Double-sided feeding low-voltage cabinet and box-type substation

Abstract

The utility model discloses a double -faced feeding low -voltage cabinet and box -type substation. The low -voltage cabinet body is equipped with the main busbar of the central horizontal arrangement along the depth direction, and a plurality of first disconnectors are arranged on the left and right sides of the upper portion of the cabinet body and are connected with the main busbar at the first end, and a plurality of groups of feeder circuit breakers are arranged on the left and right sides of the lower portion of the cabinet body and are connected with the second end of the corresponding upper first disconnectors at the first end, and a compensation control switch is arranged on the upper middle portion of the front of the cabinet body and is connected with the main busbar at the first end, and at least one compensation unit is arranged on the lower middle portion of the front of the cabinet body and is connected with the second end of the compensation control switch. The utility model realizes high -density outgoing line through the central main busbar and double -faced feeding structure, and the front central integrated compensation unit makes the shortest compensation path, and the maintenance is convenient, and the volume is compact, and the cost is reduced, and the distributed power access and load intelligent management are supported. The low -voltage cabinet can be applied to the box -type substation, realizes the integration of high -voltage distribution, transformation, feeding and compensation.

Description

Technical Field

[0001] This utility model relates to the field of low-voltage switchgear technology, and in particular to a low-voltage switchgear with integrated reactive power compensation function and dual-sided power supply capability, as well as a prefabricated substation containing the low-voltage switchgear. Background Technology

[0002] Traditional low-voltage switchgear is mostly single-sided operation with single-sided outgoing lines, with power supply circuits concentrated on one side, and reactive power compensation usually completed by a separate compensation cabinet. This approach has a large footprint, low system integration, and complex primary and secondary control cable wiring. To accommodate more outgoing circuits, low-voltage switchgear typically adopts a drawer-type outgoing line scheme, which has disadvantages such as complex structure, difficulty in installation within transformer substations, and the need for installation in a distribution room, resulting in high costs. With the large-scale integration of distributed renewable energy sources, switchgear not only needs to supply power to loads but also needs to receive power from photovoltaic, energy storage, and other systems. Traditional power distribution architectures can no longer meet the needs of renewable energy integration. How to achieve a more circuit power supply layout, compactly integrate compensation functions, and leave space for intelligent load management within limited cabinet space has always been an unresolved technical challenge. Utility Model Content

[0003] The purpose of this utility model is to provide a double-sided power-fed low-voltage switchgear to solve the technical problem of achieving a more circuit power supply layout and compactly integrating compensation functions within a limited cabinet space, while reducing size and cost.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a double-sided power-fed low-voltage switchgear, comprising a cabinet, wherein the cabinet contains: a main busbar, horizontally arranged at the center of the top of the cabinet along the depth direction of the cabinet and configured for connecting to an external power source; a plurality of first disconnect switches, arranged on the left and right sides of the upper part of the cabinet, and the first end of each first disconnect switch is electrically connected to the main busbar; a plurality of power-fed circuit breakers, correspondingly arranged at the lower part of the left and right sides of the cabinet, and the first end of each power-fed circuit breaker is electrically connected to the second end of the corresponding first disconnect switch located above it; a compensation control switch, installed in the upper front middle part of the cabinet, and its first end is electrically connected to the main busbar; and at least one compensation unit, installed in the lower front middle part of the cabinet and electrically connected to the second end of the compensation control switch.

[0005] Furthermore, it also includes an incoming line circuit breaker, which is located on one side of the upper part of the cabinet, and its outgoing terminal is connected to the main busbar; the incoming line circuit breaker is a frame circuit breaker.

[0006] Furthermore, at least one of the second terminals of the power supply circuit breaker is configured to connect to a distributed power generation device, so that the power supply circuit breaker can supply power to the main busbar; the distributed power generation device is a photovoltaic power generation device, a wind power generation device, or an energy storage device.

[0007] Furthermore, the power supply circuit breaker is a molded case circuit breaker or a miniature circuit breaker.

[0008] Furthermore, the compensation control switch is a knife fuse switch.

[0009] Furthermore, the compensation unit includes a capacitor bank and / or a static var generator.

[0010] Furthermore, the compensation unit also includes a reactor, which is electrically connected to the capacitor bank or the static var generator.

[0011] Furthermore, the cabinet is equipped with at least one load management unit, which is connected to the main busbar and configured to perform at least one of the following functions: load switching control, demand management, power regulation, or metering.

[0012] Furthermore, the load management unit is connected to an external energy management system via a communication interface to perform load adjustment according to external commands.

[0013] This utility model also provides a prefabricated substation, including a box, wherein the double-sided power-fed low-voltage switchgear described in any of the above claims is installed inside the box.

