EP3871244A1

EP3871244A1 - Earthing switch for a medium- and/or high-voltage circuit device, and corresponding circuit device

Info

Publication number: EP3871244A1
Application number: EP19820994.2A
Authority: EP
Inventors: Mariusz ROHMANN; Dirk SCHRÄDER
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2018-12-21
Filing date: 2019-11-22
Publication date: 2021-09-01
Also published as: CN113196435A; BR112021010973A2; WO2020126302A1; DE102018222848A1

Abstract

The invention relates to an earthing switch (12) for a medium- and/or high-voltage circuit device (10), wherein for earthing a contact element (18) of the circuit device (10) the earthing switch (12) has a movable switching element (20) and a contact arrangement (30) which is arranged at the free end (28) of the switching element (20) and comprises a main contact (34) and an auxiliary contact (40) for making electrical contact with the contact element (18), wherein the switching element (20) can be pivoted back and forth between a first position, in which neither the main nor the auxiliary contact (34, 40) make electrical contact with the contact element (18), and a second position, in which both the main contact (34) and the auxiliary contact (40) make electrical contact with the contact element (18). Provision is made for the auxiliary contact (40) to be formed by a rigid arm (38) of the contact arrangement (30), wherein the main contact (32) is arranged in a stationary manner within the contact arrangement (30). The invention further relates to a medium- and/or high-voltage circuit device (10) comprising an earthing switch (12) of this kind.

Description

description

Earthing switch for a medium and / or high voltage circuit device and corresponding circuit device

The invention relates to an earthing switch for a medium and / or high-voltage circuit device, wherein the earthing switch for earthing a contact element of the circuit device has a movable switching element and a contact arrangement arranged at the free end of the switching element, which has a main contact and an auxiliary contact for electrical contact of the contact element, wherein the switching element between a first position in which the main or auxiliary contact electrically contact the contact element and a second position in which both the main contact and the auxiliary contact electrically contact the contact element, and wherein the contact element is one Has structure for the electrical contact to the auxiliary contact.

The invention further relates to a corresponding switching device with such an earthing switch.

When switching on and off the coupled currents with earthing switches, depending on the voltage level and especially when switching off - caused by the continuously flowing currents - a switching arc occurs. In particular from a voltage level of 420 kV, a switching arc can extend over the entire disconnection path of the earthing switch, or can only thermally extinguish after the earthing circuit arrangement has come to a standstill in the “off” position.

To protect main contact systems from damage caused by switching arcs (arc base points), it is quite common to install auxiliary contact systems in switchgear - protecting the main contact systems from damage by switching arcs. If necessary, it is also necessary to close adjacent switchgear parts in front of the switching arcs Protect as the switching arc commutates to neighboring switchgear sections during thermal propagation and can damage neighboring analgens or, for example, cause a short circuit.

The document DE 199 49 493 A1 shows an earthing switch for a medium-voltage circuit device, the earthing switch for earthing a contact piece of the circuit device having a movable switching element and a contact arrangement arranged at the free end of the switching element, which has two contact blades as the main contact and a front Zündhorn as an auxiliary contact for electrical contacting of the contact piece, the switching element between a first position in which neither the main nor auxiliary contact electrically contact the contact piece and a second position in which both the main contact and the auxiliary contact electrically contact the contact piece back and forth be movable and wherein the contact piece has a structure formed as a slot for the electrical contact to the auxiliary contact. When the earthing switch is switched on, the auxiliary contact acts as a leading contact in relation to the main contact.

It is the object of the invention to provide measures by which the earthing switch opens very abruptly.

The problem is solved by the features of the independent claims. Advantageous refinements are specified in the subclaims.

In the earthing switch according to the invention for a medium and / or high-voltage circuit device, in which the earthing switch for earthing a contact element of the circuit device has a movable switching element and a contact arrangement arranged at the free end of the switching element, which has a main contact and an auxiliary contact for electrical contact of the contact element, the switching element being between a first position in the the main or auxiliary contact electrically contact the contact element and a second position in which both the main contact and the auxiliary contact can electrically contact the contact element and the contact element has a structure for the electrical contact to the auxiliary contact, it is provided that the Auxiliary contact is formed by a rigid arm of the contact arrangement, the main contact being arranged fixed within the contact arrangement.

The rigid arm forming the auxiliary contact can now be matched to the structure of the contact element for electrical contacting the auxiliary contact such that it releases from the contact element when the earthing switch is opened with a resilient snap movement. In this way, the earthing switch opens very abruptly at a time when the main contact is already relatively far away from the contact element.

The contact switch is generally to be understood as an arrangement of elements of the contact switch, that is, as a contact switch arrangement. One of these elements is then the contact element with its structure for making electrical contact with the auxiliary contact. This element is in the open position of the contact switch separately from the other elements of the contact switch.

