EP1675142B1 - Contact system for an electrical switching device - Google Patents

Abstract

The system has a contact (3) including a tulip-shaped contact unit, which is provided on a fixation plate. The plate is connected to an axle tube, where tube and the plate are made of copper. The contact unit has contact fingers including inner and outer surfaces. The surfaces fit into a counter contact (2) when a switching device is in a closed operating condition to form contacting surfaces for supplying current to the contact (2). An independent claim is also included for switching device including an electrical contact system.

Description

TECHNICAL AREA

The invention relates to the field of high voltage engineering, in particular the high voltage switch technology in electrical power distribution networks. It is based on a contact system for a switching device and a switching device according to the preamble of the independent claims.

STATE OF THE ART

The invention is based on the prior art according to the EP 0 844 631 , There, a contact system with a movable contact and a fixed mating contact for an electrical switching device is disclosed, wherein the contact and the mating contact each having a contact tulip or a finger basket with individually einfederbaren contact fingers. The movable contact consists of a rigid annular cylindrical contact tube with a recessed therein sunken, inner contact tulip, which ascends the fixed contact pin of the mating contact or short mating contact pin. The contact fingers of the inner tulip are spread outwards and thus generate the necessary contact force on the mating contact pin. At the same time, the rigid contact tube moves into an outer contact tulip of the mating contact and spreads its contact finger outwards. So there are an internal contact system, consisting of inner tulip of the contact and contact pin of the mating contact, and an independent external contact system consisting of contact tube of the contact and outer tulip of the mating contact, available. The inner contact system is used for controlling arcing and the external contact system for earthing short-circuit currents or short-time currents. This double contact system with two independent contact tulips corresponds to the circuit breaker system with arc and rated current contacts. In this case, the current transmission takes place in both contact tulips on the inner surfaces of the contact fingers and the spreads of the inner and the outer contact fingers for generating the contact forces happen mechanically and temporally independently.

In the DE 29 35 202 a contact system for switching devices with high short-circuit currents is shown. A rigid contact tube moves into a contact tulip and spreads their contact fingers apart, so that in turn a current transition from the outer surface of the contact tube to the inner surfaces of the contact fingers is created. In the contact tulip a erosion-resistant support sleeve is provided to prevent welding of the contact fingers in the arc. The support sleeve optionally has additional ribs or pins for keeping the contact fingers apart.

In the EP 1 068 624 a combined disconnector / earthing switch is shown, which has a in three positions (disconnector closed, disconnector open, earth closed) sliding contact part. In the center position, the contact part is retracted in a hollow cylindrical housing part of the current path, which has contact tulips on both sides for contacting pipe sections of the contact part. The contact part has at its earth-side end an earth contact tulip, which is passed through when closing the earthing by the contact tulip of the housing part. Both contact tulips are at the same potential and do not form a current transition.

In the invention reference is made to the DE 1 220 927 , There, an electrical switch is disclosed, the Switching pin is a slotted tube, which cooperates with a rigid, annular Gegenschaltstück. Inside the slotted tube, a rigid body is arranged to prevent collapse of the tube under current forces.

By doing US 4,628,164 An electric switch with a slotted switching pin is also disclosed, which engages in a more external, rigid contact tube of the mating contact.

PRESENTATION OF THE INVENTION

Object of the present invention is to provide an alternative, simplified contact system for a switching device. This object is achieved according to the invention by the features of the independent claims.

The invention consists in an electrical contact system for an electrical switching device for power supply networks, wherein the switching device has a central axis and a first contact or mating contact and a second contact, wherein at least the second contact comprises a contact tulip with a plurality of contact fingers and the contact fingers of the central In the closed operating state, the outer surfaces of the contact fingers of the contact tulip abut the first contact and an outer contacting surface for a Make current transition to the first contact. It is thus created by the contact tulip on the outer surfaces of their contact fingers a contact surface for the current transition. As a result of the current transmission to an outer surface of the contact tulip, a large-area contact or current transition surface can also be realized without a mating contact pin on the first contact. Due to the current decrease at the contact tulip outer surface, the contact tulip in the first contact of the parallel-current path in the contact fingers can be shortened and the electromagnetic load capacity can be increased even with a constant immersion depth. This makes the first contact very easy, z. B. as a rigid tube or as a ring contact, be executed. It should be noted that the contact fingers have a sufficiently strong, radially outwardly directed spring force to ensure sufficient contact force to the first contact, even if the contact fingers in addition by electromagnetic Current forces are drawn radially inward.

