Substation and power supply system

Abstract

Disclosed in the embodiments of the present application are a substation and a power supply system, which solve the problems of how to implement an environmentally friendly substation having a high-current level, a simple structure and low costs. The substation comprises a first tank, wherein first insulating oil and a high-voltage power distribution circuit immersed in the first insulating oil are provided in the first tank. An output end of a low-voltage power distribution cabinet is connected to an input end of a transformer, and an output end of the transformer is connected to an input end of the high-voltage power distribution circuit. The high-voltage power distribution circuit comprises a first oil-immersed load switch, and an oil-immersed vacuum circuit breaker and a first oil-immersed three-station isolation switch which are connected in series. The oil-immersed vacuum circuit breaker and the first oil-immersed three-station isolation switch are arranged between the input end of the high-voltage power distribution circuit and a first end of the first oil-immersed load switch, with the first end of the first oil-immersed load switch being connected to an output end of the substation, and a second end of the first oil-immersed load switch being connected to a high-voltage input end of the substation.

Description

A substation and power supply system

[0001] This application claims priority to Chinese Patent Application No. 202411896322.9, filed with the State Intellectual Property Office of China on December 19, 2024, entitled “A Substation and Power Supply System”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power system technology, and more particularly to a substation and power supply system. Background Technology

[0003] A photovoltaic (PV) and energy storage (ESS) power station typically includes a converter, a prefabricated substation, and a step-up substation. The converter's input is connected to the PV array or energy storage device, its output is connected to the low-voltage input of the prefabricated substation, the substation's output is connected to the input of the step-up substation, and the step-up substation's output is used to connect to the power grid. The converter converts the direct current (DC) output from the PV array or energy storage device into low-voltage alternating current (AC). The prefabricated substation converts this low-voltage AC to medium-voltage AC, and the step-up substation converts this medium-voltage AC to high-voltage AC and transmits it to the power grid.

[0004] The prefabricated substation comprises a container, and within the container are low-voltage switchgear, a transformer, and a ring main unit (RMU). The RMU, also known as a ring main unit, connects to the low-voltage input of the prefabricated substation. Its output connects to the input (primary side) of the transformer, and the secondary connects to the input of the RMU. The RMU's output connects to the output of the prefabricated substation. The RMU uses sulfur hexafluoride (SF6) gas as the insulating medium for insulation and arc extinguishing, ensuring safe and reliable operation.

[0005] However, SF6 gas is a potent greenhouse gas, and the use of SF6 gas for insulation and arc extinguishing in ring main units poses environmental problems. Furthermore, as gas-tight devices, ring main units have limited heat dissipation capacity, restricting the current ratings they can handle. Secondly, the complex structure of existing prefabricated substations leads to higher costs. Therefore, achieving an environmentally friendly, high-current-rated, structurally simple, and low-cost substation has become an urgent problem to be solved. Summary of the Invention

[0006] This application provides a substation and power supply system that solves the problems of how to achieve an environmentally friendly, high-current-level, simple-structure, and low-cost substation.

[0007] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0008] A first aspect of this application provides a first substation, comprising a low-voltage distribution cabinet, a transformer, and a first enclosure. The first enclosure contains first insulating oil and a high-voltage distribution circuit immersed in the first insulating oil. The output terminal of the low-voltage distribution cabinet is connected to the input terminal of the transformer, and the output terminal of the transformer is connected to the input terminal of the high-voltage distribution circuit. The high-voltage distribution circuit includes a first oil-immersed load switch and an oil-immersed vacuum circuit breaker and a first oil-immersed three-position disconnector connected in series. The oil-immersed vacuum circuit breaker and the first oil-immersed three-position disconnector are disposed between the input terminal of the high-voltage distribution circuit and a first terminal of the first oil-immersed load switch. The first terminal of the first oil-immersed load switch is connected to the output terminal of the first substation, which is used to connect to the input terminal of a step-up substation or the high-voltage input terminal of a second substation. The second terminal of the first oil-immersed load switch is connected to the high-voltage input terminal of the first substation, which is used to connect to the output terminal of a third substation.

[0009] Based on this solution, the first enclosure and high-voltage distribution circuit can achieve the functions of a ring main unit in a prefabricated substation. However, compared to existing ring main units, this application uses a first insulating oil in the first enclosure, with the high-voltage distribution circuit immersed in it. This first insulating oil can insulate and extinguish the arc of the high-voltage distribution circuit, thus eliminating the environmental issues associated with using SF6 gas as the insulating medium in ring main units. Furthermore, the first insulating oil has better heat dissipation performance, not limiting the current levels that the high-voltage distribution circuit can handle, nor limiting the current levels that the transformer connected to the high-voltage distribution circuit can handle. Therefore, it does not limit the overall current level that the first substation can handle, enabling high-current-level substations and environmentally friendly substations above 24KV. It also does not limit the number of substations that can be connected when the first substation is connected to other substations in a daisy-chain configuration. Secondly, this first substation does not require an indoor switchgear ring main unit, thus eliminating the need for a container, resulting in a simpler structure and lower cost.

[0010] In conjunction with the first aspect, in one possible implementation, the first substation further includes a second enclosure, a first high-voltage bushing, and a low-voltage bushing. The second enclosure contains a second insulating oil, and the transformer is immersed in the second insulating oil. The first enclosure and the second enclosure are connected via the first high-voltage bushing, and the second enclosure is connected to the low-voltage distribution cabinet via a low-voltage bushing.

[0011] Based on this solution, the first substation also includes a second enclosure and a first high-voltage bushing. The second enclosure contains a second insulating oil, and the transformer is immersed in the second insulating oil. The first enclosure and the second enclosure are connected by the first high-voltage bushing, which is installed on the tightly fitted wall of the first and second enclosures. This first high-voltage bushing allows the high-voltage circuit between the input terminal of the high-voltage distribution circuit and the coil on the secondary side of the transformer to pass through the first and second enclosures. This eliminates the need for high-voltage cables between the first and second enclosures, reducing the size and cost of the first substation.

[0012] In conjunction with the first aspect, in one possible implementation, the first substation further includes a busbar connector and a second high-voltage bushing. The first enclosure is connected to one end of the busbar connector via the first high-voltage bushing, and the second enclosure is connected to the other end of the busbar connector via the second high-voltage bushing.

[0013] Based on this scheme, the first substation also includes a busbar connector and a second high-voltage bushing. The first high-voltage bushing is installed on the wall of the first enclosure, allowing the high-voltage circuit between the input terminal of the high-voltage distribution circuit and one end of the busbar connector to pass through the first enclosure. The second high-voltage bushing is installed on the wall of the second enclosure, allowing the high-voltage circuit between the secondary winding of the transformer and the other end of the busbar connector to pass through the second enclosure. By providing the first high-voltage bushing, the busbar connector, and the second high-voltage bushing, the first and second enclosures can be two independent enclosures, which facilitates assembly and maintenance, increases the heat dissipation area of ​​both enclosures, and improves their heat dissipation capacity, thereby enhancing the stability of the first substation.

[0014] In conjunction with the first aspect, in one possible implementation, the first substation further includes a third high-voltage bushing and a fourth high-voltage bushing. A first terminal of the first oil-immersed load switch is connected to one end of the third high-voltage bushing, and the other end of the third high-voltage bushing is connected to the output terminal of the first substation. A second terminal of the first oil-immersed load switch is connected to one end of the fourth high-voltage bushing, and the other end of the fourth high-voltage bushing is connected to the high-voltage input terminal of the first substation.

[0015] Based on this scheme, the first terminal of the first oil-immersed load switch is connected to the output terminal of the first substation via a third high-voltage bushing, and the second terminal of the first oil-immersed load switch is connected to the high-voltage input terminal of the first substation via a fourth high-voltage bushing. Since the high-voltage bushing has good electrical insulation performance, it can ensure the safe transmission of high-voltage current, thereby improving the safety and reliability of the first substation.

