A three-dimensional multi-port DC hub substation system architecture

Abstract

The present invention provides a three-dimensional multi-port DC hub substation system architecture, including: high-voltage, medium-high-voltage, medium-voltage, and low-voltage DC busbars, as well as high-voltage DC circuit breakers, medium-high-voltage DC circuit breakers, medium-voltage DC circuit breakers, and low-voltage DC circuit breakers are respectively formed by high-voltage bidirectional DC transformers through high-voltage, medium-high-voltage, medium-voltage, and low-voltage DC ports, and high-voltage, medium-voltage, and low-voltage AC ports are formed by high-voltage bidirectional DC transformers through flexible DC converters and high-voltage AC busbars, and in combination with high-voltage, medium-voltage, and low-voltage AC circuit breakers. The present invention can cover multiple levels of DC voltages of different sequences of high, medium, and low and all levels of AC voltages, forming a power interactive hub that can realize the collection and access of new energy of different scales and the power supply of multiple types of AC and DC loads at multiple points, providing a system architecture solution for the collection, transmission, and consumption of new energy.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current substation and flexible direct current power transmission, and in particular to a three-dimensional multi-port direct current hub substation system architecture. Background Art

[0002] With the exhaustion of traditional fossil energy and the increasing prominence of environmental problems, the development and utilization of new energy has become the best choice for sustainable development. Due to the inverse distribution of new energy resources and load centers, new energy power generation has the problems of randomness and intermittency, which determines the necessity of large-capacity long-distance DC transmission.

[0003] There are three main technical routes for the existing research on the system architecture of new energy collection, transmission and consumption:

[0004] Technical route 1: Use multiple high-voltage and high-power dual-port DC / DC converters to achieve energy aggregation and access at the sending end, or multi-level DC voltage conversion at the receiving end, or interconnection between different DC transmission systems; however, multiple DC / DC converters bring about problems such as high maintenance costs, large losses, and poor economic efficiency. The interconnection of DC lines based on multiple DC / DCs has the problem that the power flow cannot be centrally controlled.

[0005] Technical route 2: Using a multi-converter cascade form can realize multi-level aggregation at the sending end or multi-point power supply at the receiving end, such as cascading LCC and MMC and connecting them to different power grids in layers (Baihetan-Jiangsu UHV hybrid DC transmission project); however, the coupling relationship between the ports is serious, and this solution can only collect new energy or multi-point power supply at the sending end and the receiving end. The access port capacity is relatively fixed and the system scalability is poor.

[0006] Technical route three: Adopting a multi-terminal flexible direct current transmission (VSC-MTDC) system, it has the advantages of conventional direct current transmission systems such as long-distance power transmission, power flow reversal and unchanged voltage polarity, and can realize multi-power supply and multi-point power receiving; however, the current research on MTDC interconnection is all at the same voltage level.

[0007] The above three technical routes cannot solve the problem that the new energy transmission project is limited to the point-to-point transmission mode of a single sending / receiving end. The sending end does not fully consider the access capacity and interaction of multiple types of new energy. The single receiving end also has problems with the scale of multiple types of loads, characteristic matching and other problems of new energy consumption in the vicinity.

[0008] It can be seen that the current renewable energy transmission projects are limited to a point-to-point transmission mode with a single sending / receiving end. The sending end does not fully consider the access capacity and interaction of various types of renewable energy. The single receiving end also has problems with the scale of multiple types of loads, characteristics matching, and other problems of nearby renewable energy consumption. Summary of the invention

