EP0320614B1 - Spring energy accumulator drive for a high voltage switch - Google Patents

Abstract

In the spiral spring (26) of the spring energy accumulator (10), the energy can be stored in order to switch on the high-voltage switch (56) in order, at the same time, to tension the switch-off spring (58). In order to be able to store the energy for more than one switching on operation, a local pressure store (74) is provided in which sufficient energy is stored to wind up the spiral spring (26) at least one more time. Between the pressure store (74) and the hydraulic motor (12) there is arranged a controllable valve (90) which opens in the event of the spiral spring (26) being partially destressed and hence the hydraulic motor (12) rotates the spring cage (18) in the direction of the arrow (C) until the spiral spring (26) is tensioned again. <IMAGE>

Description

The present invention relates to a spring energy storage drive for a high-voltage switch according to the preamble of claim 1.

Such a spring energy storage drive is described, for example, in "Speaker Energy Revue" No. 1/86 on pages 4 and 5. The energy for switching on the high-voltage switch and for simultaneously tensioning a switch-off spring memory can be stored in the spring force accumulator, which can be tensioned by means of an electric motor or by hand. With the high-voltage switch switched on and the spring-loaded energy store and the spring-loaded spring-loaded mechanism switched on, the high-voltage switch can consequently be switched off, switched on and off again without the spring-loaded energy accumulator being recharged. For reasons of security of supply, it can be required that the high-voltage switches can carry out several such switching operations even if the feed network fails. To solve this problem, it is proposed in DE-OS 35 40 674, for example, to make the storage energy of the spring energy store so large that the high-voltage switch can thus be switched on several times and at the same time the opening spring accumulator can be charged. As a result of the spring characteristics, if the spring energy accumulator is not recharged, much more energy is available for the first switching operation than for the following switching operations. On the one hand, this requires additional damping elements for the Destruction of excess energy and on the other hand a corresponding dimensioning of the spring energy storage drive for large storage energies and the resulting large forces.

It is therefore an object of the present invention to provide a spring energy storage drive, in the spring energy storage of which the energy for a single switch-on of a high-voltage switch can be stored, which can switch on the high-voltage switch at least one more time even if the supply network fails.

This object is solved by the characterizing part of claim 1. The storage energy can be stored in the spring force store for a single activation of the high-voltage switch. The energy for further switching operations is stored in a local fluid pressure accumulator, by means of which a fluid motor which can be fed via a controlled valve is driven, by means of which the spring force accumulator can be charged. In the known spring energy storage drive, the electric motor can consequently be replaced by a fluid motor which can be fed by the local fluid pressure accumulator. This can be done without substantial intervention in the spring energy storage drive.

In a preferred embodiment, a check valve is connected in parallel to the fluid motor, which is conductive in the direction from the low-pressure connection to the high-pressure connection of the fluid motor and is blocking in the opposite direction. As a result, the spring force accumulator can be pulled up by hand, for example by means of a crank, without having to intervene in the fluid circuit or in the mechanical operative connections between the fluid motor and the spring force accumulator.

In a further preferred embodiment, a control device is provided for opening the valve when the spring force accumulator is partially relaxed. This ensures that the spring force accumulator is immediately recharged during or after a switch-on process, so that the high-voltage switch can be switched on in quick succession.

The fluid motor can be drivable by means of a hydraulic fluid which can be pumped from a low-pressure container into the fluid pressure accumulator by means of a pump through a check valve. This enables retrofitting of high-voltage switches that are already installed in a switchgear, for example, without having to change the infrastructure. The original electrical supply line provided for the electric motor for charging the spring force accumulator can be connected to the pump, which only causes adjustments to the spring force accumulator drive. The same advantages have a spring force storage drive, the fluid motor of which can be driven by means of a gas, in particular compressed air, which is pumped into the fluid pressure accumulator by means of a local compressor. If a central compressed gas supply is installed in the switchgear, the fluid pressure accumulator can be connected directly to this compressed gas supply.

With a multi-pole high-voltage switch with one Spring force storage drive per pole, a single local fluid pressure accumulator can be provided for all spring force storage drives of this high-voltage switch. From this local fluid pressure accumulator, feed lines can be routed to the tensioning devices in each spring energy accumulator drive with little effort.

Further preferred embodiments are specified in the further claims.

An embodiment of the invention will be described with reference to the single figure. This shows purely schematically a spring energy storage drive with a tensioning device for charging the spring energy storage, which has a fluid motor that can be fed by a local fluid pressure accumulator.