[0016] In conjunction with the first aspect, in one possible implementation, the first substation also includes an oil tank and a first pipeline, with the oil tank connected to the first housing via the first pipeline.

[0017] Based on this scheme, the first substation also includes an oil conservator and a first pipeline. The oil conservator is connected to the first housing via the first pipeline. When the volume of the first insulating oil in the first housing expands or contracts with changes in oil temperature, the oil conservator is used to regulate the amount of first insulating oil in the first housing. Specifically, the oil conservator is used to store excess first insulating oil that has expanded in the first housing or to replenish the first housing, thereby ensuring the safe and reliable operation of the first substation. Simultaneously, the first insulating oil in the oil conservator has good thermal conductivity, and the oil conservator can also be used to transfer heat from the first housing to the outside of the oil conservator, achieving cooling of the first housing and ensuring the safe and reliable operation of the first substation.

[0018] In conjunction with the first aspect, in one possible implementation, the first substation also includes a second pipeline through which the oil tank is connected to the second housing.

[0019] Based on this solution, the aforementioned oil conservator is connected to the second housing via a second pipe. When the volume of the second insulating oil in the second housing expands or contracts with changes in oil temperature, the oil conservator is used to regulate the amount of second insulating oil in the second housing. Specifically, the oil conservator is used to store excess second insulating oil that has expanded in the second housing or to replenish the second insulating oil, thereby ensuring the safe and reliable operation of the first substation. Simultaneously, the second insulating oil in the oil conservator has good thermal conductivity, and the oil conservator can also be used to transfer heat from the second housing to the outside of the oil conservator, achieving cooling of the second housing and ensuring the safe and reliable operation of the first substation. Furthermore, the first and second housings share the same oil conservator, which can reduce the cost of the first substation.

[0020] In conjunction with the first aspect, in one possible implementation, the first substation also includes a valve located on the first pipeline.

[0021] Based on this solution, by controlling the valve to close and disconnecting the connection between the first enclosure and the oil tank, the high-voltage power distribution circuit in the first enclosure can continue to operate, and the first substation can continue to connect with other substations. At the same time, the second enclosure or the transformer in the second enclosure can be maintained separately without the need for the entire first substation to be shut down to maintain the second enclosure or the transformer in the second enclosure, thus reducing the downtime of the first substation.

[0022] In conjunction with the first aspect, in one possible implementation, the high-voltage power distribution circuit further includes a second oil-immersed load switch, one end of which is connected to the first end of the first oil-immersed load switch, and the other end of which is connected to the output terminal of the first substation.

[0023] Based on this scheme, by setting up a second oil-immersed load switch, it can be ensured that in the event of a failure of the first oil-immersed load switch, the second oil-immersed load switch can disconnect the circuit between the high-voltage input terminal and the output terminal of the first substation, thereby improving the reliability of the first substation.

[0024] In conjunction with the first aspect, in one possible implementation, the aforementioned oil-immersed load switch includes: an oil-immersed three-position load switch, or an oil-immersed vacuum load switch and a second oil-immersed three-position isolating switch connected in series.

[0025] Based on this solution, compared with the oil-immersed three-position load switch, the oil-immersed vacuum load switch adopts a vacuum arc extinguishing mechanism, which will not contaminate the first insulating oil, and has a strong load breaking capacity, a high number of breaking cycles and a long service life, which can improve the reliability of the first substation.

[0026] A second aspect of this application provides a power supply system including a converter and a first substation. The input terminal of the converter is connected to an energy storage device or a photovoltaic array, and the output terminal of the converter is connected to the low-voltage input terminal of the first substation. The output terminal of the first substation is connected to the input terminal of a step-up substation or the high-voltage input terminal of a second substation, and the high-voltage input terminal of the first substation is connected to the output terminal of a third substation. The first substation is as described in the first aspect or any possible implementation thereof.

[0027] The description of the second aspect in this application can be referred to the detailed description of the first aspect; and the beneficial effects of the second aspect can be referred to the analysis of the beneficial effects of the first aspect, which will not be repeated here. Attached Figure Description

[0028] Figure 1 is a schematic diagram of the circuit topology of a power supply system;

[0029] Figure 2 is a schematic diagram of the circuit topology of a prefabricated substation;

[0030] Figure 3 is a schematic diagram of an application scenario of a first substation provided in an embodiment of this application;

[0031] Figure 4 is a schematic diagram of the circuit topology of a first substation provided in an embodiment of this application;

[0032] Figure 5 is a schematic diagram of another circuit topology of a first substation provided in an embodiment of this application;

[0033] Figure 6 is a schematic diagram of the circuit topology of another first substation provided in an embodiment of this application;

[0034] Figure 7 is a schematic diagram of the circuit topology of another first substation provided in an embodiment of this application;

[0035] Figure 8 is a structural schematic diagram of a first substation provided in an embodiment of this application;

[0036] Figure 9 is a schematic diagram of another first substation provided in an embodiment of this application;

[0037] Figure 10 is a structural schematic diagram of another first substation provided in an embodiment of this application;

[0038] Figure 11 is a structural schematic diagram of another first substation provided in an embodiment of this application;

[0039] Figure 12 is a structural schematic diagram of another first substation provided in an embodiment of this application;

[0040] Figure 13 is a structural schematic diagram of another first substation provided in an embodiment of this application;

[0041] Figure 14 is a schematic diagram of the circuit topology of another first substation provided in an embodiment of this application;

[0042] Figure 15 is a schematic diagram of the circuit topology of another first substation provided in an embodiment of this application;

[0043] Figure 16 is a structural schematic diagram of another first substation provided in an embodiment of this application;

[0044] Figure 17 is a structural schematic diagram of another first substation provided in an embodiment of this application;

[0045] Figure 18 is a structural schematic diagram of another first substation provided in an embodiment of this application;

[0046] Figure 19 is a structural schematic diagram of another first substation provided in an embodiment of this application. Detailed Implementation

[0047] The following sections will discuss the fabrication and use of various embodiments in detail. However, it should be understood that many applicable inventive concepts provided in this application can be implemented in a variety of specific environments. The specific embodiments discussed are merely illustrative of specific ways of implementing and using this description and technology, and do not limit the scope of this application.

[0048] Unless otherwise defined, all technical terms used herein have the same meaning as commonly known to one of ordinary skill in the art.

[0049] Each circuit or other component may be described or referred to as "for" performing one or more tasks. In this context, "for" is used to imply a structure by indicating that the circuit / component includes a structure (e.g., a circuit system) that performs one or more tasks during operation. Therefore, even when the specified circuit / component is currently inoperable (e.g., not turned on), it can still be referred to as "for performing that task." Circuits / components used with the term "for" include hardware, such as circuits that perform operations.

[0050] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings. In this application, "multiple" refers to two or more. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The words "first," "second," etc., do not limit the quantity or order.

[0051] In this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0052] In this application, "low voltage", "medium voltage" and "high voltage" are all relative concepts and are not limitations on the voltage range. They should not be interpreted as limitations on the voltage range of this application.

[0053] Before introducing the embodiments of this application, the relevant technologies involved in this application will be introduced first.

