Pre-ignition device for a high-voltage vacuum interrupter

Abstract

The invention relates to a high-voltage switching device comprising a high-voltage vacuum interrupter (4) to which is switched in parallel a pre-ignition device (3) in order to reduce contact wear. Variants relate to the switching order of the vacuum interrupter and the pre-ignition device. The invention creates a technically robust system which allows reliable switching under the conditions of high-voltage and high currents and a long electrical service life.

Description

[0001] Description

[0002] Pre-ignition device for a high-voltage vacuum interrupter

[0003] The invention relates to a high-voltage switching device with pre-ignition device and a method for operating this high-voltage switching device.

[0004] Frequent switching with high current, especially in vacuum interrupters, can lead to damage to the contacts of a power switch, ultimately limiting its electrical and mechanical service life. Switching off with high current can counteract this damage, as local melting of the contact surface that occurs during switching off leads to electrical smoothing of the contact surface. However, when the switch is used on a capacitive load such as a capacitor bank, the breaking current is too low for this smoothing effect to occur. Especially with vacuum interrupters and especially in high-voltage technology, this can lead to a significantly limited service life and also to an unacceptable number of restrikes.

[0005] In medium-voltage systems, this phenomenon is resolved kinematically by carefully matching the turn-on and turn-off speeds. A positive factor here is that the so-called pre-ignition times, i.e., the exposure time of the arc occurring during turn-on, are very short due to the relatively low voltages. However, this is not the case in high-voltage systems, where the pre-ignition times deviate significantly from zero.

[0006] The invention is based on the problem of providing a solution for significantly reducing the wear of a high-voltage vacuum interrupter. This problem is solved by a high-voltage switching device with a pre-ignition device comprising the features of claim 1 and a method for operating this high-voltage switching device comprising the features of claim 7.

[0007] The high-voltage vacuum switching device according to the invention has an additional closing contact outside the vacuum interrupter, so that the closing arc does not occur in the vacuum tube and does not damage the vacuum tube.

[0008] The solution according to the invention creates a technically robust system that provides reliable switching under conditions of high voltage and high currents and has a long electrical service life.

[0009] The main contact 12 of the main switching unit 2 can be optimized for conducting the current, and the secondary contact 13 of the secondary switching unit 3 can be optimized for switching the current. This is particularly important for an embodiment of the invention in which the secondary switching unit 3 is formed with an additional vacuum tube, in particular as a secondary contact 13 in the inrush current path.

[0010] In a particular embodiment of the invention, the secondary contact and / or the main contact are switched on or off in a phase-controlled manner. This measure, possibly during operation with alternating voltage, controls the time or phase position of the opening or closing of the main contact and / or secondary contact, particularly by the drive unit in cooperation with the gear mechanism, in such a way that minimized contact wear is expected.

[0011] Advantageous developments of the invention are specified in the subclaims. The invention is explained in more detail below as an exemplary embodiment to the extent necessary for understanding, using figures. In the figures:

[0012] Fig. 1 shows a high-voltage vacuum switching device 1 according to the invention with main switching unit 2 and separate auxiliary switching unit 3,

[0013] Fig. 2 shows a high-voltage vacuum switching device according to the invention with a main switching unit and an integrated auxiliary switching unit,

[0014] Fig. 3 shows a high-voltage vacuum switching device according to the invention with a main switching unit and a secondary switching unit having a switching resistance,

[0015] Fig. 4 Switching sequence of the high-voltage vacuum switching device according to the invention, switch in off,

[0016] Fig. 5 Switching sequence of the high-voltage vacuum switching device according to the invention, pre-ignition at the secondary contact in the insulating gas,

[0017] Fig. 6 Switching sequence of the high-voltage vacuum switching device according to the invention, secondary contact closes,

[0018] Fig. 7 Switching sequence of the high-voltage vacuum switching device according to the invention, main contact closes and

[0019] Fig. 8 Switching sequence of the high-voltage vacuum switching device according to the invention, secondary contact opens.

[0020] In the figures, like designations refer to like elements.

[0021] Figure 1 shows a main switching unit 2 which is formed with a high-voltage vacuum interrupter 4 having a main contact and which is electrically connected to a power supply 5 and a power discharge 6. A secondary switching unit 3 is electrically connected to the power supply 5 and the power discharge 6, with which the secondary switching unit 3 is connected in parallel with the main switching unit 2. A secondary contact 13 is arranged in the housing of the secondary switching unit 3. The secondary switching unit 3 forms a pre-ignition device for the main switching unit 2. The main switching unit 2 and the secondary switching unit 3 are arranged in separate housings, in particular separate insulating containers. The housing of the secondary switching unit 3 may be hermetically filled with an insulating gas, in particular one free of sulfur hexafluoride (SF6-free).The main switching unit 2 and the auxiliary switching unit 3 can be mechanically actuated via a drive unit 7, an insulating rod 8 and a gear 9 in such a way that the temporal sequence of closing and opening of the main contact in the main switching unit 2 and the auxiliary contact in the auxiliary switching unit 3 is controlled.

[0022] The high-voltage vacuum switching device 1 according to Figure 2 differs from the high-voltage vacuum switching device 1 according to Figure 1 in that the high-voltage vacuum interrupter 4 of the main switching unit 2 and the switching contact 13 of the secondary switching unit 3 are arranged in a common housing, in particular a common insulating container 10.