The spring energy storage drive 10 has a hydraulic motor 12 which acts via a gear 14 on a ring gear 16 of a rotatably mounted spring cage 18. The axis of rotation 20 of the spring cage 18 coincides with the axis of a spring shaft 22. The outer end of a spiral spring 26 is attached to a laterally projecting tab 24 of the spring cage 18, the inner end of which is connected to the spring shaft 22.

An engaging pawl lever 28 is connected in a rotationally fixed manner to the spring shaft 22 and is releasably supported on an engaging pawl 30. By means of an electrically actuated switch-on magnet system 32, the switch pawl 30 can be pivoted clockwise from the position shown in the figure into a release position. At the Spring shaft 22 is also a cam disc 34 is rotatably arranged. The distance between the axis of rotation 20 and the radial running surface 36 of the cam disk 34, indicated by an arrow A, increases steadily over the course of an almost complete revolution against the direction of the arrow B. The transition from the greatest distance to the smallest distance A takes place with a slightly curved, practically radial edge 37.

A two-part roller lever 40 is arranged in a rotationally fixed manner on a pivotably mounted roller lever shaft 38 that runs parallel to the axis of rotation 20. In the free end region of the two parts of the roller lever 40, a roller 42 is rotatably mounted, on which the running surface 36 of the cam plate 34 can act. On the one hand, a turn-off pawl lever 44 sits on the roller lever shaft 38 in a rotationally fixed manner and on the other hand a transmission lever 46. The turn-off pawl lever 44 is shown in solid lines and denoted by 0 in an off position. It can be pivoted counterclockwise into a switch-on position shown in dash-dotted lines and designated I. In the switched-on position I, the switch-off pawl lever 44 is releasably supported on a switch-off pawl 48, which can be pivoted from the position shown into a release position by means of an electrically controllable switch-off magnet system 50. The position of the roller lever 40 in the switched-on position I is also indicated by dash-dotted lines.

The transmission lever 46 is operatively connected to a movable switch contact 54 of a high-voltage switch 56 and an opening spring 58 via a transmission system 52, which is only indicated.

This above-described part of the spring energy storage drive 10 operates as follows: When the engagement ratchet lever 28 is supported on the engagement pawl 30, the spring cage 18 is rotated by 360 ° in the arrow direction C by means of the hydraulic motor 12. The energy thus stored in the spiral spring 26 is sufficiently large to switch on the high-voltage switch 56 and at the same time to tension the switch-off spring 58, as will now be described. When the switch-on magnet system 32 is excited, the switch pawl 30 is pulled back into the release position, so that the spring shaft 22 together with the cam disk 34 can rotate in the direction of arrow B. The roller 42 comes to rest on the tread 36, which has the consequence that the roller lever 40 and thus the roller lever shaft 38 are pivoted counterclockwise into the switch-on position I shown in broken lines. After the release of the engagement pawl lever 28, the engagement pawl 30 immediately returns to its rest position, so that after a rotation of 360 °, the engagement pawl lever 28 again comes into contact with the engagement pawl 30. As a result of the pivoting movement of the roller lever shaft 38, the switch-off pawl lever 44 latches in the switch-on position I to the switch-off pawl 48. The pivoting of the transmission lever 46 switches the high-voltage switch 56 on and, at the same time, the switch-off spring 58 is tensioned.

The spiral spring 26 can now be tensioned again by rotating the spring cage 18 by means of the hydraulic motor 12.

To turn off the high voltage switch 56, the turn-off magnet system 50 is energized, after which the turn-off pawl 48 releases the ratchet lever 44. The switch-off contact 54 of the high-voltage switch 56 is opened by the switch-off energy stored in the switch-off spring 58 and the roller lever shaft 38 is pivoted into the switch-off position 0, which is shown in solid lines. The approximately radially inward edge 37 of the cam plate 34 leaves enough space for the pivoting movement of the roller lever 40 together with the roller 42.

In this context, it should be mentioned that a single pole of a high-voltage switch 56 or a plurality of poles can be driven by means of a single spring energy storage drive 10.

A backstop 62 acts on an output shaft 60 of the hydraulic motor 12 in such a way that turning for tensioning the spiral spring 26 is permitted, but turning back in the opposite sense is prevented. This prevents unwanted relaxation of the coil spring 26. The spiral spring 26 can also be tensioned by hand by means of a crank 64 which can be operatively connected to the transmission 14.

