EP3022754B1 - Selector switch - Google Patents

Description

The present invention relates to a load selector. The load selector comprises a diverter switch insert with a switching tube rotatable about an axis. A first phase, a second phase and a third phase are arranged along the axis of the switching tube. Each phase comprises a switching segment each having a resistor arrangement.

Such load selectors belong to on-load tap changers (in English "on-load tap changers", abbreviated OLTC) and are well known and commonly used in the prior art. They are used for uninterrupted switching between different winding taps of tapped transformers.

In general, on-load tap-changers are actuated by a motor drive when switching over. By the motor drive an output or input shaft is moved, which raises a power storage. If the energy storage fully wound, ie strained, he is unlatched, releases his energy abruptly and operated in the period of milliseconds (ms) a diverter switch insert, which performs a specific switching sequence during load switching. In this case, different switch contacts and resistor contacts are actuated in a specific time sequence. The switch contacts are used for direct connection of the respective winding tap with the load dissipation, the resistor contacts for short-term wiring, ie bridging means of one or more switching resistors. Advantageously, vacuum interrupters are used as switching elements for load switching. This is due to the fact that the use of vacuum interrupters for load switching prevents arcing in the oil and thus the oil pollution of diverter switch oil, as for example in the German patents DE 195 10 809 C1 and DE 40 11019 C1 as well as the German Offenlegungsschriften DE 42 31 353 A1 and DE 10 2007 004 530 A1 described.

A special form of load selectors are known from the prior art star point load selector. Star point load selectors have three phases along the switching tube. The contact systems of the individual phases are in the operating state at a neutral point potential. This is disclosed, for example, in the German Offenlegungsschrift DE 32 26 854 A1 , In this type of load selectors, all three phases are connected to each other via a metallic pipe section. In addition, they then additionally have a tube piece made of an insulating material put together with the metallic tube piece in order to form a Isolation against earth to take over. Furthermore, then still has to be a linkage with a bottom of an oil vessel of the load selector. A disadvantage of this load selector that Ableitkontakte the second and third phase must be individually connected to the pipe section. These phases must then be silvered, so that high costs arise. In addition to the high production costs, this star point load selector is complex due to the individual connections of the phases and the articulation with the ground and thus causes a complicated structure of a load selector.

Furthermore, from the JP H03 289 111A a spring energy storage for an on-load tap changer, which is constructed of diverter switch and selector known. The spring energy storage is used only for the operation of the diverter switch. In order to be able to control the switching times of the diverter switch, a flywheel is arranged on the spring energy store, close to the drive shaft. This serves as a holder for variably adjustable and selectable weights. During assembly of the on-load tap changer, the spring energy store can thus be adapted to the diverter switch by adjusting or replacing the weights. Due to the division of the on-load tap-changer in diverter switch and selector flywheel is designed to be large and takes up a lot of space, which is available in the diverter switch of the on-load tap-changer available.

The object of the invention is to provide a cost-effective load selector or star point load selector, which is also still simple.

This object is achieved by a load selector comprising the features of claim 1.

The load selector according to the invention comprises a diverter switch insert with a switching tube rotatable about an axis. Three phases are arranged along the axis of the switching tube. Each phase comprises a switching segment each having a resistor arrangement.

According to the invention, a flywheel is mounted on the switching tube. Further, the switching tube carries a parallel along the axis to the switching tube extending massive and electrically conductive element which is connected by means of an electrical connection to each phase.

In particular, the star point load selector according to the invention provides that the massive Element is electrically connected to the flywheel. This could for example be done by a screw of two components.

For reasons of safety, all non-live and electrically conductive parts in electrical equipment must be at the same potential (possibly earthed). Since the high-mass element and the flywheel are preferably made of metal, they are at neutral point potential. Since a bottom of the star point load selector is also made of metal, it must also be articulated. Thus, a preferred embodiment of the invention provides that between the bottom of the neutral load selector and the flywheel, an electrically conductive connecting element is arranged, which is in sliding contact with the ground.

In a further embodiment of the load selector according to the invention, a discharge contact of the first phase is connected to the high-mass element.

In a further embodiment of the load selector according to the invention each of the three phases are associated with a plurality of actuating elements on an inner wall of an oil vessel, which are each attached via at least two retaining elements on the inner wall of the oil vessel.

In this case, a diverter ring is held in the first phase with at least three holding elements on an inner surface of each actuating element. One of the at least three holding elements designed for the diverter contact diverter ring comprises an electrical connection element for the diverting contact or diverting ring. The electrical connection element is guided by the retaining element to the outer wall of the oil vessel.

