Natural commutation type hybrid AC circuit breaker and action method thereof

Abstract

The invention discloses a natural commutation type hybrid AC circuit breaker and an action method thereof. The natural commutation type hybrid AC circuit breaker comprises a mechanical switch, a commutation branch, a voltage limiting branch and a controller, the commutation branch and the voltage limiting branch are both connected with the mechanical switch in parallel, and the controller is connected with the mechanical switch and the commutation branch.

Description

Technical Field

[0001] The present invention relates to the technical field of AC circuit breakers, and more specifically, to a natural commutation hybrid AC circuit breaker and an operating method thereof. Background Art

[0002] With the construction of new power systems, the connection of a large number of new energy sources to the grid and the rapid construction of ultra-high voltage have had a great impact on the system short-circuit current. Currently, some switching devices have insufficient short-circuit current breaking capacity, and the short-circuit current breaking capacity of switching devices needs to be improved urgently. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a natural commutation hybrid AC circuit breaker and an operating method thereof.

[0004] According to one aspect of the present invention, there is provided a naturally commutated hybrid AC circuit breaker, comprising: a mechanical switch, a commutation branch, a voltage limiting branch and a controller, wherein:

[0005] The commutation branch and the voltage-limiting branch are both connected in parallel with the mechanical switch, and the controller connects the mechanical switch and the commutation branch.

[0006] Optionally, the commutation branch includes two reverse-blocking double-terminal solid-state thyristors connected in anti-parallel, a current limiting diode and a trigger circuit, wherein

[0007] The trigger circuit is connected in parallel at both ends of the reverse blocking two-terminal solid-state thyristor, and the current limiting diode is connected to the anode side of the reverse blocking two-terminal solid-state thyristor.

[0008] Optionally, the voltage-limiting branch adopts a varistor.

[0009] Optionally, the mechanical switch is a conventional AC circuit breaker, using a vacuum circuit breaker or a SF6 circuit breaker.

[0010] According to another aspect of the present invention, there is provided an operating method for a naturally commutated hybrid AC circuit breaker, comprising:

[0011] After receiving the command, the controller of the natural commutation hybrid AC circuit breaker sends an action signal to the operating structure of the mechanical switch of the natural commutation hybrid AC circuit breaker according to the action threshold corresponding to the set command;

[0012] The operating structure pulls the moving contact of the arc extinguishing chamber according to the action signal, the moving contact separates from the static contact, and an arc is generated between the two contacts;

[0013] After a delay of 3-5ms, the controller sends an action signal to the first trigger circuit T1 and the second trigger circuit T2 of the reverse blocking double-terminal solid-state thyristor of the commutation branch, and the commutation branch is triggered to conduct by the action signal;

[0014] Under the action of the arc voltage between the moving and static contacts of the arc extinguishing chamber, after the current of the mechanical switch branch is completely transferred to the conducting commutation branch, the arc between the moving and static contacts of the arc extinguishing chamber is extinguished;

[0015] After the current of the commutation branch passes through zero, the commutation branch is turned off, and the breaking process of the natural commutation hybrid AC circuit breaker is completed.

[0016] Optionally, the first trigger circuit or the second trigger circuit includes: a power supply U1, a current limiting resistor Rd, a first capacitor C1, a first diode D2, an IGBT, an inductor L1, an isolation transformer Tr, a second capacitor C2, a second diode D3 and a drift step recovery diode. The first trigger circuit and the second trigger circuit are connected in parallel at both ends of the reverse blocking two-terminal solid-state thyristor as a whole, respectively, to provide a dv / dt voltage pulse of not less than 5kV / us to the reverse blocking two-terminal solid-state thyristor, wherein,

[0017] On the primary side of the isolation transformer Tr, the power supply U1 is connected in series with the current limiting resistor Rd, the IGBT, the primary side of the isolation transformer Tr and the inductor L1, the first capacitor C1 is connected in parallel with the IGBT, the primary side of the isolation transformer Tr and the inductor L1, and the second diode D3 is connected in parallel with the first capacitor C1; on the secondary side of the isolation transformer Tr, the second capacitor C2 is connected in series with the first diode D2 and the secondary side of the isolation transformer Tr, and the drift step recovery diode is connected in parallel with the second capacitor C2 and the secondary side of the isolation transformer Tr.

