EP2283503A1

EP2283503A1 - Circuit breaker drive

Info

Publication number: EP2283503A1
Application number: EP09749546A
Authority: EP
Inventors: Franz-Josef Körber
Original assignee: ABB Technology AG
Current assignee: ABB Technology AG
Priority date: 2008-05-17
Filing date: 2009-05-06
Publication date: 2011-02-16
Also published as: CN102037533A; KR20110013404A; WO2009141056A1; DE102008024097A1

Abstract

The invention relates to a drive for actuating a high-voltage circuit breaker (1), comprising a working cylinder (3) and a working piston (16) displaceable therein, wherein a foot region (38) of the working cylinder (3) is hydraulically connected to a control line (Z), and a control valve (12) having at least the control line (Z), a pressure line (P), and a tank line (T) connected thereto, and hydraulically connecting the control line (Z) to the pressure line (P) in a first position, and hydraulically connecting the control line (Z) to the tank line (T). By shifting the control valve (12) into the first position, the working piston (16) moves to a first end position. A cutoff spring (20) is provided for moving the working piston (16) into a second end position.

Description

Circuit breaker operating mechanism

description

The invention relates to a drive for a high-voltage circuit breaker according to the preamble of claim 1.

A hydraulic drive for actuating a high-voltage circuit breaker is known from the patent application EP 0829892 A1 and comprises a working cylinder and a working piston displaceable therein. If the working piston is moved to a first end position, it closes a circuit breaker, the working piston is moved to a second end position, it opens the circuit breaker.

A generic drive further comprises a control valve, to which three fluid lines, namely a pressure line in which there is relatively high pressure fluid, a tank line, in which there is relatively low pressure fluid, and a control line are connected. The relatively low pressure of the fluid in the tank line is about one bar, so atmospheric pressure. The relatively high pressure of the fluid in the pressure line is between 200 and 600 bar.

The control valve can be brought into two positions, the control valve hydraulically connecting the control line to the pressure line in a first position and hydraulically connecting the control line to the tank line in a second position.

The working piston divides the working cylinder into two areas, which are referred to below as foot area and head area. The foot area of the working Cylinder, which is bounded by a foot side of the working piston, is hydraulically connected to the control line and is, depending on the position of the control valve, under relatively high or under relatively low pressure. The head region of the working cylinder, which is bounded by one of the foot side axially opposite the head side of the working piston, is hydraulically connected to the pressure line and is permanently under relatively high pressure.

On the head side of the working piston, a piston rod connects, which actuates the circuit breaker.

By placing the control valve in the first position, fluid under relatively high pressure flows from the pressure line into the control line and further into the foot area, whereby the pressure of the fluid in the control line and in the foot area increases. The pressure of the fluid in the foot area is now equal to the pressure of the fluid in the head area. However, the hydraulically effective area of the foot side of the working piston, which corresponds to the cross-sectional area of the working piston, is greater than the hydraulically effective area of the head side of the working piston. The hydraulically effective area of the head side of the working piston is in fact reduced by the cross-sectional area of the piston rod compared to the cross-sectional area of the working piston. Therefore, the working piston is moved to the first end position and closes the circuit breaker.

By placing the control valve in the second position, the relatively high pressure fluid from the foot region flows through the control line into the tank line, with the pressure of the fluid in the foot region and in the control line decreasing. The pressure of the fluid in the foot area is now smaller than the pressure of the fluid in the head area. Therefore, the working piston is moved to the second end position and opens the circuit breaker.

Such a drive operates according to a differential piston principle, wherein the head side of the working piston is permanently subjected to relatively high pressure, while the foot side of the working piston, depending on the position of the control valve, is acted upon with relatively high or relatively low pressure. An error in the hydraulic system of the drive, such as an internal leakage in a fluid line or failure of the hydraulic pump, which promotes fluid in a connected to the pressure line storage cylinder as needed, can lead to a blockage of the drive with closed circuit breaker, so that the circuit breaker not more can be opened.

The object of the invention is to provide a drive which can open a circuit breaker even when such a fault occurs.

This object is achieved by the features of claim 1.

According to the invention a Ausschaltfeder is provided to move the working piston in the second end position.