The result is a main contact system with the main contact and the contact element as contact and counter contact, and an auxiliary contact system with the auxiliary contact and the structure of the contact element as contact and counter contact.

According to a preferred embodiment of the invention, the structure of the contact element for the electrical contacting of the auxiliary contact is designed as a rear grip structure with an inclined slope that can be gripped behind by the rigid arm. This structure is in particular a nose structure, ie a structure in the form of a nose. This form means that the auxiliary contact is closed when the earthing switch is closed via the gently brought into a corresponding rear grip position on the rear grip structure and snaps or whips abruptly away from the contact element when opening.

In particular, it is provided that the main and auxiliary contacts are arranged in such a way that the auxiliary contact is designed as a leading auxiliary contact which contacts the contact elements when the earthing switch closes before the main contact.

According to a further preferred embodiment of the invention, the earthing switch is movably mounted on a base element. It is preferably provided that the contact element is grounded via the base element. For this purpose, the base element is or is grounded.

With regard to the base element, it is particularly preferred that the circuit device has the base element and that the earthing switch is designed as a built-on earthing switch.

With regard to the earthing switch according to the invention, it is further preferably provided that the main contact is formed by a rigid arm of the contact arrangement, the contact arrangement branching out over the two arms.

According to a preferred embodiment of the earthing switch according to the invention, the rigid arm is integrated into the contact arrangement via a torsion spring. This allows the rigid arm to be preloaded. It is preferred to see that the torsion spring is arranged at the free end of the rigid arm.

In the medium and / or high-voltage circuit device according to the invention with an earthing switch, which has a movable contact element and a contact element arranged at the free end of the switching element, it is provided that the earthing switch is an aforementioned earthing switch. The Kontaktele element is a component of the earthing switch or at least one component of the medium and / or high voltage switching device.

In the following, exemplary embodiments of the invention are shown schematically in drawings and are described in more detail below. Show:

1 shows a part of a medium and / or high voltage

Circuit device with an earthing switch according to a first preferred embodiment of the invention,

2 shows the sequence of movements when closing the earthing switch shown in FIG. 1,

Fig. 3 shows the sequence of movements when opening the ge in Fig. 1

showed grounding switch,

4 shows the sequence of movements when closing an earthing switch with a modified auxiliary contact,

5 shows the sequence of movements when the earthing switch is opened with a modified auxiliary contact,

Fig. 6 shows the sequence of movements when closing an earthing switch with a different modified auxiliary contact and

Fig. 7 shows the sequence of movements when opening the earthing switch with a different modified auxiliary contact.

Fig. 1 shows a part of a medium and / or high-voltage circuit device 10 including an earthing switch 12 for this medium and / or high-voltage circuit device 10. The earthing switch 12 is designed as a so-called Cultivator and the part shown the circuit device 10 consists of a base plate trained base element 14, which carries an insulator 16, on which a contact element 18 is arranged, which is electrically insulated from the base element 14 via the insulator 16.

The grounding switch 12 has a switching element 20 for grounding a mating contact formed by the contact element 18. The contact element 18 can be understood as a component of the earthing switch 12, but is always part of the medium and / or high-voltage circuit device 10, in which the earthing switch 12 is integrated. The contact element 18 has a structure 22, the shape and function of which will be discussed again in detail below in connection with the individual components of the switching element 20.

The switching element 20 is movable, more precisely pivotable, mounted on the base element 14 via a bearing 24 (double arrow 26) and has a contact arrangement 30 at its free end 28. The contact arrangement 30 in turn has a star arm 32 which forms a main contact 34 of the switching element 20. A rigid arm 38 branches off at a branch 36 of the contact arrangement 30 and forms an auxiliary contact 40 of the contact arrangement 30. The term contact naturally refers in particular to an electrical contact. One can therefore refer to the two arms 32, 38 as contact arms 32, 38. At the free end of the rigid arm 38 there is a spherical terminating element 42 of the auxiliary contact 40. The rigid arm 38 is preferably made of aluminum and the structure 22 of the contact element 18 is made of stainless steel.

This results in a contact arrangement 30 with a main contact 32 and an auxiliary contact 40 for the respective electrical contacting of the contact element 18 or of corresponding structures 18 of this contact element. The main contact 32 contacts the base of the contact element 18 and the auxiliary contact 40 contacts the contact element 18 via the structure 22 of the contact element 18. The structure 22 of the contact element 18 is designed for the electrical contacting of the auxiliary contact 40 as a rear grip structure with an inclined slope that can be gripped behind by the rigid arm 38. This structure 22 is in particular a nose-shaped structure 22. With this shape, the auxiliary contact 40 is gently brought into a corresponding rear grip position on the rear grip structure 22 when the earthing switch 12 is closed, and snaps or whips abruptly from the contact element 18 when it is opened path.

