tap-changer is compact and the reliability is enhanced.

Description

Non-excitation tap changer with shielding device

The present invention relates to a non-exciting tap changer with a shielding device for use in a transformer, which is an improvement over existing off-circuit tap-changers.

Background technique

In the Chinese patents CN2308152Y, CN2454878Y, CN2249959Y, several types of non-exciting tap changers and non-excited drum-shaped tap-changers with different structures are proposed. These switches have compact structure and small volume, so they occupy small internal space of the transformer during use. Lightweight and reliable operation. However, as the rated voltage level of Shaoguan increases and one of the main performance indexes of the transformer, the partial discharge limit requirement, is greatly improved, the partial discharge performance of the tap changer installed on the transformer of the voltage level tends to become weak. In the link, because there are more exposed electrified bodies on the tap changer, even if the insulating material with better insulation performance and higher processing technology are used, the partial discharge of the tap changer will be too large as the voltage level of the transformer is increased. It is difficult to meet the requirements of use. This also makes the tap-changer system too high.

On large and medium-sized transformers, the insulation level of the switch to ground is relatively high, and the level of insulation between the contacts and the phase between the switches is relatively low. Therefore, the switch is the key control part of the external partial discharge, which is often caused by the high material or structure and process requirements, which may cause the transformer partial discharge performance to be inconsistent, or may not be left in the transformer housing and the coil. The insulation distance reduces the field strength, which increases the volume of the transformer. This will increase the switch manufacturing cost, transformer use and manufacturing cost, and even the shipping cost, and the partial discharge amount will greatly reduce the reliability of the transformer operation. Summary of the invention

The technical problem to be solved by the present invention is to provide a non-exciting tap changer with a shielding device, which is not only simple and compact in structure, small in effective volume of the switched electrification body, but also uniform in electric field and partial discharge. Small amount, stable and reliable performance.

The technical solution adopted by the present invention to solve the above-mentioned problems is as follows: The upper and lower supports 1 and 2 are included, and the rotating shaft 3 is coupled between the upper and lower supports and coupled to the insulator 5, and one end of the rotating shaft is connected to the operating mechanism 4. The movable contact 7 is disposed on the rotating shaft, and the circumferential direction of the movable contact corresponds to the static contact 6 disposed therein, which is different in that a cylindrical shield cover 8 is set on the outer circumference of the static contact group.

In the above solution, the insulator 5 is a cage insulator or a tubular (tubular) insulator; the static contact is confirmed! Ben It is disposed in the inner circumferential direction of the insulator; the tap changer can be single-phase, two-phase or three-phase, and is arranged in sections along the axial direction of the switch. In the above solution, the shielding cover 8 may be cylindrical, and the shielding cover is an integral cylindrical shielding cover extending continuously in the axial direction of the switch, or may be disposed along the axial direction corresponding to the static contact or the phase number. The segmented cylindrical shield is divided into a plurality of cylindrical shields in the axial direction. The shield is made of metal, or is formed by winding a metal wire or a braided wire on the wall of the insulating material, or is formed by plating a metal conductive layer on the wall of the insulating material. The shield is electrically connected to the electrified body on the switch or on the transformer coil by a connecting wire.

According to the above scheme, an insulating cylinder can be disposed on the inner side or/and the outer side of the shielding cover; in order to enhance the shielding performance, a shielding end ring 14 can be disposed at one end or both ends of the cylindrical shielding cover, and the shielding end ring can be combined with the shielding cover 8 Connected together.

According to the above scheme, the static contact 6 can be cylindrical, directly coupled to the insulator 5, or can be worn and fixed between the upper and lower supports 1, 2; the end of the static contact is connected to the tapping lead 18, A radial terminal 19 can also be provided, one end of the radial terminal is connected to the stationary contact, and the other end is passed through the shield to be connected to the tap.