[0009] In order to solve the problem that the current new energy transmission project is limited to a point-to-point transmission mode of a single transmission / receiving end, the transmission end does not fully consider the access capacity and interaction of multiple types of new energy, and the single receiving end also has multiple types of load scales, characteristic matching and other problems of near-area new energy consumption, the present invention provides a three-dimensional multi-port DC hub substation system architecture, including: a high-voltage bidirectional DC transformer, a medium-voltage bidirectional DC transformer, a high-voltage DC bus, a medium-high voltage DC bus, a medium-voltage DC bus, a low-voltage bidirectional DC transformer, a low-voltage DC bus, a high-voltage DC circuit breaker, a medium-high voltage DC circuit breaker, a medium-voltage DC circuit breaker, a low-voltage DC circuit breaker, a high-voltage DC circuit breaker, a medium-high voltage DC circuit breaker, a medium-voltage DC circuit breaker, a low-voltage DC circuit breaker, a flexible DC converter, a high-voltage AC bus, an AC transformer, a high-voltage AC circuit breaker, a medium-voltage AC circuit breaker and a low-voltage AC circuit breaker;

[0010] The high-voltage bidirectional DC transformer is connected to the high-voltage DC bus and the high-voltage DC circuit breaker in sequence to form a high-voltage DC port; the high-voltage DC port is connected to the high-voltage DC system;

[0011] The high-voltage bidirectional DC transformer is connected to the medium-high voltage DC busbar and the medium-high voltage DC circuit breaker in sequence to form a medium-high voltage DC port; the medium-high voltage DC port is connected to the medium-high voltage DC system;

[0012] The high-voltage bidirectional DC transformer is connected to the medium-voltage and high-voltage DC busbar, the medium-voltage bidirectional DC transformer, the medium-voltage DC busbar, and the medium-voltage DC circuit breaker in sequence to form a medium-voltage DC port; the medium-voltage DC port is connected to the medium-voltage DC system;

[0013] The high-voltage bidirectional DC transformer is connected to the medium- and high-voltage DC bus, the low-voltage bidirectional DC transformer, the low-voltage DC bus, and the low-voltage DC circuit breaker in sequence to form a low-voltage DC port; the low-voltage DC port is connected to the low-voltage DC system;

[0014] The high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the flexible DC converter, the high-voltage AC bus, and the high-voltage AC circuit breaker to form a high-voltage AC port; the high-voltage bidirectional DC transformer is sequentially connected to the high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the medium-voltage AC circuit breaker to form a medium-voltage AC port;

[0015] The high-voltage bidirectional DC transformer is connected to the high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the low-voltage AC circuit breaker in sequence to form a low-voltage AC port;

[0016] The high-voltage AC port, the medium-voltage AC port, and the low-voltage AC port are all connected to AC power grids of different voltage levels.

[0017] Preferably, the number of the high-voltage DC ports, medium-high-voltage DC ports, medium-voltage DC ports, low-voltage DC ports and AC ports is determined according to demand.

[0018] Preferably, the high-voltage DC port, medium-high-voltage DC port, medium-voltage DC port, low-voltage DC port, high-voltage AC port, medium-voltage AC port and low-voltage AC port all have bidirectional power flow capabilities.

[0019] Preferably, the voltage range of the high-voltage DC port includes: no higher than ±1100kV voltage level and no lower than ±200kV voltage level;

[0020] The voltage range of the medium and high voltage DC port is: not higher than ±200kV voltage level and not lower than ±50kV voltage level;

[0021] The voltage range of the medium voltage DC port covers a voltage level of not higher than ±50kV and not lower than ±1kV;

[0022] The low voltage DC port range covers a voltage level of no higher than ±1kV.

[0023] Preferably, the high voltage direct current system comprises: a large-scale wind farm or photovoltaic station or a large-capacity direct current load.

[0024] Preferably, the medium voltage DC system comprises: a medium voltage DC distribution network.