A hydraulic pump 68 can be driven by means of an electric motor 66, by means of which hydraulic fluid, for example hydraulic oil, can be pumped from a low-pressure container 70 through a check valve 72 into a generally known hydraulic pressure accumulator 74. The check valve 72 prevents the high-pressure hydraulic fluid from flowing back to the hydraulic pump 68 and to the low-pressure container 70. In order to prevent an excessive increase in pressure in the pressure accumulator 74, the pressure accumulator 74 is connected in terms of flow to an overpressure valve 76 which opens when the pressure is too high and allows the hydraulic fluid to flow back into the low-pressure container 70 until the pressure in the pressure accumulator 74 drops to the desired value is. A pressure relay 78 is also connected in terms of flow with the pressure accumulator 74, the switch contacts 80 of which close below a lower limit value when the pressure in the pressure accumulator 74 drops and open when an upper limit value is reached. This pressure relay 78 controls the excitation coil 82 of a switch 84, by means of which the electric motor 66 can be switched on or off.

An adjustable orifice 88 for regulating the flow rate and a controllable valve 90 are connected in series between the pressure accumulator 74 and the high-pressure connection 86 of the hydraulic motor 12. The low-pressure connection 91 is fluidly connected to the low-pressure container 70. Another non-return valve 92 is connected in parallel with the hydraulic motor 12 in such a way that it is conductive in the direction from the low-pressure connection 91 to the high-pressure connection 84 of the hydraulic motor 12 and blocks in the opposite direction.

A control element 94 is provided in the spring force storage drive 10 and is operatively connected to the valve 90. This connection is indicated by dash-dotted lines. The control element 94 has a pivotable control shaft 96 which runs parallel to the axis of rotation 10 and has three one-armed levers 98, 100 and 102. In the with extended The position of the control element 94 shown in lines is the valve 90 blocking. In the position indicated by the dash-dotted lines, pivoted counterclockwise by approximately 45 degrees, the valve 90 is conductive. The lever 98 transmits the pivoting position of the control shaft 96 to the valve 90, while the lever 100 in the position shown in solid lines rests on a tongue 104 protruding radially outward from the spring shaft 22. In the position shown in broken lines, the lever 102 is pivoted into the path of a bolt 106 arranged on the spring cage 18. As indicated below, the control element 94 controls the valve 90 and an auxiliary switch 108 depending on the tension state of the coil spring 26.

The functioning of the hydraulic circuit and its control are described in more detail below. As soon as the pressure in the pressure accumulator 74 has dropped below the lower limit value, the switching contacts 80 of the pressure relay 78 close, as a result of which the excitation coil 82 of the switch 84 is excited. The switch 84 switches on the electric motor 66, as a result of which the hydraulic fluid is pumped from the low-pressure container 70 into the pressure accumulator 74. As soon as the pressure in the pressure accumulator 74 has reached the upper limit value, the switch contacts 80 of the switch 78 open, as a result of which the electric motor 66 is switched off. The check valve 72 prevents the hydraulic fluid from flowing back to the hydraulic pump. 68 and into the low-pressure container 70. If for some reason the electric motor 66 does not switch off or the pressure in the pressure accumulator 74 becomes too high for another reason, the pressure-relief valve 76 opens around the high-pressure system Preserve damage. Consequently, under normal conditions, hydraulic fluid with sufficient pressure should always be stored in the pressure accumulator 74.

When the coil spring 26 is tensioned, the control element 94 is in the position shown with solid lines. The valve 90 is blocking. When the spring shaft 22 is released by the switch pawl 30, the spring shaft 22 begins to rotate in the direction of arrow A, as a result of which the lever 100 and thus the entire control element 94 is pivoted into the position shown in broken lines as a result of the rotation of the tongue 104. The valve 90 opens and the hydraulic motor 12 begins to rotate, whereby the coil spring 26 is tensioned in the direction of arrow C. After the switching-on process of the high-voltage switch 56 has ended, the spring shaft 22 has rotated through 360 ° and in turn is supported on the switching pawl 30. The rotation of the spring cage 18 by means of the hydraulic motor 12 takes place much more slowly than the relaxation of the spiral spring 26 when the high-voltage switch 56 is switched on. As soon as the spring cage 18 has been rotated by almost 360 ° in the direction of arrow C, the bolt 106 runs onto the lever 102 and pivots it back to the position shown in solid lines, whereby the valve 90 is closed and the hydraulic motor 12 is switched off. The coil spring 26 is now sufficiently tensioned to be able to switch the high-voltage switch 56 on again. The force exerted by the spiral spring 26 on the spring cage 18 is absorbed by the backstop 62.