According to the invention, in the closed operating state, the inner surfaces of the contact fingers of the contact tulip are also in contact with the first contact and form an inner contacting surface for a further current transition to the first contact. By combining two current transitions, a very large contact area between the first and second contact can be created.

The embodiment according to claim 2 has the advantage that separate arcing contacts are provided for the switching device, so that the current transition via the outer contacting surface can take place without arc erosion.

• Design kann auch in einem Leistungsschalter realisiert sein, wobei die Kontakttulpe wiederum an den Kontaktfingerkappen den Lichtbogen überträgt und seitlich am Umfang den Betriebsstrom, Kurzzeitstrom oder Kurzschlussstrom.

In an important embodiment, the first contact has a mating contact tulip with a plurality of mating contact fingers and in a closed operating state of the switching device, the contact fingers of the contact tulip and the mating contact fingers come into touching contact with each other and form a common contact surface for the current transition or the further current transition. Such a Tulip tulip design can be used to build a low cost and tight grounding contact. In particular, the number of contact fingers per tulip can be reduced. The contact tulip transmits the arc at the contact finger caps and the short-term current or short-circuit current at the side of the circumference. These two functions have hitherto been fulfilled separately by different components in the prior art. The tulip in tulip

• Design can also be implemented in a circuit breaker, wherein the contact tulip again transmits the arc on the contact finger caps and laterally on the circumference the operating current, short-time current or short-circuit current.

In an advantageous embodiment, the mating contact tulip surrounds the contact tulip from the outside and the common Contact surface is formed by the outer surfaces of the contact fingers and by inner surfaces of the mating contact fingers. In this case, the common tulip-tulip contact surface advantageously serves for the passage of current at high short-term currents or short-circuit currents or, if appropriate, operating currents.

In a further advantageous embodiment, when the contact tulip retracts into the mating contact tulip, the mating contact fingers experience a spreading in order to generate a first contact force of the mating contact fingers against the contact fingers; and / or the contact fingers experienced during retraction of the contact tulip in the mating contact tulip compression for generating the reactive first bearing force of the contact fingers to the mating contact fingers. The interaction of the elastic spring behavior of the contact fingers and the mating contact fingers creates a very flexible, adjustment-tolerant, yet reliable contact system. In particular, contact tulips with different compression characteristics can be easily combined because the softer contact tulip simply adapts to the harder one. Also, the Tulip tulip design allows greater mechanical tolerances in the alignment of the contacts as well as operation in the event of misalignment due to thermal loads or electromagnetic current forces.

According to a further important exemplary embodiment, the first contact comprises a tubular contact part, in particular the mating contact tulip, and an inner mating contact pin, wherein when closing the switching device, the contact tulip enters the tubular contact part and ascends onto the mating contact pin. Advantageously, the contact fingers of the contact tulip when driving on the mating contact pin experience a spreading for generating a further first bearing force of the contact fingers on the tubular contact part, in particular on the mating contact fingers, and moreover for generating a second bearing force of the contact fingers on the mating contact pin.

In this configuration, so the contact tulip moves into the mating contact tulip and at the same time on the mating contact pin. As a result, a strong contact force of the contact fingers on the outer surfaces is achieved to the mating contact fingers and on the inner surfaces to the mating contact pin. In particular, the outer mating contact tulip with its contact force strengthens the contact pressure of the contact tulip on the mating contact pin. Due to the large contact or contact forces and the large contact surfaces of the contact resistance is reduced compared to conventional arrangements and increases the current carrying capacity.

Claim 8 relates to further measures to improve the contact force between the first and second contact and in particular the combined contact forces of the contact tulip and the Gegenkontakttulpe.

Claim 11 relates to an electrical switching device with an electrical contact system as described above and with the advantages mentioned there.