[0014] Compared with existing technologies, this utility model has the following advantages: Existing low-voltage switchgear typically has only 4-6 outgoing lines, and for applications requiring more outgoing circuits, a drawer-type outgoing line solution is often used. Compared with the drawer-type outgoing line solution, the power supply circuit breaker of this utility model uses a fixed molded case circuit breaker or a miniature circuit breaker, which has the following advantages: 1) The compact size allows for dense arrangement of power supply circuits within the limited space on both sides of the cabinet, with the number of circuits reaching 16 to 20, leaving ample space for the compensation unit arranged in the center at the front. 2) No drawer base, connectors, or propulsion mechanism are required, significantly reducing equipment manufacturing costs and copper busbar usage; 3) It works in conjunction with the first disconnecting switch above to achieve circuit isolation without reducing maintenance safety, while also shortening the wiring path and reducing losses.

[0015] 4) When applied to prefabricated substations, the number of feeder circuits can be increased by increasing the cabinet depth without changing the width of the transformer room and high voltage room, which is conducive to the miniaturization of prefabricated substations and the high degree of standardization in manufacturing. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the internal structure of a double-sided power-fed low-voltage switchgear according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the external structure of a double-sided power-fed low-voltage switchgear according to an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the structure of a prefabricated substation according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of this utility model will now be clearly and completely described with reference to the accompanying drawings. It should be noted that the described embodiments are only some embodiments of this utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0020] In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "longitudinal," and "depth," etc., indicate the orientation or positional relationship based on the orientation of the cabinet during normal use. Generally, the side of the cabinet backing onto the wall or partition is considered "rear," and the opposite side is considered "front." Dividing the cabinet by height, the upper part is the area for incoming lines and disconnect switches, the lower part is the area for power supply circuit breakers, and the middle part is the compensation area, where the compensation control switch is located slightly above the middle, and the compensation unit is located slightly below the middle. These orientations are only for ease of description and simplification, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0021] Furthermore, for electrical components, this article uses "first terminal" and "second terminal" to define their electrical connection ports, without presupposing the absolute direction of current flow. For example, for a feeder circuit breaker, its first terminal is the terminal connected to the first disconnecting switch, and the second terminal is the terminal connected to the external circuit breaker. When the low-voltage switchgear supplies power to the load, power flows from the first terminal to the second terminal; when an external power supply device supplies power to the low-voltage switchgear through the feeder circuit breaker, power flows from the second terminal to the first terminal. Example 1

[0022] Please see Figure 1 and Figure 2 This embodiment provides a double-sided power-fed low-voltage switchgear, including a cabinet 1. The cabinet 1 is typically a metal enclosed structure, internally divided into multiple functional compartments. For ease of explanation, a schematic diagram of the internal structure is shown; some door panels in the diagram are concealed, which does not indicate that the exposed internal structure is a technical feature.

[0023] At the top center of cabinet 1, a set of main busbars 2 is horizontally arranged along the depth direction of the cabinet. Main busbar 2 includes three-phase copper busbars (A, B, and C), and is configured to draw power from an external power source. (Appendix) Figure 1 The diagram shows a single-row main busbar centrally located. When the width of cabinet 1 is large, for ease of maintenance, main busbar 2 can be branched into a double-row main busbar, which is equivalent to expanding the main busbar in the width direction, allowing each branch main busbar to be arranged closer to its side.

[0024] The external power source can be a transformer, a mains power line, or other power supply circuit, and its connection method is not limited. In the illustrated embodiment, an incoming circuit breaker 3 is installed on one side of the upper part of the cabinet. Specifically, it can be a frame circuit breaker. Its incoming terminal is connected to the external power source, and its outgoing terminal is electrically connected to the front end of the main busbar 2, so as to introduce electrical energy into the main busbar 2.

[0025] Several first disconnecting switches 4 are arranged on the left and right sides of the upper part of the cabinet. In this document, "first disconnecting switch" is a designation used to distinguish it from other disconnecting switches (such as compensation circuit switches) and does not impose structural limitations. The first end (upper end) of each first disconnecting switch 4 is electrically connected to the main busbar 2 via a branch busbar, and the second end (lower end) is led out downwards. Several sets of feeder circuit breakers 5 are correspondingly installed on the lower part of the left and right sides of the cabinet. The first end (incoming line side) of each set of feeder circuit breakers 5 is electrically connected to the second end of the corresponding first disconnecting switch 4 located above it. The second end (outgoing line side) of the feeder circuit breaker 5 is used to connect load cables or distributed power supply devices. The feeder circuit breakers 5 can be molded case circuit breakers or miniature circuit breakers. In this way, starting from the main busbar 2, through the first disconnecting switches 4 and feeder circuit breakers 5, a feeder circuit is formed on both sides of the cabinet, achieving double-sided feeding.

