Star-delta switchgear cabinet

Abstract

The utility model relates to the technical field of electric power system relates to a star delta conversion switch cabinet, it includes the first, second knife gap subassembly of cabinet body and its inside upper and lower arrangement, top expansion module is equipped on the upper part of cabinet, and the lower part is cable room. First knife gap subassembly is electrically connected with top expansion module, is used for switching to the delta connection of external transformer, second knife gap subassembly is connected with cable room, realizes the switching of transformer star connection. The utility model discloses an integrated structure design, only one transformer cooperates this switch cabinet to replace traditional " two transformer + two switch cabinet " system, saves equipment cost and distribution room land area significantly. Simple operation, through switching knife gap can change transformer wiring mode, normal pressure sealed air insulation box ensures high reliability and low maintenance characteristics.

Description

Technical Field

[0001] This utility model relates to the field of power system technology, and in particular to a star-delta transfer switch cabinet. Background Technology

[0002] In industrial production and power supply, there are often application scenarios that require drawing power from two high-voltage power sources of different voltage levels (e.g., 10kV and 6kV) and ultimately outputting a stable low voltage (e.g., 400V). In such scenarios, the traditional and straightforward technical solution is to use two independent transformer systems, that is, to configure a dedicated transformer and matching switchgear for each of the 10kV and 6kV incoming lines.

[0003] However, this "dual transformer" solution has inherent drawbacks such as high equipment costs, large footprint, and complex system operation and maintenance costs. Purchasing two transformers and two sets of switchgear results in a huge one-time investment, while also occupying a significant amount of power distribution room space, increasing land and building costs. Furthermore, the increased number of devices within the system leads to more potential points of failure, increasing the workload and costs of daily inspections and maintenance, and the complex wiring further complicates operation and management. Therefore, there has long been an urgent need in this field for a dual power supply solution that can significantly reduce equipment costs and footprint. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a star-delta switching cabinet that is compact in structure and easy to operate.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A star-delta transfer switchgear includes a cabinet, and a first disconnector assembly and a second disconnector assembly disposed within the cabinet. A top expansion module is located at the top of the cabinet, and a cable compartment is located at the bottom. The first disconnector assembly and the second disconnector assembly are arranged vertically within the cabinet. The first disconnector assembly is electrically connected to the top expansion module and is used to switch an external transformer to a delta connection. The second disconnector assembly is electrically connected to the cable compartment and is used to switch an external transformer to a star connection.

[0007] This invention achieves significant technical advantages through its structure: by using a single transformer in conjunction with this switchgear, it can replace the traditional "two transformers + two switchgear" system, greatly saving equipment costs and the floor space required for the power distribution room; its operation is extremely simple, requiring only the switching of disconnectors to change the transformer wiring method. Compared with existing technologies, this invention, through the optimized layout of the disconnectors, makes the cabinet structure more compact and adaptable, providing an excellent solution for space-constrained scenarios.

[0008] Furthermore, an interlocking mechanism is included, which is disposed between the first disconnector assembly and the second disconnector assembly. In this solution, the interlocking mechanism prevents the simultaneous closing of the first and second disconnector assemblies through mandatory mechanical or electrical interlocking, thereby eliminating the risk of phase-to-phase short circuits caused by misoperation during the switching process, making the entire switching operation both simple and safe and reliable.