In normal working operation, the check valve is 92 is closed and thus prevents the hydraulic fluid from flowing from the supply line to the high-pressure connection 86 back to the low-pressure container 70. However, it may happen that the spiral spring 26 has to be pulled up manually by means of the crank 64 during revision or assembly work. In this process, the hydraulic motor 12 goes into a pumping operation and pumps hydraulic fluid from the high-pressure connection 84 to the low-pressure connection 86. The check valve 92 opens and allows a hydraulic fluid flow to circulate between the hydraulic motor 12 and the check valve 92.

The position of the auxiliary switch 108 provides information about the position of the control element 94 and thus also about the tension state of the spiral spring 26. This auxiliary switch 108 is often required for feedback to a central control room or for other monitoring tasks. It can be readily appreciated that an auxiliary switch 108 can also be used to control an electrically actuated valve 90.

In the case of high-voltage switches 54, in which each pole can be driven by means of its own spring energy storage drive 10, it is advisable to use a single pressure accumulator 74 for winding up the coil springs 26 of all poles.

Spring force drive 10 with the arrangements according to the invention for tensioning the spring force store can also be used in high-voltage switches in which only the switch contacts 54 are closed with the spring drive 10, on the other hand, the opening of the Switch contacts 54 can be done by a separate drive or by an opening spring 58 which is tensioned with a separate drive.

Claims (13)

1. A spring energy store drive for a high voltage switch, comprising a spring energy store (26) which may be charged by means of a tensioning device, with whose stored energy the high voltage switch (56) may be closed once, characterised in that the tensioning device has a fluid motor (12) which may be supplied via a controlled valve (90) by a local fluid accumulator (74), the storable energy content of which at least equals the stored energy of the spring energy store (26).
2. A spring energy store drive according to claim 1, characterised in that a flow rate regulator, preferably an adjustable restrictor (88), is provided between the fluid accumulator (74) and the fluid motor (12).
3. A spring energy store drive according to claim 1 or 2, characterised in that a non-return valve (92) is connected in parallel with the fluid motor (12), which conducts in the direction from the low pressure connection (91) to the high pressure connection (86) of the fluid motor (12) and blocks in the opposite direction.
4. A spring energy store drive according to one of claims 1 to 3, characterised in that the fluid motor (12) has an output shaft (60) to which a back stop (62) is operatively connected.
5. A spring energy store drive according to claim 4, characterised in that the output shaft (60) acts on a gear unit (14) which is operatively connected to the spring energy store (26).
6. A spring energy store drive according to claim 1 or 2, characterised in that a pressure relief valve (76) is in flow connection with the fluid accumulator (74).
7. A spring energy store drive according to claim 1, characterised by a control device (94) for opening the valve (90) when the spring energy store (26) is partially untensioned.
8. A spring energy store drive according to claim 7, characterised in that the control device (94) has a control member (94), operatively connected with the valve (90), which may be moved into an opening position when the spring energy store (26) is partially untensioned and into a closing position when the spring energy store (26) is tensioned.
9. A spring energy store drive according to claim 7, characterised in that there is provided an electrically operable valve (90), controllable by means of an auxiliary switch (108), wherein the auxiliary switch (108) may be closed when the spring energy store (26) is partially untensioned, and opened when the spring energy store (26) is tensioned.
10. A spring energy store drive according to one of claims 1 to 4, characterised in that the fluid motor (12) may be operated by means of a hydraulic fluid which can be pumped by means of a pump (68) through a non-return valve (72) from a low pressure tank (70) into the fluid accumulator (74), and the pump (68) may preferably be controlled by a pressure relay (78) which is in flow connection with the fluid accumulator (74).
11. A spring energy store drive according to one of claims 1 to 4, characterised in that the fluid motor (12) may be operated by means of a gas, particularly compressed air, which is passed from a central compressed gas supply or by means of a local compressor through a non-return valve into the fluid accumulator.
12. A spring energy store drive according to one of claims 1 - 11, comprising at least one spiral spring provided as the spring energy store (26), the inside end of which acts on a rotatable and lockable shaft (22) on which a cam plate is seated, secured against rotation, and comprising a lever (40) arranged so as to be secured against rotation on a lever shaft (38) parallel to this shaft (22), which lever shaft is frictionally connected to a cut-off spring store (58) and to at least one mobile switch contact (54) of the high voltage switch (56), on which lever (40) the cam plate (34) acts such that the lever shaft (38) may be swivelled from a disconnecting position into a connecting position, the fluid motor (12) being operatively connected to the external end of the spiral spring for the purpose of tensioning the said spiral spring.
13. A multiple-pole high voltage switch (56) comprising one spring energy store drive (10) according to one of claims 1 to 12 per pole, characterised in that a single local fluid accumulator (74) is provided for all the spring energy store drives (10).

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