The circuit breaker is thus switched on by means of a known hydraulic drive system and switched off by means of a mechanical drive system which comprises the opening spring.

The breaking capacity of the circuit breaker is thus independent of the functionality of the hydraulic drive system. Even with a partial or complete loss of oil, the circuit breaker can be turned off.

According to an advantageous embodiment of the invention, the head portion of the working cylinder is hydraulically connected to the tank line.

When switching on the circuit breaker then creates a pressure difference within the working cylinder, since the fluid is under relatively high pressure in the foot area and the fluid in the head area under relatively low pressure. This increases the turn-on speed of the circuit breaker. Furthermore, it is advantageous that a part of the pressure line, namely the supply line to the head region of the working cylinder, is saved. By placing the control valve in the first position, the relatively high pressure fluid flows from the pressure line into the control line and further into the foot area, increasing the pressure of the fluid in the control line and in the foot area. The pressure of the fluid in the foot area is now greater than the pressure of the fluid in the head area. The working piston is moved against the force exerted by the opening force in the first end position and closes the circuit breaker.

By placing the control valve in the second position, the relatively high pressure fluid from the foot region flows through the control line into the tank line, with the pressure of the fluid in the foot region and in the control line decreasing. The pressure of the fluid in the foot area is now equal to the pressure of the fluid in the head area. The working piston is moved by the force exerted by the opening force in the second end position and opens the circuit breaker.

According to a further advantageous development of the invention, a latch, in particular a mechanical latch, is provided, which fixes the working piston in the first end position. By releasing the latch, the opening spring then moves the working piston to the second end position.

By means of such a latch a simplified mode of operation of the drive is possible. In this mode, the circuit breaker can be opened even in the event of a defect on the control valve.

By moving the control valve to the first position, the power switch is turned on. The latch then fixes the working piston in the first end position. The control valve remains in the first position only briefly, during the power-up process, and then returns to the second position. The under relatively high pressure fluid flows from the foot area through the control line in the tank line and the pressure of the fluid in the foot and in the control line drops. The pressure of the fluid in the foot area is now equal to the pressure of the fluid in the head area. The working piston is held by the latch in the first end position. By releasing the latch, the opening spring pushes the working piston into the second end position and switches off the circuit breaker. Advantageously, a valve spring, which presses the control valve in the second position, and a turn-on coil, which pushes the control valve in the first position when current flows, provided.

To turn on the circuit breaker in this embodiment, only a short-term current flow through the turn-on is necessary. When the current drops, the valve spring pushes the control valve back to the second position.

Further advantageous embodiments of the invention can be found in the dependent claims.

Reference to the following drawings, in which embodiments of the invention are illustrated, the invention, advantageous embodiments and other advantages will be described in more detail.

Show it:

Error! Reference source not found. a drive with open circuit breaker,

Error! Reference source not found. a drive during a closing operation of the circuit breaker

Error! Reference source not found. a drive with a closed circuit breaker

In error! Reference source could not be found, a drive with an open circuit breaker 1 is shown.

In a working cylinder 3, a working piston 16 is slidably disposed, which separates the working cylinder 3 in a foot portion 38 and a head portion 40. The foot region 38 is thereby delimited by the foot side 34 of the working piston 16 and the head region 40 by the head side 36 of the working piston 16. At the top 36, a piston rod 48 connects, which operates the circuit breaker 1. The working cylinder 3 is designed as a differential cylinder.

In the illustration shown, the working piston 16 is in a second end position and the circuit breaker 1 is open.

At the foot portion 38 of the working cylinder 3, a control line Z is connected, which is also connected to a control valve 12. To the control valve 12 are further a pressure line P, in which there is fluid under relatively high pressure, and a tank line T, in which there is fluid under relatively low pressure connected. The fluid is preferably hydraulic oil.

In the illustration shown, the control valve 12 is in a second position, in which it connects the control line Z to the tank line T hydraulically. In the control line Z and in the foot region 38 of the working cylinder 3 is thus also the fluid under relatively low pressure.

The pressure line P is also connected to a storage cylinder 4, which serves as a storage for the fluid under relatively high pressure. The storage cylinder 4 contains a storage piston 42, which is pressed by a storage spring 17 against the fluid, whereby the relatively high pressure of the fluid is generated. The storage spring 17 is designed for example as a spiral spring, leaf spring or gas spring.

