UA70325C2 - Power tap-changer - Google Patents

Abstract

The invention relates to a selector switch for tapped transformers to enable continuous tap switching with respect to a tapped winding, whereby fixed stepped contacts are arranged inside a cylinder made of insulating material on a horizontal plane for each phase. A rotating actuating shaft is located inside the insulating cylinder. The actuating shaft has a moveable hinged contact carrier for each phase that is to be switched and vacuum switching cells are respectively and vertically arranged on said contact carrier.

Description

Description of the invention

The invention relates to a power selector for transformers with stepped voltage regulation for 2 continuous switching of taps of the regulating winding of the transformer.

Such power selectors are already known from the German patent 38 33 126 C2.

Power selectors are used to switch under load the taps of the regulating windings of transformers in order to compensate for voltage changes.

By eliminating the commonly used separate selectors and power switches, the 710 power selectors are less expensive to manufacture and easier to use.

During the switching process, electric arcs occur in the power selectors on various contacts. To prevent this, in the above-mentioned German patent 38 33 126 C2, a power selector is provided, in which in each phase to be switched, two movable simultaneously movable mechanical switching contacts are installed on a common contact holder, and, in series with each of the two movable 72 mechanical switching contacts contacts are switched on by one vacuum switching element, also installed on the contact holder. Fixed contacts of the power selector connected to the taps of the winding, which can be contacted by movable mechanical switching contacts, are placed on a concentric ring in the wall of a cylindrical housing made of insulating material. The vacuum switching elements are placed horizontally on the contact holder and their control or actuation is carried out by a cam track located on another concentric ring, which in the axial direction is placed between the ring of fixed contacts and the additional contact ring.

This famous power selector has several drawbacks.

Firstly, due to the horizontal position of the vacuum switching elements placed on the common contact holder, the body and, thereby, the entire power selector have an undesirably large diameter. Depending on the nominal switching power, vacuum switching elements have certain minimum Ge) dimensions, especially in the longitudinal direction. In addition, a drive pusher protrudes from the vacuum switching element in the longitudinal direction. Therefore, it is obvious that the common contact holder must have the size in the radial direction of the power selector determined by the dimensions of the vacuum element and its drive means, which determines the overall diameter of the latter. at

Based on this general size problem, a particular disadvantage of the horizontal placement of vacuum switching elements according to the prior art is that when the power selector is filled with oil in the upper folds of the bellows of the vacuum switching element, the oil is not completely displaced by the air. As a result of this, during the operation of the vacuum switching element, there is an uneven Ha») loading of the folds of the bellows, as a result of which there is a danger of its destruction. Reliable extraction of air residues from the folds of a horizontally placed bellows is possible only when filling the power selector with oil under vacuum; however, such a vacuum filling of the selector with oil in place, for example, after carrying out preventive work, is impossible or can be realized only with unacceptably great difficulties. In addition, it should be taken into account that the power selector, as a rule, is extended along the axis, that is, it has a large structural height. The stationary contacts of individual phases are placed in a circle one above the other, placed in C 70 the upper part of the power selector are the means for actuating the rotary drive shaft inside the power selector, on which the contact holders of each phase are installed, as well as the elements of the support unit for the drive shaft in the lower part of the power selector also require space, as a result of which the power selector, as mentioned above, has a significant size in the axial direction. The consequence of this is that the drive shaft inside the power selector is also very long. Such shafts are usually made of fiberglass-reinforced plastic or other insulating material, although metal drive shafts have also been proposed. In well-known and power selectors, the contact holders are fixed on the drive shaft with the help of fastening screws. av | German patent 44 14 951 C1 describes another option for attaching the contact holder to the drive shaft using a clamping flange. o As a result of tolerances, different temperature expansion of the oil tank and switch package, bending forces, etc. in known power selectors, problems may arise during the interaction of contact elements placed on individual holders - especially vacuum switching elements - with drive means placed around the circle, in particular because the drive pushers of vacuum switching elements usually have a relatively small linear working stroke.