[0026] The cabinet 1 has several outgoing cabinet doors 10, each with an opening at the corresponding position of the feeder circuit breaker 5, facilitating operation and maintenance when the door 10 is closed. A smart digital display 8 is installed on the upper outgoing cabinet door 10 corresponding to the feeder circuit breaker 5. A terminal box 9 is located in the empty space next to the first disconnect switch 4, which can be used to install terminal blocks, surge protectors, and other control switches. In this embodiment, there are 4 first disconnect switches 4 (2 on each side) and 16 feeder circuit breakers 5 (8 on each side). The number of first disconnect switches 4 and feeder circuit breakers 5 can be set according to actual user needs. The length of the cabinet 1 in the depth direction can adjust the installation space for the first disconnect switches 4 and feeder circuit breakers 5, thus allowing this invention to double the number of first disconnect switches 4 and feeder circuit breakers 5 simply by increasing the depth of the low-voltage cabinet 1.

[0027] A compensation control switch 6 is installed in the upper front part of the cabinet 1. The first end of the compensation control switch 6 is electrically connected to the main busbar 2. The compensation control switch 6 can be a knife fuse switch to provide short circuit and overload protection. The operating handle of the compensation control switch 6 can be operated by closing the compensation cabinet door 11.

[0028] At least one compensation unit 7 is installed in the lower front part of the cabinet 1, electrically connected to the second terminal of the compensation control switch 6. The compensation unit 7 can be a fixed or modular structure, with a door at the front for maintenance. The function of the compensation unit 7 is to provide reactive power to the main busbar 2 and improve the power factor. Depending on the application scenario, the compensation unit 7 can include only capacitor banks, switched by contactors or composite switches to achieve fixed or step reactive power compensation; it can also include only static var generators (SVG) to achieve dynamic continuous reactive power compensation and harmonic mitigation capabilities; or it can include both capacitor banks and SVG to achieve hybrid compensation. In addition, reactors can be connected in series or parallel in the compensation unit 7 to form passive or active filter branches to better absorb harmonics. When the compensation control switch 6 is a knife-fuse switch, its fuse can provide backup protection for the downstream capacitor bank or SVG module, improving system safety.

[0029] In a preferred embodiment, cabinet 1 has a width of 1500mm, a height of 1800mm, and a depth of 1600mm, with the compensation area having a width of 1000mm and the compensation unit 7 having a depth of 1000mm. These dimensions are not limited to this embodiment; those skilled in the art can adjust them according to the number of outgoing circuits, the size of the components used, and the gaps between components. This layout allows both the compensation control switch 6 and the compensation unit 7 to be located at the front of the cabinet, in the middle area between the two side power supply circuits. The compensation circuit draws power from the main busbar 2, resulting in a very short path; maintenance personnel can operate the compensation control switch 6 from the front door of the cabinet, and open the front door to inspect and replace the compensation unit 7 without having to go around to the rear of the cabinet, greatly facilitating maintenance. The middle area between the two side power supply circuits is separated by a partition to create space for power supply and space for reactive power compensation. Example 2

[0030] This embodiment, based on Embodiment 1, specifically provides bidirectional transmission functionality to some of the feeder circuit breakers. The second end of at least one feeder circuit breaker 5 is configured to connect to distributed power generation devices, such as photovoltaic power generation devices, wind power generation devices, or energy storage devices. In this case, the feeder circuit breaker 5 allows bidirectional current transmission: the electrical energy generated by the distributed power generation device is fed back to the main busbar 2 via the feeder circuit breaker 5 and the first disconnecting switch 4, and then distributed by the main busbar 2 to other loads or fed into the power grid via the incoming line circuit breaker 3.

[0031] To ensure safety, the selected power supply circuit breaker 5 should have bidirectional protection capability, or its protection setting should allow reverse power. This flexible configuration makes the low-voltage switchgear not only a power distribution unit, but also a local energy interconnection node. Example 3

[0032] Please see Figure 2 In this embodiment, at least one load management unit 12 is also provided inside the cabinet 1. The load management unit 12 can be an intelligent controller, PLC, dedicated measurement and control module, etc. It is connected to the main busbar 2 for power supply and obtains system power parameters through voltage and current sampling. The load management unit 12 is configured to perform at least one function of load switching control, demand management, or power regulation. For example, when the total system load exceeds the demand limit, the load management unit 12 can automatically disconnect the secondary feeder circuit breaker 5 according to a preset strategy; during peak photovoltaic power generation, it can instruct the energy storage system to charge or start controllable loads to achieve power balance.

