A superconducting switch station with an outgoing closed loop and a method of operation thereof

Abstract

The application relates to a superconducting switch station with an outgoing line closed loop and a working method thereof, the superconducting switch station is connected with a transformer substation through a superconducting cable, the superconducting switch station is powered by the transformer substation, outgoing lines of the superconducting switch station are connected in a closed loop, superconducting current limiters are connected in series on the outgoing lines, a petal type power distribution network is further designed, comprising the following steps: two superconducting switch stations are connected with two transformer substations through superconducting cables, the two superconducting switch stations are powered by the two transformer substations, two looped networks of the two superconducting switch stations are connected through normally closed tie switches, the tie switches are connected in series with superconducting current limiters, and a superconducting reactor is installed on a bus of one of the superconducting switch stations. Compared with the prior art, the application integrates large-capacity switch stations, superconducting cables, superconducting reactors, superconducting current limiters and other devices to establish a superconducting switch station, realizes outgoing line closed loop design and closed loop operation, can limit short-circuit current, reduce breaking pressure of a circuit breaker, and improves power supply capacity and power supply reliability.

Description

Technical Field

[0001] This invention relates to the field of superconducting power equipment technology, and in particular to a superconducting switch station with closed-loop outgoing lines and its operating method. Background Technology

[0002] Currently, substations in urban centers often face limitations such as small construction land area and a shortage of outgoing line bays. When users apply for power supply, they may face the problem of no bays available. Traditionally, the power supply range of substations is mostly expanded by setting up switching stations. However, ordinary switching stations are limited by the transmission capacity of the incoming lines, and the power supply capacity of a single station cannot effectively match the substation capacity.

[0003] Based on this, existing technologies consider the application of superconducting power equipment such as superconducting cables, superconducting reactors, and superconducting current limiters in urban central areas to improve the power supply capacity and reliability of the power grid in these areas. Among these, the outstanding advantages of superconducting cables are large capacity, low loss, self-limiting current, and environmental friendliness. Their transmission capacity can replace at least 4 to 6 conventional cables of the same voltage, or replace conventional cables of two higher voltage levels. For example, a 35kV superconducting cable is equivalent to the transmission capacity of a 220kV ordinary cable, and a 10kV superconducting cable is equivalent to the transmission capacity of a 110kV ordinary cable. Using superconducting cables for power transmission can significantly reduce the voltage level of substations, enabling the relocation of high-voltage substation equipment from the central urban area to the suburbs.

[0004] In addition, with the increasing number of power grid cable lines, a large amount of reactive power is back-transmitted, resulting in insufficient inductive reactive power compensation and high voltage levels. It is necessary to install parallel reactors. However, oil-immersed reactors are noisy and dry-type reactors occupy a large area, making their application in urban substations with limited space very difficult. Superconducting reactors, which use superconducting materials as working windings, have the advantages of small footprint and low noise compared with conventional reactors.

[0005] Superconducting current limiters exhibit a "superconducting state" during normal operation, with very low impedance. When a fault occurs, they can quickly respond by becoming a larger impedance to suppress short-circuit current, and automatically return to the "superconducting state" after the fault is cleared. They can quickly, smoothly, and effectively limit the short-circuit current of the system, significantly reducing the breaking pressure of circuit breakers. Conventional methods mainly increase the impedance of the power grid by using high-impedance transformers or current-limiting reactors, which undoubtedly increases the transmission loss and voltage drop of the power grid.

[0006] However, to fully leverage the advantages of superconducting power equipment, simply replacing a single superconducting device is insufficient. Therefore, it is currently urgent to integrate equipment such as large-capacity switch stations, superconducting cables, superconducting reactors, and superconducting current limiters to establish superconducting switch stations.

[0007] Furthermore, in traditional distribution networks, substation outgoing lines mostly adopt a "closed-loop design, open-loop operation" power supply mode. The tie switch is in the open position under normal operating conditions, and load transfer is only carried out under special circumstances such as maintenance or faults by selecting a suitable closing point and power supply path. This traditional power supply method cannot guarantee uninterrupted power supply to dual power sources and important users during faults. Existing technology designs form a ring network with two outgoing lines and operates in a closed-loop mode. However, due to the close interconnection of power grids in central urban areas, the system's short-circuit capacity is large, and short-circuit currents at various voltage levels are prone to exceeding limits, which also makes the selection of circuit breakers difficult. Summary of the Invention

[0008] The purpose of this invention is to overcome the defects of the prior art by providing a superconducting switch station with outgoing closed-loop operation and its working method, thereby achieving closed-loop operation of outgoing lines, improving power supply capacity and reliability, limiting short-circuit current, and reducing the breaking pressure of circuit breakers.