[0054] Figure 1 shows a circuit topology diagram of a power supply system 100. This power supply system 100 can be applied to a photovoltaic-storage power station. The power supply system 100 includes a converter 110 and a prefabricated substation 120. The input terminal of the converter 110 is connected to the output terminal of the energy storage device or photovoltaic array 200. The output terminal of the converter 110 is connected to the low-voltage input terminal of the prefabricated substation 120. The output terminal of the prefabricated substation 120 is connected to the input terminal of a step-up substation 300, and the output terminal of the step-up substation 300 is connected to the power grid 400. When the input terminal of the converter 110 is connected to the energy storage device, the converter 110 can be a power conversion system (PCS). This converter 110 is used to convert the DC power output from the energy storage device into AC power and transmit it to the prefabricated substation 120, or to convert the AC power output from the prefabricated substation 120 into DC power and transmit it to the energy storage device. This power supply system 100 can be called an energy storage power supply system. When the input terminal of converter 110 is used to connect to a photovoltaic array, converter 110 can be a photovoltaic inverter. Converter 110 converts the direct current output from the photovoltaic array into alternating current and transmits it to the prefabricated substation 120. This power supply system 100 can be called a photovoltaic power supply system. When the power supply system 100 includes multiple converters 110, with some converters 110 having their input terminals connected to energy storage devices and the remaining converters 110 having their input terminals connected to a photovoltaic array, this power supply system 100 can be called a photovoltaic-energy storage power supply system.

[0055] The converter 110 is used to convert the DC power output by the energy storage device or photovoltaic array 200 into low-voltage AC power, the box-type substation 120 is used to convert the low-voltage AC power into medium-voltage AC power, and the step-up substation 300 is used to convert the medium-voltage AC power into high-voltage AC power and transmit it to the power grid 400.

[0056] Figure 2 shows a circuit topology diagram of a prefabricated substation 120. The prefabricated substation 120 includes a container 121, and within the container 121, a low-voltage distribution cabinet 122, low-voltage bushings L, an oil-immersed transformer 123, a first high-voltage bushing B1, a second high-voltage bushing B2, a ring main unit 124, a third high-voltage bushing B3, and a fourth high-voltage bushing B4. The input terminal of the low-voltage distribution cabinet 122 is connected to the low-voltage input terminal of the prefabricated substation 120, and the output terminal of the low-voltage distribution cabinet 122 is connected to the input terminal of the oil-immersed transformer 123 via the low-voltage bushing L. The output terminal of the oil-immersed transformer 123 is connected to one end of the first high-voltage bushing B1, the other end of the first high-voltage bushing B1 is connected to one end of the second high-voltage bushing B2, and the other end of the second high-voltage bushing B2 is connected to the input terminal of the ring main unit 124. Ring main unit 124 is connected to the output terminal of box-type substation 120 via the third high-voltage bushing B3 and high-voltage cable. The output terminal of box-type substation 120 is used to connect to the input terminal of step-up substation 300 or the high-voltage input terminal of the first box-type substation via high-voltage cable. Ring main unit 124 can also be connected to the high-voltage input terminal of box-type substation 120 via the fourth high-voltage bushing B4 and high-voltage cable. The high-voltage input terminal of box-type substation 120 is used to connect to the output terminal of the second box-type substation via high-voltage cable. Thus, the box-type substation 120 can achieve daisy-chain networking.

[0057] The aforementioned high-voltage bushing refers to a device that provides insulation and support for high-voltage circuits passing through partitions such as walls or enclosures. In this application, a device that provides insulation and support for low-voltage circuits passing through partitions such as walls or enclosures is referred to as a low-voltage bushing.

[0058] In one example, referring to Figure 2, the low-voltage distribution cabinet 122 includes an air circuit breaker (ACB) 1221 and multiple molded case circuit breakers (MCCBs) 1222. One end of each MCCB 1222 is connected to the input terminal of the low-voltage distribution cabinet 122 and then to the output terminal of multiple converters 110. The other end of each MCCB 1222 is connected to one end of the air circuit breaker 1221, and the other end of the air circuit breaker 1221 is connected to the output terminal of the low-voltage distribution cabinet 1222. Both the air circuit breaker 1221 and the MCCB 1222 are mechanical switching devices, which can be used to connect, carry, and disconnect current under normal circuit conditions, and can also be used to connect, carry, and disconnect current for a specified time under specified abnormal circuit conditions. The molded case circuit breaker 1222 is smaller in size and volume, and is used in low-current scenarios, such as residential or commercial buildings. The frame circuit breaker 1221 is larger in size and volume, and is used in high-current scenarios, such as large industrial facilities. The molded case circuit breaker 1222 and the frame circuit breaker 1221 can be used in combination; for example, the output terminals of multiple molded case circuit breakers 1222 can be connected to the input terminal of a frame circuit breaker 1221.

[0059] Referring again to Figure 2, the oil-immersed transformer 123 includes an oil tank 1231 and an oil conservator 1232, which are connected by a pipe 1233. The oil tank 1231 contains transformer oil, and a transformer T is immersed in the transformer oil. The primary winding of the transformer T is connected to the input terminal of the oil-immersed transformer 123, and the secondary winding of the transformer T is connected to the output terminal of the oil-immersed transformer 123.

[0060] Referring again to Figure 2, the ring main unit 124 is an electrical device consisting of a set of power transmission and distribution equipment (high-voltage switchgear) housed in a metal or non-metal insulated cabinet or assembled into a modular ring main unit. Its core components utilize load switches and fuses, offering advantages such as simple structure, small size, low price, improved power supply parameters and performance, and enhanced power supply safety. The ring main unit 124 includes a housing 1241 containing SF6 gas, a vacuum circuit breaker (VCB) 1242, a three-position disconnect switch 1243, a first three-position load switch 1244, and a second three-position load switch 1245. One end of the vacuum circuit breaker 1242 is connected to the input terminal of the ring main unit 124, and the other end of the vacuum circuit breaker 1242 is connected to one end of the three-position disconnector 1243. The other end of the three-position disconnector 1243 is connected to one end of the first three-position load switch 1244 and one end of the second three-position load switch 1245. The other end of the first three-position load switch 1244 is connected to the output terminal of the prefabricated substation 120 through the third high-voltage bushing B3, and the other end of the second three-position load switch 1245 is connected to the high-voltage input terminal of the prefabricated substation 120 through the fourth high-voltage bushing B4. In this configuration, the ring main unit 124 can be referred to as a CVC-type ring main unit. Compared to CVC-type ring main units, in which ring main unit 124 includes a second three-position load switch 1245 but excludes the first three-position load switch 1244, and the other end of the three-position disconnector 1243 is directly connected to the output terminal of the prefabricated substation 120 via a third high-voltage bushing B3, this ring main unit 124 can be called a DVC-type ring main unit. By incorporating SF6 gas as the insulating medium for insulation and arc extinguishing, the safe and reliable operation of ring main unit 124 can be ensured.

[0061] In this vacuum circuit breaker 1242, both the arc-extinguishing medium and the insulating medium in the contact gap after arc extinguishing are in high vacuum, offering advantages such as small size, light weight, suitability for frequent operation, and no need for maintenance during arc extinguishing. In the following embodiments of this application, the vacuum circuit breaker that can be immersed in insulating oil is referred to as an oil-immersed vacuum circuit breaker.

[0062] A three-position switchgear (3PS) is a switch with three positions: closed, open, and grounded. A three-position switchgear can include the aforementioned three-position disconnector 1243 and a three-position load switch (1244 or 1245). The three-position disconnector is used to isolate the power supply, ensuring the circuit is in a safe state during maintenance or repair. Isolation indicates that the circuit is broken and that the gap between the power supply side and the load side is large. The three-position load switch is used to cut off and protect the load current in the circuit, including overload and short-circuit protection. Cut-off indicates that the circuit is broken and the load has been removed. In this application, a three-position disconnector that can be immersed in insulating oil is referred to as an oil-immersed three-position disconnector, and a three-position load switch that can be immersed in insulating oil is referred to as an oil-immersed three-position load switch.

