A current transfer device

Abstract

The present invention discloses a current transfer device, comprising: multiple groups of static contact assemblies and multiple groups of moving contact assemblies; the number of the static contact assemblies is one group more than the number of the moving contact assemblies; the moving contact assemblies are arranged on a driving rod and correspond to the static contacts; wiring terminals are vertically arranged on both sides of the static contact assemblies, and the two wiring terminals are respectively connected to the positive and negative poles of an external power supply; a certain gap is provided between the moving contact assemblies and the static contact assemblies, so that when the wiring terminals are connected to the external power supply, the moving contact assemblies are driven by the driving rod to separate from the static contact assemblies to form an arc. By the cooperation of the static contact assemblies and the moving contact assemblies, a very high arc voltage can be established on the main current branch within a very short time to ensure that the current of the main current branch is transferred to the current transfer branch, and the device has the characteristics of fast arc voltage increase, strong reliability, compact size and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current circuit breaker equipment, and in particular to a current transfer device. Background Art

[0002] With the rapid development of flexible DC transmission and distribution technology based on voltage source converters, the construction of multi-terminal flexible DC systems connecting multiple converter stations has gradually matured. However, the fault current in the DC grid system has no zero crossing point, so traditional AC circuit breakers are not applicable in the DC system. In addition, the fault current rise rate in the DC system is large, and a DC circuit breaker that can break the fault current within a few milliseconds is required to quickly remove the faulty equipment or line to ensure the stable operation of the non-fault part of the DC system.

[0003] In order to ensure the rapid removal of faulty equipment or lines, the most commonly used method at this stage is to use a hybrid DC circuit breaker to remove the fault. Hybrid DC circuit breakers have become one of the core technologies in the development of medium and high voltage DC circuit breakers due to their fast fault removal speed and low stable current loss, and have been successfully applied in DC power grids. According to different shutdown principles, hybrid circuit breakers can be divided into forced commutation type and natural commutation type. However, the current forced commutation hybrid DC circuit breakers still have problems such as large conduction loss, high cost, heat dissipation, relatively complex structure and components. Summary of the invention

[0004] The present invention provides a current transfer device for establishing a very high arc voltage on a main current branch in a very short time, thereby ensuring that the current of the main current branch is transferred to the current transfer branch.

[0005] A current transfer device provided in an embodiment of the present invention is applied to a main common-current branch of a naturally commutated hybrid DC circuit breaker; the device comprises: a plurality of groups of static contact assemblies and a plurality of groups of moving contact assemblies; the number of the static contact assemblies is one more than the number of the moving contact assemblies; the moving contact assemblies are arranged on a driving rod and correspond to the static contact assemblies;

[0006] Both sides of the static contact assembly are vertically provided with connection terminals, and the two connection terminals are respectively connected to the positive and negative poles of the external power supply;

[0007] There is a certain gap between the moving contact assembly and the stationary contact assembly, so that when the wiring terminal is connected to the external power supply, the moving contact assembly is driven by the driving rod to separate from the stationary contact assembly to form an arc.

[0008] Optionally, the device further comprises: a hydrogen arc chamber; the hydrogen arc chamber is arranged below the moving contact assembly, and the hydrogen arc chamber is used to separate the hydrogen plasma in the arc.

[0009] Optionally, the moving contact assembly is provided with a fan-shaped groove having equal depth and curvature;

[0010] The moving contact assembly is staggered with the fan-shaped groove and is covered by the stationary contact assembly.

[0011] Optionally, the number of the moving contact assemblies is 3, and the number of the stationary contact assemblies is 4.

[0012] Optionally, the stationary contact assembly consists of a stationary contact connector and a stationary contact; the stationary contact is installed on the edge of the stationary contact connector.

[0013] Optionally, the multi-point static contact connector is an insulating component.

[0014] Optionally, the moving contact assembly is composed of a moving contact connector and a moving contact; the multi-point moving contacts are arranged at the edge of the fan-shaped groove and correspond one-to-one with the multi-point static contacts.

[0015] Optionally, the moving contact connector is the insulating component.

[0016] Optionally, the gas in the hydrogen arc chamber is pure hydrogen.

[0017] Optionally, the connection relationship between the wiring terminal and the stationary contact assembly is welding.