[0009] The objective of this invention can be achieved through the following technical solution: a superconducting switch station with a closed-loop outgoing line, which is connected to a substation via a superconducting cable, and the substation supplies power to the superconducting switch station. The outgoing lines of the superconducting switch station are in a closed-loop connection, and a superconducting current limiter is connected in series on the outgoing lines.

[0010] Furthermore, multiple normally closed switches are provided on the outgoing line.

[0011] A method for operating a superconducting switch station includes: supplying power to the superconducting switch station via a superconducting cable using a substation;

[0012] The outgoing lines of the superconducting switch station are designed for closed-loop operation.

[0013] A superconducting current limiter connected in series on the output line is used to limit the short-circuit current.

[0014] A petal-shaped power distribution network based on a superconducting switch station includes a first superconducting switch station and a second superconducting switch station. The first and second superconducting switch stations are respectively connected to two substations via superconducting cables and are powered by the two substations. The two ring networks of the first and second superconducting switch stations are connected in the middle by a normally closed tie switch.

[0015] Furthermore, the connecting switch includes two normally closed switches connected in series.

[0016] Furthermore, a superconducting current limiter is connected in series between the two normally closed switches.

[0017] Furthermore, a superconducting reactor is installed on the busbar of the first superconducting switch station.

[0018] Furthermore, the superconducting reactor is connected to a tap changer.

[0019] Furthermore, the capacity of the superconducting reactor is specifically designed based on the reactive power backfeed situation under different operating modes of the incoming and outgoing lines of the two superconducting switch stations.

[0020] A method for operating a petal-shaped power distribution network based on superconducting switch stations includes: supplying power to two superconducting switch stations via superconducting cables using two substations;

[0021] Both superconducting switch stations adopt a closed-loop operation mode for outgoing lines to achieve balanced load distribution;

[0022] Inductive reactive power compensation using superconducting reactors;

[0023] When a short-circuit fault occurs at any point of the two superconducting switch stations and their outgoing lines, a superconducting current limiter is used to limit the current from the non-faulty switch stations.

[0024] When the superconducting current limiter malfunctions or requires maintenance, the connecting switch in the middle of the two superconducting switch stations' ring network is disconnected to de-energize the superconducting current limiter, allowing the two superconducting switch stations and their outgoing lines to continue operating normally.

[0025] Furthermore, the superconducting reactor achieves segmented adjustment of its compensation capacity through a tap switch.

[0026] Furthermore, the cold box of the superconducting cable is equipped with a refrigeration unit. The cold box of the superconducting cable and the cold box of the superconducting power equipment are respectively equipped with a first coil heat exchanger and a second coil heat exchanger. The superconducting power equipment includes a superconducting reactor and a superconducting current limiter. The first coil heat exchanger is filled with a first liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting cable. The outside of the first coil heat exchanger is filled with a second liquid nitrogen. The cold head of the refrigeration unit is immersed in the second liquid nitrogen.

[0027] The second coil heat exchanger contains a third liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting power equipment. The second coil heat exchanger contains a fourth liquid nitrogen.

[0028] The outlet of the first coil heat exchanger is connected to the inlet of the superconducting power equipment cold box, and the outlet of the superconducting power equipment cold box is connected to the liquid nitrogen inlet of the superconducting cable.

[0029] A method for operating a shared chiller in a superconducting switch station, wherein the chiller provides cooling to the cold box of the superconducting cable to maintain the low temperature of the second liquid nitrogen, the second liquid nitrogen transfers cooling to the first liquid nitrogen through a first coil heat exchanger, and the first liquid nitrogen flows between the first coil heat exchanger and the superconducting cable to transfer cooling to the superconducting cable, thereby ensuring that the superconducting cable is maintained in a low-temperature superconducting state.

[0030] The first liquid nitrogen also transfers its cooling capacity to the fourth liquid nitrogen through flow. The fourth liquid nitrogen then transfers its cooling capacity to the third liquid nitrogen through the second coil heat exchanger. The third liquid nitrogen flows between the second coil heat exchanger and the superconducting power equipment, thereby transferring its cooling capacity to the superconducting power equipment and ensuring that the superconducting power equipment is maintained in a low-temperature superconducting state.