The utility model has the following advantages: 1. A shielding cover is arranged outside the static contact, and the shielding cover separates the main shape of the electrified body in the tap changer into the cover, and if necessary, the weak insulating material is also shielded. The transformer coil and the box are effectively shielded. At this time, the electric field between the charged bodies in the cover is an in-phase electric field, and the whole is a large electrode. The shield cover is generally connected to the tapping lead or the rotating shaft of the transformer coil or the box with a relatively low potential (generally driving the contact potential), thus greatly improving the electric field distribution of the switch, and the partial discharge amount of the switch is greatly reduced, and the tapping can be performed. The structure of the switch becomes simple and compact, and the volume of the switch is correspondingly reduced, so that the switch occupies less effective space of the transformer, and at the same time, the switching process is simplified, the switch manufacturing cost and the transformer use and manufacturing cost are reduced. 2. Due to the uniform distribution of the electric field and the small amount of partial discharge, the stability and reliability of the performance of the tap changer will be further enhanced. For some switches, there is a large difference in the section potential of the axial local electric field in the phase. At this time, the axial length of each shield can be shortened, and the section of the electric field difference can be shielded. The section of the electric field can be unshielded, that is, the divided cylinder is used. The shield is partially short-circuited or connected to other charged bodies, which simplifies the manufacturing process of the shield or facilitates insulation between the shield and the internal electrodes. 3. The insulation tube is arranged inside the shield cover, which is beneficial to improve the internal insulation level between the shield cover and each static contact, and reduce the outer diameter of the shield cover. The addition of an insulating cylinder on the periphery of the shielding cover helps to improve the insulation level of the switch to the transformer coil and the box, and further reduces the internal space occupied by the switch, which is beneficial to the design and operation reliability of the transformer.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front cross-sectional view showing an embodiment of the present invention.

Figure 2 is a cross-sectional view taken along line E-E of Figure 1.

Figure 3 is a cross-sectional view taken along line FF of Figure 1; Figure 4 is a front cross-sectional view showing a second embodiment of the present invention.

Figure 5 is a front cross-sectional view showing a third embodiment of the present invention.

detailed description

Three embodiments of the present invention are further described below in conjunction with the accompanying drawings.

The first embodiment is shown in Figures 1, 2, and 3, and is a single-phase five-speed non-excited single-bridge jumper drum tap changer. The switch comprises two parts, the upper part is the operating mechanism 4, and the lower part is The switch body is engaged with the clutch 13 at the upper portion of the rotating shaft 3 and the joint 12 at the lower portion of the operating mechanism, and is a movable clutch structure. The upper portion of the operating mechanism is mounted on the transformer case 20. The switch body comprises a cylindrical insulator 5, wherein the inner side of the insulator is provided with six spaced apart columnar static contacts 6 through the fastener 11, and the upper support 1 and the lower portion are disposed above and below the static contact in the insulator. The support 2 is provided with a rotating shaft 3 between the upper and lower supports, and a plurality of moving contacts 7 are arranged on the rotating shaft corresponding to the static contacts 6 and connected in parallel between the two static contacts, and the moving contacts are The quantity is determined by the switch current parameter, and the moving contact is composed of a support member 16, a pin 21, and a spring 17 connected to the main shaft, and the contact body can be annular, so that the movable contact and the static contact Column 6 is in reliable contact. The outer periphery of the insulator 5 is provided with a cylindrical shield cover 8. In order to enhance the axial-to-ground electric field shielding, an arc-shaped shield end ring 14 is disposed at the upper and lower ends of the shield cover 8, and the overall height thereof is higher than that of all the electrified bodies in the cover. All of them are effectively shielded from the outside, and the shield is connected to the switch shaft holder 24 through the connecting conductor 15, and is kept at the same potential, and the connecting conductor 15 is insulated and wrapped. In order to improve the insulation between the static contact 6 and the fixing member 11 and the shield case 8 and the external insulation of the shield cover, the inner insulation tube 9 and the outer insulation tube 10 are respectively disposed inside and outside the shield case. Further, on the upper and lower ends of the columnar stationary contact 6, a tapping lead 18 is provided, and each of the tapping leads is provided with a covering insulating layer 23.

The second embodiment is shown in FIG. 4, which differs from the previous embodiment mainly in that the shield cover 8 is composed of upper and lower sections, and is located at the upper half and the lower half of the electric field weak, respectively, and the static contact is The upper and lower support joints and the tapped wire joint are partially shielded, and the upper and lower shields are connected by short wires 22, and the columnar static contacts 6 are directly fixed to the upper and lower supports 1, 2 Therefore, the internal electric field between the static contact and the shield is better, and the volume is relatively smaller. Another difference is that the two-stage shield cover 8 is composed of a tubular insulator wound around a metal braided wire or directly wound by a wire. There are two kinds of wire winding methods, which can be wound up and down along the axial wall of the insulator, or in the insulator. The outer circumference is spirally wound. When the switching voltage level is not high, the inner and outer insulating cylinders 9 and 10 may not be provided, and the insulating layer may be directly coated inside and outside the shielding cover 8. The other parts are the same as in the previous embodiment.