[0025] Preferably, the low-voltage DC system includes: a low-voltage DC distribution network, a DC microgrid or a distributed DC power supply.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention provides a multi-port DC hub substation system architecture, including: a high-voltage bidirectional DC transformer, a medium-voltage bidirectional DC transformer, a high-voltage DC bus, a medium-high voltage DC bus, a medium-voltage DC bus, a low-voltage bidirectional DC transformer, a low-voltage DC bus, a high-voltage DC circuit breaker, a medium-high voltage DC circuit breaker, a medium-high voltage DC circuit breaker, a low-voltage DC circuit breaker, a flexible DC converter, a high-voltage AC bus, an AC transformer, a high-voltage AC circuit breaker, a medium-voltage AC circuit breaker and a low-voltage AC circuit breaker; the high-voltage bidirectional DC transformer is sequentially connected to the high-voltage DC bus and the high-voltage DC circuit breaker to form a high-voltage DC port; the high-voltage DC port is connected to a high-voltage DC system; the high-voltage bidirectional DC transformer is sequentially connected to the medium-high voltage DC bus and the medium-high voltage DC circuit breaker to form a medium-high voltage DC port; the medium-high voltage DC port is connected to a medium-high voltage DC system; the high-voltage bidirectional DC transformer is sequentially connected to the medium-high voltage DC bus, the medium-voltage bidirectional DC transformer, the medium-voltage DC bus, The medium-voltage DC circuit breaker is connected to form a medium-voltage DC port; the medium-voltage DC port is connected to the medium-voltage DC system; the high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the low-voltage bidirectional DC transformer, the low-voltage DC bus, and the low-voltage DC circuit breaker to form a low-voltage DC port; the low-voltage DC port is connected to the low-voltage DC system; the high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the flexible DC converter, the high-voltage AC bus, and the high-voltage AC circuit breaker to form a high-voltage AC port; the high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the medium-voltage AC circuit breaker to form a medium-voltage AC port; the high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the low-voltage AC circuit breaker to form a low-voltage AC port; the high-voltage AC port, the medium- and low-voltage AC port, and the low-voltage AC port are all connected to AC power grids of different voltage levels. The present invention provides multiple levels of DC voltage in different sequences of high, medium and low and all levels of AC voltage, forming a power interaction hub that can realize the collection and access of new energy sources of different scales and power supply of multiple types of AC and DC loads at multiple points, providing a system architecture solution for the collection, transmission and consumption of new energy.

[0028] 2. The high-voltage DC port, medium-high-voltage DC port, low-voltage DC port and AC port provided by the present invention have the ability of bidirectional power flow, and fully consider the access capacity and interaction of various types of new energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a three-dimensional multi-port DC hub substation system provided by the present invention;

[0030] Figure 2 A schematic diagram of the internal structure of a three-dimensional multi-port DC hub substation provided by the present invention;

[0031] Figure 3 A schematic diagram of a typical application case of a three-dimensional multi-port DC hub substation provided by the present invention;

[0032] Figure 4 A schematic diagram of a sending-end scenario of a three-dimensional multi-port DC hub substation provided by the present invention;

[0033] Figure 5 A schematic diagram of a receiving-end scenario of a three-dimensional multi-port DC hub substation provided by the present invention;

[0034] Figure 6 A schematic diagram of a scenario of new energy collection along a three-dimensional multi-port DC hub substation provided by the present invention;

[0035] Figure 7 A schematic diagram of a load power supply scenario along the way of a three-dimensional multi-port DC hub substation provided by the present invention. DETAILED DESCRIPTION

[0036] The present invention is to realize the collection and access of multiple types of new energy sources at the sending end of the DC transmission system, the power supply of multiple points at the receiving end, the collection of new energy sources or load power supply along the transmission line, and the interconnection of DC lines / networks of different voltage levels and types, and designs a "three-dimensional" multi-port DC hub substation. Its "three-dimensional" is mainly reflected in the fact that the hub substation can provide AC and DC access ports of multiple voltage levels, which can cover multiple levels of DC voltages of high, medium and low sequences such as ±800kV, ±500kV, ±200kV, ±100kV, ±35kV, ±10kV, ±750V, and all levels of AC voltage, forming a power interactive hub that can realize the collection and access of new energy sources of different scales and the power supply of AC and DC loads at multiple points and types, and provide a system architecture solution for the collection, transmission and consumption of new energy.