[0018] Optionally, the working principle of the first trigger circuit or the second trigger circuit is:

[0019] When the first trigger circuit or the second trigger circuit does not apply a trigger signal, the IGBT is turned off, and the power supply U1 charges the first capacitor C1, wherein the current limiting resistor Rd plays a current limiting role;

[0020] After the first trigger circuit or the second trigger circuit applies a trigger signal, the IGBT is turned on, the first capacitor C1 discharges to the inductor L1 through the primary side of the isolation transformer Tr, the second diode D3 plays a freewheeling role, and the induced voltage generated on the secondary side of the isolation transformer Tr charges the first capacitor C2 through the drift step recovery diode. After the voltage of the first capacitor C2 is increased to make the drift step recovery diode enter the off state, a voltage pulse is generated, and the output is applied to both ends of the reverse blocking two-terminal solid-state thyristor, and the first diode D2 plays a protective and buffering role.

[0021] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0022] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of the above aspects of the present invention.

[0023] Therefore, the naturally commutated hybrid AC circuit breaker provided by the present invention can improve the short-circuit current breaking capacity of the AC circuit breaker without changing the arc extinguishing chamber structure of the AC circuit breaker or redesigning the AC circuit breaker by mixing the pulse power semiconductor device RBDT into a commutation branch on the basis of the existing AC circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0025] Figure 1 is a structural schematic diagram of a naturally commutated hybrid AC circuit breaker provided by an exemplary embodiment of the present invention;

[0026] Figure 2 It is a flow chart of an operation method of a naturally commutated hybrid AC circuit breaker provided by an exemplary embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of a trigger circuit provided by an exemplary embodiment of the present invention;

[0028] Figure 4 It is a working flow chart of a trigger loop provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0029] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described here.

[0030] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0031] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0032] It should also be understood that, in the embodiments of the present invention, “plurality” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0033] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0034] In addition, the term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0035] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0036] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0038] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0039] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0040] Figure 1 1 is a schematic diagram of the structure of a naturally commutated hybrid AC circuit breaker provided in the first aspect of the embodiment of the present invention. Figure 1 As shown, the natural commutation hybrid AC circuit breaker includes: a mechanical switch, a commutation branch, a voltage limiting branch and a controller, wherein:

[0041] The commutation branch and the voltage-limiting branch are both connected in parallel with the mechanical switch, and the controller connects the mechanical switch and the commutation branch.

[0042] Specifically, on the basis of traditional AC circuit breakers, through the application of pulse power semiconductor devices, the high di / dt and dv / dt carrying capacity of these special devices is utilized to transfer short-circuit current, thereby improving its large-capacity fast-breaking capability without changing the AC circuit breaker itself.

[0043] Further, refer to Figure 1As shown, the commutation branch includes two anti-parallel RBDTs, a current limiting diode and a trigger circuit. The trigger circuit is connected in parallel at both ends of the RBDT, and the current limiting diode is connected to the anode side of the RBDT.

[0044] RBDT stands for reverse blocking double-terminal solid-state thyristor, which is a special pulse power semiconductor device. The device is a four-layer thyristor-like device, but without a gate. The device can only be triggered by applying a pulse voltage with a dv / dt greater than 5kV / us between the anode and the cathode. The triggering conduction time is microseconds, and it can withstand a current rise rate of tens of kA / us. After conduction, the tube voltage drop is equivalent to that of the thyristor, and lower than that of fully controlled devices such as IGBT.

[0045] The voltage limiting branch adopts a varistor.

[0046] The mechanical switch is a conventional AC circuit breaker, which may be a vacuum circuit breaker or a SF6 circuit breaker.