[0033] Furthermore, the load management unit 12 connects to an external energy management system via a communication interface (such as RS485, Ethernet, wireless communication, etc.) to perform load regulation according to external commands. This allows the low-voltage switchgear to be perfectly integrated into smart microgrids and photovoltaic-storage-charging integrated systems, possessing a high level of intelligence.

[0034] Depending on the needs, the space where the load management unit 12 is located can also be used to install a low-pressure metering box.

[0035] Example of a prefabricated substation Please see Figure 3 This utility model also protects a prefabricated substation, in which a double-sided fed low-voltage switchgear 30 of any of the aforementioned embodiments or combinations thereof is installed inside the enclosure 20. The enclosure 20 can be divided into a transformer compartment 21 and a high-voltage compartment 22, with the double-sided fed low-voltage switchgear 30 installed in the low-voltage compartment. The transformer compartment 21 houses the transformer, and the high-voltage compartment 22 houses the high-voltage switchgear. The main busbar of the double-sided fed low-voltage switchgear 30 is connected to the low-voltage side of the transformer via cables or busbar trunking. This layout achieves integrated high-voltage power distribution, transformation, low-voltage double-sided feeding, and reactive power compensation, resulting in a compact structure and complete functions. The compact enclosure of the prefabricated substation includes an outgoing line door 23 and a compensation door 24. The double-sided fed low-voltage switchgear 30 can supply low-voltage loads from one side and connect distributed power sources such as photovoltaics and energy storage to the other side. Opening the outgoing line door 23 allows for the operation and maintenance of the low-voltage outgoing equipment. Opening the compensation box door 24 allows for direct maintenance of the low-voltage built-in compensation unit in front of the cabinet, significantly improving the functional density and ease of operation and maintenance of the transformer.

[0036] The length variation of the double-sided power-fed low-voltage cabinet 30 in the depth direction can adjust the installation space of the first disconnecting switch 4 and the power supply circuit breaker 5, so that the width of the transformer chamber 21 and the high-voltage chamber 22 inside the enclosure 20 of this utility model does not need to be adjusted, thus achieving small footprint and convenient manufacturing.

[0037] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A double-sided power-fed low-voltage switchgear, comprising a cabinet, characterized in that, The cabinet interior is equipped with: The main busbar is horizontally arranged at the center of the top of the cabinet along the depth direction and is configured to connect to an external power source. Several first disconnect switches are arranged on the left and right sides of the upper part of the cabinet, and the first end of each first disconnect switch is connected to the main busbar. Several sets of power supply circuit breakers are respectively installed on the lower part of the left and right sides of the cabinet, and the first end of each power supply circuit breaker is electrically connected to the second end of the first disconnecting switch located above it. A compensation control switch is installed in the upper front middle part of the cabinet, and its first end is connected to the main busbar. At least one compensation unit is installed in the lower front part of the cabinet and is electrically connected to the second end of the compensation control switch.

2. The double-sided power-fed low-voltage switchgear according to claim 1, characterized in that, It also includes an incoming line circuit breaker, which is located on one side of the upper part of the cabinet and its outgoing terminal is connected to the main busbar; the incoming line circuit breaker is a frame circuit breaker.

3. The double-sided power-fed low-voltage switchgear according to claim 1, characterized in that, At least one of the feeder circuit breakers is configured to connect to a distributed power supply device so that the feeder circuit breaker can feed power to the main busbar; the distributed power supply device is a photovoltaic power generation device, a wind power generation device, or an energy storage device.

4. The double-sided power-fed low-voltage switchgear according to claim 1, characterized in that, The power supply circuit breaker is a molded case circuit breaker or a miniature circuit breaker.

5. The double-sided power-fed low-voltage switchgear according to claim 1, characterized in that, The compensation control switch is a knife fuse switch.

6. The double-sided power-fed low-voltage switchgear according to claim 1, characterized in that, The compensation unit includes a capacitor bank and / or a static var generator.

7. The double-sided power-fed low-voltage switchgear according to claim 6, characterized in that, The compensation unit also includes a reactor, which is electrically connected to the capacitor bank or the static var generator.

8. The double-sided power-fed low-voltage switchgear according to claim 1, characterized in that, The cabinet is also equipped with at least one load management unit, which is connected to the main busbar and configured to perform at least one of the following functions: load switching control, demand management, power regulation, or metering.

9. The double-sided power-fed low-voltage switchgear according to claim 8, characterized in that, The load management unit connects to an external energy management system via a communication interface to perform load regulation according to external commands.

10. A prefabricated substation, comprising a enclosure, characterized in that, The enclosure is equipped with a double-sided power-fed low-voltage switchgear according to any one of claims 1 to 9.

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