[0018] It can be seen from the above technical solutions that the present invention has the following advantages:

[0019] A current transfer device of the present invention is applied to the main common-current branch of a naturally commutated hybrid DC circuit breaker; the device comprises: a plurality of groups of static contact assemblies and a plurality of groups of moving contact assemblies; the number of the static contact assemblies is one more than the number of the moving contact assemblies; the moving contact assemblies are arranged on a driving rod and correspond to the static contacts; both sides of the static contact assemblies are vertically provided with wiring terminals, and the two wiring terminals are respectively connected to the positive and negative poles of an external power supply; a certain gap is provided between the moving contact assembly and the static contact assembly, so that when the wiring terminals are connected to the external power supply, the moving contact assembly is driven by the driving rod to separate from the static contact assembly to form an arc.

[0020] In this way, when the current transfer device of the present invention is connected in series with a naturally commutated hybrid DC circuit breaker, a very high arc voltage can be established on the main current branch in a very short time through the cooperation of the static contact assembly and the moving contact assembly, ensuring that the current of the main current branch is transferred to the current transfer branch. It has the characteristics of fast arc voltage increase, strong reliability, compact size and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a schematic diagram of a typical topological structure of a forced commutation hybrid DC circuit breaker;

[0023] Figure 2 A schematic diagram of the topological structure of the auxiliary current transfer module combined with power electronic devices;

[0024] Figure 3 A schematic diagram of the topological structure of the auxiliary current transfer module of the coupled voltage structure;

[0025] Figure 4 A schematic diagram of the composition of an embodiment of a current transfer device of the present invention;

[0026] Figure 5 is a side cross-sectional view of an embodiment of a current transfer device of the present invention;

[0027] Figure 6 A schematic diagram of current flow in an embodiment of a current transfer device of the present invention.

[0028] In the figure: 1. first terminal; 2. second terminal; 3. static contact connector; 4. moving contact connector; 5. static contact; 6. moving contact; 7. hydrogen arc chamber; a. external auxiliary switch; b. residual current breaking device; c. auxiliary current transfer module; d. fast mechanical switch; e. main current branch; f. solid-state switch; g. current transfer branch; h. lightning arrester group; i. energy absorption branch; D1. first moving contact assembly; D2. second moving contact assembly; D3. third moving contact assembly; J1. first static contact assembly; J2. second static contact assembly; J3. third static contact assembly; J4. fourth static contact assembly; h1. first short arc; h2. second short arc; h3. third short arc; h4. fourth short arc; h5. fifth short arc; h6. sixth short arc. DETAILED DESCRIPTION

[0029] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0030] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] See also Figure 1-Figure 3 , Figure 1 The typical topological structure diagram of the forced commutation hybrid DC circuit breaker is shown in Figure 1. Figure 2 The topological structure diagram of the auxiliary current transfer module combined with power electronic devices is shown in Figure 1. Figure 3 The topological structure diagram of the auxiliary current transfer module of the coupled voltage structure. The hybrid DC circuit breaker is one of the core technologies currently developed in the field of medium and high voltage DC circuit breakers. According to different shutdown principles, the hybrid circuit breaker can be divided into two types: forced commutation type and natural commutation type. Figure 1 The figure is a schematic diagram of a typical topological structure of a forced commutation hybrid DC circuit breaker, including: a main current branch e, a current transfer branch g and an energy absorption branch i, wherein the main current branch e is composed of a fast mechanical switch d (generally a fast vacuum switch) and an auxiliary current transfer module c, the current transfer branch g is composed of a solid-state switch f, and the energy absorption branch i is composed of a lightning arrester group h. More specifically, the auxiliary current transfer module c in the main current branch e generally includes: two topologies including an auxiliary current transfer module as a power electronic device combination structure and an auxiliary current transfer module as a coupled voltage structure, as shown in FIG. Figure 2 and Figure 3 As shown. When the external auxiliary switch a is closed, the residual current interrupter b is also closed, forcing the commutation hybrid DC circuit breaker to interrupt the current, and the solid-state switch f on the current transfer branch g is turned on, while the fast mechanical switch d on the main current branch e is disconnected, and the auxiliary current transfer module c is activated to transfer the current to the current transfer branch g. When the fast mechanical switch d is opened to the required opening distance, the solid-state switch f on the current transfer branch g is disconnected, and the current is finally cut off by the energy absorption branch i.

[0033] In the typical topological structure of the naturally commutated hybrid DC circuit breaker, the main current branch only includes a mechanical switch. When the current is interrupted, the solid-state switch on the current transfer branch is turned on, and the mechanical switch on the main current branch is disconnected and arcs. The arc voltage of the mechanical switch is used to open the solid-state switch, and finally the current is transferred to the solid-state switch. When the mechanical switch is opened to the required opening distance, the solid-state switch is closed, and finally the current is cut off by the energy absorption branch.