[0009] Furthermore, the top expansion module integrates a head-end interface group for connecting to the external high-voltage power supply and the head end of the transformer winding; the cable compartment integrates the tail-end interface group for connecting to the tail end of the transformer winding; the head-end interface group includes a first head-end interface, a second head-end interface, and a third head-end interface; the tail-end interface group includes a first tail-end interface, a second tail-end interface, and a third tail-end interface; the first disconnector assembly includes a first changeover switch, a second changeover switch, and a third changeover switch; the second disconnector assembly includes a fourth changeover switch, a fifth changeover switch, and a sixth changeover switch; the first pins of the first changeover switch, the second changeover switch, and the third changeover switch are respectively connected to the first head-end interface, the second head-end interface, and the third head-end interface; the second pin of the first changeover switch is connected to the first tail-end interface and the first pin of the fourth changeover switch; the second pin of the second changeover switch is connected to the second tail-end interface and the first pin of the fifth changeover switch; the second pin of the third changeover switch is connected to the third tail-end interface and the first pin of the sixth changeover switch; the second pins of the fourth changeover switch, the fifth changeover switch, and the sixth changeover switch are connected in parallel. The switchgear in this solution achieves flexible switching of the external transformer winding connection method through its specific internal electrical connections. The principle is as follows: the first-end interface group and the last-end interface group are respectively used to connect the first and last ends of each phase winding of the transformer, forming the electrical interface for the switching operation; when the first disconnector assembly is closed and the second disconnector assembly is open, the first, second, and third changeover switches are turned on, allowing current to flow from the first-end interface and directly to the last-end interface via the corresponding changeover switch. At this time, the first and last ends of each phase winding are directly connected, while the last ends of the three phase windings are not short-circuited, thus enabling... Electrically, a closed loop with a delta connection is constructed. When the second disconnector assembly is closed and the first disconnector assembly is open, the fourth, fifth, and sixth changeover switches are turned on, and their second pins are connected in parallel to form a common point. This connection method electrically short-circuits the three tail-end interfaces of the transformer, forming a standard star connection, and its virtual neutral point is formed by this parallel point. The key to this design is that by using two sets of disconnector assemblies to control the head-end and tail-end interface groups in different combinations, the reliable switching of the transformer between delta and star connection topologies is efficiently achieved. It should be noted that in this invention, either the moving contact or the stationary contact of each changeover switch can be defined as the first pin, and the other can be defined as the second pin.

[0010] Furthermore, the switchgear also includes a first power interface for connecting to a first power source and a second power interface for connecting to a second power source. The first power interface is connected to the first, second, and third head-end interfaces via a first input branch, a second input branch, and a third input branch, respectively. The second power interface is connected to the first, second, and third head-end interfaces via a fourth input branch, a fifth input branch, and a sixth input branch, respectively. In this design, both the first and second power interfaces are connected to the head-end interface group via their respective input branches. This design provides independent input channels for two different high-voltage power sources (such as 6kV and 10kV), enabling adaptation to the target power source while switching the transformer connection via the disconnector assembly, without the need for an additional power switching switch. This simplifies the system structure and improves reliability.

[0011] Furthermore, the interlocking mechanism is a mechanical interlocking mechanism, including an interlocking baffle driven by an operating mechanism; and / or, the interlocking mechanism is an electrical interlocking mechanism, which realizes interlocking logic through a control circuit.

[0012] Furthermore, a mechanism module is provided at the front of the cabinet. The mechanism module is operatively connected to the first knife switch assembly and the second knife switch assembly and is used to drive them to perform closing and opening operations.

[0013] Furthermore, the top expansion module includes a cable sleeve, a bracket for mounting the cable sleeve, and the head interface group integrated thereon.

[0014] Furthermore, phase-to-phase insulating barriers are provided between the first, second, and third transfer switches of the first disconnector assembly, and between the fourth, fifth, and sixth transfer switches of the second disconnector assembly. This design inserts high-strength insulating barriers between high-voltage live conductors to separate and seal the independent compartments of each phase conductor. This effectively extends the creepage distance and electrical clearance, blocks possible inter-phase arcing paths, and thus structurally forces reliable inter-phase isolation.

[0015] Furthermore, the vertical arrangement of the first disconnector assembly and the second disconnector assembly corresponds to the vertical position of the top expansion module and the cable compartment.

[0016] Furthermore, the cables of the top expansion module are led out from the top of the cabinet, and the cables of the cable compartment are led out from the bottom of the cabinet. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the switch cabinet from one angle.

[0018] Figure 2 It is the electrical schematic diagram of the switch cabinet;

[0019] Figure 3 This is an overall schematic diagram of the switch cabinet;

[0020] Figure 4 This is a cross-sectional view of the switch cabinet from one angle.

[0021] Figure 5 This is the electrical schematic diagram of the first disconnect switch assembly in conjunction with the transformer;

[0022] Figure 6 This is the electrical schematic diagram of the second disconnector assembly in conjunction with the transformer.

