On-load tap changer

Abstract

An on-load tap changer (1) for performing load changes without power interruption, comprising a first module (20) having a first module shaft (22) and a second module (40) having a second module shaft (42), the first module shaft (22) operating the first module (20), the second module shaft (42) operating the second module (40), the first module shaft (22) driving the second module shaft (42) such that the second module (40) is operated in a time-shifted manner relative to the first module (20).

Description

Technical Field

[0001] The present invention relates to a on-load tap changer that performs load switching without power interruption between different winding taps of a tapped transformer.

Background Art

[0002] On-load tap changers are well-known in the prior art and generally consist of a load switch and a selector. A load switch equipped with a vacuum interrupter and a boundary resistor is arranged in one container. The selector consists of a number of bars arranged in the system. Contacts serving as terminals for individual taps of the control winding are arranged in different planes on those bars. In the selector, two selector arms are fixed to the opening and closing supports. They contact the bars, the load switch, and the contacts of the selector and are connected to each other via a transmission device.

[0003] The operation of the on-load tap changer is performed using a drive unit. The drive unit, on the one hand, energizes a spring-type energy accumulator to operate the load switch and, on the other hand, moves the selector arms to pre-select the contacts to be connected. In that case, both the load switch and the selector always operate the switching means for all three phase contacts simultaneously. Since the same contacts of each phase must be operated at the same time, this necessarily causes a sudden increase in the rotational moment. The drive unit, the spring-type accumulator, and the transmission device must be designed so that they can withstand the sudden increase in the rotational moment.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem of the present invention is to realize an on-load tap changer that generates a clearly smaller sudden increase in rotational moment during operation, is configured simply and compactly, and guarantees a safer function at that time.

Means for Solving the Problems

[0005] This problem is solved by the on-load tap changer according to claim 1. In this case, the features of the dependent claims form an advantageous improved configuration of the present invention.

[0006] In a first aspect, the present invention relates to an on-load tap changer that performs load switching between different winding taps of a tapped transformer without power outage, A first module equipped with a first module shaft, A second module equipped with a second module shaft, It has, This first module shaft operates the first module, This second module shaft operates the second module, The first and second module shafts are mechanically connected to each other such that the first module shaft drives the second module shaft, causing the second module to operate with a time lag relative to the first module. I propose a tap changer that operates under load.

[0007] The division of the on-load tap changer into individual modules and their offset mechanical connection significantly reduces the dramatic increase in rotational moment. This is achieved by the fact that the components to be operated in the on-load tap changer modules are indeed driven simultaneously, but in a slightly offset sequence. In this case, the offset is just large enough that it does not cause unfavorable electrical interactions between the individual phases of the tapped transformer, but the resulting increase in rotational moment occurs in a slightly offset manner. This clearly allows for the use of simpler, and therefore cheaper, motors. Furthermore, since the individual parts of the drive shaft must withstand smaller loads of rotational moment, these parts can be made smaller in size. This also positively impacts the overall cost of the changer. Without offset mechanical connection, the same components in each module would be moved or operated simultaneously. The required forces would be added together, which would necessitate a drive unit with corresponding performance.

[0008] Each module can be configured in any form as needed, for example, it may have a single module shaft. The first module shaft of the first module is mechanically connected to the second module shaft of the second module. In this case, these module shafts are mechanically connected to each other in a staggered manner so that the operation of the individual modules is performed in a staggered manner. In other words, although the two module shafts do indeed begin to rotate simultaneously, the actions on the constituent elements in their modules (opening and closing of vacuum switches) are performed in a time-staggered manner.

[0009] These modular shafts can be connected to each other in any form as needed, for example, via insulating rods, insulating shafts, or chains.

[0010] These modules, in particular the offset configuration between module shafts, can be configured in any form as needed, for example, as an insulating shaft configured to match the offset connection pins in the module shaft, or as a module shaft configured to match the insulating shaft with an offset housing. In this case, how the offset between module shafts is ultimately achieved is not important.

[0011] This load changer can be configured in any form as needed, and for example, it may have at least two or more modules. Each of these modules is assigned to one phase of a tapped transformer.

[0012] Each module can be configured in any form as needed, for example, it may have at least one load changer and one selector. In this case, the load changer may have at least one switching element and one current limiting element. This at least one switching element may be configured as a vacuum switch or a simple mechanical switch. This current limiting element is advantageously a resistor, a choke coil, or a current-dependent resistor. The selector comprises at least one selector arm, advantageously two selector arms as a fine-tuning selector and / or one pre-selector arm as a pre-selector.