[0023] The high-voltage vacuum switching device 1 according to Figure 3, in addition to the high-voltage vacuum switching device 1 according to Figure 1, has an on-resistor 11, which is electrically connected in series with the auxiliary contact 13 of the auxiliary switching unit 3 between the power supply 5 and the power discharge 6. The auxiliary contact of the auxiliary switching unit 3 and the on-resistor 11 may be arranged together in a housing, in particular an insulating container. The on-resistor 11 limits the on-current.

[0024] Fig. 4 to Fig. 8 show characteristic switching sequences of closing and opening the main contact 12 in the main switching unit 2 and the auxiliary contact 13 in the auxiliary switching unit 3, controlled by the drive unit 7 and the gear 9. The drive unit and the insulating rod have been omitted for the sake of clarity. In the switching sequence in Fig. 4, the high-voltage vacuum switching device 1 is switched off, the main contact 12 in the main switching unit 2 and the auxiliary contact 13 in the auxiliary switching unit 3 are opened. In the switching sequence in Fig. 5, the lower contact piece of the auxiliary contact 13 is moved upwards by the drive unit a portion of the entire contact path, with pre-ignition 14 occurring at the auxiliary contact in the insulating gas. In the switching sequence in Fig. 6, the lower contact piece of the auxiliary contact 13 is moved upwards by the drive unit the entire contact path, and the auxiliary contact 13 is closed.In the switching sequence shown in Fig. 7, the lower contact piece of the secondary contact is moved upwards the entire contact path by the drive unit, the secondary contact is closed, and the main contact is closed by the drive unit. In the switching sequence shown in Fig. 8, the lower contact piece of the secondary contact is moved downwards the entire contact path by the drive unit, the secondary contact 13 is open, and the main contact 12 is closed.

[0025] High voltage in the sense of the invention is understood to mean a voltage of 72.5 kilovolts and higher.

[0026] The present invention has been explained in detail for illustrative purposes using specific embodiments. Elements of the individual embodiments can also be combined with one another. The invention is therefore not intended to be limited to individual embodiments, but is limited solely by the appended claims. List of reference symbols

[0027] 1 - High-voltage vacuum switching device

[0028] 2 - Main switching unit

[0029] 3 - Auxiliary switching unit, pre-ignition device

[0030] 4 - Vacuum interrupter

[0031] 5 - Power supply

[0032] 6 - Power Discharge

[0033] 7 - Drive unit

[0034] 8 - I insulating rod

[0035] 9 - Gearbox

[0036] 10 - Common housing

[0037] 11 - Switching resistor for current limiting

[0038] 12 - Main contact

[0039] 13 - Secondary contact

[0040] 14 - Pre-ignition at the auxiliary contact a - Switch in off b - Pre-ignition at the auxiliary contact in the insulating gas c - Auxiliary contact closes d - Main contact closes e - Auxiliary contact opens

Claims

Patent claims 1. High-voltage switching device with pre-ignition device comprising a main switching unit (2) which is formed with a high-voltage vacuum interrupter (4) having a main contact (12) and which is electrically connected to a power supply (5) and a power discharge (6), a drive unit (7) by means of which the high-voltage vacuum interrupter can be mechanically actuated, characterized in that a secondary switching unit (3) having a secondary contact (13) is electrically connected to the power supply and the power discharge, can be mechanically actuated by the drive unit and forms a pre-ignition device for the high-voltage vacuum interrupter.

2. High-voltage switching device according to claim 1, characterized in that the auxiliary switching unit (3) has a housing which is filled with an insulating gas, in particular one free from sulfur hexafluoride.

3. High-voltage switching device according to one of the preceding claims, characterized in that the main switching unit (2) and the secondary switching unit (3) have a common housing (10).

4. High-voltage switching device according to one of the preceding claims, characterized in that the auxiliary switching unit (3) is formed with an additional vacuum tube, in particular as a secondary contact (13) in the inrush current path.

5. High-voltage switching device according to one of the preceding claims, characterized in that the auxiliary switching unit (3) has an ohmic resistor (11) connected in series with the auxiliary contact (13) for limiting the inrush current.

6. High-voltage switching device according to one of the preceding claims, characterized in that the main switching unit (2) and the auxiliary switching unit (3) can be mechanically actuated via a drive unit (7), an insulating rod (8) and a gear (9) in such a way that the temporal sequence of closing and opening of the main contact (12) in the main switching unit (2) and of the auxiliary contact (13) in the auxiliary switching unit (3) is controlled.

7. Method for operating a high-voltage switching device according to one of the preceding claims, characterized in that, starting from a switching state in which both the main contact (12) and the secondary contact (13) are open, first the secondary contact is closed and then the main contact is closed.

8. Method for operating a high-voltage switching device according to one of the preceding claims, characterized in that, starting from a switching state in which both the main contact (12) and the secondary contact (13) are closed, first the secondary contact is opened and then the main contact is opened.

9. Method for operating a high-voltage switching device according to one of the preceding claims, characterized in that the secondary contact (13) and / or the main contact (12) are switched on in a phase-controlled manner to limit the contact load by a high inrush current.

10. Method for operating a high-voltage Switching device according to one of the preceding claims, characterized in that the secondary contact (13) and / or the main contact (12) are / will be switched off in a phase-controlled manner.

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