Separating unit with electromagnetic drive

Abstract

A mechanical circuit breaker unit for interrupting a line includes a contact arrangement and an electromagnetic drive. The contact arrangement has first and second fixed contacts and a guided moving contact. The electromagnetic drive moves the moving contact. The separating unit can assume a first state and a second state. No electric connection exists between the first and second fixed contacts in the first state. The moving contact electrically connects the two fixed contacts to each other in the second state. The separating unit can be transferred from the second state into the first state by moving the moving contact. The second fixed contact has a recess for receiving the moving contact, and the moving contact engages at least partly into the recess when the separating unit is in the first state.

Claims

1. A circuit breaker unit for interrupting an electrical line, the circuit breaker unit comprising: a contact arrangement with a first fixed contact, a second fixed contact, and a movably mounted, guided moving contact; an electromagnetic drive for moving said moving contact; the circuit breaker unit having a first state wherein no electrical connection exists between said first and second fixed contacts; the circuit breaker unit having a second state wherein said moving contact electrically connects said first and second fixed contacts to one another; and wherein the circuit breaker unit is transferable from the second state into the first state by movement of said moving contact; said second fixed contact having a recess formed therein for receiving said moving contact, and said moving contact protruding at least partially into said recess when the circuit breaker unit is in the first state.

2. The circuit breaker unit according to claim 1, wherein said first fixed contact has a recess formed therein for receiving said moving contact, and said moving contact protrudes at least partially into said recess of said first fixed contact when the circuit breaker unit is in the second state.

3. The circuit breaker unit according to claim 1, wherein the recess formed in said second fixed contact is configured for guiding said moving contact in longitudinal moving direction.

4. The circuit breaker unit according to claim 1, wherein said moving contact is a peg-shaped pin contact.

5. The circuit breaker unit according to claim 1, wherein said moving contact has a ferromagnetic core and a conductive outer casing.

6. The circuit breaker unit according to claim 1, wherein said moving contact has a weight between 1 g and 10 kg.

7. The circuit breaker unit according to claim 1, wherein each of said first and second fixed contacts is in a form of an electrically conductive tulip.

8. The circuit breaker unit according to claim 1, wherein said moving contact and said first and second fixed contacts are formed with circular cylinder symmetry, and said moving contact is displaceable along a cylinder axis of said moving contact.

9. The circuit breaker unit according to claim 1, which further comprises a housing filled with insulating gas.

10. The circuit breaker unit according to claim 9, wherein said insulating gas in said housing has a pressure of 1 bar to 10 bar.

11. The circuit breaker unit according to claim 9, wherein said electromagnetic drive comprises a coil disposed within said housing and arranged concentrically around said moving contact.

12. The circuit breaker unit according to claim 9, wherein said electromagnetic drive comprises a coil disposed outside said housing and arranged concentrically around said moving contact.

13. The circuit breaker unit according to claim 1, wherein said electromagnetic drive comprises a coil disposed concentrically around said moving contact.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) The invention will be discussed in more detail below on the basis of FIGS. 1 to 5.

(2) FIG. 1 shows an embodiment of a circuit breaker unit according to the invention in a schematic cross-sectional illustration;

(3) FIG. 2 shows a further embodiment of the circuit breaker unit according to the invention in a schematic cross-sectional illustration;

(4) FIG. 3 shows an embodiment of a moving contact in a schematic cross-sectional illustration;

(5) FIG. 4 shows a first usage example of the circuit breaker unit according to the invention in a schematic illustration;

(6) FIG. 5 shows a second usage example of the circuit breaker unit according to the invention in a schematic illustration.

DESCRIPTION OF THE INVENTION

(7) In detail, FIG. 1 illustrates a schematic cross section through a mechanical circuit breaker unit 1 according to the invention. The circuit breaker unit 1 comprises a contact arrangement which has a first fixed contact 2, a second fixed contact 3 and a moving contact 4. Furthermore, the circuit breaker unit 1 comprises an electromagnetic drive means which has two coils 5, 6.

(8) The circuit breaker unit 1 is connected by way of the two fixed contacts 2, 3 to a power path of a switching system.

(9) In the exemplary embodiment shown in FIG. 1, the circuit breaker unit 1 exhibits cylindrical symmetry. The moving contact 4 is accordingly in the form of a peg-shaped pin contact. The fixed contacts 2, 3 are in the form of tulip contacts with (circular) cylinder symmetry. The coils 5, 6 are each of ring-shaped form, and are positioned concentrically around the fixed contacts 2, 3, wherein the coil 5 is assigned to the first fixed contact 2, and the coil 6 is assigned to the second fixed contact 3. The axes of symmetry of the circuit breaker unit 1 is indicated by the line 9.