[0031] Furthermore, the cold box of the superconducting cable is equipped with a refrigeration unit, and the cold box of the superconducting cable and the thermostat of the superconducting power equipment are respectively equipped with a first coil heat exchanger and a second coil heat exchanger. The superconducting power equipment includes a superconducting reactor and a superconducting current limiter. The first coil heat exchanger is filled with a first liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting cable. The outside of the first coil heat exchanger is filled with a second liquid nitrogen, and the cold head of the refrigeration unit is immersed in the second liquid nitrogen.

[0032] The inlet of the second coil heat exchanger is connected to the outlet of the first coil heat exchanger, and the outlet of the second coil heat exchanger is connected to the liquid nitrogen inlet of the superconducting cable.

[0033] A method for operating a shared chiller in a superconducting switch station, wherein the chiller provides cooling to the cold box of the superconducting cable to maintain the low temperature of the second liquid nitrogen, the second liquid nitrogen transfers cooling to the first liquid nitrogen through a first coil heat exchanger, and the first liquid nitrogen flows between the first coil heat exchanger and the superconducting cable to transfer cooling to the superconducting cable, thereby ensuring that the superconducting cable is maintained in a low-temperature superconducting state.

[0034] The first liquid nitrogen also transfers its cooling capacity to the second coil heat exchanger through its flow, ensuring that the thermostat of the superconducting power equipment is maintained in a low-temperature superconducting state.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] This invention connects a superconducting switch station to a substation via a superconducting cable, allowing the substation to supply power to the switch station. The design incorporates a closed-loop connection for the switch station's outgoing lines, with a superconducting current limiter connected in series on each line. This enables the switch station's outgoing lines to operate in a closed-loop manner, improving power supply reliability. Simultaneously, the superconducting current limiter can be used to restrict short-circuit current, reducing the breaking pressure on circuit breakers.

[0037] This invention also designs a petal-shaped power distribution network based on superconducting switch stations. Two substations supply power to two superconducting switch stations with closed-loop outgoing lines. A normally closed tie switch is connected between the two loop networks of the two superconducting switch stations, and a superconducting current limiter is connected in series. This adopts a closed-loop operation mode using the tie switch, which greatly improves power supply reliability. A fault in either of the two incoming power lines will not cause power interruption, enabling balanced load distribution and full utilization of equipment capacity, effectively improving overall power supply capacity. Furthermore, when a short-circuit fault occurs at any point in either of the two superconducting switch stations or their outgoing lines, the superconducting current limiter can function to limit the current from the non-faulty switch station, thereby preventing excessive short-circuit current at the fault point and reducing the breaking pressure on the circuit breaker.

[0038] The present invention designs a connecting switch comprising two normally closed switches connected in series, which can be operated in open loop if necessary. In the event of a fault in the superconducting current limiter or when maintenance is required, disconnecting the two switches de-energizes the superconducting current limiter, thereby ensuring the continued normal operation of the two superconducting switch stations and their outgoing lines.

[0039] This invention involves installing a superconducting reactor on the busbar of one of the superconducting switch stations, which can effectively solve the problems of insufficient inductive reactive power compensation and high voltage levels. In practice, the capacity of the superconducting reactor can be designed according to the reactive power backfeed situation under different operating modes of the incoming and outgoing lines of the two superconducting switch stations. In addition, a tap changer is designed on the reactor to realize segmented adjustment of the compensation capacity.

[0040] This invention proposes a scheme for sharing a chiller between superconducting cables and superconducting power equipment (including superconducting reactors and superconducting current limiters). The design involves installing a first coil heat exchanger and a second coil heat exchanger in the cold boxes of the superconducting cable and the superconducting power equipment, respectively. The outlet of the first coil heat exchanger is connected to the inlet of the superconducting power equipment's cold box, and the outlet of the superconducting power equipment's cold box is connected to the liquid nitrogen inlet of the superconducting cable. Therefore, only the cold box of the superconducting cable needs a chiller, while the cold box of the superconducting power equipment does not require a chiller but only needs to be connected to the liquid nitrogen pipeline of the superconducting cable. After the cooling capacity of the chiller is transferred to the superconducting cable, the remaining cooling capacity can be transferred to the superconducting power equipment. This improves the utilization rate of the chiller, reduces the number of chillers required, and makes the chiller's spatial arrangement in the substation more flexible, meeting various substation design requirements.

