WO2008031302A1

WO2008031302A1 - Non-excited tap-changer with shielding device

Info

Publication number: WO2008031302A1
Application number: PCT/CN2007/000516
Authority: WO
Inventors: Wei Qin
Original assignee: Wuhan Taipu Transformer Changer Co., Ltd.
Priority date: 2006-09-12
Filing date: 2007-02-14
Publication date: 2008-03-20
Also published as: DE112007001415T5; DE112007001415B4; CN1933055A; CN1933055B

Abstract

A non-excited drum tap-changer for a transformer includes an upper pedestal (2) and a lower pedestal (3). Insulated shafts (4) are positioned around the upper pedestal (2) and the lower pedestal (3), characterized in that fixed contacts are positioned in a circle along the insulated shafts separately. A moving contact assembly is mounted between the upper pedestal (2) and the lower pedestal (3) and inside of the fixed contacts in a circle. The moving contact assembly is connected to a driving unit. Moving contacts (7) are mounted on the circumference of the moving contact assembly in a circle and correspond to the fixed contacts.

Description

Non-excited cage-shaped tap changer for transformers

The present invention relates to a non-excited cage tap changer for a transformer, which is a further improvement of the existing non-excited cage tap changer.

Background technique

The existing non-excited cage-shaped tap changer mainly comprises upper and lower supports and insulating rods arranged circumferentially spaced along the upper and lower supports, and static contacts are arranged at intervals in the axial direction of each insulating rod, and static contact on each insulating rod The heads are correspondingly formed into a circumferential static contact group, and a middle shaft is disposed between the upper and lower supports, and the movable shaft is connected between the two adjacent static contacts through the support member on the central shaft, When the shaft rotates and is positioned, the moving contact is rotated circumferentially and respectively connected with different static contact groups to realize the adjustment function. The cage switch of this structure usually has three layers of dynamic and static contacts arranged in the axial direction to form a typical three-phase non-excited cage-shaped tap changer. When used as a single-phase, three-phase high-current switch, the three-phase parallel can be used as one phase or each phase in parallel with multiple sets of dynamic and static contact groups. When the existing cage switch is used as a three-phase, the maximum current is generally 1200 A. Due to manufacturing dispersion and lead tension, the insulation rod is deformed and the like, so that the shunts are difficult to be uniform when connected in parallel, so it is generally used as a single phase. For 2500A to 3000A. However, the biggest drawback of the structure for manufacturing a large current switch is that the cage stiffness is seriously insufficient, the volume is large, the shielding is complicated at high voltage, the local field strength is too large, the partial discharge is large, the structure is complicated, and the manufacturing cost is high. . In addition, due to the large radius of the moving contact, the sliding of the moving contact when the middle shaft rotates causes the operating torque to be large, and the positioning accuracy of the moving contact is low, which often causes poor contact and affects the performance of the switch.

At present, as the capacity of a single transformer is getting larger and larger, the current and voltage of the transformer are getting higher and higher, so the requirements on the switch specifications are also increasing. The disadvantages of the traditional switch are more prominent, the operational reliability is reduced, and the failure rate is improve.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art described above and to provide a non-excited cage-type tap changer with good rigidity, stable and reliable contact, and small operating torque.

The technical solution adopted by the present invention to solve the above-mentioned problems is as follows: The upper and lower supports 2, 3, and the upper and lower supports are circumferentially coupled with an insulating rod 4, which is different in the insulation rod. An annular static contact 5 is disposed at an axial interval, and a movable contact assembly is disposed between the upper and lower supports and the inner side of the annular static contact, and the movable contact assembly is coupled with an upper and lower transmission device, and the outer periphery of the movable contact assembly Corresponding to the annular static contact, a movable contact 7 is connected to the adjacent two static contacts.

According to the above aspect, the movable contact assembly includes a sleeve-shaped support member 8 and is circumferentially disposed on the outer circumference of the sleeve-shaped support member. The strip-shaped moving contact 7 is provided with a spring 10.