In a further embodiment of the invention it is provided that the diverter ring of the second and third phase is formed as a guide ring, which is fastened via at least three holding elements on the inner wall of the oil vessel. It is preferred that the guide ring has no electrically conductive property and thus can be made of a kontengünstigen material.

It is further provided that each stage contact is provided on an inner surface of each actuating element with an electrical connection element for the respective stage contact. About the associated holding element, the electrical connection element is guided to the outer wall of the oil vessel.

In addition to the benefits already described brings the load selector invention also Advantageous that avoided by the direct electrical connection with the massive element of the individual phases, the previously used from the prior art complex and costly connection of the silvered phases of the Ableitkontakte. By using the electrical conductivity of the massive element, the individual phases can be connected to the massive element inside the oil vessel. This results in the advantage that Ableitkontakte be saved in the second and third phase and on top of an additional electrical connection of the Ableitkontakte all three phases on the outside of the oil vessel completely eliminated. There is only a single electrical leakage contact over the first phase.

Thus, an inexpensive and resource-saving load selector has been created with the invention, which is also simple in construction due to the previously described embodiment.

• Fig. 1 eine Perspektivansicht eines dreiphasigen Lastwählers;
• Fig. 2 eine Schnittansicht des Lastwählers entlang der in Fig. 1 eingezeichneten Schnittlinie A-A;
• Fig. 3 eine Perspektivansicht des Lastumschaltereinsatzes des dreiphasigen Lastwählers nach Fig. 1, wobei die drei am Schaltrohr befestigten Schaltsegmente und das massereiche Element zu sehen sind;
• Fig. 4 eine weitere Perspektivansicht des Lastumschaltereinsatzes des dreiphasigen Lastwählers nach Fig. 1, wobei die drei am Schaltrohr befestigten Widerstandsanordnungen und das massereiche Element zu sehen sind;
• Fig. 5 eine Schnittansicht des Lastwählers in Form eines erfindungsgemäßen Sternpunktlastwählers;
• Fig. 6 eine perspektivische Schnittansicht des Sternpunktlastwählers nach Fig. 5 von unten, bei der die Schwungmasse mit dem massereichen Element und dem Boden elektrisch leitend verbunden ist;
• Fig. 7 eine schematische Darstellung eines von mehreren Betätigungselementen, die die Betätigungsanordnung jeder Phase bilden; und
• Fig. 8 eine weitere perspektivische Schnittansicht zur Verdeutlichung des inneren Aufbaus des erfindungsgemäßen Sternpunktlastwählers nach Fig. 5.

In the following, the invention and its advantages will be described in more detail with reference to the accompanying drawings. Show it:

• Fig. 1 a perspective view of a three-phase load selector;
• Fig. 2 a sectional view of the load selector along in Fig. 1 drawn section line AA;
• Fig. 3 a perspective view of the diverter switch insert of the three-phase load selector after Fig. 1 , wherein the three switching segments attached to the switching tube and the massive element can be seen;
• Fig. 4 another perspective view of the diverter switch insert of the three-phase load selector after Fig. 1 showing the three resistor assemblies attached to the switch tube and the high-mass element;
• Fig. 5 a sectional view of the load selector in the form of a star point load selector according to the invention;
• Fig. 6 a perspective sectional view of the star point load selector after Fig. 5 from below, in which the flywheel is electrically connected to the massive element and the ground;
• Fig. 7 a schematic representation of one of a plurality of actuators forming the actuator assembly of each phase; and
• Fig. 8 a further perspective sectional view to illustrate the internal structure of the star point load selector according to the invention Fig. 5 ,

For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures, which are required for the description of the respective figure. The illustrated embodiments are merely examples of how the load selector or star point load selector according to the invention can be configured and thus do not represent a final limitation of the invention.

Fig. 1 shows a perspective view of a three-phase on-load tap changer or load selector 1 according to the invention. The load selector 1 has a drive 3, such as an electric motor, with a gear 5, which raises a power accumulator, not shown. If the stored energy is fully absorbed, ie tensioned, it is unlatched, releases its energy abruptly and actuates a switching tube 15 of a diverter switch insert 14. The rotating switching tube 15 is held in an oil vessel 18. The oil vessel 18 is closed at the top with a lid 19 and also carries a bottom 21st

The load selector 1 according to the invention has a first phase L1, a second phase L2 and a third phase L3, which are arranged one above the other in the oil vessel 18. Over the three phases L1, L2, L3 sits a preselector 37. In the view shown here electrical connection elements 38 are provided for preselector contacts on the oil vessel wall 17 of the oil vessel 18. Electrical connection elements 39 for stage contacts 392 (see Fig. 5 . 7 . 8th ) of the three phases L1, L2, L3 are also arranged on the load selector 1 so that they engage through the oil vessel wall 17 of the oil vessel 18.