The tank line T is connected to a tank 6, which serves as a reservoir for the fluid under relatively low pressure. Furthermore, the tank line T is connected to the head portion 40 of the working cylinder 3, in which there is also the fluid under relatively low pressure.

A designed as a compression spring valve spring 21 pushes the control valve 12 in the second position. Alternatively, the valve spring 21 can also be executed as a tension spring.

Externally at an end face of the housing of the working cylinder 3, the head portion 40 adjacent, a cylindrical spring housing 26 is fixed, which a Ausschaltfeder 20 encloses. The piston rod 48 breaks through the said end face of the working cylinder 3 and the end face of the spring housing 26. The opening spring 20 is designed in this example as a spiral spring and arranged concentrically around the piston rod 48 around. A design as a plate spring is conceivable.

On the piston rod 48, a spring plate 24 is fixed outside of the working cylinder 3, which is also enclosed by the spring housing 26. The opening spring 20 is designed in this example as a compression spring which is supported in the interior of the spring housing 26 at the end facing away from the working cylinder 3, and presses the spring plate 24 in the direction of the working cylinder 3 out.

In the illustration shown, the opening spring 20 thus presses over the spring plate 24 and the piston rod 48, the working piston 16 in the second end position.

The opening spring 20 can also be executed as a tension spring. In this case, it is fastened, for example, to the end face of the working cylinder 3, which is interrupted by the piston rod 48, and to the spring plate 24, and pulls the spring plate 24 in the direction of the working cylinder 3.

The opening spring can also attack in other places. For example, the working cylinder 3 can also be embodied as a synchronizing cylinder, wherein a second piston rod adjoins the base 34 of the working piston 16. This second piston rod then breaks through the end region of the working cylinder 3 adjacent to the foot region 38 and projects out of the working cylinder 3. At this second piston rod outside the working cylinder 3 also a spring plate can be fastened, on which acts the opening spring. The opening spring is executable in this case as a compression spring, wherein it presses the spring plate away from the working cylinder 3, or as a tension spring, wherein it pulls the spring plate away from the working cylinder.

Furthermore, it is conceivable to release the opening spring from the drive and to arrange directly on or in the circuit breaker 1. The drive further comprises a Einschaltspule 13, a Ausschaltspule 11 and a latch, which comprises a fixed to the piston rod 48 latch 32, a pawl spring 22 and a pawl 30. The function of these components will be discussed later.

In error! Reference source could not be found, the drive is out of error! Reference source could not be found during a circuit breaker 1 closing operation.

To close the circuit breaker 1, the closing coil 13 is driven, so that it is traversed by a current. The Einschaltspule 13 now pushes the control valve 12 against the force applied by the valve spring 21 in a first position in which the control valve 12 hydraulically connects the control line Z to the pressure line P.

The under relatively high pressure fluid flows from the pressure line P in the control line Z and on in the foot portion 38 of the working cylinder 3. The pressure in the foot region 38 on the foot side 34 of the working piston 16 increases and the working piston 16 is counteracted by the opening spring 20 applied force moved to a first end position. The piston rod 48 closes the circuit breaker first

On the piston rod 48, outside of the spring housing 26 and outside of the working cylinder 3, the aforementioned catch 32 is attached. The already mentioned pawl 30 is arranged and configured such that it engages immediately after switching on the circuit breaker 1 in the catch 32 and the working piston 16 is fixed in the first end position.

In error! Reference source could not be found, the drive is out of error! Reference source could not be found, with closed circuit breaker 1 shown.

After the circuit breaker 1 is closed, the turn-on coil 13 is deactivated and the current through the turn-on coil 13 drops. The valve spring 21 pushes the control valve 12 back to the second position in which the control valve 12 hydraulically connects the control line Z to the tank line T.

The under relatively high pressure fluid flows from the foot portion 38 of the working cylinder 3 in the control line Z and on in the tank line T. The pressure in the foot portion 38 of the working cylinder 3 falls off.

The pawl 30 remains engaged in the catch 32 and continues to fix the working piston 16 in the first end position. The circuit breaker 1 thus remains closed.

