AC / DC Hybrid Flexible Power Supply System and Control Method for Cross-Strait Railway

Abstract

The present invention discloses an AC / DC hybrid flexible power supply system and a control method for a cross-strait railway. The system includes a first three-phase power system, a first central substation, a second three-phase power system, a second central substation, an offshore wind power system, and a cross-strait railway tunnel power supply system. The present invention can achieve coordinated control among the three-phase power grid, the central substation, the offshore wind power system, the energy storage device, the train, and the loads along the traction network, ensure the safe and stable power supply for the cross-strait railway and the loads along the line, and make full use of the system energy.

Description

Technical Field

[0001] The present invention relates to the technical field of AC-DC hybrid flexible power supply, and particularly relates to an AC-DC hybrid flexible power supply system and a control method for a cross-strait railway. Background Art

[0002] Facing the major engineering requirements of cross-strait railways, the existing railway traction power supply system cannot ensure the stable and safe power supply of long-distance cross-sea tunnels, making it difficult to achieve the full-course coherent operation of trains in the "land-strait-land" section. Moreover, it is very difficult to build traction substations that can access external power in undersea tunnels.

[0003] Currently, in railway tunnels, relatively simple and small-footprint sectionalizing substations, autotransformer substations, etc. are mainly installed inside the railway tunnels, and traction substations are installed outside the tunnels to achieve power supply for relatively long tunnels. However, it is difficult to make the phase, amplitude, and frequency between the two power supply arms output after the traction transformer steps down completely consistent, and sectionalized power supply is required. Moreover, the traction load is a single-phase load, which will generate negative sequence current when reflected to the three-phase power grid, causing three-phase voltage imbalance. At the same time, there are also problems such as reactive power and harmonics.

[0004] For long-distance cross-strait railways, if the power supply systems on both sides of the strait have inconsistent power supply systems, the required traction power supply system not only needs to ensure coherent power supply throughout the line and have good power quality, but also needs to consider the compatibility of power systems. In addition, there are generally rich wind power resources in the strait. Whether the offshore wind power resources can be fully utilized has also become an important consideration factor. Since the existing traction power supply system cannot achieve through-power supply due to electrical phase separation, there are certain power quality problems in the system, and it cannot be compatible with the power systems at both ends. Moreover, its structure determines that it is difficult to access new energy sources such as wind power. Therefore, there is an urgent need to design a power supply system for cross-strait railways and coordinate the control of the system energy. Summary of the Invention

[0005] Aiming at the above deficiencies in the prior art, the present invention provides an AC-DC hybrid flexible power supply system and a control method for a cross-strait railway to achieve coherent power supply of trains in the "land-strait-land" section, ensure good power quality of the cross-strait railway traction power supply system and have compatibility with different power systems; coordinate the control of the cross-strait railway traction power supply system to achieve full utilization of the offshore wind power in the strait and the system energy.

[0006] To achieve the above invention purpose, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention proposes an AC-DC hybrid flexible power supply system for a cross-strait railway, including:

[0008] The first three-phase power system is installed on the land on one side of the strait and is used to supply electric energy to the first central station connected thereto, or receive the electric energy returned by the first central station connected thereto;

[0009] The first central station is installed on the land on one side of the strait and is used to collect electric energy from the first three-phase power system, regulate the output voltage of the collected electric energy, and then output it to the traction network and DC bus connected thereto respectively to supply electric energy to the cross-strait railway electrical equipment and / or the cross-strait railway tunnel power supply system; or receive the electric energy returned by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and regulate the output voltage of the received electric energy and then return it to the first three-phase power system;

[0010] The second three-phase power system is installed on the land on the other side of the strait and is used to supply electric energy to the second central station connected thereto, or receive the electric energy returned by the second central station connected thereto;

[0011] The second central station is installed on the land on the other side of the strait and is used to collect electric energy from the second three-phase power system, regulate the output voltage of the collected electric energy, and then output it to the traction network and DC bus connected thereto respectively to supply electric energy to the cross-strait railway electrical equipment and / or the cross-strait railway tunnel power supply system; or receive the electric energy returned by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and regulate the output voltage of the received electric energy and then return it to the second three-phase power system;

[0012] The offshore wind power system is installed on the strait and is used to generate electric energy and output the generated electric energy to the DC bus connected thereto to supply electric energy to the cross-strait railway electrical equipment and / or the cross-strait railway tunnel power supply system;

[0013] The cross-strait railway tunnel power supply system is installed on the strait and is used to receive the electric energy transmitted by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and store the received electric energy; or output the stored electric energy to the traction network and DC bus connected thereto to supply electric energy to the cross-strait railway electrical equipment.