[0037] Embodiment 1:

[0038] A three-dimensional multi-port DC hub substation system architecture, such as Figure 1 and Figure 2 As shown, including:

[0039] High-voltage bidirectional DC transformer, medium-voltage bidirectional DC transformer, high-voltage DC bus, medium-high-voltage DC bus, medium-voltage DC bus, low-voltage bidirectional DC transformer, low-voltage DC bus, high-voltage DC circuit breaker, medium-high-voltage DC circuit breaker, medium-voltage DC circuit breaker, low-voltage DC circuit breaker, flexible DC converter, high-voltage AC bus, AC transformer, high-voltage AC circuit breaker, medium-voltage AC circuit breaker and low-voltage AC circuit breaker;

[0040] The high-voltage bidirectional DC transformer is connected to the high-voltage DC bus and the high-voltage DC circuit breaker in sequence to form a high-voltage DC port; the high-voltage DC port is connected to the high-voltage DC system;

[0041] The high-voltage bidirectional DC transformer is connected to the medium-high voltage DC busbar and the medium-high voltage DC circuit breaker in sequence to form a medium-high voltage DC port; the medium-high voltage DC port is connected to the medium-high voltage DC system;

[0042] The high-voltage bidirectional DC transformer is connected to the medium-voltage and high-voltage DC busbar, the medium-voltage bidirectional DC transformer, the medium-voltage DC busbar, and the medium-voltage DC circuit breaker in sequence to form a medium-voltage DC port; the medium-voltage DC port is connected to the medium-voltage DC system;

[0043] The high-voltage bidirectional DC transformer is connected to the medium- and high-voltage DC bus, the low-voltage bidirectional DC transformer, the low-voltage DC bus, and the low-voltage DC circuit breaker in sequence to form a low-voltage DC port; the low-voltage DC port is connected to the low-voltage DC system;

[0044] The high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the flexible DC converter, the high-voltage AC bus, and the high-voltage AC circuit breaker to form a high-voltage AC port; the high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the medium-voltage AC circuit breaker to form a medium-voltage AC port;

[0045] The high-voltage bidirectional DC transformer is connected to the medium- and high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the low-voltage AC circuit breaker in sequence to form a low-voltage AC port;

[0046] The high-voltage AC port, the medium-voltage AC port, and the low-voltage AC port are all connected to AC power grids of different voltage levels.

[0047] like Figure 2 As shown, there is more than one high voltage DC port, and it can be multiple, such as Figure 2 As shown, high voltage DC port 1 ... high voltage DC port N;

[0048] The high voltage DC port is connected to the high voltage DC system.

[0049] The high-voltage DC port is connected to the high-voltage DC system through a DC transmission line and DC / DC; the high-voltage DC system here includes large-scale wind farms or photovoltaic stations or large-capacity DC loads.

[0050] Further, the number of high-voltage DC ports, medium-high-voltage DC ports, low-voltage DC ports, and AC ports is determined according to demand. Here, it can include only one or more of the following ports: high-voltage DC ports, medium-high-voltage DC ports, low-voltage DC ports, and AC ports. It can also be the following high-voltage DC ports, medium-high-voltage DC ports, low-voltage DC ports, and AC ports, and each type of port data is one or more. It can be adjusted according to actual needs.

[0051] Furthermore, the low voltage DC port is connected to a distributed power source or a small microgrid system of 1 kV or below.

[0052] The voltage range of the high-voltage DC port includes: no higher than ±1100kV voltage level and no lower than ±200kV voltage level, which can be ±800kV voltage level or ±500kV voltage level; the voltage of the high-voltage DC port covers voltage levels such as ±800kV and ±500kV, which can be used for GW-level large-scale collection of new energy, or transmission to remote load centers via DC transmission lines, or receiving power transmitted by remote DC lines at the sending end.

[0053] The voltage range of the medium and high voltage DC port covers: no higher than ±200kV voltage level, no lower than ±50kV voltage level; it can be one or more of the following: ±200kV voltage level, ±100kV voltage level, ±35kV voltage level, ±10kV voltage level. The voltage of the medium and high voltage DC port covers voltage levels such as ±200kV, ±100kV, ±35kV, and ±10kV, and can be connected to hundreds of MW-level new energy sources nearby, connected to DC distribution systems, etc.