[0041] This invention addresses a solution for sharing a chiller between superconducting cables and superconducting power equipment. It further designs a first coil heat exchanger and a second coil heat exchanger, respectively, within the cold box of the superconducting cable and the thermostat of the superconducting power equipment. The inlet of the second coil heat exchanger is connected to the outlet of the first coil heat exchanger, and the outlet of the second coil heat exchanger is connected to the liquid nitrogen inlet of the superconducting cable. This achieves a more compact design, eliminating the need for a separate cold box for the superconducting power equipment. It not only achieves the goal of sharing a chiller but also simplifies the structure and reduces the size of the superconducting power equipment, facilitating the installation of multiple superconducting power devices within a superconducting switchyard and improving the economics of construction and operation. Attached Figure Description

[0042] Figure 1 A schematic diagram of a superconducting switchyard for closed-loop operation of outgoing lines;

[0043] Figure 2 This is a schematic diagram of a conventional petal-shaped power distribution network;

[0044] Figure 3 This invention relates to a petal-shaped power distribution network based on a superconducting switch station.

[0045] Figure 4 A schematic diagram of the working scheme of a traditional chiller for superconducting cables;

[0046] Figure 5 This is a schematic diagram of the shared chiller scheme for the superconducting switch station in Example 3;

[0047] Figure 6 This is a schematic diagram of the shared chiller scheme for the superconducting switch station in Example 4. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] like Figure 1 As shown, a superconducting switch station with outgoing closed loop is connected to a substation via a superconducting cable, and the substation supplies power to the superconducting switch station. The superconducting switch station has an outgoing closed loop connection, with a superconducting current limiter connected in series on the outgoing line and multiple normally closed switches installed on the outgoing line. In this embodiment, four normally closed switches are installed on the outgoing line.

[0051] The above-mentioned superconducting switch station operation method includes: using a substation to supply power to the superconducting switch station through a superconducting cable;

[0052] The outgoing lines of the superconducting switch station are designed and operate in a closed loop, enabling closed-loop design and operation of outgoing lines under the same power supply, thus improving power supply reliability.

[0053] A superconducting current limiter connected in series on the outgoing line is used to limit the short-circuit current and reduce the breaking pressure of the circuit breaker.

[0054] Example 2

[0055] Current conventional petal-shaped power distribution networks, such as Figure 2 As shown, each pair of outgoing lines from a substation forms a ring network, creating a petal-like structure, with the ring network operating in a closed loop. Each pair of ring networks from different power source substations is interconnected by a tie switch, forming a tangent petal shape. This petal-shaped distribution network has high reliability; however, when a power source substation experiences a power outage, it still undergoes the processes of power outage, fault location, fault isolation, load transfer, and power restoration. Furthermore, during operation, load imbalances and the coexistence of heavy and light loads can still easily occur.

[0056] Therefore, based on Embodiment 1, this embodiment designs the outgoing lines of both superconducting switch stations to adopt a petal-shaped power distribution network, such as... Figure 3 As shown, it includes a first superconducting switch station and a second superconducting switch station. The first and second superconducting switch stations are respectively connected to two substations via superconducting cables and are powered by the two substations. The two ring networks of the first and second superconducting switch stations are connected in the middle by a normally closed tie switch. The tie switch includes two normally closed switches connected in series, and a superconducting current limiter is connected in series between the two normally closed switches.

[0057] In addition, superconducting reactors are installed on the busbars of the first superconducting switch station to effectively address the problems of insufficient inductive reactive power compensation and excessively high voltage levels. The superconducting reactors are connected to tap changers to achieve segmented adjustment of the compensation capacity. The specific capacity of the superconducting reactors is designed based on the reactive power backfeed situation under different operating modes of the incoming and outgoing lines of the two superconducting switch stations.

[0058] The above-mentioned working method of the petal-shaped power distribution network based on superconducting switch stations includes: using two substations to supply power to two superconducting switch stations through superconducting cables;

[0059] Both superconducting switch stations adopt a closed-loop operation mode for outgoing lines to achieve balanced load distribution;

[0060] Inductive reactive power compensation using superconducting reactors;

[0061] When a short-circuit fault occurs at any point of the two superconducting switch stations and their outgoing lines, a superconducting current limiter is used to limit the current from the non-faulty switch stations.

[0062] When the superconducting current limiter malfunctions or requires maintenance, the connecting switch in the middle of the two superconducting switch stations' ring network is disconnected to de-energize the superconducting current limiter, allowing the two superconducting switch stations and their outgoing lines to continue operating normally.