[0063] A load switch is a switching device that falls between a circuit breaker and a disconnector. It is generally equipped with a simple arc-extinguishing device and can open and close circuits under load. It can switch on and off certain load currents and overload currents, but cannot interrupt short-circuit currents. In this application, a load switch that can be immersed in insulating oil is referred to as an oil-immersed load switch. This oil-immersed load switch can include the aforementioned oil-immersed three-position load switch. Load switches can also include vacuum load switches. These vacuum load switches use vacuum dielectric arc extinguishing, have strong load breaking capacity, high breaking count, and long service life. In this application, a vacuum load switch that can be immersed in insulating oil is referred to as an oil-immersed vacuum load switch.

[0064] However, SF6 gas is a potent greenhouse gas. The use of SF6 gas for insulation and arc extinguishing in ring main unit 124 poses environmental problems. In high-altitude applications, the insulation and leakage issues of ring main unit 124 become prominent, leading to poor reliability and environmental performance. Furthermore, as a gas-tight device, ring main unit 124 has limited heat dissipation capacity, restricting the current rating it can handle (e.g., 630A). This also limits the current rating of the oil-immersed transformer 123 connected to ring main unit 124, thus restricting the overall current rating that the substation 120 can handle and the number of substations it can connect to in a daisy-chain network. Secondly, the ring main unit 124 is an indoor switchgear device. The prefabricated substation 120 requires a container 121 to house the ring main unit 124, which complicates the structure and increases the cost of the prefabricated substation 120. Therefore, achieving an environmentally friendly, high-current-level, structurally simple, and low-cost substation has become an urgent problem to solve. Furthermore, there are currently no environmentally friendly solutions for prefabricated substations with voltage levels above 24KV. Therefore, achieving environmental protection for substations with voltage levels above 24KV has also become an urgent issue to address.

[0065] Based on this, this application provides a substation that uses insulating oil as the insulating medium for insulation and arc extinguishing, instead of SF6 gas, thus solving environmental problems. Furthermore, compared to the ring main unit 124, which is a gas-sealed device with limited heat dissipation capacity, insulating oil has better heat dissipation performance and does not limit the current levels the substation can handle, thus enabling high-current-level substations and environmentally friendly substations above 24KV. Secondly, this substation does not require indoor switchgear ring main unit 124 or container 121, resulting in a simpler structure and lower cost.

[0066] Figure 3(a) shows a circuit topology diagram of an application scenario of a first substation 500 provided in this application embodiment. The first substation 500 can be applied to a power supply system 600, which can be applied to a photovoltaic-storage power station. The power supply system 600 also includes a converter 610. The input terminal of the converter 610 is connected to the output terminal of the energy storage device or photovoltaic array 200, and the output terminal of the converter 610 is connected to the low-voltage input terminal of the first substation 500. The output terminal of the first substation 500 is connected to the input terminal of the step-up substation 300.

[0067] The converter 610 is used to convert the DC power output by the energy storage device or photovoltaic array 200 into low-voltage AC power. The first substation 500 is used to convert the low-voltage AC power into medium-voltage AC power. The step-up substation 300 is used to convert the medium-voltage AC power into high-voltage AC power and transmit it to the power grid 400.

[0068] In one possible embodiment, as shown in Figure 3(b), which illustrates another application scenario of the first substation 500 provided in this application embodiment, the output terminal of the first substation 500 is connected to the high-voltage input terminal of the second substation 700, the output terminal of the second substation 700 is connected to the input terminal of the step-up substation 300, and the high-voltage input terminal of the first substation 500 is connected to the output terminal of the third substation 800. Thus, the second substation 700, the first substation 500, and the third substation 800 can form a daisy-chain network. The second substation 700 and the third substation 800 can be the same substation as the first substation 500 provided in this application embodiment, or they can be prefabricated substations, such as the prefabricated substation 120 mentioned above. This application embodiment does not limit this; this application embodiment uses the example of the second substation 700 and the third substation 800 being the same substation as the first substation 500 provided in this application embodiment for illustrative purposes.

[0069] In one possible embodiment, when the input terminal of converter 610 is used to connect to a photovoltaic array, converter 610 can be a photovoltaic inverter. Converter 610 converts the direct current (DC) output from the photovoltaic array into alternating current (AC) and transmits it to the first substation 500. This power supply system 600 can be referred to as a photovoltaic power supply system. When the input terminal of converter 610 is used to connect to an energy storage device, converter 610 can be an energy storage converter. Converter 610 converts the DC output from the energy storage device into AC and transmits it to the first substation 500; or, it converts the AC output from the first substation 500 into DC and transmits it to the energy storage device. This power supply system 600 can be referred to as an energy storage power supply system. In a power supply system 600 that includes multiple converters 610, where the input terminals of some converters 610 are used to connect to an energy storage device and the input terminals of the remaining converters 610 are used to connect to a photovoltaic array, the power supply system 600 can be called a photovoltaic-energy storage power supply system.

[0070] Figure 4 shows a circuit topology diagram of a first substation 500 provided in an embodiment of this application. The first substation 500 includes a low-voltage distribution cabinet 510, a transformer 520, and a first enclosure 530. The first enclosure 530 contains a first insulating oil and a high-voltage distribution circuit 540 immersed in the first insulating oil.

[0071] Referring to Figure 4, the input terminal of the low-voltage distribution cabinet 510 is connected to the low-voltage input terminal of the first substation 500, the output terminal of the low-voltage distribution cabinet 510 is connected to the input terminal of the transformer 520, and the output terminal of the transformer 520 is connected to the input terminal of the high-voltage distribution circuit 540. The high-voltage distribution circuit 540 includes a first oil-immersed load switch 541 and an oil-immersed vacuum circuit breaker 542 and a first oil-immersed three-position disconnect switch 543 connected in series. Among them, the oil-immersed vacuum circuit breaker 542 and the first oil-immersed three-position disconnector 543 are arranged between the input terminal of the high-voltage power distribution circuit 540 and the first terminal of the first oil-immersed load switch 541. The first terminal of the first oil-immersed load switch 541 is connected to the output terminal of the first substation 500. Referring to Figure 3(a) and Figure 3(b), the output terminal of the first substation 500 is used to connect to the input terminal of the step-up substation 300 or the high-voltage input terminal of the second substation 700. The second terminal of the first oil-immersed load switch 541 is connected to the high-voltage input terminal of the first substation 500. Referring to Figure 3(b), the high-voltage input terminal of the first substation 500 is used to connect to the output terminal of the third substation 800.

[0072] In one possible embodiment, the oil-immersed vacuum circuit breaker 542 and the first oil-immersed three-position disconnector 543, connected in series, are disposed between the input terminal of the high-voltage power distribution circuit 540 and the first terminal of the first oil-immersed load switch 541. Referring to FIG4, one end of the oil-immersed vacuum circuit breaker 542 is connected to the input terminal of the high-voltage power distribution circuit 540, the other end of the oil-immersed vacuum circuit breaker 542 is connected to one end of the first oil-immersed three-position disconnector 543, and the other end of the first oil-immersed three-position disconnector 543 is connected to the first terminal of the first oil-immersed load switch 541. Alternatively, as shown in FIG5(a), one end of the first oil-immersed three-position disconnector 543 is connected to the input terminal of the high-voltage power distribution circuit 540, the other end of the first oil-immersed three-position disconnector 543 is connected to one end of the oil-immersed vacuum circuit breaker 542, and the other end of the oil-immersed vacuum circuit breaker 542 is connected to the first terminal of the first oil-immersed load switch 541. The embodiments of this application do not limit the specific series connection order of the oil-immersed vacuum circuit breaker 542 and the first oil-immersed three-position disconnector 543.

[0073] In one possible embodiment, the first insulating oil includes mineral insulating oil, silicone oil, or vegetable oil, etc. The embodiments of this application do not limit the specific type of the first insulating oil.