Further embodiments, advantages and applications of the invention will become apparent from the dependent claims, from the claim combinations and from the following description and the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

ein erstes Ausführungsbeispiel der Erfindung mit einer aussen kontaktierenden Kontakttulpe und einem optionalen Gegenkontaktstift; und

Fig. 2

ein zweites Ausführungsbeispiel der Erfindung mit einer Kontakttulpe und einer Gegenkontakttulpe.

It show schematically

Fig. 1

a first embodiment of the invention with an externally contacting contact tulip and an optional mating contact pin; and

Fig. 2

A second embodiment of the invention with a contact tulip and a mating contact tulip.

In the figures, like parts are given the same reference numerals.

WAYS FOR CARRYING OUT THE INVENTION

Fig. 1 shows a contact area of an electrical switching device. The electrical contact system 1 comprises a first contact or mating contact 2 and a second contact 3, which are typically arranged concentrically with respect to a central axis 12. The second contact 3 comprises a contact tulip 3 a, the contact fingers 30 of which have with respect to the axis 12 substantially radially inwardly directed inner surfaces 300 and substantially radially outwardly directed outer surfaces 301. In the simplest case, the first contact 2 comprises a rigid contact tube 2b and additionally, for example, a mating contact pin 2c arranged concentrically therein (shown in dashed lines). According to the invention, in the illustrated closed operating state of the switching device, the outer surfaces 301 of the contact fingers 30 of the contact tulip 3a on the first contact 2 and form an outer contact surface 301 for a current transition 13 to the first contact 2, namely the contact tube or ring contact 2b. The contact force of the contact fingers 30 on the first contact 2 can be generated, for example, by compressing or spreading the contact tulip 3a or optionally by other means.

Advantageously, the contact fingers 30 are designed to spring inwards. In order to increase the spring force, additional pressure springs can be mounted inside the contact tulip 3a, which exert a contact force on the contact fingers 30 directed away from the central axis 12, ie directed essentially radially outwards. It is also important to ensure that on the outer contacting surface 301, the outwardly directed first contact force of the contact fingers 30 to the first contact 2 is sufficiently strong, so that the contact fingers 30 also absorb and overcompensate in the spring-inward state additionally inwardly pulling current forces so that anytime a sufficient initial contact force and thus a sufficiently low-impedance current transition 13 is ensured at the outer contacting surface 30.

The first contact 2 comprises a contact inner part 2c, which also makes electrical contact with the inner surfaces 300 of the contact fingers 30 of the contact tulip 3a when closing the switch or in the closed operating state and forms a further current transition 14 to the first contact 2 via this inner contacting surface 300. The inner contact part 2 c is preferably in Fig. 1 and 2 illustrated rigid mating contact pin 2c, but could also be an inner tulip 2c. In this way, at least a first current-carrying operating state of the switching device is present, in which the contact fingers 30 of the contact tulip 3 a current transition 13 on its outer surface 301, z. B. for short-term current in an earth electrode, and at a further current transition 14 on its inner surface 300, z. B. for an arc current, have. The two operating states can occur simultaneously and should be encompassed by the term "closed operating state" of the switching device. The closed operating state should also include closing operations and should include at least one such operating state in which power is transmitted through the contact system 1 or may be such. As a Vorzündphase, arc phase, contact phase for power transmission 13, 14 or a fully retracted state of the contacts 2, 3rd

In the internal, preferably pin-shaped mating contact 2c, an arc current can be transmitted during a closing operation of the switching device between the contact tulip 3a, in particular the contact finger caps 31 of the contact fingers 30, and the pin 2c. The contact finger caps 31 thus form at the contact tulip 3a together with the mating contact pin 2c arc contacts 31, 2c of the switching device. When retracting the contacts 2, 3, the inner mating contact 2c is preferably used to the above-described current transition 14 via the Inner surfaces 300 of the contact fingers 30 of the contact tulip 3a to create. The mechanical function of the inner mating contact 2c is to spread open their contact fingers 30 when the contact tulip 3a rests on them and thereby provide a further first contact force of the contact fingers 30 against the tubular contact part 2b, in particular against a mating contact tulip 2a Fig. 2 , to generate and moreover to generate a second bearing force of the contact fingers 30 on the inner mating contact 2c itself.