[0054] The voltage range of the medium voltage DC port covers: not higher than ±50kV voltage level and not lower than ±1kV voltage level.

[0055] The low voltage DC port covers a voltage level not higher than ±1kV. The technical solution provided by the present invention covers multiple access ports of DC voltages of different levels of high, medium and low and all levels of AC voltages.

[0056] The AC port includes a high-voltage AC port, a medium-voltage AC port and a low-voltage AC port, which can be connected to AC power grids of different voltage levels.

[0057] The high-voltage DC port, medium-high-voltage DC port, low-voltage DC port and AC port have the ability to transmit power in both directions, and the systems connected to each port can achieve power complementarity and mutual assistance.

[0058] DC lines of different voltage levels and types can be interconnected to form a DC power grid.

[0059] The present invention will be further described below:

[0060] like Figure 2 As shown, the "three-dimensional" port DC hub substation is mainly composed of high-voltage large-capacity bidirectional DC transformer (DC / DC), flexible DC converter (AC / DC), medium / high voltage DC circuit breaker, AC transformer and other equipment. The bidirectional DC transformer B in the figure represents the medium-voltage bidirectional DC transformer, and the bidirectional DC transformer C represents the low-voltage bidirectional DC transformer. Among them:

[0061] (1) As the core equipment of hub substations, high-voltage and large-capacity bidirectional direct current transformers (DC / DC) are responsible for converting different levels of DC voltages to achieve multi-level conversion access / output of DC voltages;

[0062] (2) Flexible DC converter (AC / DC) is mainly used for power exchange between AC / DC power grids. Its DC end is connected to the corresponding DC bus in the substation, and its AC end is equipped with AC transformers of different conversion levels to achieve different AC voltage levels output in the DC hub substation.

[0063] (3) The DC circuit breaker can achieve rapid fault isolation between the DC substation and the connected DC system to avoid affecting other ports of the substation. The DC circuit breaker can be optimized and configured according to the specific topological characteristics and port requirements. For ease of understanding, the DC circuit breaker is drawn as shown in the dotted box in this diagram, which can be deleted accordingly according to specific needs.

[0064] A schematic diagram of the overall scenario of a typical application case of a multi-port DC hub substation is shown in Figure 3 As shown, based on a multi-port DC hub substation, the present invention designs three different construction schemes:

[0065] (1) Position 1 is the new energy collection access side at the sending end. Figure 4 As shown, it can realize the collection and access of multiple renewable energy sources and local multi-point power supply, while improving the remote and near-region consumption capacity of renewable energy;

[0066] (2) Position 2 is the DC bus side of the receiving end of the DC transmission system. Figure 5 As shown, while realizing multi-point power supply, it can effectively connect local renewable energy sources of different scales with AC and DC loads, forming power interaction between multiple ports and multiple voltage levels;

[0067] (3) Position 3 is the busbar along the DC transmission line, which can be divided into the new energy collection along the way according to the specific access point requirements. Figure 6 The power supply of the load along the way is Figure 7 Two major application scenarios.

[0068] The present invention designs a "three-dimensional" multi-port DC hub substation solution, forming a power interactive hub that can realize the collection and access of new energy of different scales and the power supply of multiple types of AC and DC loads, providing a system architecture solution for the collection, transmission and consumption of new energy. Based on the designed "three-dimensional" multi-port DC hub substation solution, the present invention provides three hub substation construction plans:

[0069] The sending-end construction plan can realize the collection and access of multiple renewable energy sources and local multi-point power supply, while improving the remote and near-region renewable energy consumption capacity;

[0070] The receiving-end construction solution can effectively connect different scales of new energy and AC and DC loads in the local area while realizing multi-point power supply, forming power interaction between multiple ports and multiple voltage levels;

[0071] The construction plan along the transmission line can realize the collection and access of new energy sources along the way and the power supply of loads along the way.