[0074] In one possible embodiment, as shown in FIG4, the first oil-immersed load switch 541 includes an oil-immersed three-position load switch 5411; or, as shown in FIG5(a), the first oil-immersed load switch 541 includes an oil-immersed vacuum load switch 5412 and a second oil-immersed three-position disconnector 5413 connected in series. This embodiment does not limit the specific implementation. Compared to the oil-immersed three-position load switch 5411, the oil-immersed vacuum load switch 5412 employs a vacuum arc-extinguishing mechanism, which does not contaminate the first insulating oil. Furthermore, it has a strong load breaking capacity, a high number of breaking cycles, and a long service life, thereby improving the reliability of the first substation 500.

[0075] In one possible embodiment, when the first oil-immersed load switch 541 includes an oil-immersed vacuum load switch 5412 and a second oil-immersed three-position disconnector 5413 connected in series, as shown in FIG5(a), one end of the oil-immersed vacuum load switch 5412 is connected to the first end of the first oil-immersed load switch 541, the other end of the oil-immersed vacuum load switch 5412 is connected to one end of the second oil-immersed three-position disconnector 5413, and the other end of the second oil-immersed three-position disconnector 5413 is connected to the second end of the first oil-immersed load switch 541. Alternatively, as shown in FIG5(b), one end of the second oil-immersed three-position disconnector 5413 is connected to the first end of the first oil-immersed load switch 541, the other end of the second oil-immersed three-position disconnector 5413 is connected to one end of the oil-immersed vacuum load switch 5412, and the other end of the oil-immersed vacuum load switch 5412 is connected to the second end of the first oil-immersed load switch 541. The embodiments of this application do not limit the specific series connection order of the oil-immersed vacuum load switch 5412 and the second oil-immersed three-position disconnect switch 5413.

[0076] In one possible embodiment, the first substation 500 provided in this application can be applied to a charging station (also known as a new energy charging station). When the first substation 500 is applied to a charging station, the current flowing through the oil-immersed vacuum circuit breaker 542 and the first oil-immersed three-position disconnector 543 in the high-voltage distribution circuit 540 is relatively small, for example, tens of amps. Therefore, the selection requirements for the oil-immersed vacuum circuit breaker 542 and the first oil-immersed three-position disconnector 543 can be reduced, thereby reducing the cost of the first substation 500. However, the ring main unit 124 in the aforementioned box-type substation 120 is a medium-voltage standardized power distribution device. When the box-type substation 120 is applied to a charging station, the selection of the devices is not optimized, which will result in a higher cost for the box-type substation 120.

[0077] In one possible embodiment, as shown in FIG4, the low-voltage distribution cabinet 510 includes molded case circuit breakers 511 and frame circuit breakers 512. One end of the molded case circuit breaker 511 is connected to the input terminal of the low-voltage distribution cabinet 510 and then to the output terminal of the converter 610. The other end of the molded case circuit breaker 511 is connected to one end of the frame circuit breaker 512, and the other end of the frame circuit breaker 512 is connected to the output terminal of the low-voltage distribution cabinet 510. This application embodiment does not limit the specific number of molded case circuit breakers 511 or frame circuit breakers 512 included in the low-voltage distribution cabinet 510.

[0078] As exemplarily shown in Figure 5(a), this is a schematic diagram of the circuit topology of a first substation 500 provided in an embodiment of this application. The low-voltage distribution cabinet 510 may include a frame-type circuit breaker 512 and a plurality of plastic-cased circuit breakers 511. One end of the plurality of plastic-cased circuit breakers 511 is connected to the output terminal of the low-voltage distribution cabinet 510 and then connected to the output terminal of a plurality of converters 610 respectively. The other end of the plurality of plastic-cased circuit breakers 511 is connected to one end of the frame-type circuit breaker 512, and the other end of the frame-type circuit breaker 512 is connected to the coil on the primary side of the transformer 520.

[0079] For example, as shown in Figure 5(b), a circuit topology diagram of a first substation 500 provided in an embodiment of this application is presented. The low-voltage distribution cabinet 510 may include multiple molded case circuit breakers 511 and two frame circuit breakers 512. One end of each of the multiple molded case circuit breakers 511 is connected to the output terminal of the low-voltage distribution cabinet 510 and then to the output terminal of multiple converters 610. The other end of a portion of the multiple molded case circuit breakers 511 is connected to one end of a frame circuit breaker 512, and the other end of the remaining multiple molded case circuit breakers 511 is connected to one end of another frame circuit breaker 512. The other ends of the two frame circuit breakers 512 are respectively connected to two coils on the primary side of the transformer 520.

[0080] In the first substation 500 provided in this application embodiment, the first enclosure 530 and the high-voltage distribution circuit 540 can realize the functions of the ring main unit 124 in the aforementioned box-type substation 120. However, compared to the aforementioned ring main unit 124, this application provides a first insulating oil in the first enclosure 530, and the high-voltage distribution circuit 540 is immersed in the first insulating oil. This first insulating oil can insulate and extinguish the arc of the high-voltage distribution circuit 540, thus eliminating the environmental problem of the ring main unit 124 using SF6 gas as the insulating medium. At the same time, the first insulating oil has better heat dissipation performance, which does not limit the current level that the high-voltage distribution circuit 540 can handle, nor does it limit the current level that the transformer 520 connected to the high-voltage distribution circuit 540 can handle. Therefore, it does not limit the overall current level that the first substation 500 can handle, thereby realizing a high-current-level first substation 500, realizing an environmentally friendly first substation 500 of 24KV and above, and not limiting the number of substations that can be connected when the first substation 500 is connected to other substations in a daisy-chain network. Secondly, the first substation 500 does not require the installation of indoor switchgear ring network cabinet 124, and therefore does not require the installation of container 121. The structure of the first substation 500 is simpler and the cost is lower.

[0081] In one possible embodiment, as shown in FIG6, the first substation 500 further includes a second enclosure 550, a first high-voltage bushing B1, and a low-voltage bushing L. The second enclosure 550 contains a second insulating oil, and the transformer 520 is immersed in the second insulating oil. The first enclosure 530 is connected to the second enclosure 550 via the first high-voltage bushing B1, and the second enclosure 550 is connected to the low-voltage distribution cabinet 510 via the low-voltage bushing L.

[0082] Specifically, referring to Figure 6, the first housing 530 and the second housing 550 are connected through the first high-voltage bushing B1, including: the input terminal of the high-voltage power distribution circuit 540 in the first housing 530 is connected to one end of the first high-voltage bushing B1, and the coil on the secondary side of the transformer 520 in the second housing 550 is connected to the other end of the first high-voltage bushing B1.

[0083] Referring to Figure 6, the second enclosure 550 is connected to the low-voltage distribution cabinet 510 through a low-voltage bushing L, including: the coil of the primary side of the transformer 520 in the second enclosure 550 is connected to one end of the low-voltage bushing L, and the other end of the low-voltage bushing L is connected to the input terminal of the low-voltage distribution cabinet 510.

[0084] In one possible embodiment, the second insulating oil includes mineral insulating oil, silicone oil, or vegetable oil, etc. This application does not limit the specific type of the second insulating oil. The type of the second insulating oil may be the same as or different from the type of the first insulating oil; this application does not limit this in this regard.

[0085] The first substation 500 provided in this embodiment further includes a second enclosure 550 and a first high-voltage bushing B1. The second enclosure 550 contains a second insulating oil, and the transformer 520 is immersed in the second insulating oil. The first enclosure 530 and the second enclosure 550 are connected by the first high-voltage bushing B1, which is disposed on the tightly fitted wall of the first enclosure 530 and the second enclosure 550. The first high-voltage bushing B1 allows the high-voltage circuit between the input terminal of the high-voltage distribution circuit 540 and the coil on the secondary side of the transformer 520 to pass through the first enclosure 530 and the second enclosure 550. This eliminates the need for high-voltage cables between the first enclosure 530 and the second enclosure 550, reducing the size and cost of the first substation 500.