Fig. 2 shows a sectional view taken along the line AA Fig. 1 of the load selector 1, wherein a plan view of the phase L1 is shown. On an inner wall 20 of the oil vessel 18 for the second phase L2 a plurality of the contour of the inner wall 20 of the oil vessel 18 adapted actuating elements 50, which constitute an actuating arrangement 41, are arranged. Electrical connection elements 39 for the step contacts 392 (see Fig. 5 . 7 . 8th ) engage through the corresponding actuating elements 50 and through the oil vessel wall 17 to the outer wall 16. Umbrella caps 30 on the outer wall 16 of the oil vessel 18 stop the For this purpose, the electrical connection elements 39 for the step contacts, not shown here, and the electrical connection elements 68 for the discharge contact, not shown, interact with the step contacts 30 via the shield caps 30, so that the actuation elements 50 on the inner wall 20 of the oil vessel 18 are supported. The umbrella caps 30 rest on the outer wall 16 of the oil vessel 18. Each of the actuators 50 has at least two cams 51, 52 (see Fig. 7 ), which cooperate with corresponding and provided with rollers 43 operating levers 45 of the switching segment 25 of the corresponding phase L1, L2, L3.

The switching tube 15 carries in each phase L1, L2, L3 a holder 40 to which a massive element 36, the respective resistor assembly 27 and the respective switching segment 25 are mounted. The switching segment 25 is mounted such that the rollers 43 of the actuating lever 45 with the corresponding control cams 51, 52 of the actuators 50 cooperate.

3 and 4 show various perspective views of the diverter switch insert 14 of the three-phase load selector 1 after Fig. 1 , At the switching tube 15 of the diverter switch insert 14 three switching segments 25 are attached, so that the load selector 1 is divided into the three phases L1, L2, L3. In addition to the switching segments 25, resistance circuits 27, which are assigned to the individual phases L1, L2, L3 of the load selector 1, are likewise fastened to the switching tube 15. By turning the switching tube 15 contacts 29S for stage contacts or contacts 29A for Ableitkontakte can be connected directly, the contacts 29S, 29A with corresponding and not shown Ableitkontakten 391 (only in the first phase L1) or the stage contacts 392, also not shown cooperate (see also Fig. 8 ). A predetermined switching sequence is by means of the control cams 51, 52 (see Fig. 7 ) realized in which a plurality of vacuum interrupters (not shown) in the individual switching segments 25 are opened or closed.

According to the invention, a flywheel mass 35 is mounted on the switching tube 15. In addition, the switching tube 15 carries a massive element 36, as described below.

Fig. 5 shows a perspective sectional view of the load selector 1 in the form of a neutral load selector. This load selector 1 comprises a rotatable about an axis A switching tube 15 and the three phases L1, L2, L3, which are arranged along the axis A of the switching tube 15. Also, the load selector 1 includes in each of the phases L1, L2, L3 Switching segment 25, each with a resistor assembly 27 (see Fig. 4 ).

As already mentioned above, according to the invention, a flywheel mass 35 is mounted on the switching tube 15. Furthermore, the switching tube 15 carries a parallel along the axis A to the switching tube 15 extending massive and electrically conductive element 36, which is connected by means of an electrical connection 55 with each phase L1, L2, L3.

The massive element 36 and the flywheel 35 are needed in particular to support the temporal movement sequence of the switching operation, so that the rotation of the switching tube 15 causing triggering of the energy storage (not shown) performs a defined circuit or defined setting of the individual switching states of the Lastwählers 1.

In particular, the load selector 1 provides that the high-mass element 36 is electrically conductively connected to the flywheel mass 35. This could be done for example via a screw 54 of the flywheel 35 with the massive element 36, as in Fig. 6 shown. Since the high-mass element 36 and the flywheel 35 are preferably made of metal or an electrically conductive material, as well as the bottom 21 of the load selector 1 is made of metal, all metallic and electrically conductive parts should basically be at the same potential (neutral point potential). Thus, as shown here, between the bottom 21 of the load selector 1 and the flywheel 35, an electrically conductive connecting element 53 is arranged, which is in sliding contact with the bottom 21. This function could for example take over a spring-loaded connecting element 53.