In the embodiment with internal mating contact 2c, the contact tulip 3a assumes three different functions, namely at the beginning of the closing arc contact on the contact finger caps 31 and retracting transmission of high and high currents 13, 14 at the contact finger outer surfaces 301 and the contact finger inner surfaces 300. The contact tulip 3a acts So depending on switch type as arcing contact 31 (earthing, disconnector, circuit breaker) and at the same time as a short-circuit current contact 300, 301 or short-time current contact 300, 301 (earthing, disconnector, circuit breaker) or rated current contact 300, 301 (disconnector, circuit breaker). In particular, the outer contacting surface 301 of the contact tulip 3a transmits a short-time current up to 63 kA for 3 s, and / or a shock current, in particular up to 170 kA. The types of switches include: quicker, combined disconnector / earthing, switcher and possible other variants of power distribution switching devices. The switching device is typically arranged in a dead tank breaker (DTB), in an encapsulated gas-insulated switchgear (GIS) or in an outdoor switch (LTB).

Fig. 2 shows a preferred embodiment in which the contact tulip 3a is similar as in Fig. 1 is constructed and in addition the first contact 2, a further contact tulip 2a, here called Gegenkontakttulpe 2a, has. The mating contact or mating contact pin 2c also assumes the same functions as previously discussed and could also be tulip-like. Thus, the first contact 2 a mating contact pin 2c for driving up the contact tulip 3a and a mating contact tulip 2a for retracting the contact tulip 3a.

The contact tulips 3a, 2a and optionally 2c are also referred to as finger baskets and have a plurality of typically cylindrical arranged, individually and relatively independently einfederbaren contact fingers 20, 30. The deflection may be inwardly towards the axis 12 by compressing the contact fingers 30 (eg, by the mating contact cup 2a) or outwardly away from the axis 12 by spreading the mating contact fingers 20 (eg, through the contact tulip 3a) or Contact finger 30 (eg, by mating contact pin 2c). The contact tulips 3a, 2a and optionally 2c may be made of a slotted tube. A contact tulip should have at least two contact fingers which are sufficiently flexible and in particular radially expandable. Due to the tulip in tulip design, the number of contact fingers 30, 20 can be reduced and in particular halved at each of the contact tulips 3a, 2a involved. Thus, at the mating contact tulip 2a, the number of mating contact fingers 20 could be reduced from 44 to 24 without sacrificing performance in tests with 63 kA short-time current and 170 kA surge current. 6 contact fingers can already be sufficient on the contact tulip 3a in order to ensure the desired current carrying capacity at the current transitions 13, 14.

At least one of the contacts 2, 3 should be movable. For example, drive means for axially moving the second contact 3 and in particular for retracting its contact tulip 3a in the first contact 2 are present. The first contact 2 itself can be fixed or movable. A double movement of both contacts 2, 3 or other forms of contact movement are possible. In general, the invention has no restriction with regard to the movement of the first and second contacts 2, 3.

In the following some constructional details concerning the externally contactable contact tulip 3a (FIG. Fig. 1 . 2 ) and with respect to the internally contactable mating contact tulip 2 a (FIG. Fig. 2 ) discussed.

In the contact tulip 3a, a support sleeve 7 may be arranged. Advantageously, the support sleeve 7 is cylindrical and is inserted or mounted concentrically in the contact finger tulip 3a. The inner sides of the contact fingers 30 rest on the support sleeve 7. The sleeve 7 in particular supports the contact fingers 30 in the area of the contact finger necks 32 and leaves room for the contact finger caps 31 at the tulip opening. The support sleeve 7 serves to prevent a collapse of the contact tulip 3a or its contact fingers 30 under current forces and the contact tulip 3a also at asymmetric current forces, caused by electromagnetic transverse forces to keep in a centered position, so as to ensure a symmetrical contact force of all contact fingers 30. Advantageously, the support sleeve 7 Teflon and in particular a proportion of glass fiber. The glass fiber content can be up to a maximum of 25, for example. The support sleeve 7 may also be made of metal.