[0086] In one possible embodiment, as shown in FIG7, the first substation 500 further includes a bus connector 560 and a second high-voltage bushing B2. The first housing 530 is connected to one end of the bus connector 560 through the first high-voltage bushing B1, and the second housing 550 is connected to the other end of the bus connector 560 through the second high-voltage bushing B2.

[0087] Specifically, referring to Figure 7, the first housing 530 is connected to one end of the bus connector 560 via the first high-voltage bushing B1, and the second housing 550 is connected to the other end of the bus connector 560 via the second high-voltage bushing B2. This includes: the input terminal of the high-voltage distribution circuit 540 in the first housing 530 is connected to one end of the first high-voltage bushing B1, and the other end of the first high-voltage bushing B1 is connected to one end of the bus connector 560; the coil on the secondary side of the transformer 520 in the second housing 550 is connected to one end of the second high-voltage bushing B2, and the other end of the second high-voltage bushing B2 is connected to the other end of the bus connector 560.

[0088] In one possible embodiment, referring to Figures 6 or 7, the first substation 500 further includes a third high-voltage bushing B3 and a fourth high-voltage bushing B4. A first end of a first oil-immersed load switch 541 is connected to one end of the third high-voltage bushing B3, and the other end of the third high-voltage bushing B3 is connected to the output end of the first substation 500. A second end of the first oil-immersed load switch 541 is connected to one end of the fourth high-voltage bushing B4, and the other end of the fourth high-voltage bushing B4 is connected to the high-voltage input end of the first substation 500. Understandably, both the third high-voltage bushing B3 and the fourth high-voltage bushing B4 are installed on the wall of the first enclosure 530. The third high-voltage bushing B3 is used to allow the high-voltage circuit between the first terminal of the first oil-immersed load switch 541 and the output terminal of the first substation 500 to pass through the first enclosure 530. The fourth high-voltage bushing B4 is used to allow the high-voltage circuit between the second terminal of the first oil-immersed load switch 541 and the high-voltage input terminal of the first substation 500 to pass through the first enclosure 530. Since the high-voltage bushings have good electrical insulation performance, they can ensure the safe transmission of high-voltage current, thereby improving the safety and reliability of the first substation 500.

[0089] In one possible embodiment, taking the circuit topology of the first substation 500 as shown in Figure 7 as an example, when the first substation 500, the second substation 700, and the third substation 800 are connected in a daisy-chain network, the circuit topology of the power supply system 600 is shown in Figure 7. The output terminal of the first substation 500 is used to connect to the high-voltage input terminal of the second substation 700, the output terminal of the second substation 700 is connected to the input terminal of the step-up substation 300, and the high-voltage input terminal of the first substation 500 is used to connect to the output terminal of the third substation 800, so that the second substation 700, the first substation 500, and the third substation 800 can be connected in a daisy-chain network. When the circuit topology of the first substation 500 is as shown in Figures 4-6, or the circuit topology of the first substation 500 shown in other figures in the embodiments of this application, and the first substation 500, the second substation 700 and the third substation 800 are connected in a daisy-chain network, the circuit topology of the power supply system 600 can refer to the circuit topology of the power supply system 600 shown in Figure 7. The embodiments of this application will not be described in detail here.

[0090] The first substation 500 provided in this embodiment further includes a bus connector 560 and a second high-voltage bushing B2. The first high-voltage bushing B1 is disposed on the wall of the first enclosure 530, and is used to allow the high-voltage circuit between the input terminal of the high-voltage distribution circuit 540 and one end of the bus connector 560 to pass through the first enclosure 530. The second high-voltage bushing B2 is disposed on the wall of the second enclosure 550, and is used to allow the high-voltage circuit between the coil on the secondary side of the transformer 520 and the other end of the bus connector 560 to pass through the second enclosure 550. By providing the first high-voltage bushing B1, the bus connector 560, and the second high-voltage bushing B2, the first enclosure 530 and the second enclosure 550 can be two independent enclosures, which is beneficial for assembly and maintenance, and can increase the heat dissipation area of ​​the first enclosure 530 and the second enclosure 550, thereby improving their heat dissipation capacity and thus enhancing the stability of the first substation 500.

[0091] In one possible embodiment, the circuit topology of the first substation 500 shown in FIG6 is used as an example in the following embodiments of this application to further describe the structure of the first substation 500. As shown in FIG6, the first substation 500 provided in the embodiments of this application also includes an oil tank 570 and a first pipe 580, wherein the oil tank 570 is connected to the first housing 530 through the first pipe 580.

[0092] In one possible embodiment, referring to FIG6, the oil reservoir 570 may include a breathing tube 571 and an airbag 572 disposed inside the oil reservoir 570. The airbag 572 is used to contain air and is connected to the atmosphere through the breathing tube 571. The breathing tube 571 and the airbag 572 are used to maintain the amount of oil in the oil reservoir 570 within a reasonable range.

[0093] The first substation 500 provided in this embodiment further includes an oil conservator 570 and a first conduit 580. The oil conservator 570 is connected to the first housing 530 via the first conduit 580. When the volume of the first insulating oil in the first housing 530 expands or contracts with changes in oil temperature, the oil conservator 570 is used to adjust the amount of first insulating oil in the first housing 530. Specifically, the oil conservator 570 is used to store excess first insulating oil that has expanded in the first housing 530 or to replenish the first insulating oil in the first housing 530, thereby ensuring the safe and reliable operation of the first substation 500. Simultaneously, the first insulating oil in the oil conservator 570 has good thermal conductivity, and the oil conservator 570 can also be used to transfer heat from the first housing 530 to the outside of the oil conservator 570, thereby achieving cooling of the first housing 530 and ensuring the safe and reliable operation of the first substation 500.

[0094] In one possible embodiment, as shown in Figure 6, the first substation 500 further includes a second pipe 590, through which the oil tank 570 is connected to the second housing 550. In this case, the first insulating oil and the second insulating oil can be the same type of insulating oil.

[0095] In one possible embodiment, the first housing 530 and the second housing 550 may not share the oil tank 570. The first substation 500 may also include an oil tank and pipeline corresponding to the second housing 550. The second housing 550 is connected to the corresponding oil tank through the corresponding pipeline. The oil tank corresponding to the second housing 550 is used to adjust the amount of second insulating oil in the second housing 550. Specifically, the oil tank is used to store the excess second insulating oil in the second housing 550 or to replenish the second insulating oil in the second housing 550. At this time, the first insulating oil and the second insulating oil may be the same type of insulating oil or different types of insulating oil. This application embodiment does not limit this.

[0096] In one possible embodiment, taking the circuit topology of the first substation 500 as shown in Figure 6 as an example, Figure 8(a) shows a schematic diagram of the structure of the first substation 500, and Figure 8(b) shows a top view of some components of the first substation 500. The third high-voltage bushing B3 and the fourth high-voltage bushing B4 can be installed on the wall of the first enclosure 530 away from the second enclosure. The operating shafts K of each switch in the high-voltage distribution circuit 540 can extend from the two opposite walls of the first enclosure 530 to control the corresponding switches. Referring to Figure 8(a), the low-voltage distribution cabinet 510 can be an outdoor waterproof cabinet, thereby preventing damage to the components in the low-voltage distribution cabinet 510. Referring to Figures 8(a) and 8(b), the following embodiments of this application use the example of the first substation 500 receiving or outputting three-phase high-voltage AC power, and the first substation 500 including a corresponding three-phase AC circuit, for illustrative purposes.

[0097] In one possible embodiment, as shown in Figure 8(c), the first substation 500 may further include radiators 5100 disposed on both sides of the second enclosure 550, the radiators 5100 being connected to the second enclosure 550, and the radiators 5100 being used to cool the second insulating oil in the second enclosure 550.