(10) The first fixed contact 2 has a recess 21. The dimensions of the recess 21 are such that a sub region of the recess 21 can serve as damping chamber.

(11) The second fixed contact 3 likewise has a recess 31.

(12) FIG. 1 shows the circuit breaker unit 1 in a second state, in which an electrical connection is produced between the first fixed contact 2 and the second fixed contact 3. In the position illustrated in FIG. 1, the moving contact 4 engages both into the recess 21 and into the recess 31. Here, the surface of the moving contact 4 and the surface of the first fixed contact 2, and the surface of the moving contact 4 and the surface of the second fixed contact 3, make contact with one another in order to produce the electrical connection. It is however likewise conceivable for the contacting to be produced indirectly by way of an electrically conductive intermediate material arranged between the moving contact and the respective fixed contact. An intermediate material of said type is for example an electrically conductive lubricant.

(13) The entire region in which the contacting takes place is enclosed in gas-tight fashion by a housing 7. The housing is filled, in the interior 8 thereof, with an insulating gas. In the exemplary embodiment shown in FIG. 1, the insulating gas is SF.sub.6.

(14) A current flow in the coil 6 generates a magnetic field which, owing to the resulting reluctance force on the moving contact, effects the movement thereof in the direction of the second fixed contact 3. The moving contact 4 thus engages deeper into the recess 31, wherein the contact between the moving contact 4 and the first fixed contact 2 is severed. The circuit breaker unit 1 is thus moved into the first state, in which there is no electrical connection between the two fixed contacts 2, 3.

(15) In order to move the moving contact 4 (partially) out of the recess 31 again, a current flow is generated in the coil 5 (with no current being conducted by the coil 6), whereby the corresponding reluctance force effects a movement of the moving contact 4 in the direction of the coil 5, wherein the moving contact 4 engages into the recess 21 in the first fixed contact 2 and effects contacting between the first fixed contact 2 and the moving contact 4. Here, the length of the moving contact 4 is dimensioned such that the moving contact 4 can, in one end position (which substantially corresponds to the position of the moving contact illustrated in FIG. 1), produce the electrical connection between the two fixed contacts 2, 3, such that the circuit breaker unit 1 is situated in the second state.

(16) A rising current flow in the coil 5 can, with utilization of the Lorentz force, effect the movement of the moving contact 4 in the direction of the second fixed contact 3, wherein the circuit breaker unit 1 can be transferred from the second state into the first state. A corresponding current increase in the coil 6 can effect a movement of the moving contact 4 back into the position shown in FIG. 1.

(17) In the exemplary embodiment of FIG. 1, the coils 5, 6 are arranged within the housing 7. The supply lines (not illustrated) to the coils 5, 6 are accordingly equipped with gas-tight leadthroughs (not illustrated).

(18) FIG. 2 shows a further exemplary embodiment of a circuit breaker unit 1 according to the invention in a schematic illustration.

(19) Identical and similar parts are denoted by the same reference numerals in FIGS. 1 and 2, and this also applies to the further FIGS. 3 and 4. To avoid repetitions, only the differences in relation to the embodiment of FIG. 1 will be discussed in detail in the description of the embodiment of FIG. 2.

(20) The exemplary embodiment of FIG. 2 corresponds substantially to the exemplary embodiment of FIG. 1, with the difference that the cylindrical-shaped housing 7 has a smaller diameter. The coils 5, 6 are accordingly arranged outside the housing 7. In this exemplary embodiment, it is thus possible to dispense with gas-tight leadthroughs of the supply lines to the coils 5, 6.

(21) FIG. 3 shows an exemplary embodiment of the moving contact 4 in a schematic cross-sectional illustration. The moving contact 4 has a geometry with (circular) cylinder symmetry, wherein the axis of symmetry is indicated by the line 9.

(22) The moving contact 4 comprises a ferromagnetic core 41 composed of iron, and an outer casing 42 composed of aluminum, which exhibits good conductivity. Here, the ferromagnetic core 41 has the function of building up and/or intensifying the magnetic field of the moving contact 4, which magnetic field interacts with the magnetic field of the coils 5, 6.