The third embodiment, as shown in FIG. 5, is a two-phase tap changer, the operating mechanism 4 and the switch body are coupled into one body, the two phases of the switch are arranged vertically in the axial direction, and the rotating shafts of the upper and lower phases are concentric; each phase Both upper and lower supports 1, 2, rotating shaft 3 and moving and static contacts are installed in the long cylindrical insulator 5; cylindrical gold is provided in the outer circumference of each phase of the insulation. The shielding cover 8 is provided with an arc-shaped shielding end ring 14 at the upper and lower ends of the shielding cover 8, and an inner insulating tube 9 is disposed between the inner insulating members 5 of the shielding cover; the radial connecting terminal 19 is connected behind the static contact, and the radial connecting terminal The insulator 5 and the shield cover 8 are connected to the tapping lead. The radial terminals are insulated from the shield 8. In addition, a shield ring 25 is provided between the two phases of the switch and the ground. The other parts are the same as in the previous embodiment.

All of the above embodiments can realize three-phase integration, and are arranged along the axial section, and the switch length dimension is large at this time.

In the above embodiment, the insulator 5 may be a cage shape, and the contact may be a clip type; at this time, the non-excited cage tap changer is used. In the above embodiment, the shield is generally configured with the switch, and can also be set when the switch is installed and used.

The invention is applicable to the non-excitation tap-changers of various wiring principles including linear tuning, single-bridge bridging, double-bridge bridging, conversion, series-parallel, positive and negative tuning, and the like.

The operating mechanism 4 of the present invention can be manually or electrically operated and can be applied to different fuel tank configurations. The switch has a simple structure, a small amount of partial discharge, and reliable operation.

Claims

Claim

1. A non-exciting tap changer with a shielding device, comprising upper and lower bearings (1, 2), a rotating shaft (3) and an insulator (5) connected between the upper and lower supports, one end of the rotating shaft Connected to the operating mechanism (4), a moving contact (7) is arranged on the rotating shaft, and the moving contact has a circumferential direction corresponding to the static contact (6) disposed therein, which is characterized by the static contact group The outer peripheral suit has a cylindrical shield (8).

2. A non-exciting tap changer with a shielding device according to claim 1, characterized in that the insulator (5) is a cage insulator or a cylindrical insulator.

A non-exciting tap changer with a shielding device according to claim 1 or 2, wherein said static contact is mounted in the inner circumferential direction of the insulator.

The off-circuit tap-changer with shielding device according to claim 1 or 2, characterized in that the tap changer is single-phase, two-phase or three-phase, and is arranged in sections along the switch axis.

The off-circuit tap-changer with shielding device according to claim 1 or 2, wherein the shield (8) is cylindrical, and the shield is a monolithic continuous extension along the axial direction of the switch. The cylindrical shield is either a segmented cylindrical shield that is axially spaced apart.

The off-circuit tap-changer with shielding device according to claim 5, wherein the shield is made of metal or is wound with a metal wire or a braided wire on the wall of the insulating material. Or it is formed by plating a metal conductive layer on the wall of the insulating material.

7. A non-exciting tap changer with a shielding device according to claim 1 or 2, characterized in that the shield is electrically connected to the electrified body on the switch or on the transformer coil by means of a connecting conductor.

A non-exciting tapping switch with a shielding device according to claim 1 or 2, characterized in that an insulating cylinder is provided on the inner side or/and the outer side of the shield case.

A non-exciting tap changer with a shielding device according to claim 1 or 2, characterized in that a shield end ring (14) is provided at one or both ends of the cylindrical shield (8).

10. The off-circuit tap-changer with shielding device according to claim 1 or 2, characterized in that a radial terminal (19) is provided, one end of the radial terminal is connected to the static contact, and the other end is shielded. The cover and the insulating barrel are connected to the tapping leads.