[0034] However, at present, the forced commutation hybrid DC circuit breaker still has problems such as large conduction loss, high cost, heat dissipation requirement, relatively complex structure and components. Although the above-mentioned natural commutation hybrid DC circuit breaker has a simple structure, it is limited by the size of the arc voltage during the commutation process, and often causes current transfer failure due to the arc voltage of the mechanical switch of the main current branch being too low.

[0035] A current transfer device of the present invention is mainly used to establish a very high arc voltage on a main current branch in a very short time to ensure that the current of the main current branch is transferred to the current transfer branch.

[0036] For details, please refer to Figure 4-Figure 6 , Figure 4 is a schematic diagram of the composition of an embodiment of a current transfer device of the present invention, Figure 5 is a side sectional view of an embodiment of a current transfer device of the present invention, Figure 6 The present invention is a schematic diagram of the current flow of a current transfer device according to an embodiment of the present invention. The current transfer device is applied to the main common-current branch of a naturally commutated hybrid DC circuit breaker. The device comprises: a plurality of groups of static contact assemblies and a plurality of groups of moving contact assemblies. The number of the static contact assemblies is one more than the number of the moving contact assemblies. The moving contact assemblies are arranged on the driving rod and correspond to the static contact assemblies.

[0037] Both sides of the static contact assembly are vertically provided with connection terminals, and the two connection terminals are respectively connected to the positive and negative poles of the external power supply;

[0038] There is a certain gap between the moving contact assembly and the stationary contact assembly, so that when the wiring terminal is connected to the external power supply, the moving contact assembly is driven by the driving rod to separate from the stationary contact assembly to form an arc.

[0039] In an embodiment of the present invention, the first terminal 1 and the second terminal 2 are respectively located on both sides of the static contact assembly and connected to the positive and negative poles of the external power supply, and the gap between the moving contact assembly and the static contact assembly is for the moving contact assembly to generate an arc when driven by the driving rod.

[0040] Furthermore, the device also includes: a hydrogen arc chamber 7; the hydrogen arc chamber 7 is arranged below the moving contact assembly, and the hydrogen arc chamber 7 is used to separate the hydrogen plasma in the arc.

[0041] Furthermore, the moving contact assembly is provided with a fan-shaped groove having equal depth and curvature;

[0042] The moving contact assembly is staggered with the fan-shaped groove and is covered by the stationary contact assembly.

[0043] In an embodiment of the present invention, the moving contact assembly is provided with a fan-shaped groove with equal depth and arc, and the moving contact assembly moves on the fan-shaped groove based on the stationary contact assembly in a staggered manner to generate multiple arcs.

[0044] Furthermore, the number of the moving contact assemblies is 3, and the number of the stationary contact assemblies is 4.

[0045] Furthermore, the stationary contact assembly is composed of a stationary contact connector and a stationary contact; the stationary contact is installed on the edge of the stationary contact connector.

[0046] Furthermore, the multi-point static contact connector is an insulating component.

[0047] Furthermore, the moving contact assembly is composed of a moving contact connector and a moving contact; the multi-point moving contacts are arranged at the edge of the fan-shaped groove and correspond one-to-one with the multi-point static contacts.

[0048] In an embodiment of the present invention, the moving contact assembly includes: a first moving contact assembly D1, a second moving contact assembly D2, and a third moving contact assembly D3; the static contact assembly includes: a first static contact assembly J1, a second static contact assembly J2, a third static contact assembly J3, and a fourth static contact assembly J4; the edges of the first static contact assembly J1 and the second static contact assembly J2 are respectively connected to two ends of the first moving contact assembly D1; the edges of the second moving contact assembly D2 and the third moving contact assembly D3 are respectively connected to two ends of the second moving contact assembly D2; the edges of the third moving contact assembly D3 and the fourth moving contact assembly D4 are respectively connected to two ends of the third moving contact assembly D3; the six contacts generated thereby can generate a first short arc h1, a second short arc h2, a third short arc h3, a fourth short arc h4, a fifth short arc h5, and a sixth short arc h6.

[0049] Furthermore, the moving contact connecting piece is the insulating component.