The task of the invention is to eliminate these shortcomings and to develop a power selector of the specified kind, in which 22 compact placement of vacuum switching elements and their reliable activation at

GF) under different operating conditions.

This task is solved in the power selector for transformers with step voltage regulation for uninterrupted switching of taps of the regulating winding of the transformer, and the power selector contains a cylindrical housing made of insulating material, connected to the taps of the regulating winding, fixed 60 contacts are placed inside along the circumference of the cylindrical housing in a dedicated for of each phase on a horizontal level, in the center of the cylindrical body with the possibility of rotation is installed a drive shaft, on which also with the possibility of rotation is installed a dedicated contact holder for each horizontal level of fixed contacts, each of the contact holders contains at least two mechanical contacts installed with the possibility of forming an electrical contact with fixed contacts of a given horizontal level, at least one of the bo contacts on each contact holder is directly electrically connected to the first vacuum switching element, and at least one other contact on each each contact holder through a switching resistor is electrically connected to the second vacuum switching element, and the opposite terminals of both vacuum switching elements on the contact holder are electrically connected to the power tap, due to the fact that all contact holders are mounted on the drive shaft with the possibility of movement independently of each other, and both vacuum switching elements are mounted on the contact holder vertically in such a way that their drive pushers are oriented parallel to the axis of the drive shaft.

In addition - according to the additional claims of the invention - each contact holder is installed on the drive shaft with the possibility of deflection around the axis of rotation, each of the contacts consists of at least 70 one upper part and at least one lower part, moreover, each part of the contact with the help of at least one spring are pressed against each other in such a way that when placed opposite the fixed contact, they mechanically cover it from both sides, forming an electrical contact, the fixed contacts placed inside the cylindrical body are made elongated in the horizontal direction, and, moreover, they do not match the internal contour of the cylindrical body, but straight shape, and on the inner wall 7/5 of the cylindrical body for each phase and, thus, for each horizontal level of fixed contacts, a control ring is installed, which has an upper control circuit and a lower control circuit, on each contact holder for both vacuum switching elements nts, a lever is installed on the axis of rotation, and the lever is designed in such a way that one end of it is connected to the drive pusher of the vacuum switching element, and the other end has the ability to move along one of the control circuits in such a way that - in 2o depending on the spatial the shape of this control circuit - the corresponding vacuum switching element can be turned on, and each power tap consists of a concentric tap-off contact ring installed on the inner wall of the cylindrical body, from which the connecting element is brought out, and on the corresponding contact holder with the possibility of forming an electrical contact with the tap-off contact the ring is fitted with a tap-off contact electrically connected to the vacuum switching elements mounted on this contact holder, and each contact holder contains two additional rollers mounted in such a way that they cover the tap-off contact ring on both sides, i) zd there is a forced direction of the contact holder, and the control ring and lead contact ring of each phase are made in the form of a single structural element.

In the power selector according to the invention, the vacuum switching elements are placed on the MU contact holders vertically. Contact holders contain sliding contacts. They are precisely guided by rollers in the guide ring. Control of the vacuum switching elements is carried out by cams in this guide ring. with

Knife sliding contacts installed in the contact holder divert the current through the lead-off ring. with

Other sliding knife contacts installed on the contact holder make it possible to supply current.

According to another feature of the invention, the contact holders are movably mounted on the drive shaft. at

A special advantage of the invented power selector, along with reduced dimensions, is that all M. forces when actuating the vacuum switching elements, as well as contact forces through the lead-off ring and fixed contacts are radially transmitted to the stable oil tank. Thanks to this, the radial load of the switching package is eliminated, in particular, its bending, and the resulting change in the actuation time of the vacuum switching elements, as well as a reduction in contact forces. "

Thanks to the installed contact holder with the possibility of rotation or axial movement, which is guided along the axis by a guide ring, a normal switching process is ensured even when it is shifted in height due to tolerances and different temperature expansion of the oil tank and the switch;" package

Below, examples of the implementation of the invention are explained in more detail with the use of figures. They depict:

Fig. 1 An example of the form of execution of the invented power selector in a partial side section, - and Fig. 2 A fragment of the contact holder of this power selector in a section from above,

Fig. 3 The scheme underlying the power selector according to the invention, o Fig. A4 Modified scheme according to Fig. 3, 2) Fig. 5 Typical switching sequence in the power selector according to the invention.