The earthing switch 12 shown here is an earthing switch 12 in the form of a so-called mounting earth for disconnector of any type. However, it can also be designed as a stand-alone grounding switch 12.

The auxiliary contact 40 is specifically formed by an aluminum rod (ko African, AL 7075 T6) and the structure 22 of the contact element 18 by a stainless steel nose.

The stainless steel nose is, as I said, part of the fixed contact element 18 of the earthing switch 12 and the conical aluminum rod is part of the movable contact assembly 30 of the earthing switch 12. The conical aluminum rod has a small end element 42 made of stainless steel for dielectric shielding at the free end tion and to accommodate the switching arc.

The design of the auxiliary contact 40 is thus characterized in detail by the following features:

- Aluminum rod (attached to the switching element 20 via the branch 36) with

o Material AL 7075 T6 (certain flexibility, spring characteristics, good conductivity),

o conical shape (allows flexibility over the entire length of the rod) and

o round end element 42 made of stainless steel. The structure 22 serving as an auxiliary mating contact is a stainless steel nose which is part of the contact element 18 serving as a mating contact.

Figures 2 to 7 now show different variants of the earthing switch 12 and its movement when closing (arrow 44) and when opening (arrow 46).

This results in the following mode of operation of the auxiliary contact 40:

When the earthing switch 12 (FIGS. 2, 4 and 6) is switched on, the auxiliary contact 40 acts as a leading contact with respect to the main contact 34 of the contact arrangement 30 of the earthing switch 12. The bending-resistant arm 38 formed as an aluminum rod with the round end element 42 made of stainless steel contacts during the Run of the main contact system 18, 34 with the run-in slope of the structure 22 designed as a stainless steel nose, until the arm 38 then engages in the structure 22 by the further movement of the contact arrangement 30. The current path is closed by the auxiliary contact system 22, 38, 42 ge and the main contact system 18, 32 can turn on voltage freely.

When the earthing switch 12 (FIGS. 3, 5 and 7) is switched off, the auxiliary contact system 22, 38, 42 is still closed. The main contact system 18, 32 of the earthing switch 12 can open voltage-free. The structure 22, which is designed as a stainless steel nose, prevents the rigid arm 38 of the auxiliary contact 40, which is designed as an aluminum rod, from moving in the “off” direction when opening with the main contact 34 formed by the rigid arm 32 (earth arm). The rigid arm 38 tensions ( similar to a whip) until the protruding length of the rigid arm 38 has passed through the nose-shaped structure 22. When the rigid arm 38 leaves the structure 22, it whips back into its starting position (arrow 48). The electrical contact of the auxiliary contact system 22, 38, 42 thereby opens at a very high speed Rapid switching of the auxiliary contact system 22, 38, 42 avoids a switching arc or is only weak or minimal.

FIG. 2 shows the sequence of movements when the earthing switch 12 shown in FIG. 1 is closed, and FIG. 3 shows the sequence of movements when the earthing switch 12 shown in FIG. 1 is opened.

This variant is referred to below as auxiliary contact system 22, 38, 42 with a short, rigid arm 38 (in particular aluminum rod).

The following switching sequence and the following advantages and disadvantages of this variant result:

Activation: Contacting auxiliary contact system 22, 38, 42 -> contacting main contact system 18, 32.

Switching off: Switching off the main contact system -> preloading auxiliary contact system 22, 38, 42 -> quick switch-off.

Advantages :

Cost-effective variant for switching small induced currents and voltages up to the nominal voltage level of 245 kV (to be restricted or expanded in the case of a detailed design).

Disadvantage :

Violation of the impact distance of the unfavorable earthing in such designed cultivation veins, possible due to the protrusion of the rigid arm 38 designed as an aluminum rod (possible necessity of avoidance by design adjustments to the base element 14).

Fig. 4 shows the sequence of movements when closing a Va riante of the earthing switch 12 with a slightly different auxiliary contact 40. FIG. 5 shows the sequence of movements when the earthing switch 12 already shown in FIG. 4 is opened.

This variant is referred to below as auxiliary contact system 22, 38, 42 with a long, rigid arm 38 (in particular aluminum rod).

Switching off: Switching off the main contact system -> preloading the auxiliary contact system -> fast switching off.

Advantages :

Cost-effective variant for switching induced currents and voltages of the nominal voltage level 245 to 420 kV (to be restricted or expanded in the case of detailed design).

Disadvantage :

Fig. 6 shows the sequence of movements when closing a further variant of the earthing switch 12 with a slightly modified auxiliary contact 40. Fig. 7 shows the sequence of movements when the earthing switch 12 already shown in Fig. 4 is opened. In this variant, the rigid arm 38 is on attached free end of the rigid arm 32 and points with its free end in the opposite direction as the rigid arm 32 ("hanging attachment"). This variant is referred to below as auxiliary contact system 22, 38, 42 with a long rigid arm 38 (in particular aluminum rod) and spring support.