[0023] Label Explanation:

[0024] Cabinet 1, Cable compartment 11, Phase-to-phase insulation partition 12, First knife switch assembly 2, First changeover switch K1, Second changeover switch K2, Third changeover switch K3, Second knife switch assembly 3, Fourth changeover switch K4, Fifth changeover switch K5, Sixth changeover switch K6, Top expansion module 4, Cable head 41, Bracket 42, Cable sleeve 43, First head interface A1, Second head interface A2, Third head interface A3, First tail interface A4, Second tail interface A5, Third tail interface A6, First input branch U1, Second input branch U2, Third input branch U3, Fourth input branch U4, Fifth input branch U5, Sixth input branch U6, Mechanism module 9, Operating mechanism 91. Detailed Implementation

[0025] The embodiments of this utility model are described below with reference to the accompanying drawings:

[0026] See Figure 1-6 As shown, this utility model discloses a star-delta switching cabinet, including a cabinet 1, and a first disconnector assembly 2 and a second disconnector assembly 3 disposed within the cabinet 1; the cabinet 1 is a normal pressure sealed air-insulated structure, with a top expansion module 4 disposed on its upper part and a cable compartment 11 disposed on its lower part; the first disconnector assembly 2 and the second disconnector assembly 3 are arranged vertically inside the cabinet 1; the first disconnector assembly 2 is electrically connected to the top expansion module 4 and is used to switch the external transformer to a delta connection; the second disconnector assembly 3 is electrically connected to the cable compartment 11 and is used to switch the external transformer to a star connection.

[0027] In one embodiment, an interlocking mechanism (not shown) is also included, which is disposed between the first disconnector assembly 2 and the second disconnector assembly 3. In this solution, the interlocking mechanism prevents the simultaneous closing of the first and second disconnector assemblies 2 and 3 through mandatory mechanical or electrical interlocking, thereby eliminating the risk of phase-to-phase short circuits caused by misoperation during the switching process, making the entire switching operation both simple and safe and reliable.

[0028] See Figure 2 , 5-6, the top expansion module 4 integrates a head-end interface group for connecting to the external high-voltage power supply and the head end of the transformer winding; the cable compartment 11 integrates the tail-end interface group for connecting to the tail end of the transformer winding; the head-end interface group includes a first head-end interface A1, a second head-end interface A2, and a third head-end interface A3; the tail-end interface group includes a first tail-end interface A4, a second tail-end interface A5, and a third tail-end interface A6; the first disconnect switch assembly 2 includes a first changeover switch K1, a second changeover switch K2, and a third changeover switch K3; the second disconnect switch assembly 3 includes a fourth changeover switch K4, a fifth changeover switch K5, and a sixth changeover switch K6; the first changeover switch K1... The first pins of the second changeover switch K2 and the third changeover switch K3 are respectively connected to the first head interface A1, the second head interface A2, and the third head interface A3; the second pin of the first changeover switch K1 is connected to the first tail interface A4 and the first pin of the fourth changeover switch K4; the second pin of the second changeover switch K2 is connected to the second tail interface A5 and the first pin of the fifth changeover switch K5; the second pin of the third changeover switch K3 is connected to the third tail interface A6 and the first pin of the sixth changeover switch K6; the second pins of the fourth changeover switch K4, the fifth changeover switch K5, and the sixth changeover switch K6 are connected in parallel. The switchgear in this solution achieves flexible switching of the external transformer winding wiring method through its specific internal electrical connections. The principle is as follows: The first-end interface group and the last-end interface group are respectively used to connect the first and last ends of each phase winding of the transformer, forming the electrical interface for the switching operation. When the first disconnector assembly 2 is closed and the second disconnector assembly 3 is open, the first, second, and third changeover switches K1, K2, and K3 are turned on, allowing current to flow from the first-end interfaces A1, A2, and A3 and directly to the last-end interfaces A4, A5, and A6 via the corresponding changeover switches. At this time, the first and last ends of each phase winding are directly connected, while the last ends of the three phase windings are not short-circuited. This creates an electrical closed loop in a delta connection. When the second disconnector assembly 3 is closed and the first disconnector assembly 2 is open, the fourth, fifth, and sixth changeover switches K4, K5, and K6 are connected, and their second pins are connected in parallel to form a common point. This connection electrically short-circuits the three tail-end interfaces A4, A5, and A6 of the transformer, forming a standard star connection. The virtual neutral point is formed by this parallel connection point. The key to this design is that by using two sets of disconnector assemblies 2 and 3 to control the head-end and tail-end interface groups in different combinations, the reliable switching of the transformer between delta and star connection topologies is efficiently achieved.