Fig. 1 shows the first embodiment of the invented power selector, in which a rotatable contact holder C is installed on the drive shaft 2, on which vacuum sp switching elements 27, 28 are vertically placed.

Details of the constructive implementation:

The power selector consists of a cylindrical body 1 made of insulating material, along the axis of which a drive shaft 2, made mainly of insulating material, is installed. The drive shaft 2 is installed in a known manner with the possibility of rotation; Maltese mechanisms, not shown in more detail, are used for this.

F) The installation of the drive shaft 2 on the support at the bottom of the cylinder 1 is also not shown in detail. On the drive shaft 2, in each level of the fixed contacts 16 for the winding taps, the explanation of which will be given below, a contact holder Z is provided, with the possibility of rotation, installed in the support in bracket 4 on drive shaft 2. Support bracket 4 is fixed on drive shaft 2 with screws 4.1, 4.2.

The contact holder Z consists of a support element 5, a supporting body 6, and a contact body 7. Individual parts of the contact holder Z are connected to each other with screws 8, 9. In the shown example, the contact body 7 in turn consists of an upper part 10 and a lower part 11; both parts are connected by a screw 12. The contact housing 7 can also be made as one part. The support element 65 5 has a support hole 13, into which a finger 14 is inserted, which provides connection to the support bracket 4 with the possibility of rotational movement. Finger 14 is locked by pin 15.

In general, thanks to this fastening, the entire contact holder Z as a finished structural unit has the ability to rotate around the finger 14 and, thereby, relative to the stationary drive shaft 2.

In the wall of the cylindrical housing 1 - for each phase in a separate level - fixed contacts 16 are installed, electrically connected to the terminals of the regulating winding of the transformer with stepped voltage regulation.

Contacts 17, 18 touching them can form an electrical connection with fixed contacts 16. These contacts 17, 18 are placed in a horizontal direction next to each other in such a way that when turning the drive shaft 2, and with it the contact holder C, one of the contacts 17, 18 reaches the adjacent stationary contact 16 earlier than the other of these contacts leaves the previous stationary contact. At the same time, 7/0 Contact 17 acts as a switching contact, and the other contact 18 acts as an auxiliary contact.

Fig. 2 in the top view shows the placement of both contacts 17, 18 next to each other on the contact holder Z, as well as their interaction with the fixed contact 16. In the example of the invention shown in Fig. 2, the switching contact 17 in order to give it the greatest possible load capacity is made in the form of two electrically interconnected parts 17a, 170. Each of the contacts 17, 18 consists of the upper part 75 17.1, 18.1 and the lower part 17.2, 18.2. Thus, in the special design of the switching contact 17 shown in Fig. 2, it consists of a total of four parts, namely two upper parts 17.1a, 17.15 and two lower parts 17.2a, 17.20. Such a dual performance of the contact 17 acting as a switching contact is appropriate for many different applications, but is not necessary for the present invention.

Both the upper parts 17.1, 18.1 and the lower parts 17.2, 18.2 of each of both contacts 17, 18 are installed

In the body 7 with the possibility of rotation around separate axes of rotation 19, 20, 21, 22. They are pressed against each other by springs 23, 24, 25, 26 in the direction of the fixed contact 16 placed between them.

In other words: the upper parts 17.1, 18.1, as well as the corresponding parts 17.2 18.2 of the contacts on both sides press on the stationary contact 16 with a certain contact force. Thanks to the above-described installation on the rotary supports around the axes of rotation 19, 20, 21, 22, it is possible to run into the fixed contact 16. In fig. 1 and 2, it is VISIBLE to see only the parts of the contacts, the axis of rotation and the spring placed in the direction of vision from the front and above.