This variant with an additional spring element, here a torsion spring 50, on the fixed end of the aluminum rod and hanging the attachment of the aluminum rod produces a particularly fast switching speed.

Activation: Contacting auxiliary contact system -> contacting main contact system.

Advantages :

Variant for switching induced currents and voltages at the nominal voltage level from 420kV (to restrict or expand with detailed design). Due to the design, there is no violation of the impact distance of the unfavorable earth position in the case of cultivators, due to the protrusion of the rigid arm 38, which is designed as an aluminum rod.

Disadvantage :

More complex and cost-intensive than the versions without a torsion spring.

The advantages of using the auxiliary contact arrangement are as follows:

- The earthing switch continues to run during the opening process and thus protects the main contact (switching capacitive and inductive residual currents). - Caster can be adjusted by the diameter and length of the aluminum sta.

- The speed, and thus the switching capacity of the auxiliary contact, is due to the flexibility of the

Determined aluminum rod and thus adaptable by diameter and length of the aluminum rod.

- Minimizing the use of aluminum and stainless steel compared to conventional solutions and avoiding the use of other special materials such as Tungsten.

- By using the low mass, the rod accelerates faster (a higher switching speed) compared to systems with massive auxiliary contacts and spring support

- Use in earthing switches only with swivel movement and in earthing switches with swivel-push movement.

- In particular, the elasticity of the selected aluminum enables such a high speed when leaving the stainless steel hook that practically no arc occurs (so short in time that it is possible to switch virtually arc-free - 'ho-arc feature'). In comparison, conventional solutions always lead to long (large) arcs.

Reference symbol list:

10 medium and / or high voltage switching device

12 earthing switches

14 basic element

16 isolator

18 contact element

20 switching element

22 nose structure

24 bearings

26 double arrow (swivel movement)

28 free end

30 contact arrangement

32 rigid arm

34 main contact

36 branch

38 rigid arm

40 auxiliary contact

42 final element

44 arrow

46 arrow

48 arrow

50 torsion spring

Claims

1. Earthing switch (12) for a medium and / or high voltage circuit device (10), the earthing switch (12) for earthing a contact element (18) of the Schaltungsein device (10) a movable switching element (20) and one on the free End (28) of the switching element (20) arranged contact arrangement (30) which comprises a main contact (34) and an auxiliary contact (40) for electrically contacting the contact element (18), the switching element (20) between one First position in which neither main nor auxiliary contact (34, 40) electrically contact the contact element (18) and a second position in which both the main contact (34) and the auxiliary contact (40) electrically contact the contact element (18) contact is movable back and forth and wherein the contact element (18) has a structure (22) for the electrical contact to the auxiliary contact (40),

characterized ,

that the auxiliary contact (40) is formed by a rigid arm (38) of the contact arrangement (30), the main contact (32) being arranged within the contact arrangement (30).

2. Earthing switch according to claim 1,

characterized ,

that the structure (22) of the contact element (18) for the electrical contacting of the auxiliary contact (40) is designed as a behind-grip structure with a running slope, in particular as a nose structure, which can be gripped by the rigid arm (38).

3. Earthing switch according to claim 1 or 2,

characterized ,

that the main and auxiliary contacts (34, 40) are arranged in such a way that the auxiliary contact (40) is designed as a leading auxiliary contact (40) which contacts the contact element (18) when the earthing switch (12) is closed before the main contact (34) contacted.

4. earthing switch according to one of claims 1 to 3,

characterized ,

that the earthing switch (12) on a base element (14) is mounted movably.

5. earthing switch according to claim 4,

characterized ,

that the grounding of the contact element (18) via the Basisele element (14).

6. earthing switch according to claim 4 or 5,

characterized ,

that the circuit device (10) has the base element (14) and the earthing switch (12) is designed as an attached earthing switch.

7. earthing switch according to one of claims 1 to 6,

characterized ,

that the main contact (34) is formed by a rigid arm (32) of the contact arrangement (30), the contact arrangement (30) branching out over the two arms (32, 38).

8. Earthing switch according to one of claims 1 to 7,

characterized ,

that the rigid arm (38) via a spring element, in particular a special torsion spring (50), is integrated into the contact arrangement (30).

9. earthing switch according to claim 8,

characterized ,

that the spring element is arranged at the free end of the rigid arm (32).

10. Medium and / or high-voltage circuit device (10) with an earthing switch (12), the element for grounding a contact (18), a movable switching element (20) and one at the free end (28) of the switching element (20) arranged contact - Arrangement (30), since you can draw rchge, since the earthing switch (12) is designed according to one of claims 1 to 9.