[0014] Furthermore, the cross-strait railway tunnel power supply system specifically includes:

[0015] At least one energy storage device is installed in the cross-strait railway tunnel and is used to store the electric energy transmitted by the DC-DC converter connected thereto; or transmit the stored electric energy through the DC-DC converter;

[0016] A direct current converter, which is set to correspond one-to-one with a storage device, is used to collect electric energy from a DC bus connected thereto, and after performing electric energy conversion on the collected electric energy, transmit it to the corresponding energy storage device; or collect electric energy from the corresponding energy storage device, and after performing electric energy conversion on the collected electric energy, transmit it to the DC bus.

[0017] At least one inverter station, which is arranged in a cross-strait railway tunnel, is used to collect electric energy from a DC bus connected thereto, and after performing electric energy conversion on the collected electric energy, transmit it to a traction network connected thereto to provide electric energy for cross-strait railway electrical equipment; or collect electric energy from the traction network, and after performing electric energy conversion on the collected electric energy, transmit it to the DC bus.

[0018] Further, the offshore wind power system specifically includes:

[0019] At least one offshore wind turbine, which is arranged on the strait, is used to generate electric energy and transmit the generated electric energy to a step-up transformer connected thereto;

[0020] The step-up transformer, which is set to correspond one-to-one with the offshore wind turbine, is used to perform step-up conversion on the electric energy transmitted by the corresponding offshore wind turbine and then transmit it to a busbar;

[0021] An offshore converter station, which is arranged on the strait, is used to collect electric energy from the busbar, and after performing electric energy conversion on the collected electric energy, output it to a first onshore converter station and a second onshore converter station respectively through two submarine cables;

[0022] The first onshore converter station, which is arranged on the land on one side of the strait, is used to perform electric energy conversion on the electric energy transmitted by the submarine cable and then transmit it to the DC bus to provide electric energy for cross-strait railway electrical equipment and / or a cross-strait railway tunnel power supply system;

[0023] The second onshore converter station, which is arranged on the land on the other side of the strait, is used to perform electric energy conversion on the electric energy transmitted by the submarine cable and then transmit it to the DC bus to provide electric energy for cross-strait railway electrical equipment and / or a cross-strait railway tunnel power supply system.

[0024] Further, the cross-strait railway electrical equipment specifically includes:

[0025] Cross-strait railway operation trains and / or loads along the cross-strait railway tunnel.

[0026] In a second aspect, the present invention proposes a control method applied to the above AC-DC hybrid flexible power supply system for a cross-strait railway, including the following steps:

[0027] S1. Obtain the operating conditions of the trains running in the cross-strait railway tunnel;

[0028] S2. Obtain the state of charge of the energy storage device in the cross-strait railway tunnel power supply system;

[0029] S3. According to the operating conditions of the running trains and the state of charge of the energy storage device, coordinate the power supply control and energy allocation for the cross-strait railway electrical equipment by using the First Central Office, the Second Central Office, the offshore wind power system, and the cross-strait railway tunnel power supply system.

[0030] Further, the operating conditions of the running trains specifically include:

[0031] Traction condition and regenerative braking condition.

[0032] Further, the state of charge of the energy storage device specifically includes:

[0033] Minimum state of charge, intermediate state of charge, and maximum state of charge.

[0034] Further, step S3 specifically includes:

[0035] When the operating condition of the running train is the traction condition, judge whether the output energy of the offshore wind power system is greater than or equal to the energy required by the cross-strait railway electrical equipment;

[0036] If the output energy of the offshore wind power system is greater than or equal to the energy required by the cross-strait railway electrical equipment, judge whether the energy storage device is in the minimum state of charge or the intermediate state of charge;

[0037] If the energy storage device is in the minimum state of charge or the intermediate state of charge, supply the output energy of the offshore wind power system to the cross-strait railway electrical equipment, and store the remaining energy of the offshore wind power system in the energy storage device;

[0038] If the energy storage device is in the maximum state of charge, supply the output energy of the offshore wind power system to the cross-strait railway electrical equipment, and return the remaining energy of the offshore wind power system to the three-phase power system through the nearest central office;

[0039] If the output energy of the offshore wind power system is less than the energy required by the cross-strait railway electrical equipment, judge whether the energy storage device is in the minimum state of charge;

[0040] If the energy storage device is in the minimum state of charge, supply the output energy of the central office and the offshore wind power system to the cross-strait railway electrical equipment;

[0041] If the energy storage device is in the intermediate state of charge or the maximum state of charge, supply the output energy of the energy storage device and the offshore wind power system to the cross-strait railway electrical equipment.