In addition, vacuum and) switching elements 27, 28 are fixed on each contact holder with the help of clamps 29, 30, 31, 32 in such a way that bellows 33, 34, as well as drive pushers 35, 36 of vacuum switching elements 27, 28 oriented upwards. Of the structural elements just described in Fig. 1, only those that lie ahead in the direction of vision are also visible. Two levers 37, 38 are used to actuate the drive pushers 35, 36 and the vacuum switching elements 27, 28, on the free ends of each of which the axes 41, 42 of the control rollers 39, 40 are installed. The other free ends of the levers 37, 38 act on drive pushers 35, 36. Rotatable levers 37, 38 are mounted on axes 43, 44; the axis of rotation of these levers can also be common. The control rollers 39, 40 of both levers 37, 38 in turn touch the control ring 45, which has an upper control circuit 46 and a lower control circuit 47. The control ring 45 extends along the inner wall of the cylindrical body 1. It can be seen from Fig. 1 that the first control the roller 39 touches the lower control circuit 47, i.e., passes along it, and in the same way the second control roller 40 passes along the upper control circuit 46. Thus, both control circuits 46, 47 serve to actuate the vacuum switching contacts 27 , 28, when when the roller 39, 40 hits the cam, the lever 37, 38 rotates around its axis 43, 44 and presses on the corresponding drive pusher 35, 36 of the vacuum "switching element 27, 28, with c In addition, on the inner surface of the cylindrical body 1, a lead-off contact ring 48 is installed, which has an external connecting element 49 and serves for power voltage removal. Very simple;" thus, the control ring 45 and the lead contact ring 48 can be combined into one structural part, as shown in fig. 1. In turn, the lead-off contact ring 48 touches the mechanical lead-off contact 45. 50, which is placed on the contact holder Z and similarly to the contacts 17, 18 described above, consists of the upper-I part 50.1 of the lead-off contact and the lower part 50.2 of the lead-off contact. These two parts 50.1, 50.2 of the lead-off contact with the possibility of rotation are mounted on separate axes 53, 54 and springs 51, 52 and are pressed against each other in such a way that they cover the lead-off 2) contact ring 48 with a certain contact force.

Finally, the contact holder C contains two more rollers 55, 56, which roll on both sides of the lead ring 48 and guide the entire contact holder C. Thanks to the described design, compensation of all kinds of tolerances, as well as deflection of the long drive shaft, is ensured. Installed with the possibility of deviation relative to the drive shaft, the Z contact holders are always accurately guided by the lead contact target 48, thanks to which, despite the described tolerances,

Precise control of the rollers 39, 40 is ensured and, thus, actuation of the vacuum switching elements 27, 28 - despite their very small working stroke.

F) Fig. 3 shows the scheme implemented by the power selector according to the invention. Electrical connections between ka contacts 17, 18 and vacuum switching elements 27, 28, and from them to the lead contact 50, in Fig. 1, which corresponds to this scheme, are not shown. in Fig. 4 shows a diagram in which, as shown in Fig. 2, the switching contact 17 consists of parts of contacts 17.1, 17.2 placed opposite each other. In Fig. 2, which corresponds to this scheme, electrical connections are also not shown. It is obvious that the principles of operation do not differ, that is, both according to the scheme according to Fig. 3 and according to the scheme according to Fig. 4, the same sequence of switching is achieved.

An example of such a switching sequence is shown in Fig. 5. 65 This shows the power selector with different switching steps. Such a power selector with different switching steps is known in principle from the European patent EP 0160 125. In it, the average distance between the fixed contact connected to the main winding and both adjacent fixed contacts for the winding taps is greater; than the average distance between the remaining fixed contacts. This makes it possible to use the power selector also for transformers with higher nominal voltage values; thanks to this

Resistance to larger voltage outages can be achieved. Fixed contacts of various designs suitable for such power selectors have already been described in this publication.