[0013] Each module shaft can be configured in any form as needed, for example, with connecting pins, bolts, feather keys, or any other connecting components at each end. In this case, the connecting pins are not parallel to the axis, but are advantageously offset from each other by up to 15°. These connecting pins, bolts, or feather keys can be located on only one side or extend throughout the entire module shaft.

[0014] Each module shaft can be configured in any form as needed, for example, with a first connecting pin at a first end and a second connecting pin at a second end. This first connecting pin can extend along a first axis A, and this second connecting pin can extend along a second axis B, and these axes A and B are not parallel to each other, but advantageously offset by an angle of up to 15°.

[0015] This drive unit can be configured in any form as needed, and for example, it may include at least one motor and / or one transmission device. This motor may be configured as a synchronous motor with a multi-turn absolute encoder or as a DC motor with a microswitch.

[0016] These module shafts and insulating shafts can be defined as being connected via a clutch comprising a clutch and / or a plurality of clutch plates.

[0017] It can be defined that this motor is directly connected to the insulating shaft or the first module shaft of the on-load tap-changer, either directly or via a transmission device, an angle transmission or a rod.

[0018] Hereinafter, the present invention and its advantages will be described in detail with reference to the accompanying drawings.

Brief Description of the Drawings

[0019] [Figure 1] Schematic diagram of the first implementation configuration of the on-load tap-changer [Figure 2a] Detailed view of the module shaft [Figure 2b] Front view of the module shaft [Figure 3] Perspective view of a plurality of module shafts of the on-load tap-changer according to the present invention [Figure 4] Another detailed view of the module shaft

Modes for Carrying Out the Invention

[0020] The same reference numerals are used for the same or equivalent components of the present invention. Further, for the sake of clarity, each drawing shows only the reference numerals necessary for the description of that drawing. The illustrated implementation is merely an example of how the on-load tap-changer according to the present invention can be configured, and thus does not ultimately limit the present invention.

[0021] Figure 1 illustrates a schematic structure of an on-load tap changer 1 according to the present invention. It has a first module 20, a second module 40, and a third module 60. Each of these modules 20, 40, and 60 is assigned to one phase of a tapped transformer. The first module 20 includes a first module shaft 22. The first module shaft 22 has its first end 23 connected to or coupled with a drive unit 2. The drive unit 2 is configured as a motor drive unit with or without a transmission device and is advantageously mechanically connected to the first end 23 of the first module shaft 22 via a first insulating shaft 21. The first module 20 includes a load changer 30 and a selector 35. The load changer 30, in particular its vacuum switch, is operated directly by the first module shaft 22. Here, two cam discs 32 are mounted on the first module shaft 22 and open and close the vacuum switch when they rotate. Furthermore, the first module shaft 22 is equipped with a first bevel gear 36 that drives the second bevel gear 37, and this second bevel gear further operates the individual selector arms of the selector 35. Therefore, when the first module shaft 22 is driven, the load changer 30 and the selector 35 are operated in a predetermined order, and the first module 20 of the load tap changer 1 is operated.

[0022] Furthermore, this on-load tap changer 1 has a second module 40 and a third module 60. These three modules 20, 40, and 60 are identically configured. These three modules are further mechanically connected to each other via second and third insulating shafts 41 and 61. The drive unit 2 drives the first module 20 via the first insulating shaft 21, the first module 20 drives the second module 40 via the second insulating module 41, and the second module 40 drives the third module 60 via the third insulating module 61. These second and third modules 40 and 60 each include load changers 50 and 70, selectors 55 and 75, and module shafts 42 and 62, respectively. Each selector 55 and 75 is driven by bevel gears 56, 57, 76, and 77, respectively.

[0023] Figure 2a shows a detailed view of the first module shaft 22, which has a first connection pin 24 at its first end 23. By means of this first connection pin 24, the first module shaft 22 is connected to the drive unit 2, for example via a first insulating shaft 21. Furthermore, the first module shaft 22 has a second connection pin 26 at its second end 25. This second connection pin 26 is not arranged parallel to the axis of the first connection pin 24 on the module shaft 22. In other words, this second connection pin 26 is arranged at a slight angle with respect to the first connection pin 24. As an alternative configuration of these connection pins, bolts, feather keys or any other connecting components can be used. This connection pin can protrude only on one side or can extend from one side to the opposite second side.