The contact tulip 3a is advantageously in the area of the tulip bottom, ie in a Fußpunktbereich the contact fingers 30, provided with an external thread 8 for screwing the contact tulip 3a in a support tube 10. The support tube 10 is used for power transmission and has at the other end coil contact springs 11 for current collection at a not shown on the current path. The contact tulip 3a should be fixed to the tulip bottom on a mounting plate 9. For example, a mounting plate 9 made of copper (Cu) with a support tube 10 made of aluminum (A1) be bolted. Advantageously, a mounting or bottom plate 9 made of copper with a support tube 10 is also made of copper by electrofusion. As a result, the contact contact resistance of the contact tulip 3a to the support tube 10 can be significantly reduced.

The mating contact tulip 2 a is in turn fastened to a base plate 4 and surrounded concentrically by a holding tube 5. The holding tube 5 is surrounded in the opening region of the first contact 2 by a burn-resistant cap 50. The cap 50 serves as protection against arc erosion and as a dielectric shielding of the contact system 1, in particular the mating contact tulip 2 a and in the retracted operating state also the contact tulip 3 a. The shielding cap 50, the mating contact pin cap 21 and the contact finger cap 31 are made of or contain particularly erosion-resistant material, such. As a tungsten-copper (WCu) alloy. The caps 50, 21, 31 can be back-filled with copper. The contact fingers 30 and / or the mating contact fingers 20 are made of or preferably contain a copper-chromium-zirconium (CuCrZr) alloy to achieve a high spring force at the same time high electrical conductivity.

To increase the first contact force of the contact fingers 30 to the mating contact fingers 20 and / or increase the second bearing force of the contact fingers 30 on the mating contact pin 2c, the contact tulip 3a can be widened from the contact finger tips 31 to the contact finger necks 32, so that the contact tulip 3a during retraction into the tubular contact part 2b (FIG. Fig. 1 ) or in the mating contact tulip 2a (FIG. Fig. 2 ) is progressively compressible. Also, the mating contact tulip 2a may have a contact spring 6 embracing it for compressing the mating contact fingers 20.

The invention also relates to an electrical switching device for a power supply network, in particular an earth electrode, Schnellerder, disconnector or circuit breaker having the above-described electrical contact system 1.

LIST OF REFERENCE NUMBERS

1

Electrical contact system

2

first contact, fixed contact, tulip / pin contact, current path contact, mating contact

2a

First contact tulip, counter contact tulip

2 B

Contact tube, ring contact

2c

Inner mating contact, mating contact pin, arcing contact

20

First contact fingers, mating finger

200

Inner surfaces of the first contact or the first contact fingers

21

Mating contact finger cap, erosion resistant cap, WCu cap

3

Second contact, running contact, tulip contact, earthing contact

3a

Second contact tulip, contact tulip

30

Second contact fingers, Laufkontaktfinger

300

Inner surface of the contact fingers

301

Outer surface of the contact fingers

31

Contact finger cap, erosion resistant cap, WCu cap (for contact fingers)

32

Contact finger neck (for contact fingers), CuCrZr

4

Mounting plate, base plate

5

Support tube

50

Shielding Cap, Abbrandfest Cap, WCu Cap (for holding tube)

6

contact spring

7

Support sleeve, Teflon glass sleeve

8th

Screw thread (for contact tulip)

9

Fixing plate, Cu plate

10

Support tube, aluminum tube

11

spiral contacts

12

Central axis, symmetry axis

13

Electricity transfer to outer surface of the contact tulip

14

Electricity transfer to the inner surface of the contact tulip

Claims (11)