[0029] In one specific embodiment, the moving contacts (here referred to as first pins) of the first changeover switch K1, the second changeover switch K2, and the third changeover switch K3 are connected one-to-one with the first head interface A1, the second head interface A2, and the third head interface A3 of the head interface group, and the stationary contacts (here referred to as second pins) are connected one-to-one with the first tail interface A4, the second tail interface A5, and the third tail interface A6; the stationary contacts (here referred to as first pins) of the fourth changeover switch K4, the fifth changeover switch K5, and the sixth changeover switch K6 are connected one-to-one with the first tail interface A4, the second tail interface A5, and the third tail interface A6, and the moving contacts (here referred to as second pins) of the fourth changeover switch K4, the fifth changeover switch K5, and the sixth changeover switch K6 are connected in parallel.

[0030] In practical applications, it is assumed that the external transformer includes a first winding L1, a second winding L2, and a third winding L3. The first end of the first winding L1 is connected to the first starting end interface A1, and the last end of the first winding L1 is connected to the first ending end interface A4; the first end of the second winding L2 is connected to the second starting end interface A2, and the last end of the second winding L2 is connected to the second ending end interface A5; the first end of the third winding L3 is connected to the third starting end interface A3, and the last end of the third winding L3 is connected to the third ending end interface A6. When it is necessary to switch the transformer to a delta connection, the operating mechanism 91 drives the first disconnector assembly 2 to close (i.e., the first changeover switch K1, the second changeover switch K2, and the third changeover switch K3 are connected), while the second disconnector assembly 3 remains open (i.e., the fourth changeover switch K4, the fifth changeover switch K5, and the sixth changeover switch K6 are disconnected). At this time, the current flows in from the first end interface A1, A2, and A3, and flows directly to the tail end interface A4, A5, and A6 through the first changeover switch K1, the second changeover switch K2, and the third changeover switch K3, so that the first and tail ends of the first winding L1, the second winding L2, and the third winding L3 are directly connected, forming a delta connection closed loop. When it is necessary to switch the transformer to a star connection, the operating mechanism 91 drives the second disconnector assembly 3 to close (i.e., the fourth changeover switch K4, the fifth changeover switch K5, and the sixth changeover switch K6 are turned on), while the first disconnector assembly 2 remains open (i.e., the first changeover switch K1, the second changeover switch K2, and the third changeover switch K3 are disconnected). At this time, the second pins of the fourth changeover switch K4, the fifth changeover switch K5, and the sixth changeover switch K6 are connected in parallel, shorting the first tail interface A4, the second tail interface A5, and the third tail interface A6 together, forming a virtual neutral point for the star connection, thereby completing the star connection conversion. This embodiment clearly demonstrates the electrical connection relationship between the transformer winding and the switchgear interface, as well as the actual operation process of changing the wiring method through the switching of disconnector assemblies.

[0031] To ensure operational safety and prevent simultaneous connection of different power supplies and incompatible transformer configurations, switches are installed on each input branch. Specifically, a first main power switch is installed on the first input branch U1, the second input branch U2, and the third input branch U3, while a second main power switch is installed on the fourth input branch U4, the fifth input branch U5, and the sixth input branch U6. A program lock is provided between the second main power switch (controlling the second power supply) and the second disconnector assembly 3 (for star connection). When it is necessary to close the second disconnector assembly 3 to switch to a star connection, the second main power switch must first be in the open state; otherwise, the mechanism for operating the second disconnector assembly 3 will be mechanically or electrically locked and unable to operate. Conversely, when the second disconnector assembly 3 is in the closed state, the second main power switch can also be closed. Similarly, the same program lock is provided between the first main power switch (controlling the first power supply) and the first disconnector assembly 2 (for delta connection). This set of interlocking mechanisms, together with the interlocking mechanism between the first and second disconnector assemblies 2 and 3 inside the cabinet, constitutes a double safety protection, mandating the safe operating procedure of "selecting the power supply first, then switching the connection method" or "switching the connection method first, then connecting the power supply," fundamentally eliminating serious accidents such as equipment damage or phase-to-phase short circuits that may be caused by mismatch between the power supply and transformer connection methods.