To open the circuit breaker 1, the pawl 30 is pulled out of the catch 32, whereby the latch is released. The opening spring 20 then presses on the spring plate 24 and the piston rod 48, the working piston 16 in the second end position and opens the circuit breaker first

In the illustration shown here, the latch comprises, in addition to the detent 32 and the pawl 30, also a pawl spring 22. The pawl spring 22 is designed as a compression spring in this example and arranged such that it presses the pawl 30 out of the detent 32.

As long as the opening coil 11 is flowed through by a current, this pushes the pawl 30 against the force applied by the pawl spring 22 force into the catch 32 into it.

In this example, the power switch 1 remains turned on while the opening coil 11 is driven, so as long as a current flows through the opening coil 11. To open the circuit breaker 1, the opening coil 11 is deactivated, the current through the opening coil 11 drops off and the pawl spring 22 presses the pawl 30 out of the catch 32 out. As a result, the circuit breaker 1 is opened.

This arrangement of the pawl spring 22 has the advantage that in case of failure of the auxiliary voltage of the circuit breaker 1 is opened automatically. A Blocking of the circuit breaker 1 in the closed state is thus avoided.

It is also conceivable to arrange the pawl spring 22 such that it presses the pawl 30 into the catch 32, the opening coil 11, when the current flows, pressing the pawl 30 out of the catch 32 against the force exerted by the pawl spring 22.

In this embodiment, only a brief current flow through the opening coil 11 is necessary to open the circuit breaker 1.

Of course, the pawl spring 22 can also be executed as a tension spring. Likewise, a latch without pawl spring is conceivable.

LIST OF REFERENCE NUMERALS

P pressure line

T tank line

Z control line

1 circuit breaker

3 working cylinders

4 storage cylinders

6 tank

11 opening coil

12 control valve

13 switch-on coil

16 working pistons

17 memory spring

20 opening spring

21 valve spring

22 pawl spring

24 spring plate

26 spring housing

30 pawl

32 catch

34 foot side of the working piston

36 head side of the working piston

38 foot area of the working cylinder

40 head area of the working cylinder

42 accumulator piston

48 piston rod

Claims

claims

A drive for operating a high voltage circuit breaker (1) comprising a power cylinder (3) and a displaceable therein working piston (16), wherein a foot portion (38) of the working cylinder (3) is hydraulically connected to a control line (Z), and a control valve (12) to which at least the control line (Z), a pressure line (P) and a tank line (T) are connected, and which in a first position hydraulically connects the control line (Z) to the pressure line (P), and which a second position, the control line (Z) hydraulically connects to the tank line (T), wherein by moving the control valve (12) in the first position of the working piston (16) is moved to a first end position, characterized in that a Ausschaltfeder (20) for moving the working piston (16) into a second one

End position is provided.

2. Drive according to claim 1, characterized in that a head portion (40) of the working cylinder (3) is hydraulically connected to the tank line (T).

3. Drive according to one of the preceding claims, characterized in that a latch is provided which fixes the working piston (16) in the first end position, and wherein by releasing the latch, the opening spring (20) the working piston (16) in the second end position emotional.

4. Drive according to claim 3, characterized in that on the head side (36) of the working piston (16), a piston rod (48) for actuating the circuit breaker (1) connects, which cooperates with the latch.

5. Drive according to claim 4, characterized in that the latch comprises a on the piston rod (48) fixed catch (32) and a pawl (30), wherein the pawl (30) by engagement in the notch (32) the working piston (30). 16) fixed in the first end position.

6. Drive according to claim 5, characterized in that a pawl spring (22) which pushes the pawl (30) out of the notch (32) out, and a Ausschaltspule (11), which in current flow, the pawl (30) in the notch (32) presses are provided.

7. Drive according to one of the preceding claims, characterized in that a valve spring (21), which presses the control valve (12) in the second position, and a closing coil (13), which at flow of current, the control valve (12) in the first position expresses, are provided.

8. Drive according to one of the preceding claims, characterized in that the opening spring (20) is designed as a tension spring.

9. Drive according to one of claims 1 to 7, characterized in that the opening spring (20) is designed as a compression spring.