[0024] Figure 2b shows a front view of the module shaft 22. Axis A represents the direction of the first connection pin 24. Axis B represents the direction of the second connection pin 26. These axes A and B are preferably arranged offset from each other at an angle W1 of up to 15°. Here, when the second module shaft 42 is installed behind and connected to the first module shaft 22, the first connection pin 44 of the second module shaft 42 extends parallel to the axis of the second connection pin 26 of the first module shaft 22. Each module shaft 22, 42, 62 is similarly configured, that is, the second connection pins 26, 46, 66 are arranged offset with respect to the first connection pins 24, 44, 64 respectively. Axis C represents the direction of the second connection pin 46 of the second module shaft 42 which is not shown here. The angle W2 between axis B and C is the same as the angle W1 between axis A and B.

[0025] Figure 3 shows a detailed view of two module shafts connected to each other, in particular the first module shaft 22 and the second module shaft 42. The first connecting pin 24 at the first end 23 of the first module shaft 22 is offset from the second connecting pin 26 at the second end 25. The first end 23 of the first module shaft 22 is connected to the drive unit 2 via the first insulating shaft 21. The connection between the first insulating shaft 21 and the first module shaft 22 is advantageously achieved using a clutch 19 with two clutch plates. However, any type of clutch can be used. The second end 25 of the first module shaft 22 is connected to the first end 43 of the second module shaft 42 via the second insulating shaft 41. Here, as is clear, the first connecting pins 24 and 44 of each module shaft 22 and 42 are connected to each other in an offset manner. When the drive unit 2 starts rotating or driving the first insulating shaft 21, the other shafts also rotate together. However, since the cam discs of the second module 40 or the third module 60, as well as the first bevel gear, are positioned offset from the cam disc of the first module 20 and the first bevel gear, the operation of modules 20, 40, and 60 is performed in an offset manner.

[0026] Here, the insulating shafts 41 and 61 are configured identically; in other words, the clutches 19 at each end are identical. As an alternative configuration to the module shaft with offset connecting pins, the insulating shaft can also be equipped with offset clutches at each end. In this way, the offset mechanical connection of the modules is similarly realized. These modules are driven simultaneously and in common, but are operated with a time delay.

[0027] Figure 4 shows a detailed view of one of the module shafts 20, 40, and 60, specifically the first module shaft 20, while the second and third module shafts 40 and 60 are identically configured. This module shaft 20 houses two cam discs 32 for operating the vacuum switch and a first bevel gear 36 for operating the selector 35. Rotation of the module shaft 20 within 360° controls the operation of the load changer 30 and the selector 35. Depending on the position of the module shaft 20, individual operations of the load tap changer, such as opening and closing the vacuum switch during the switching process, are performed at predetermined times. If at least two module shafts 40 and 60 are connected in a offset manner, the operation of the second module 40 will be performed in a correspondingly slightly offset manner relative to the first module 20; in short, modules 20, 40, and 60 are identically configured. In this case, the second module 40 is indeed driven simultaneously with the first module 20, but the original operation of the second module 40 (opening and closing of the vacuum switch) is performed with a time delay.

[0028] As an alternative configuration to module shafts 20, 40, and 60 with offset connection pins, an insulated shaft can also have offset housings at both ends. This allows the module shafts to be mechanically connected in an offset manner from one another. Furthermore, the present invention may also encompass the following embodiments: 1. An on-load tap changer (1) that performs load switching without power outage, A first module (20) equipped with a first module shaft (22), A second module (40) equipped with a second module shaft (42), It has, This first module shaft (22) operates the first module (20), This second module shaft (42) operates the second module (40), An on-load tap changer in which the first module shaft (22) drives the second module shaft (42), and the first and second module shafts (22, 42) are mechanically connected to each other such that the first module shaft (22) drives the second module shaft (42), and the second module (40) is operated in a time-delayed manner relative to the first module (20). 2. In the on-load tap changer (1) described in 1 above, An on-load tap changer in which the drive unit (2) drives the first module shaft (22). 3. In the on-load tap changer (1) described in 1. or 2. above, A third module (60) is provided, which includes a third module shaft (62). An under load tap changer in which the second and third module shafts (42, 62) are mechanically connected to each other such that the third module shaft (62) operates the third module (60), and the second module shaft (42) drives the third module shaft (62), causing the third module (60) to be operated in a time-delayed manner relative to the second module (40). 4. In the load tap changer (1) described in any one of 1. to 3. above, An on-load tap changer in which the aforementioned modules (20, 40, 60) are connected to each other via insulating shafts (21, 41, 61). 5. In the load tap changer (1) described in any one of 1. to 4. above, Each module shaft (22, 42, 62) is equipped with a first connecting pin (24, 44, 64) and a second connecting pin (26, 46, 66). This is an on-load tap changer in which the first connection pins (24, 44, 64) are positioned offset from the second connection pins (26, 46, 66). 6. In the load tap changer (1) described in any one of 1. to 5. above, An under load tap changer in which the first module shaft (22) is connected to a second module shaft (42) via a second insulating shaft (41), and the second module shaft (42) is connected to a third module shaft (62) via a third insulating shaft (61). 7. In the load tap changer (1) described in any one of 1. to 6. above, An on-load tap changer in which each module (20, 40, 60) is assigned to one phase of a tapped transformer. 8. In the load tap changer (1) described in any one of 1. to 7. above, Each module (20, 40, 60) is a load-operated tap changer with load selectors (30, 50, 70) and selectors (35, 55, 75). [Explanation of Symbols]