1. Electrical contact system (1) for an electrical switching device for power supply systems, in particular for a high-speed grounding switch or circuit breaker, the switching device having a central axis (12) and a first contact or mating contact (2) and a second contact (3), at least the second contact (3) comprising a contact tulip (3a) having a plurality of contact fingers (30), and the contact fingers (30) having outer faces (301), which face away from the central axis (12), and inner faces (300), which face the central axis (12), in a closed operating state of the switching device the contact tulip (3a) being moved into the first contact (2), in addition, in the closed operating state, the outer faces (301) of the contact fingers (30) of the contact tulip (3a) bearing against the first contact (2) and forming an outer contact-making face (301) for a current transfer (13) to the first contact (2), characterized in that in the closed operating state (3) the inner faces (300) of the contact fingers (30) of the contact tulip (3a) also bear against the first contact (2) and form an inner contact-making face (300) for a further current transfer (14) to the first contact (2).
2. Electrical contact system (1) according to Claim 1, characterized in that contact finger caps (31) on the contact tulip (3a), together with an inner mating contact (2c) of the first contact (2), in particular an inner tulip (2c), form arcing contacts (31, 2c) of the switching device.
3. Electrical contact system (1) according to one of the preceding claims, characterized in that

   a) the first contact (2) has a mating contact tulip (2a; 2c) having a plurality of mating contact fingers (20), and

   b) in a closed operating state of the switching device the contact fingers (30) of the contact tulip (3a) and the mating contact fingers (20) come into touching contact with one another and form a common contact face (200, 301; 300) for the current transfer (13) or the further current transfer (14).
4. Electrical contact system (1) according to Claim 3, characterized in that in the closed operating state of the switching device

   a) the mating contact tulip (2a) engages around the contact tulip (3a) from the outside, and

   b) the common contact face (200, 301) is formed by the outer faces (301) of the contact fingers (30) and by inner faces (200) of the mating contact fingers (20).
5. Electrical contact system (1) according to one of Claims 3-4, characterized in that, in order to produce a first bearing force of the mating contact fingers (20) against the contact fingers (30),

   a) the mating contact fingers (20) are spread apart when the contact tulip (3a) is moved into the mating contact tulip (2a) and/or

   b) the contact fingers (30) are compressed when the contact tulip (3a) is moved into the mating contact tulip (2a).
6. Electrical contact system (1) according to one of the preceding claims, characterized in that the first contact (2) comprises a tubular contact part (2a, 2b), in particular the mating contact tulip (2a) according to Claims 3-5, and an inner mating contact pin (2c), the contact tulip (3a) moving into the tubular contact part (2a, 2b) and onto the mating contact pin (2c) when the switching device is closed.
7. Electrical contact system (1) according to Claim 6, characterized in that the contact fingers (30) of the contact tulip (3a) are spread apart when it is moved onto the mating contact pin (2c) in order to produce a further first bearing force of the contact fingers (30) against the tubular contact part (2a, 2b), in particular against the mating contact fingers (20), and in order to produce a second bearing force of the contact fingers (30) against the mating contact pin (2c).
8. Electrical contact system (1) according to one of Claims 3-7, characterized in that, in order to increase the first bearing force of the contact fingers (30) against the mating contact fingers (20) as defined in Claim 5 and/or in order to increase the second bearing force of the contact fingers (30) against the mating contact pin (2c) as defined in Claim 7,

   a) the contact tulip (3a) is widened toward the contact finger necks (32) by the contact finger caps (31), with the result that the contact tulip (3a) is capable of being progressively compressed when it is moved into the tubular contact part (2b) or the mating contact tulip (2a) and/or

   b) the mating contact tulip (2a) has a contact spring (6) engaging around it in order to compress the mating contact fingers (20).
9. Electrical contact system (1) according to one of the preceding claims, characterized in that

   a) the contact tulip (3a) has a supporting sleeve (7) to prevent the contact tulip (3a) from collapsing under current forces and in order to keep the contact tulip (3a) in a centered position even in the event of asymmetric current forces, and

   b) in particular the supporting sleeve (7) contains Teflon and preferably a proportion of glass fibers.
10. Electrical contact system (1) according to one of the preceding claims, characterized in that

    a) the switching device is a grounding switch, a high-speed grounding switch, a disconnector or circuit breaker and/or

    b) the outer contact-making face (301) of the contact tulip (3a) transfers a short-circuit current, a short-term current, in particular up to 63 kA over 3 s, and/or a surge current, in particular up to 170 kA.
11. Electrical switching device for a power supply system, in particular grounding switch, high-speed grounding switch, disconnector or circuit breaker, characterized by an electrical contact system (1) according to one of the preceding claims.

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