[0050] In the embodiment of the present invention, any single arc will have a near-pole voltage drop. Although the arc near-pole voltage drop value varies with the cathode material and the gas medium, the change is not large and is basically around 15V. Figure 6The six short arc near-pole voltage drops in the device greatly increase the arc voltage. Since the metal phase arc can be formed when the moving and static contacts open a very small gap, and the arc near-pole voltage drop will be generated in the metal phase arc stage, the present invention can achieve separation of the moving and static contact surfaces in a very short time, generate multiple arcs, and quickly increase the arc voltage of the entire device.

[0051] To sum up, the most obvious advantage of the current transfer device based on a multi-contact hydrogen arc chamber of the present invention is that it can quickly and efficiently generate a higher arc voltage when breaking the current. When used in series with the fast vacuum switch on the main current branch, it can ensure that the current on the main current branch is transferred to the transfer branch.

[0052] Furthermore, the gas in the hydrogen arc chamber is pure hydrogen.

[0053] In the embodiment of the present invention, due to the fast movement speed of hydrogen molecules and the high thermal conductivity of hydrogen plasma, the arc column potential gradient increases with the increase of gas thermal conductivity. Therefore, under the same conditions, compared with other gases, the arc voltage of hydrogen is high, and the arc voltage generated by separating the moving and static contacts when current is flowing is higher.

[0054] Furthermore, the connection relationship between the wiring terminal and the stationary contact assembly is welding.

[0055] A current transfer device of the present invention is applied to the main common-current branch of a naturally commutated hybrid DC circuit breaker; the device comprises: a plurality of groups of static contact assemblies and a plurality of groups of moving contact assemblies; the number of the static contact assemblies is one more than the number of the moving contact assemblies; the moving contact assemblies are arranged on a driving rod and correspond to the static contacts; both sides of the static contact assemblies are vertically provided with wiring terminals, and the two wiring terminals are respectively connected to the positive and negative poles of an external power supply; a certain gap is provided between the moving contact assembly and the static contact assembly, so that when the wiring terminals are connected to the external power supply, the moving contact assembly is driven by the driving rod to separate from the static contact assembly to form an arc.

[0056] In this way, when the current transfer device of the present invention is connected in series with a naturally commutated hybrid DC circuit breaker, a very high arc voltage can be established on the main current branch in a very short time through the cooperation of the static contact assembly and the moving contact assembly, ensuring that the current of the main current branch is transferred to the current transfer branch. It has the characteristics of fast arc voltage increase, strong reliability, compact size and low cost.

[0057] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A current transfer device, characterized in that: Applicable to the main current branch of a naturally commutated hybrid DC circuit breaker; the current transfer device comprises: a plurality of groups of static contact assemblies and a plurality of groups of moving contact assemblies; the number of the static contact assemblies is one more than the number of the moving contact assemblies; the moving contact assembly is arranged on the driving rod and corresponds to the static contact assembly; Both sides of the static contact assembly are vertically provided with connection terminals, and the two connection terminals are respectively connected to the positive pole and the negative pole of the external power supply; There is a certain gap between the moving contact assembly and the stationary contact assembly, so that when the wiring terminal is connected to the external power supply, the moving contact assembly is driven by the driving rod to separate from the stationary contact assembly to form an arc; The current transfer device further comprises: a hydrogen arc chamber; the hydrogen arc chamber is arranged below the moving contact assembly, and the hydrogen arc chamber is used to separate the hydrogen plasma in the arc; The moving contact assembly is provided with a sector-shaped groove having equal depth and arc; The moving contact assembly is staggered with the fan-shaped groove and is covered by the stationary contact assembly.

2. The current transfer device according to claim 1, characterized in that: The number of the moving contact assemblies is 3, and the number of the stationary contact assemblies is 4.

3. The current transfer device according to claim 1, characterized in that: The stationary contact assembly is composed of a stationary contact connector and a stationary contact; the stationary contact is installed on the edge of the stationary contact connector.

4. The current transfer device according to claim 3, characterized in that: The stationary contact connector is an insulating component.

5. The current transfer device according to claim 3 or 4, characterized in that: The moving contact assembly is composed of a moving contact connector and a moving contact; the moving contact is arranged at the edge of the fan-shaped groove and corresponds to the static contact one by one.

6. The current transfer device according to claim 5, characterized in that: The moving contact connecting piece is an insulating component.

7. The current transfer device according to claim 1, characterized in that: The gas in the hydrogen arc chamber is pure hydrogen.

8. The current transfer device according to claim 1, characterized in that: The connection relationship between the wiring terminal and the stationary contact assembly is welding.

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