[0098] In one possible embodiment, referring to Figures 4, 6 and 8, when the first oil-immersed load switch 541 includes an oil-immersed three-position load switch 5411, Figures 9(a) and 9(b) show the structural schematic diagram of some components in the first substation 500, and Figure 9(c) shows the structural schematic diagram of the high-voltage power distribution circuit 540.

[0099] In one possible embodiment, referring to Figures 5, 6 and 8, when the first oil-immersed load switch 541 includes an oil-immersed vacuum load switch 5412 and a second oil-immersed three-position disconnect switch 5413 connected in series, Figures 10(a) and 10(b) show the structural schematic diagram of some components in the first substation 500, and Figure 10(c) shows the structural schematic diagram of the high-voltage power distribution circuit 540.

[0100] In one possible embodiment, as shown in Figures 11(a) and 11(b), which are schematic diagrams of the structure of some components in the first substation 500, the operating shafts K of each switch in the high-voltage distribution circuit 540 can extend from the side of the first housing 530 away from the second housing 550. The third high-voltage bushing B3 and the fourth high-voltage bushing B4 can be set on two opposite walls of the first housing 530. By changing the position of the operating shafts K and the high-voltage bushings, the switches can be operated more conveniently, or the high-voltage bushings can be connected more conveniently through high-voltage cables. The specific setting position of the operating shafts K and the high-voltage bushings in the first housing 530 is not limited in this embodiment. Figures 8 and 11 are exemplary illustrations.

[0101] In one possible embodiment, the structure of some components in the first substation 500 is shown in FIG11. In conjunction with FIG4 and FIG6, when the first oil-immersed load switch 541 includes an oil-immersed three-position load switch 5411, FIG12(a) and FIG12(b) show the structural schematic diagram of some components in the first substation 500, and FIG12(c) shows the structural schematic diagram of the high-voltage power distribution circuit 540.

[0102] In one possible embodiment, the structure of some components in the first substation 500 is shown in FIG11. In conjunction with FIG5 and FIG6, when the first oil-immersed load switch 541 includes an oil-immersed vacuum load switch 5412 connected in series and a second oil-immersed three-position disconnect switch 5413, FIG13(a) and FIG13(b) are schematic diagrams of the structure of some components in the first substation 500, and FIG13(c) is a schematic diagram of the structure of the high-voltage power distribution circuit 540.

[0103] The first substation 500 provided in this embodiment has an oil conservator 570 connected to a second housing 550 via a second pipe 590. When the volume of the second insulating oil in the second housing 550 expands or contracts with changes in oil temperature, the oil conservator 570 is used to regulate the amount of second insulating oil in the second housing 550. Specifically, the oil conservator 570 is used to store excess second insulating oil that has expanded in the second housing 550 or to replenish the second insulating oil in the second housing 550, thereby ensuring the safe and reliable operation of the first substation 500. Simultaneously, the second insulating oil in the oil conservator 570 has good thermal conductivity, and the oil conservator 570 can also be used to transfer heat from the second housing 550 to the outside of the oil conservator 570, thereby achieving cooling of the second housing 550 and ensuring the safe and reliable operation of the first substation 500. Furthermore, the first housing 530 and the second housing 550 share the oil conservator 570, which can reduce the cost of the first substation 500.

[0104] In one possible embodiment, as shown in FIG6, the first substation 500 further includes a valve 5110, which is disposed on the first pipeline 580 and is used to open or close the connection between the first enclosure 530 and the second enclosure 550.

[0105] Referring to Figure 6, before performing maintenance on the second enclosure 550 or the transformer 520 within it, disconnect the frame-type circuit breaker 512 in the low-voltage distribution cabinet 510, close the oil-immersed vacuum circuit breaker 542, and ground the first oil-immersed three-position disconnector 543 to ensure that the first high-voltage bushing B1 is grounded. Simultaneously, disconnect the connection between the first enclosure 530 and the second enclosure 550 via valve 5110. At this point, maintenance can be performed on the second enclosure 550 or the transformer 520 within it, thus restoring the high-voltage distribution circuit. Substation 540 can continue to operate. The high-voltage input terminal of the first substation 500 can receive high-voltage AC power output from the third substation 800. This high-voltage AC power can be transmitted to the output terminal of the first substation 500 through the first oil-immersed load switch 541. Referring to Figure 3(a), the output terminal of the first substation 500 can output this high-voltage AC power to the step-up substation 300. Alternatively, referring to Figure 3(b), the output terminal of the first substation 500 can output this high-voltage AC power to the step-up substation 300 through the second substation 700. It is understood that by setting valve 5110, the second enclosure 550 or the transformer 520 in the second enclosure 550 can be maintained separately without requiring the entire first substation 500 to be shut down for maintenance of the second enclosure 550 or the transformer 520 in the second enclosure 550, thus reducing the downtime of the first substation 500.

[0106] In one possible embodiment, before maintaining the first enclosure 530 or the high-voltage power distribution circuit 540 within the first enclosure 530, the frame-type circuit breaker 512 in the low-voltage distribution cabinet 510 is disconnected, the oil-immersed vacuum circuit breaker 542 is closed, and the first oil-immersed three-position disconnect switch 543 and the first oil-immersed load switch 541 are grounded. At this time, maintenance can be performed on the first enclosure 530 or the high-voltage power distribution circuit 540 within the first enclosure 530. It is understood that the first substation 500 needs to be shut down entirely at this time.

[0107] In one possible embodiment, before performing maintenance on the low-voltage distribution cabinet 510, both the plastic-cased circuit breaker 511 and the frame circuit breaker 512 in the low-voltage distribution cabinet 510 are disconnected, the oil-immersed vacuum circuit breaker 542 is closed, and the first oil-immersed three-position disconnecting switch 543 is grounded. At this time, the low-voltage distribution cabinet 510 can be maintained.

[0108] The first substation 500 provided in this application embodiment, by closing the control valve 5110, cuts off the connection between the first enclosure 530 and the oil tank 570. The high-voltage power distribution circuit 540 in the first enclosure 530 can continue to work, and the first substation 500 can continue to form a network with other substations. At the same time, the second enclosure 550 or the transformer 520 in the second enclosure 550 can be maintained separately without the need for the entire first substation 500 to be shut down to maintain the second enclosure 550 or the transformer 520 in the second enclosure 550, which can reduce the downtime of the first substation 500.

[0109] In one possible embodiment, as shown in FIG14, the high-voltage power distribution circuit 540 further includes a second oil-immersed load switch 544, one end of which is connected to the first end of the first oil-immersed load switch 541, and the other end of which is connected to the output end of the first substation 500.

[0110] In one possible embodiment, if the first oil-immersed load switch 541 is grounded before maintenance is performed on the first enclosure 530 or the high-voltage power distribution circuit 540 within the first enclosure 530, the second oil-immersed load switch 544 can be grounded. This ensures that, in the event of a failure of the first oil-immersed load switch 541, the high-voltage AC power received at the high-voltage input terminal of the first substation 500 will not be transmitted to the output terminal of the first substation 500, thereby improving the reliability of the first substation 500.

[0111] In one possible embodiment, as shown in FIG14, the second oil-immersed load switch 544 includes an oil-immersed three-position load switch 5441; or, as shown in FIG15, the second oil-immersed load switch 544 includes an oil-immersed vacuum load switch 5442 and a second oil-immersed three-position disconnector 5443 connected in series. This embodiment does not limit the specific implementation. Compared to the oil-immersed three-position load switch 5411, the oil-immersed vacuum load switch 5442 employs a vacuum arc-extinguishing mechanism, which does not contaminate the first insulating oil. Furthermore, it has a strong load breaking capacity, a high number of breaking cycles, and a long service life, thereby improving the reliability of the first substation 500. The specific connection method of the oil-immersed vacuum load switch 5442 and the second oil-immersed three-position disconnect switch 5443 can refer to the specific connection method of the oil-immersed vacuum load switch 5412 and the second oil-immersed three-position disconnect switch 5413 in the first oil-immersed load switch 541. The specific connection method of the oil-immersed vacuum load switch 5442 and the second oil-immersed three-position disconnect switch 5443 is not repeated here. The specific series connection order of the oil-immersed vacuum load switch 5442 and the second oil-immersed three-position disconnect switch 5443 is not limited in this embodiment.