According to the above scheme, the upper and lower transmission device is composed of a transmission screw 6 and a screw sleeve 11 connected between the upper and lower supports, the screw sleeve is connected with the support member 8, and the inner side of the support member is arranged with the fixed guide rod 15; The upper end of the device is associated with the operating mechanism 1. The operating mechanism drives the transmission screw, and the axial displacement of the movable contact is driven by the up and down movement of the screw sleeve to realize the change of the tap position.

According to the above scheme, the annular static contact 5 is connected to each of the insulating rods.

The annular static contact of the invention is arranged as needed, and is only connected to one phase of the coil as a single-phase switch, and correspondingly, a movable contact assembly is arranged, and the single-phase structure switch is connected in series or two or three in the axial direction, each The item corresponds to a moving contact assembly, and each of the static contacts is connected to two phases and three phases of the coil, which will constitute a two-phase, three-phase tap changer. Since the phase-to-phase insulation tends to be higher than the insulation between the contacts of each phase, the height of the gate is high, and even if it is placed on the transformer, the effective axial space inside the transformer can be fully utilized.

The beneficial effects of the invention are as follows: 1. The cage switch adopts an annular static contact and an axial movement structure of the movable contact in the ring, the static contact is convenient for processing and the circumferential roundness is good, and the accuracy is more easily ensured, so the axial movement is movable. The static contact contact state is consistent, the contact is stable and reliable, the switch operating torque is small when the axial movement is moving, and the positioning precision is 髙; 2. The static contact is annular and the multi-point is connected with the insulating rod to strengthen the cage body The stiffness effect makes the structural rigidity of the cage switch greatly improved. The axial electrode is ring-shaped, and the insulation and partial discharge performance are good. The moving contact is symmetrically arranged along the middle, and the force is mutually offset, so the rigidity of the central shaft is good. Strong anti-short circuit, especially suitable for large current, especially single-phase switch with high insulation level between contacts; 3. Static contact is distributed along the axial direction of the insulating rod of the switch body, and the support member and the moving contact are also axially arranged at the static touch. In the head, the inner space of the annular static contact is effectively utilized, the outer diameter of the switch is greatly reduced, and the annular static contact also acts as an external shield, which is beneficial to greatly improve the phase and external Insulation level, reduce partial discharge, simplify high voltage electric field; 4. Simple structure and low production cost.

DRAWINGS

Figure 1 is a front elevational view of one embodiment of the present invention.

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

Figure 3 is an enlarged view of I in Figure 1. .

Figure 4 is a schematic diagram of the wiring of the single bridge jumper function of the present invention.

Figure 5 is a schematic diagram of single-phase series-parallel connection of the present invention

Fig. 6 is a schematic diagram showing the wiring of the three-phase sigma-delta conversion function of the present invention. detailed description

Embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

An embodiment of the present invention, as shown in Figures 1, 2, and 3, is a single-phase non-excited cage tap changer having upper and lower supports 2, 3, and a drive screw 6 is disposed between the upper and lower supports. The upper part of the driving screw is connected with the operating mechanism 1, and the driving screw is arranged with the screw sleeve 11 connected with the supporting member to form a screw type upper and lower transmission device; 6-8 pieces are arranged around the upper and lower supports The insulating rod 4 is arranged with an annular static contact 5 on the inner side of the insulating rod, and the annular static contact is connected with each insulating rod through a screw 13. The annular static contact can be arranged in the axial direction, usually 4~6 a ring terminal 9 is disposed on the outer side of the ring-shaped static contact, and is connected to the transformer tap wire; a movable contact assembly is disposed corresponding to the ring-shaped static contact, and the movable contact assembly includes a sleeve-shaped support member 8 at A plurality of strip-shaped movable contacts 7 are disposed on the outer circumference of the sleeve-shaped support member, and the contact surface of the strip-shaped movable contacts is a circular arc surface, which is movablely engaged by the upper and lower chucks 17, and a radial acting spring 10 is disposed behind. The moving contact can be radially adjusted, and the moving contact 7 is adjacent to the two The static contact phase is connected, the support member 8 of the movable contact assembly is coupled with the screw sleeve 11 of the screw type upper and lower transmission device, and two fixed guide rods 15 are arranged; when the operating mechanism 1 drives the transmission, the screw 6 rotates. When the moving contact assembly moves up and down, it also performs radial floating during the shifting process, thereby realizing various tap position changes. In order to improve the external electric field, a pressure equalizing cover 16 may be disposed on the outer periphery of the screw 13 connecting the annular static contacts for shielding. The spacing of the annular stationary contacts is determined by the level of insulation therebetween. The number of moving contacts 7 is determined by the size of the switching current, and the number of terminals 9 is determined by the switching current and the number of transformer leads. When the phase of the switch and the level of the ground potential are high, a shield ring 12 can be provided between the upper and lower supports. This embodiment can also be used as a single-phase series-parallel connection.

The tap changer structure of the present invention can realize single-phase series-parallel connection according to different wiring manners, as shown in FIG. 5; single-bridge jumper connection can also be realized, as shown in FIG. 4; and three-phase Υ_Δ conversion wiring, such as Figure 6 shows.

If the invention is a two-phase, three-phase switch, the upper and lower transmission devices and the insulating rod are lengthened, and the moving and static contacts of the single-phase structure are repeatedly arranged, and the two-phase and three-phase synchronous adjustment can be realized.

• The invention is particularly suitable for high voltage, high current and small gears, which can meet the needs of large and special transformers.

Claims

Claim

1. A non-exciting cage-shaped tap changer for a transformer, comprising upper and lower supports (2, 3), an insulating rod (4) is circumferentially coupled between the upper and lower supports, characterized by an insulating rod The annular static contact (5) is disposed at an axial interval, and a movable contact assembly is disposed between the upper and lower supports and the inner side of the annular static contact, and the movable contact assembly is coupled with an upper and lower transmission device, and the movable contact The outer circumference of the assembly corresponds to the annular static contact and the movable contact (7) is bridged with the adjacent two static contacts.

A non-excited cage-type tap changer for a transformer according to claim 1, wherein said movable contact assembly comprises a sleeve-shaped support member (8), and a strip is formed in a circumferential direction of the sleeve-shaped support member. Move the contact (7) and configure the spring (10).

3. A non-excited cage tap changer for a transformer according to claim 1 or 2, wherein said upper and lower transmission means are driven screw (6) and screw sleeve (11) connected between the upper and lower supports. The screw sleeve is connected with the support member, and the inner side of the support member is arranged with the fixed guide rod (15).

A non-excited cage-type tap changer for a transformer according to claim 1 or 2, characterized in that the upper end of the upper and lower transmission means is associated with the operating mechanism (1).

A non-excited cage-type tap changer for a transformer according to claim 1 or 2, characterized in that said annular stationary contact (5) is associated with each of the insulating rods (4).

6. The non-excited cage-type tap changer for a transformer according to claim 1 or 2, wherein the annular static contact is arranged 4 to 6 in the axial direction, and the outer side of the annular static contact is provided with a terminal (9) .

A non-excited cage-type tap changer for a transformer according to claim 1 or 2, characterized in that a shield ring (12) is provided between the upper and lower supports.

The non-excited cage-type tap changer for a transformer according to claim 1 or 2, characterized in that 6 to 8 insulating rods (4) are arranged around the upper and lower supports, and the insulating rod An annular static contact (5) is arranged on the inner side in the axial direction, and the annular static contact is connected to each of the insulating rods by screws (13), and a pressure equalizing cover (16) is disposed on the outer circumference of the screw connecting the annular static contacts.