[0029] 1. On-load tap changer 2 Drive unit 19 Clutch 20 First Module 21 First insulating shaft 22 First module shaft 23 First end of the first module shaft 22 24 First connection pin of the first module shaft 22 25 Second end of the first module shaft 22 26 Second connection pin of the first module shaft 22 30 Load switch 32 Cam disk 35 Selector 36 First bevel gear 37. Second bevel gear 40 Second Module 41 Second insulating shaft 42 Second modular shaft 43 First end of the second module shaft 42 44 First connecting pin of the second module shaft 42 45 Second end of the second module shaft 42 46 Second connection pin of the second module shaft 42 50 Load switch 55 Selector 60 Third Module 61 Third insulating shaft 62 Third Module Shaft 63 First end of the third module shaft 62 64 First connecting pin of the third module shaft 62 65 The second end of the third module shaft 62 66 Second connection pin of the third module shaft 62 70 Load switch 75 Selector

Claims

1. An on-load tap changer (1) that performs load switching without power outage, A first module (20) comprising a first module shaft (22) connected to a drive unit (2), and a first load switch (30) and a first selector (35) operated by a drive mechanism of the first module shaft (22), A second module (40) comprises a second module shaft (42), and a second load switch (50) and a second selector (55) operated by a drive mechanism of the second module shaft (42), It has, The first module shaft (22) is provided with a first connecting pin (24) and a second connecting pin (26), the second module shaft (42) is provided with a third connecting pin (44), the second connecting pin (26) is positioned offset from the first connecting pin (24) in the direction driven by the drive unit (2), and the first and second module shafts (22, 42) are mechanically connected via the second connecting pin (26) and the third connecting pin (44), which are positioned at the same angle to each other, and at least Furthermore, the structure of the first module shaft (22) including the drive mechanism and the first connecting pin (24) and the structure of the second module shaft (42) including the drive mechanism and the third connecting pin (44) are identical in shape, so that the first load changer (30) and the first selector (35) of the first module (20) and the second load changer (50) and the second selector (55) of the second module (40) are operated in a time-delayed manner. The on-load tap changer is such that the drive unit (2) is mechanically connected to the first module shaft (22) via the first insulating shaft (21) by the first connecting pin (24), and the first module shaft (22) is mechanically connected to the second module shaft (42) via the second insulating shaft (41) by the second connecting pin (26) and the third connecting pin (44).

2. In the on-load tap changer (1) according to claim 1, A third module (60) is provided, which includes a third module shaft (62) and a third load switch (70) and a third selector (75) operated by a drive mechanism of the third module shaft (62). This third module shaft (62) is mechanically connected to the third module shaft (62) via a third insulating shaft (61) positioned between the second module shaft (42) and the third module shaft (62) by a fourth connecting pin (46) positioned at the other end of the second module shaft (42) at a further angle to the third connecting pin (44) in the direction driven by the drive unit (2), and a fifth connecting pin positioned at one end of the third module shaft (62) at the same angle as the fourth connecting pin (46), thereby configuring the load-on tap changer such that the second load changer (50) and the second selector (55) of the second module (40) and the third load changer (70) and the third selector (75) of the third module (60) are operated in a time-delayed manner.

3. In the on-load tap changer (1) according to claim 1 or 2, An on-load tap changer in which each of the aforementioned modules (20, 40, 60) is assigned to one phase of a tapped transformer.

Images