[0072] The following is a further introduction to each construction plan with reference to the attached drawings:

[0073] like Figure 4 As shown, an embodiment of the present invention provides a schematic diagram of a sending-end scenario of a multi-port DC hub substation. Figure 3 Construction Plan 1: A "three-dimensional" multi-port DC hub substation is designed on the sending side to achieve effective access to multiple renewable energy sources. Figure 4 As shown, the wind farm and photovoltaic power station are connected to the high-voltage DC port of the hub substation via DC cables. The local AC power grid is connected to the hub substation through the high-voltage AC port to realize the local consumption of new energy. Excess new energy can also be transmitted to the load center area via DC transmission lines, thereby realizing multi-point consumption of new energy.

[0074] like Figure 5 As shown, an embodiment of the present invention provides a schematic diagram of a "three-dimensional" multi-port DC hub substation receiving end scenario. Figure 3 Construction Plan 2 builds a "three-dimensional" multi-port DC hub substation on the receiving side. The DC high-voltage port of the hub substation can be connected to DC transmission lines of different types and voltage levels to achieve DC line interconnection. The DC medium- and high-voltage ports can be connected to the local new energy collection system, the DC medium-voltage port can be connected to the DC distribution network, the DC low-voltage port can be connected to small DC microgrids, electric vehicles and distributed power sources, and the AC port can be connected to AC power grids of different voltage levels. Based on the bidirectional flow of power between ports, energy complementarity and mutual assistance between AC power grids can be achieved.

[0075] like Figure 6 As shown, the embodiment of the present invention provides a schematic diagram of a scenario where new energy is collected along the way of a multi-port DC hub substation. Figure 3 Construction Plan 3 designs a "three-dimensional" multi-port DC hub substation along the transmission route. The hub substation can realize the access of new energy sources with different voltage levels along the route.

[0076] like Figure 7 As shown, the embodiment of the present invention provides a schematic diagram of a "three-dimensional" multi-port DC hub substation load power supply scenario along the way, for Figure 3 Construction Plan 3 designs a "three-dimensional" multi-port DC hub substation along the transmission route. The AC port of the hub substation can realize multi-point power supply along the transmission line, and the DC port can be connected to the local DC power grid.

[0077] The present invention proposes a "three-dimensional" multi-port DC hub substation solution to achieve the collection and access of multiple types of new energy sources at the sending end of the DC transmission system, multi-point power supply at the receiving end, and new energy collection or load power supply along the transmission line, while realizing the interconnection of DC lines / networks of different voltage levels and types.

[0078] A "three-dimensional" multi-port DC hub substation can provide AC and DC access ports of multiple voltage levels, covering multiple levels of DC voltages in high, medium and low sequences such as ±800kV, ±500kV, ±200kV, ±100kV, ±35kV, ±10kV, ±750V, and all levels of AC voltage, forming a power interactive hub that can realize the collection and access of new energy sources of different scales and power supply of multiple types of AC and DC loads at multiple points.

[0079] Each AC and DC port of a "three-dimensional" multi-port DC hub substation output has the ability to flow power in both directions, which can achieve power complementarity and mutual assistance between port connection systems.

[0080] A "three-dimensional" multi-port DC hub substation, in which each port outlet is equipped with an AC / DC circuit breaker, can achieve rapid physical isolation, reduce fault coupling between connected systems, and improve the system's power supply reliability and fault response capabilities.

[0081] A "three-dimensional" multi-port DC hub substation can interconnect DC lines of different voltage levels and types, thereby forming a DC power grid.

[0082] The present invention provides a "three-dimensional" multi-port DC hub substation, which designs three construction schemes, namely, the sending end construction scheme, the receiving end construction scheme and the transmission line construction scheme. Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown in the figure, the construction plan along the transmission line can be divided into two application scenarios: new energy collection and power supply for loads along the way according to the specific access point requirements.

[0083] A "three-dimensional" multi-port DC hub substation sending-end construction plan can realize the collection and access of multiple renewable energy sources and local multi-point power supply, while improving the remote and near-region absorption capacity of renewable energy.