[0032] In one embodiment, the switchgear further includes a first power interface for connecting to a first power source and a second power interface for connecting to a second power source. The first power interface is connected to the first terminal interface A1, the second terminal interface A2, and the third terminal interface A3 via a first input branch U1, a second input branch U2, and a third input branch U3, respectively. The second power interface is connected to the first terminal interface A1, the second terminal interface A2, and the third terminal interface A3 via a fourth input branch U4, a fifth input branch U5, and a sixth input branch U6, respectively. In this scheme, the first power interface and the second power interface are connected to the terminal interface group via their respective input branches U1, U2, U3, U4, U5, and U6. This design provides independent input channels for two different high-voltage power sources (such as 6kV and 10kV), enabling adaptation to the target power source while switching the transformer connection via the disconnector assemblies 2 and 3, without the need for an additional power switching switch, simplifying the system structure and improving reliability.

[0033] In one embodiment, the interlocking mechanism is a mechanical interlocking mechanism, including an interlocking baffle driven by an operating mechanism 91; and / or, the interlocking mechanism is an electrical interlocking mechanism, which implements interlocking logic through a control circuit.

[0034] In one embodiment, a mechanism module 9 is provided at the front of the cabinet 1. The mechanism module 9 is operatively connected to the first knife switch assembly 2 and the second knife switch assembly 3 and is used to drive them to perform closing and opening operations.

[0035] In one embodiment, mechanism module 9 achieves miniaturization through a specially designed flattened transmission mechanism. This mechanism is significantly compressed in the thickness direction, and combined with the optimized layout of the overall switchgear frame, it significantly reduces the overall depth of the switchgear. This design not only reduces the space occupied in the installation site and improves economy, but also makes it more suitable for deployment under special site conditions. In addition, mechanism module 9 makes extensive use of molded parts, resulting in a simple structure and a small number of parts, further achieving compactness and integration of the structure while ensuring functional reliability.

[0036] In one embodiment, the top expansion module 4 includes a cable sleeve 43, a bracket 42 for mounting the cable sleeve, and the head interface group integrated thereon. The cable sleeve 43 is mounted on the top of the cabinet via the bracket 42, and a cable head 41 is fitted onto the cable sleeve.

[0037] In one embodiment, interphase insulating partitions 12 are provided between the first transfer switch K1, the second transfer switch K2, and the third transfer switch K3 of the first disconnector assembly 2, and between the fourth transfer switch K4, the fifth transfer switch K5, and the sixth transfer switch K6 of the second disconnector assembly 3. This solution inserts a high-strength insulating barrier between high-voltage live conductors to separate and seal the independent compartments of each phase conductor. This effectively extends the creepage distance and electrical clearance, blocks possible interphase arcing paths, and thus structurally forces reliable interphase isolation.

[0038] In one embodiment, the vertical arrangement of the first disconnector assembly 2 and the second disconnector assembly 3 corresponds to the vertical position of the top expansion module 4 and the cable chamber 11.

[0039] In one embodiment, the cable of the top expansion module 4 is led out from the upper part of the cabinet 1, and the cable of the cable chamber 11 is led out from the lower part of the cabinet 1.

[0040] This utility model achieves significant technical advantages through the aforementioned structure: by using a single transformer in conjunction with this switchgear, it can replace the traditional "two transformers + two switchgear" system, significantly saving equipment costs and the floor space required for the power distribution room; its operation is extremely simple, requiring only switching of the disconnect switches to change the transformer wiring method; at the same time, the use of a normal pressure sealed air-insulated enclosure gives it high reliability and low maintenance advantages; the interlocking between the disconnect switches inside the cabinet and the program lock with the incoming line cabinet constitute a double safety guarantee, fundamentally eliminating misoperation; in addition, the miniaturization of the mechanism module 9 and the optimized layout of the disconnect switches make the cabinet 1 more compact and adaptable, providing an excellent solution for space-constrained scenarios.