Regardless of this, it is particularly advantageous to make the fixed contacts 16 not curved, that is, parallel to the curvature of the cylindrical body 1, but equal, as shown in Fig.2. Whereas according to the prior art, both upper and lower parts 17.1,18.1; 17. 2,18,2 movable contacts always slide on the same 7/0 track on the curved fixed contacts 16, when moving along the straight fixed contacts 16, parts of the movable contacts touch different points on the surface of the fixed contacts, due to which their wear is reduced. i6 1. . 45 40 16 FIG. 1 -

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Claims (8)

The formula of the invention. "" 1. Power selector for transformers with stepped voltage regulation for continuous switching of taps of the regulating winding of the transformer, and the power selector contains a cylindrical body made of insulating material, and the fixed contacts connected to the taps of the regulating winding are placed inside along the circumference of the cylindrical body in the lead for each phase on the horizontal level, and in the center of the cylindrical body with the possibility of rotation is installed a drive shaft, on which also with the possibility of rotation is installed a holder Ge) of the contacts set aside for each horizontal level of fixed contacts, and each of the contact holders contains at least two mechanical contacts installed with 5r The possibility of forming an electrical contact with the fixed contacts of a given horizontal level, and at least one of the contacts on each contact holder is directly electrically connected to the first sl vacuum switching element, and at least one this other contact on each contact holder is electrically connected through a switching resistor to a second vacuum switching element, the opposite terminals of both vacuum switching elements on the contact holder being electrically connected to a power Tap, which differs in that all the (3) contact holders installed on the drive shaft (2) with the possibility of moving independently of each other, as well as the fact that both vacuum switching elements iF) (27, 28) are installed on the contact holder (3) vertically in such a way that their drive pushers (35, Zb ) are oriented parallel to the axis of the drive shaft (2). 2. The power selector according to claim 1, which differs in that each contact holder (3) is installed on the drive shaft (2) with the possibility of deflection around the axis of rotation. C. The power selector according to claim 1 or 2, which is characterized by the fact that each of the contacts (17) consists of at least one upper part (17.1, 18.1) and at least one lower part (17.2, 18.2), and each part (17.1, 18.1 ; 17.2, 18.2) of the contact with the help of at least one spring (23, 24, 25, 26) are pressed against each other in such a way that when placed opposite the fixed contact (16), they mechanically 65 cover it from both sides, forming an electrical contact. 4. The power selector according to claim 1-3, which differs in that it is placed inside the cylindrical body (1) fixed contacts (16) are made elongated in the horizontal direction, and they have a straight shape, not coordinated with the internal contour of the cylindrical body (1). 5. A power selector according to one of claims 1-4, which is characterized by the fact that a control ring (45) is installed on the inner wall of the cylindrical housing (1) for each phase and, thus, for each horizontal level of fixed contacts (16), which has an upper control circuit (46) and a lower control circuit (47), as well as the fact that a lever (37, 38), as well as the fact that the lever is designed in such a way that one end of it is connected to the drive pusher (35, 36) of the vacuum switching element (27, 28), and the other end has 7/0 The ability to move one at a time from the control circuits (46, 47) in such a way that - depending on the spatial shape of this control circuit (46, 47) - the corresponding vacuum switching element (27, 28) can be turned on. 6. Power selector according to one of claims 1-5, which is characterized by the fact that each power take-off consists of a concentric lead-off contact ring 7/5 (48) installed on the inner wall of the cylindrical body (1), from which the connecting element (49) is brought out ), and on the corresponding holder (3) of contacts with the possibility of forming an electrical contact with the lead contact ring (48), a lead contact (50) is installed, electrically connected to the vacuum switching elements (27, 28) installed on this holder (3) contacts 7. A power selector according to one of claims 1-6, which is characterized in that each holder (3) of the contacts contains two 2o additional rollers (55, 56), installed in such a way that they cover on both sides the lead contact ring (48) , making a forced direction of the contact holder (3). 8. A power selector according to one of claims 1-7, which is characterized by the fact that the control ring (45) and the lead-off contact ring (48) of each phase are made as a single structural element. триигя я " : " " : : povs Official Bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2004, M 10, 15.10.2004. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine IF) with (ze) "c) and - - and? -i («c) (95) ime) sl ime) 60 b5