[0084] A "three-dimensional" multi-port DC hub substation receiving end construction plan can effectively connect new energy sources of different scales and AC and DC loads in the local area while realizing multi-point power supply, forming power interaction between multi-port and multi-voltage levels.

[0085] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A three-dimensional multi-port DC hub substation system architecture, characterized in that: include: High-voltage bidirectional DC transformer, medium-voltage bidirectional DC transformer, high-voltage DC bus, medium-high-voltage DC bus, medium-voltage DC bus, low-voltage bidirectional DC transformer, low-voltage DC bus, high-voltage DC circuit breaker, medium-high-voltage DC circuit breaker, medium-voltage DC circuit breaker, low-voltage DC circuit breaker, flexible DC converter, high-voltage AC bus, AC transformer, high-voltage AC circuit breaker, medium-voltage AC circuit breaker and low-voltage AC circuit breaker; The high-voltage bidirectional DC transformer is connected to the high-voltage DC bus and the high-voltage DC circuit breaker in sequence to form a high-voltage DC port; the high-voltage DC port is connected to the high-voltage DC system; The high-voltage bidirectional DC transformer is connected to the medium-high voltage DC busbar and the medium-high voltage DC circuit breaker in sequence to form a medium-high voltage DC port; the medium-high voltage DC port is connected to the medium-high voltage DC system; The high-voltage bidirectional DC transformer is connected to the medium-voltage and high-voltage DC busbar, the medium-voltage bidirectional DC transformer, the medium-voltage DC busbar, and the medium-voltage DC circuit breaker in sequence to form a medium-voltage DC port; the medium-voltage DC port is connected to the medium-voltage DC system; The high-voltage bidirectional DC transformer is connected to the medium- and high-voltage DC bus, the low-voltage bidirectional DC transformer, the low-voltage DC bus, and the low-voltage DC circuit breaker in sequence to form a low-voltage DC port; the low-voltage DC port is connected to the low-voltage DC system; The high-voltage bidirectional DC transformer is sequentially connected to the medium- and high-voltage DC bus, the flexible DC converter, the high-voltage AC bus, and the high-voltage AC circuit breaker to form a high-voltage AC port; the high-voltage bidirectional DC transformer is sequentially connected to the high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the medium-voltage AC circuit breaker to form a medium-voltage AC port; The high-voltage bidirectional DC transformer is connected to the high-voltage DC bus, the flexible converter, the high-voltage AC bus, the AC transformer, and the low-voltage AC circuit breaker in sequence to form a low-voltage AC port; The high-voltage AC port, the medium-voltage AC port, and the low-voltage AC port are all connected to AC power grids of different voltage levels.

2. The system architecture according to claim 1, characterized in that: The number of the high-voltage DC ports, medium-high-voltage DC ports, medium-voltage DC ports, low-voltage DC ports and AC ports is determined according to demand.

3. The system architecture according to claim 1, characterized in that: The high-voltage DC port, medium-high-voltage DC port, medium-voltage DC port, low-voltage DC port, high-voltage AC port, medium-voltage AC port and low-voltage AC port all have the capability of bidirectional power flow.

4. The system architecture according to claim 1, characterized in that: The voltage range of the high-voltage DC port includes: no higher than ±1100kV voltage level and no lower than ±200kV voltage level; The voltage range of the medium and high voltage DC port is: not higher than ±200kV voltage level and not lower than ±50kV voltage level; The voltage range of the medium voltage DC port covers a voltage level of not higher than ±50kV and not lower than ±1kV; The low voltage DC port range covers a voltage level of no higher than ±1kV.

5. The system architecture according to claim 1, characterized in that: The high-voltage direct current system includes: a large-scale wind farm or photovoltaic station or a large-capacity direct current load.

6. The system architecture according to claim 1, characterized in that: The medium voltage DC system comprises: a medium voltage DC distribution network.

7. The system architecture according to claim 1, characterized in that: The low voltage DC system includes: a low voltage DC distribution network, a DC microgrid or a distributed DC power supply.

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