[0112] In one possible embodiment, the structure of some components in the first substation 500 is shown in FIG8. In conjunction with FIG14, when the second oil-immersed load switch 544 includes an oil-immersed three-position load switch 5441, FIG16(a) and FIG16(b) show the structural schematic diagram of some components in the first substation 500, and FIG16(c) shows the structural schematic diagram of the high-voltage power distribution circuit 540.

[0113] In one possible embodiment, the structure of some components in the first substation 500 is shown in FIG8. In conjunction with FIG15, when the second oil-immersed load switch 544 includes an oil-immersed vacuum load switch 5442 and a second oil-immersed three-position disconnect switch 5443 connected in series, FIG17(a) and FIG17(b) are schematic diagrams of the structure of some components in the first substation 500, and FIG17(c) is a schematic diagram of the structure of the high-voltage power distribution circuit 540.

[0114] In one possible embodiment, the positions of the operating shaft K and the high-voltage bushing in the first substation 500 are changed. The structure of some components in the first substation 500 is shown in Figure 11. Referring to Figure 14, when the second oil-immersed load switch 544 includes an oil-immersed three-position load switch 5441, Figures 18(a) and 18(b) show the structural schematic diagram of some components in the first substation 500, and Figure 18(c) shows the structural schematic diagram of the high-voltage power distribution circuit 540.

[0115] In one possible embodiment, the positions of the operating shaft K and the high-voltage bushing in the first substation 500 are changed. The structure of some components in the first substation 500 is shown in Figure 11. Referring to Figure 15, when the second oil-immersed load switch 544 includes an oil-immersed vacuum load switch 5442 and a second oil-immersed three-position disconnect switch 5443 connected in series, Figures 19(a) and 19(b) show schematic diagrams of the structure of some components in the first substation 500, and Figure 19(c) shows a schematic diagram of the structure of the high-voltage power distribution circuit 540.

[0116] This application provides a first substation 500. By setting a second oil-immersed load switch 544, it can be ensured that in the event of a failure of the first oil-immersed load switch 541, the second oil-immersed load switch 544 can disconnect the circuit between the high-voltage input terminal and the output terminal of the first substation 500, thereby improving the reliability of the first substation 500.

[0117] Based on this, as shown in Figures 3(a) and 3(b), this application embodiment also provides a power supply system 600, which includes a converter 610 and a first substation 500. The input terminal of the converter 610 is used to connect to the output terminal of an energy storage device or a photovoltaic array 200, and the output terminal of the converter 610 is connected to the low-voltage input terminal of the first substation 500. The output terminal of the first substation 500 is used to connect to the input terminal of a step-up substation 300 or the high-voltage input terminal of a second substation 700, and the high-voltage input terminal of the first substation 500 is used to connect to the output terminal of a third substation 800. The circuit topology and structure of the first substation 500 can be the circuit topology and structure of the first substation 500 shown in any of the figures in Figures 4-19 above.

[0118] In one possible embodiment, when the input terminal of the inverter 610 is used to connect to a photovoltaic array, the power supply system 600 can be referred to as a photovoltaic power supply system. When the input terminal of the inverter 610 is used to connect to an energy storage device, the power supply system 600 can be referred to as an energy storage power supply system. When the power supply system 600 includes a plurality of inverters 610, wherein the input terminals of some of the inverters 610 are used to connect to an energy storage device, and the input terminals of the remaining inverters 610 are used to connect to a photovoltaic array, the power supply system 600 can be referred to as a photovoltaic-energy storage power supply system.

[0119] The above detailed description of the first substation 500 and the analysis of its beneficial effects can be applied to the power supply system 600, and will not be repeated here in the embodiments of this application.

[0120] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A first substation, characterized in that, The first substation includes a low-voltage distribution cabinet, a transformer, and a first enclosure. The first enclosure contains a first insulating oil and a high-voltage distribution circuit immersed in the first insulating oil. The output terminal of the low-voltage distribution cabinet is connected to the input terminal of the transformer, and the output terminal of the transformer is connected to the input terminal of the high-voltage distribution circuit. The high-voltage power distribution circuit includes a first oil-immersed load switch and an oil-immersed vacuum circuit breaker and a first oil-immersed three-position disconnector connected in series. The oil-immersed vacuum circuit breaker and the first oil-immersed three-position disconnector are located between the input terminal of the high-voltage power distribution circuit and the first terminal of the first oil-immersed load switch. The first terminal of the first oil-immersed load switch is connected to the output terminal of the first substation. The output terminal of the first substation is used to connect to the input terminal of a step-up substation or the high-voltage input terminal of a second substation. The second terminal of the first oil-immersed load switch is connected to the high-voltage input terminal of the first substation. The high-voltage input terminal of the first substation is used to connect to the output terminal of a third substation.

2. The first substation according to claim 1, characterized in that, The first substation also includes a second enclosure, a first high-voltage bushing and a low-voltage bushing. The second enclosure is equipped with a second insulating oil, and the transformer is immersed in the second insulating oil. The first enclosure and the second enclosure are connected through the first high-voltage bushing, and the second enclosure is connected to the low-voltage distribution cabinet through the low-voltage bushing.

3. The first substation according to claim 2, characterized in that, The first substation also includes a bus connector and a second high-voltage bushing; The first enclosure is connected to one end of the bus connector via the first high-voltage bushing, and the second enclosure is connected to the other end of the bus connector via the second high-voltage bushing.

4. The first substation according to any one of claims 1-3, characterized in that, The first substation also includes a third high-voltage bushing and a fourth high-voltage bushing; The first end of the first oil-immersed load switch is connected to one end of the third high-voltage bushing, and the other end of the third high-voltage bushing is connected to the output end of the first substation. The second end of the first oil-immersed load switch is connected to one end of the fourth high-voltage bushing, and the other end of the fourth high-voltage bushing is connected to the high-voltage input end of the first substation.

5. The first substation according to any one of claims 1-4, characterized in that, The first substation also includes an oil tank and a first pipeline, the oil tank being connected to the first housing via the first pipeline.

6. The first substation according to claim 5, characterized in that, The first substation also includes a second pipeline, through which the oil tank is connected to the second housing.

7. The first substation according to claim 6, characterized in that, The first substation also includes a valve, which is installed on the first pipeline.

8. The first substation according to any one of claims 1-7, characterized in that, The high-voltage power distribution circuit also includes a second oil-immersed load switch, one end of which is connected to the first end of the first oil-immersed load switch, and the other end of which is connected to the output end of the first substation.

9. The first substation according to any one of claims 1-8, characterized in that, The oil-immersed load switch includes: an oil-immersed three-position load switch, or an oil-immersed vacuum load switch and a second oil-immersed three-position isolating switch connected in series.

10. A power supply system, characterized in that, The system includes a converter and a first substation. The input terminal of the converter is used to connect to an energy storage device or a photovoltaic array. The output terminal of the converter is connected to the low-voltage input terminal of the first substation. The output terminal of the first substation is used to connect to the input terminal of a step-up substation or the high-voltage input terminal of a second substation. The high-voltage input terminal of the first substation is used to connect to the output terminal of a third substation. The first substation is the first substation as described in any one of claims 1-9.

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