[0041] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A star-delta transfer switch cabinet, characterized in that, It includes a cabinet, and a first knife switch assembly and a second knife switch assembly disposed within the cabinet; The upper part of the cabinet is equipped with a top expansion module, and the lower part is equipped with a cable compartment; The first disconnect switch assembly and the second disconnect switch assembly are arranged vertically inside the cabinet; the first disconnect switch assembly is electrically connected to the top expansion module and is used to switch the external transformer to a delta connection; the second disconnect switch assembly is electrically connected to the cable compartment and is used to switch the external transformer to a star connection.

2. The star-delta transfer switch cabinet according to claim 1, characterized in that, It also includes an interlocking mechanism, which is disposed between the first disconnector assembly and the second disconnector assembly.

3. The star-delta transfer switch cabinet according to claim 2, characterized in that, The top expansion module integrates a head end interface group for connecting an external high-voltage power supply and the head end of the transformer winding; The cable compartment integrates a tail end interface group for connecting the tail end of the transformer winding; The first-end interface group includes a first-end interface, a second-end interface, and a third-end interface; The tail end interface group includes a first tail end interface, a second tail end interface, and a third tail end interface; The first disconnect switch assembly includes a first changeover switch, a second changeover switch, and a third changeover switch; The second disconnector assembly includes a fourth changeover switch, a fifth changeover switch, and a sixth changeover switch; The first pins of the first changeover switch, the second changeover switch, and the third changeover switch are respectively connected to the first terminal interface, the second terminal interface, and the third terminal interface; The second pin of the first changeover switch is connected to the first tail end interface and the first pin of the fourth changeover switch; The second pin of the second changeover switch is connected to the second tail terminal interface and the first pin of the fifth changeover switch; The second pin of the third changeover switch is connected to the third tail terminal interface and the first pin of the sixth changeover switch; The second pins of the fourth, fifth, and sixth changeover switches are connected in parallel.

4. The star-delta transfer switch cabinet according to claim 3, characterized in that, The switch cabinet also includes a first power interface for connecting to a first power source and a second power interface for connecting to a second power source. The first power interface is connected to the first head interface, the second head interface, and the third head interface through the first input branch, the second input branch, and the third input branch, respectively. The second power interface is connected to the first head interface, the second head interface, and the third head interface via the fourth input branch, the fifth input branch, and the sixth input branch, respectively.

5. The star-delta transfer switch cabinet according to claim 3, characterized in that, The interlocking mechanism is a mechanical interlocking mechanism, including an interlocking baffle driven by an operating mechanism; and / or, the interlocking mechanism is an electrical interlocking mechanism, which realizes interlocking logic through a control circuit.

6. The star-delta transfer switch cabinet according to claim 1, characterized in that, The front of the cabinet is provided with a mechanism module, which is operatively connected to the first disconnect switch assembly and the second disconnect switch assembly, and is used to drive them to perform closing and opening operations.

7. The star-delta transfer switchgear according to claim 4, characterized in that, The top expansion module includes a cable sleeve, a bracket for mounting the cable sleeve, and the head interface group integrated thereon.

8. The star-delta transfer switch cabinet according to claim 1, characterized in that, A phase-to-phase insulating partition is provided between the first, second, and third changeover switches of the first disconnector assembly, and between the fourth, fifth, and sixth changeover switches of the second disconnector assembly.

9. The star-delta transfer switch cabinet according to claim 1, characterized in that, The vertical arrangement of the first disconnector assembly and the second disconnector assembly corresponds to the vertical position of the top expansion module and the cable compartment.

10. The star-delta transfer switch cabinet according to claim 4, characterized in that, The cables of the top expansion module are led out from the top of the cabinet, and the cables of the cable compartment are led out from the bottom of the cabinet.

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