[0047] Figure 2 is a schematic flow chart of an operation method of a naturally commutated hybrid AC circuit breaker provided in the second aspect of an embodiment of the present invention, with reference to Figure 2 As shown, the operation method 200 of the natural commutation hybrid AC circuit breaker includes:

[0048] Step 201: after receiving the command, the controller of the natural commutation hybrid AC circuit breaker sends an action signal to the operating structure of the mechanical switch of the natural commutation hybrid AC circuit breaker according to the action threshold corresponding to the set command;

[0049] Step 202: the operating structure pulls the moving contact of the arc extinguishing chamber according to the action signal, the moving contact is separated from the static contact, and an arc is generated between the two contacts;

[0050] Step 203: After a delay of 3-5 ms, the controller sends an action signal to the first trigger circuit T1 and the second trigger circuit T2 of the reverse blocking double-terminal solid-state thyristor of the commutation branch, and the commutation branch is triggered to conduct by the action signal;

[0051] Step 204: under the action of the arc voltage between the moving and static contacts of the arc extinguishing chamber, after the current of the mechanical switch branch is completely transferred to the conducting commutation branch, the arc between the moving and static contacts of the arc extinguishing chamber is extinguished;

[0052] Step 205: After the current of the commutation branch passes through zero, the commutation branch is turned off, and the breaking process of the natural commutation hybrid AC circuit breaker is completed.

[0053] Specifically, the specific action process is as follows:

[0054] (1) After receiving the command, the controller sends an action signal to the hybrid AC circuit breaker according to the set action threshold;

[0055] (2) The controller sends an action signal to the operating mechanism of the mechanical switch Km. The operating mechanism pulls the moving contact of the arc extinguishing chamber, and the moving contact separates from the static contact, generating an arc between the two contacts.

[0056] (3) After a delay of 3-5 ms, the controller sends an action signal to the RBDT trigger circuits T1 and T2 of the commutation branch, and the commutation branch is triggered to conduct;

[0057] (4) Under the action of the arc voltage between the moving and static contacts of the arc extinguishing chamber, the current in the mechanical switch Km branch is transferred to the commutation branch;

[0058] (5) After the current is completely transferred to the commutation branch, the arc between the moving and static contacts of the arc extinguishing chamber is extinguished;

[0059] (6) After the current in the commutation branch passes through zero, the commutation branch is shut down and the breaking process ends.

[0060] Figure 3 It is a schematic diagram of a trigger circuit of a specific implementation mode of the present invention. The trigger circuit includes a power supply U1, a current limiting resistor Rd, a capacitor C1, a diode D3, an IGBT, an inductor L1, an isolation transformer Tr, a capacitor C2, a diode D2 and a DSRD (drift step recovery diode). The trigger circuit is connected in parallel at both ends of the RBDT as a whole to provide a dv / dt voltage pulse of not less than 5kV / us to the RBDT.

[0061] DSRD, the full name of which is drift step recovery diode, is a pulse power semiconductor device that achieves nanosecond shutdown based on the drift step recovery effect. The device is normally in the on state, and its reverse recovery process after current flow can quickly shut down to form a higher dv / dt voltage pulse, creating conditions for RBDT triggering.

[0062] Figure 4 It is a working flow chart of the trigger circuit of the specific implementation mode of the present invention. When the trigger signal is not applied, the IGBT is turned off, the power supply U1 charges the capacitor C1, and Rd plays a current limiting role; after the trigger signal is applied, the IGBT is turned on, the capacitor C1 discharges to L1 through the primary side of the isolation transformer Tr, the diode D3 plays a freewheeling role, and the induced voltage generated on the secondary side of the isolation transformer Tr charges the capacitor C2 through DSRD. After the voltage of the capacitor C2 is increased to make DSRD enter the off state, a voltage pulse is generated, and the output is applied to both ends of RBDT, and the diode D2 plays a protective and buffering role.

[0063] Therefore, the naturally commutated hybrid AC circuit breaker provided by the present invention can improve the short-circuit current breaking capacity of the AC circuit breaker without changing the arc extinguishing chamber structure of the AC circuit breaker or redesigning the AC circuit breaker by mixing the pulse power semiconductor device RBDT into a commutation branch on the basis of the existing AC circuit breaker.

[0064] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A naturally commutated hybrid AC circuit breaker, characterized in that: include: Mechanical switch, commutation branch, voltage limiting branch and controller, wherein: The commutation branch and the voltage-limiting branch are both connected in parallel with the mechanical switch, and the controller is connected with the mechanical switch and the commutation branch.