[0063] Example 3

[0064] like Figure 4 As shown, in the current working scheme of the superconducting cable's chiller, the coil heat exchanger is immersed in the cold box of the superconducting cable. The inside of the coil heat exchanger is filled with first liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting cable. The outside of the coil heat exchanger is filled with second liquid nitrogen, located inside the cold box. The cold head of the chiller is immersed in the second liquid nitrogen inside the cold box, providing cooling to the cold box to maintain the low temperature of the second liquid nitrogen. The second liquid nitrogen transfers its cooling to the first liquid nitrogen inside the coil heat exchanger. The first liquid nitrogen flows between the coil heat exchanger and the superconducting cable, thereby transferring its cooling to the superconducting cable and ensuring that the superconducting cable is maintained in a low-temperature superconducting state.

[0065] If a cooling design is implemented for the superconducting switch station proposed in the embodiment, it is often necessary to equip the superconducting cable and the superconducting power equipment (superconducting reactor or superconducting current limiter) with separate cooling units, and also to redundantly configure backup cooling units. This will undoubtedly increase the construction cost and structural complexity of the superconducting switch station.

[0066] This embodiment takes into account that superconducting cables typically require a large amount of cooling, while superconducting power equipment requires a much smaller amount, differing by up to one order of magnitude. Therefore, based on Embodiment 1, this embodiment proposes a working mode in which the superconducting cable and the superconducting power equipment (superconducting reactor or superconducting current limiter) share a chiller. Figure 5 As shown. This embodiment uses a superconducting reactor as an example for illustration, wherein the cold box of the superconducting cable and Figure 4 The structures are similar. The cold box of the superconducting reactor is not equipped with a refrigeration unit. The internal coil heat exchanger of the superconducting reactor cold box contains a third type of liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting reactor. The external coil heat exchanger of the superconducting reactor cold box contains a fourth type of liquid nitrogen. The outlet of the coil heat exchanger in the superconducting cable cold box is connected to the inlet of the superconducting reactor cold box, and the outlet of the superconducting reactor cold box is connected to the liquid nitrogen inlet of the superconducting cable.

[0067] During the operation of the refrigerator, the refrigerator transfers cooling energy to the first liquid nitrogen through the coil heat exchanger in the superconducting cable cold box. The first liquid nitrogen transfers cooling energy to the fourth liquid nitrogen through flow. The fourth liquid nitrogen transfers cooling energy to the third liquid nitrogen through the coil heat exchanger in the superconducting reactor cold box. The third liquid nitrogen flows between the coil heat exchanger in the superconducting reactor cold box and the superconducting reactor, thereby transferring cooling energy to the superconducting reactor and ensuring that the superconducting reactor is maintained in a low-temperature superconducting state.

[0068] Therefore, after the cooling capacity of the refrigerator is transferred to the superconducting cable, the remaining cooling capacity can be transferred to the superconducting reactor; thus greatly improving the utilization rate of the refrigerator and reducing the number of refrigerators required.

[0069] Furthermore, the large size and high noise of the chiller necessitate stringent requirements for its installation location, necessitating noise reduction measures in the chiller room. In substations, the installation locations of cables, reactors, and current limiters may be some distance apart. This makes it difficult to centrally arrange the chillers in conventional solutions, resulting in a large footprint and challenging placement. In the solution proposed in this embodiment, the cold box of the superconducting substation equipment does not require a chiller; it only needs to be connected to the liquid nitrogen pipeline of the superconducting cable to receive cooling. This allows for greater flexibility in substation space arrangement and easily meets various substation design requirements.

[0070] Example 4

[0071] This embodiment proposes a working method in which superconducting cables and superconducting power equipment (superconducting reactors or superconducting current limiters) share a chiller. Figure 6 As shown, this embodiment also uses a superconducting reactor as an example for explanation. The difference from embodiment three is that in this embodiment, the coil heat exchanger is arranged inside the thermostat of the superconducting reactor. The inlet of the coil heat exchanger inside the thermostat of the superconducting reactor is connected to the outlet of the coil heat exchanger of the superconducting cable. The outlet of the coil heat exchanger inside the thermostat of the superconducting reactor is connected to the liquid nitrogen inlet of the superconducting cable. The rest of the structural design is the same as in embodiment three.