Fig. 7 shows a schematic representation of a plurality of actuators 50 for forming the actuator assembly 41 (see Fig. 2 ), which are arranged in each phase L1, L2, L3 on the inner wall 20 of an oil vessel 18. Each actuating element 50 is fastened to the inner wall 20 of the oil vessel 18 via at least two retaining elements 31.

It includes, as in Fig. 8 1, one of the three holding elements 31 for the diverter ring 391 of the first phase L1 has a single electrical connection element 68 for the diverting ring 391, which is guided to the outer wall 16 of the oil container 18. Furthermore, it is provided in the load selector 1, that each of the diverter ring 391 of the second and third phase L2, L3 is formed as a guide ring, which is also attached via at least three retaining elements 31 on the inner wall 20 of the oil vessel 18. The guide ring 391 are assigned no electrical connection elements, so that it is made of a non-conductive and cost-effective material can be made. Furthermore, the step contacts 392 are also on holding elements 31 on the inner surface 65 (see Fig. 7 ) of each actuator 50 is supported. In this case, then an electrical connection element 39 of the respective stage contact 391 is guided to the outer wall 16 of the oil vessel 18.

LIST OF REFERENCE NUMBERS

1

On-load tap-changer, load selector

3

drive

5

transmission

14

Diverter switch insert

15

switching tube

16

Outer wall of the oil vessel

17

Oil vessel wall

18

oil vessel

19

cover

20

Inner wall of the oil vessel

21

ground

25

switching segment

27

resistor arrangement

29A

movable contact for discharge contact

29S

mobile contact for step contact

30

canopy

31

retaining element

35

Inertia

36

massive element

37

selection

38

electrical connection element for preselector contact

39

electrical connection element for step contact

391

Discharge contact, diverting ring, guide ring

392

stages Contact

40

bracket

41

actuator assembly

43

role

45

actuating lever

50

jig

51

Upper cam

52

Lower cam

53

electrically conductive connecting element

54

screw

55

electrical connection

65

Inner surface of the actuating element

68

electrical connection element for discharge contact / discharge ring

A

axis

A-A

intersection

L1

first phase

L2

second phase

L3

third phase

Claims (8)

1. Load selector (1), comprising
   a load changeover switch insert (14) with a switching tube (15) rotatable about an axis (A) and
   a first phase (L1), a second phase (L2) and a third phase (L3) arranged along the axis (A) of the switching tube (15), wherein each phase (L1, L2, L3) comprises a switching segment (25) with a respective resistance arrangement (27),
   characterised in that
   a flywheel mass (35) is mounted on the switching tube (15) and the switching tube (15) comprises a high-mass and electrically conductive element (36), which extends parallelly along the axis (A) with respect to the switching tube (15) and which is connected with each phase (L1, L2, L3) by means of an electrical connection (55) and
   the flywheel mass (35) and the high - mass element (36) are needed for assisting the movement course of the switching process overtime of the load selector (1).
2. Load selector (1) according to claim 1, wherein the high-mass element (36) is electrically conductively connected with the flywheel mass (35).
3. Load selector (1) according to claim 2, wherein arranged between a base (21) of the neutral-point load selector (1) and the flywheel mass (35) is an electrically conductive connecting element (53) which is in wiping contact with the base (21).
4. Load selector (1) according to any one of the preceding claims, wherein a diverter contact (391) of the first phase (L1) is connected with the high-mass element (36).
5. Load selector (1) according to any one of the preceding claims, wherein several actuating elements (50) at an inner wall (20) of an oil tank (18) are associated with each phase (L1, L2, L3), each of the actuating elements being fastened to the inner wall (20) of the oil tank (18) by way of at least three mounting elements (31).
6. Load selector (1) according to any one of the preceding claims, wherein a diverter ring (391) in the first phase (L1) is mounted on an inner surface (65) of each actuating element (50) by at least three mounting elements (31) and wherein one of the at least three mounting elements (31) for the diverter ring (391) comprises an electrical terminal element (68), which is led through the mounting element (31) to an outer wall (16) of the oil tank (18), for the diverter ring (391).
7. Load selector (1) according to claim 6, wherein the diverter ring (391) of the second and third phases (L2, L3) is constructed as a guide ring, which is fastened to the inner wall (20) of the oil tank (18) by way of at least three mounting elements (31).
8. Load selector (1) according to any one of claims 5 to 7, wherein each step contact (392) is provided at an inner surface (65) of each actuating element (50) with an electrical terminal element (39) for the respective step contact (392) and is led via the associated mounting element (31) to the outer wall (16) of the oil tank (18).

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