(23) The diameter, shown in FIG. 3, of the core 41 may be varied (in relation to the diameter of the moving contact 4) in a manner dependent on the usage situation.

(24) FIG. 4 shows a usage example of the circuit breaker unit 1 in a schematic illustration. FIG. 4 illustrates a hybrid switching system 10, wherein the hybrid switching system 10 comprises the circuit breaker unit 1.

(25) The hybrid switching system 10 has a main path 12 and a bypass path 13. The main path 12 and the bypass path 13 are connected in parallel with respect to one another. The main path 12 comprises the circuit breaker unit 1 and an auxiliary switch 11. The bypass path 13 comprises a power switch 14.

(26) The auxiliary switch 11 comprises a number of electronic switches, which are in the form of IGBT modules.

(27) The power switch 14 comprises a multiplicity of electronic switches which are connected in series and which are in the form of IGBT modules. The multiplicity of electronic switches of the power switch 14 is several times greater than the number of electronic switches of the auxiliary switch 11. For example, the auxiliary switch 11 may have two IGBT modules, whereas the power switch 14 may comprise up to several hundred IGBT modules.

(28) During the normal operation of an installation into which the hybrid switching system 10 is integrated, the operating current flows substantially via the main path 12, because the resistance of the power switch 14 is very much greater than the resistance of the circuit breaker unit 1 and of the auxiliary switch 11.

(29) In the event of a short circuit, the current in the main path increases initially approximately exponentially. The auxiliary switch 11 is, for this purpose, designed to disconnect with the least possible time delay, preferably in the range of microseconds, in such a situation, whereby the current that rises further is commutated into the bypass path 13. The circuit breaker unit 1 is then transferred into the first state, such that the auxiliary switch 11 is not damaged by the high applied voltage (of up to several hundred kilovolts).

(30) The current that is commutated into the bypass path can subsequently be limited by way of the power switch 14.

(31) Depending on the arrangement of the electronic switches in the power switch 14 and in the auxiliary switch 11, the hybrid switching system 10 may be formed as a unidirectional or bidirectional switch. In the exemplary embodiment of FIG. 4, the hybrid switching system 10 is designed as a bidirectional switch, as is graphically indicated by way of corresponding symbols.

(32) FIG. 5 shows a simple example of a multi-terminal system 22 with three inverter stations 15, 16, 17, which are in the form of self-controlled multi-stage inverters.

(33) The inverter station 15 is connected to a three-phase alternating-current voltage network 201, which is not illustrated in any more detail in FIG. 5. The inverter stations 16 and 17 are likewise connected to alternating-current voltage networks 202 and 203 respectively.

(34) At the direct-current voltage side, the inverter stations 15, 16, 17 are connected to one another via the two direct-current lines 18 and 19, which are of different polarity.

(35) The energy provided in the alternating-current voltage network 201 is converted, in the inverter station 15, into direct-current voltage. By way of direct-current lines 18, 19, the energy is transported from the inverter station 15 to the two inverter stations 16, 17, where the energy is converted into alternating current again and fed into the alternating-current voltage networks 202 and 203. The circuit breaker unit 1 is arranged in the direct-current line 18.

(36) If a fault occurs for example at the inverter station 17, the direct-current voltage line is connected into a voltage-free and current less state, such that the circuit breaker unit 1 can be transferred into its opening (first) state. The direct-current line 18 can thus be interrupted, and the faulty inverter station 17 separated from the intact part of the system. Subsequently, the intact part of the system, which comprises the inverter stations 15, 16, can be set in operation again. The entire process can be completed in less than 300 ms, such that a possible outage of the energy to be provided by the system can be minimized in terms of time.

(37) It is self-evidently possible for the circuit breaker unit according to the invention to also be used in relatively large systems and DC networks with a greater number of inverter stations. The use of said circuit breaker unit according to the invention may be particularly advantageous for example in intermeshed DC networks.

LIST OF REFERENCE NUMERALS

(38) 1 Circuit breaker unit 2 First fixed contact 21 Recess 3 Second fixed contact 31 Recess 4 Moving contact 41 Core 42 External casing 5, 6 Coil 7 Housing 8 Housing interior 9 Line 10 Hybrid switching system 11 Auxiliary switch 12 Main path 13 Bypass path 14 Power switch 15, 16, 17 HVDC installation 18, 19 Direct-current line 201, 202, 203 Alternating-current voltage network 22 Multi-terminal system