[0072] Therefore, this embodiment enables superconducting cables and superconducting power equipment to share a chiller, while eliminating the need for a cold box in the superconducting power equipment, thus achieving a more compact structural design for the superconducting power equipment and reducing its installation volume.

[0073] In summary, the superconducting switchgear proposed in this scheme adopts a "closed-loop design and closed-loop operation" method for its outgoing lines, which can effectively improve power supply reliability. Connecting superconducting current limiters in series in the outgoing lines can limit short-circuit current and reduce the breaking pressure on circuit breakers. Installing superconducting reactors on the busbars of the superconducting switchgear can effectively solve the problems of insufficient inductive reactive power compensation and excessively high voltage levels. Furthermore, a closed-loop operation scheme for outgoing lines under different power sources is proposed. Specifically, the outgoing lines of both superconducting switchgears adopt a petal-shaped distribution network, and the normally closed tie switch between the two ring networks of the two superconducting switchgears is connected in series with a superconducting current limiter, thus adopting a closed-loop operation mode with the tie switch, further improving power supply capacity and reliability. Applying this technical solution has the following advantages:

[0074] (1) Limiting short-circuit current

[0075] If a short circuit fault occurs at any point in either of the two superconducting switch stations or their outgoing lines, the superconducting current limiter can function to limit the current from the non-faulty switch station, thereby preventing excessive short circuit current at the fault point and reducing the breaking pressure on the circuit breaker.

[0076] (2) High reliability

[0077] The power supply is highly reliable; a fault in either of the two power input lines will not cause a power outage.

[0078] (3) Strong power supply capacity

[0079] The load distribution of the outgoing lines from the two superconducting switch stations is balanced, the capacity of the equipment is fully utilized, and the overall power supply capacity is improved.

[0080] Two superconducting switch stations share centralized inductive reactive power compensation from superconducting reactors, which saves on equipment quantity, cost, and space compared to multi-point, multi-equipment compensation methods.

[0081] (4) High utilization rate of refrigeration unit

[0082] Installing multiple superconducting power devices within a single superconducting switch station allows for the sharing of chillers, improving the economic efficiency of construction and operation.

[0083] (5) The tie switch consists of two normally closed switches connected in series, and can be operated in open loop if necessary. When the superconducting current limiter malfunctions or needs maintenance, the two normally closed switches can be disconnected to de-energize the superconducting current limiter, ensuring that the two superconducting switch stations and their outgoing lines can still operate normally.

Claims

1. A petal-shaped power distribution network based on a superconducting switch station, characterized in that, The superconducting switch station is a closed-loop outgoing superconducting switch station, which is connected to the substation via a superconducting cable. The substation supplies power to the superconducting switch station. The outgoing lines of the superconducting switch station are closed-loop connected, and a superconducting current limiter is connected in series on the outgoing lines. Multiple normally closed switches are installed on the outgoing lines. The petal-shaped power distribution network includes a first superconducting switch station and a second superconducting switch station. The first and second superconducting switch stations are respectively connected to substation A and substation B via superconducting cables, and are powered by substation A and substation B respectively. The two ring networks of the first and second superconducting switch stations are connected in the middle by a normally closed tie switch.

2. The petal-shaped power distribution network based on a superconducting switch station according to claim 1, characterized in that, The connecting switch comprises two normally closed switches connected in series.

3. A petal-shaped power distribution network based on a superconducting switch station according to claim 2, characterized in that, A superconducting current limiter is connected in series between the two normally closed switches.

4. A petal-shaped power distribution network based on a superconducting switch station according to claim 1, characterized in that, A superconducting reactor is installed on the busbar of the first superconducting switch station.

5. A petal-shaped power distribution network based on a superconducting switch station according to claim 4, characterized in that, The superconducting reactor is connected to a tap changer.

6. A petal-shaped power distribution network based on a superconducting switch station according to claim 4, characterized in that, The capacity of the superconducting reactor is specifically designed based on the reactive power backfeed situation under different operating modes of the incoming and outgoing lines of the two superconducting switch stations.

7. A method for operating a superconducting switch station, applied to a petal-shaped power distribution network based on a superconducting switch station as described in claim 1, characterized in that, include: The superconducting switch station is powered by a substation via a superconducting cable; The outgoing lines of the superconducting switch station are designed for closed-loop operation. A superconducting current limiter connected in series on the output line is used to limit the short-circuit current.