2. The naturally commutated hybrid AC circuit breaker according to claim 1, characterized in that: The commutation branch includes two reverse-blocking double-terminal solid-state thyristors connected in anti-parallel, a current limiting diode and a trigger circuit, wherein The trigger circuit is connected in parallel at both ends of the reverse blocking two-terminal solid-state thyristor, and the current limiting diode is connected to the anode side of the reverse blocking two-terminal solid-state thyristor.

3. The naturally commutated hybrid AC circuit breaker according to claim 1, characterized in that: The voltage limiting branch adopts a varistor.

4. The naturally commutated hybrid AC circuit breaker according to claim 1, characterized in that: The mechanical switch is a conventional AC circuit breaker, which is a vacuum circuit breaker or a SF6 circuit breaker.

5. An operating method for a naturally commutated hybrid AC circuit breaker according to any one of claims 1 to 4, characterized in that: include: After receiving the command, the controller of the natural commutation hybrid AC circuit breaker sends an action signal to the operating structure of the mechanical switch of the natural commutation hybrid AC circuit breaker according to the set action threshold corresponding to the command; The operating structure pulls the moving contact of the arc extinguishing chamber according to the action signal, the moving contact is separated from the static contact, and an arc is generated between the two contacts; After a delay of 3-5ms, the controller sends the action signal to the first trigger circuit T1 and the second trigger circuit T2 of the reverse blocking double-terminal solid-state thyristor of the commutation branch, and the commutation branch is triggered to conduct by the action signal; Under the action of the arc voltage between the moving and static contacts of the arc extinguishing chamber, after the current of the mechanical switch branch is completely transferred to the conducting commutation branch, the arc between the moving and static contacts of the arc extinguishing chamber is extinguished; After the current of the commutation branch passes through zero, the commutation branch is turned off, and the breaking process of the natural commutation hybrid AC circuit breaker is completed.

6. The method according to claim 5, characterized in that The first trigger circuit or the second trigger circuit comprises: a power supply U1, a current limiting resistor Rd, a first capacitor C1, a first diode D2, an IGBT, an inductor L1, an isolation transformer Tr, a second capacitor C2, a second diode D3 and a drift step recovery diode. The first trigger circuit and the second trigger circuit are connected in parallel at both ends of a reverse blocking two-terminal solid-state thyristor as a whole, respectively, to provide a dv / dt voltage pulse of not less than 5kV / us to the reverse blocking two-terminal solid-state thyristor, wherein: On the primary side of the isolation transformer Tr, the power supply U1 is connected in series with the current limiting resistor Rd, the IGBT, the primary side of the isolation transformer Tr and the inductor L1, the first capacitor C1 is connected in parallel with the IGBT, the primary side of the isolation transformer Tr and the inductor L1, and the second diode D3 is connected in parallel with the first capacitor C1; on the secondary side of the isolation transformer Tr, the second capacitor C2 is connected in series with the first diode D2 and the secondary side of the isolation transformer Tr, and the drift step recovery diode is connected in parallel with the second capacitor C2 and the secondary side of the isolation transformer Tr.

7. The method according to claim 6, characterized in that The working principle of the first trigger circuit or the second trigger circuit is: When the first trigger circuit or the second trigger circuit does not apply a trigger signal, the IGBT is turned off, and the power supply U1 charges the first capacitor C1, wherein the current limiting resistor Rd plays a current limiting role; After the first trigger circuit or the second trigger circuit applies a trigger signal, the IGBT is turned on, the first capacitor C1 discharges to the inductor L1 through the primary side of the isolation transformer Tr, the second diode D3 plays a freewheeling role, and the induced voltage generated on the secondary side of the isolation transformer Tr charges the first capacitor C2 through the drift step recovery diode. After the voltage of the first capacitor C2 is increased to make the drift step recovery diode enter the off state, a voltage pulse is generated, and the output is applied to both ends of the reverse blocking two-terminal solid-state thyristor, and the first diode D2 plays a protective and buffering role.

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