8. A petal-shaped power distribution network based on a superconducting switch station according to claim 5, characterized in that, The cold box of the superconducting cable is equipped with a refrigeration unit. The cold box of the superconducting cable and the cold box of the superconducting power equipment are respectively equipped with a first coil heat exchanger and a second coil heat exchanger. The superconducting power equipment includes a superconducting reactor and a superconducting current limiter. The first coil heat exchanger is filled with a first liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting cable. The outside of the first coil heat exchanger is filled with a second liquid nitrogen. The cold head of the refrigeration unit is immersed in the second liquid nitrogen. The second coil heat exchanger contains a third liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting power equipment. The second coil heat exchanger contains a fourth liquid nitrogen. The outlet of the first coil heat exchanger is connected to the inlet of the superconducting power equipment cold box, and the outlet of the superconducting power equipment cold box is connected to the liquid nitrogen inlet of the superconducting cable.

9. A petal-shaped power distribution network based on a superconducting switch station according to claim 5, characterized in that, The cold box of the superconducting cable is equipped with a refrigeration unit. The cold box of the superconducting cable and the thermostat of the superconducting power equipment are respectively equipped with a first coil heat exchanger and a second coil heat exchanger. The superconducting power equipment includes a superconducting reactor and a superconducting current limiter. The first coil heat exchanger is filled with a first liquid nitrogen, which is connected to the liquid nitrogen inside the superconducting cable. The outside of the first coil heat exchanger is filled with a second liquid nitrogen. The cold head of the refrigeration unit is immersed in the second liquid nitrogen. The inlet of the second coil heat exchanger is connected to the outlet of the first coil heat exchanger, and the outlet of the second coil heat exchanger is connected to the liquid nitrogen inlet of the superconducting cable.

10. A method for operating a shared chiller in a superconducting switch station, applied to a petal-shaped power distribution network based on a superconducting switch station as described in claim 8, characterized in that... The refrigerator provides cooling to the cold box of the superconducting cable to maintain the low temperature of the second liquid nitrogen. The second liquid nitrogen transfers cooling to the first liquid nitrogen through the first coil heat exchanger. The first liquid nitrogen flows between the first coil heat exchanger and the superconducting cable to transfer cooling to the superconducting cable, ensuring that the superconducting cable is maintained in a low-temperature superconducting state. The first liquid nitrogen also transfers its cooling capacity to the fourth liquid nitrogen through flow. The fourth liquid nitrogen then transfers its cooling capacity to the third liquid nitrogen through the second coil heat exchanger. The third liquid nitrogen flows between the second coil heat exchanger and the superconducting power equipment, thereby transferring its cooling capacity to the superconducting power equipment and ensuring that the superconducting power equipment is maintained in a low-temperature superconducting state.

11. A method for operating a shared chiller in a superconducting switch station, applied to a petal-shaped power distribution network based on a superconducting switch station as described in claim 9, characterized in that... The refrigerator provides cooling to the cold box of the superconducting cable to maintain the low temperature of the second liquid nitrogen. The second liquid nitrogen transfers cooling to the first liquid nitrogen through the first coil heat exchanger. The first liquid nitrogen flows between the first coil heat exchanger and the superconducting cable to transfer cooling to the superconducting cable, ensuring that the superconducting cable is maintained in a low-temperature superconducting state. The first liquid nitrogen also transfers its cooling capacity to the second coil heat exchanger through its flow, ensuring that the thermostat of the superconducting power equipment is maintained in a low-temperature superconducting state.

12. A method for operating a petal-shaped power distribution network based on a superconducting switch station, applied to a petal-shaped power distribution network based on a superconducting switch station as described in claim 6, characterized in that, include: Two superconducting switch stations are powered by two substations via superconducting cables; Both superconducting switch stations adopt a closed-loop operation mode for outgoing lines to achieve balanced load distribution; Inductive reactive power compensation using superconducting reactors; When a short-circuit fault occurs at any point of the two superconducting switch stations and their outgoing lines, a superconducting current limiter is used to limit the current from the non-faulty switch stations. When the superconducting current limiter malfunctions or requires maintenance, the connecting switch in the middle of the two superconducting switch stations' ring network is disconnected to de-energize the superconducting current limiter, allowing the two superconducting switch stations and their outgoing lines to continue operating normally.

13. The operating method of a petal-shaped power distribution network based on a superconducting switch station according to claim 12, characterized in that, The superconducting reactor achieves segmented adjustment of its compensation capacity through a tap switch.

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