[0042] Further, step S3 specifically includes:

[0043] When the operating condition of the running train is the regenerative braking condition, it is judged whether the output energy of the train regenerative braking system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel;

[0044] If the output energy of the train regenerative braking system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel, it is judged whether the energy storage device is in the minimum state of charge or the intermediate state of charge;

[0045] If the energy storage device is in the minimum state of charge or the intermediate state of charge, the output energy of the train regenerative braking system is supplied to the loads along the cross-strait railway tunnel, and the remaining energy of the train regenerative braking system and the output energy of the offshore wind power system are stored in the energy storage device;

[0046] If the energy storage device is in the maximum state of charge, the output energy of the train regenerative braking system is supplied to the loads along the traction network, and the remaining energy of the train regenerative braking system and the output energy of the offshore wind power system are sent back to the three-phase power system through the nearest central substation;

[0047] If the output energy of the train regenerative braking system is less than the energy required by the loads along the cross-strait railway tunnel, it is judged whether the sum of the output energy of the train regenerative braking system and the output energy of the offshore wind power system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel;

[0048] If the sum of the output energy of the train regenerative braking system and the output energy of the offshore wind power system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel, it is judged whether the energy storage device is in the minimum state of charge or the intermediate state of charge;

[0049] If the energy storage device is in the minimum state of charge or the intermediate state of charge, the output energy of the train regenerative braking system and the output energy of the offshore wind power system are supplied to the loads along the cross-strait railway tunnel, and the remaining energy of the offshore wind power system is stored in the energy storage device;

[0050] If the energy storage device is in the maximum state of charge, the output energy of the train regenerative braking system and the output energy of the offshore wind power system are supplied to the loads along the cross-strait railway tunnel, and the remaining energy of the offshore wind power system is sent back to the three-phase power system through the nearest central substation;

[0051] If the sum of the output energy of the train regenerative braking system and the output energy of the offshore wind power system is less than the energy required by the loads along the cross-strait railway tunnel, it is judged whether the energy storage device is in the intermediate state of charge or the maximum state of charge;

[0052] If the energy storage device is in the intermediate state of charge or the maximum state of charge, the output energy of the train regenerative braking system, the output energy of the offshore wind power system and the output energy of the energy storage device are supplied to the loads along the cross-strait railway tunnel;

[0053] If the energy storage device is in the minimum state of charge, the output energy of the train regenerative braking system, the output energy of the offshore wind power system, and the output energy of the central station are supplied to the loads along the cross-strait railway tunnel.

[0054] The present invention has the following beneficial effects:

[0055] (1) The present invention can realize the coordinated control among the three-phase power grid, the central station, the offshore wind power system, the energy storage device, the train, and the loads along the traction network, ensure the safe and stable power supply for the cross-strait railway and the loads along the line, and make full use of the system energy.

[0056] (2) For the AC-DC hybrid flexible power supply system proposed by the present invention, the central station uses power electronic devices to make the output voltage controllable, and can realize the traction power supply between different power systems, solving the problem of incompatibility between different power systems.

[0057] (3) For the AC-DC hybrid flexible power supply system proposed by the present invention, the central station uses power electronic devices to realize the controllability of the output voltage, thereby eliminating the electrical phase separation, realizing the continuous power supply of the train in the "land-strait-land" section, and having good power quality; the inverter station in the tunnel can reduce the influence of the traction network voltage drop and ensure that the traction network voltage is at a normal level.

[0058] (4) For the AC-DC hybrid flexible power supply system proposed by the present invention, the offshore wind power new energy and the energy storage device can be connected to the DC bus, making full use of the rich wind power resources in the strait. Description of the Drawings

[0059] Figure 1 It is a schematic structural diagram of an AC-DC hybrid flexible power supply system for a cross-strait railway in Embodiment 1;

[0060] Figure 2 It is a schematic structural diagram of the cross-strait railway tunnel power supply system in Embodiment 1;

[0061] Figure 3 It is a schematic structural diagram of the offshore wind power system in Embodiment 1

[0062] Figure 4 It is a schematic flowchart of the control method in Embodiment 2. Detailed Embodiments

[0063] The following describes the detailed embodiments of the present invention to facilitate those skilled in the art of the present technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the detailed embodiments. For those of ordinary skill in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0064] Example 1

[0065] As Figure 1 shown, the embodiment of the present invention provides a hybrid AC-DC flexible power supply system for a cross-strait railway, including:

[0066] The first three-phase power system, which is arranged on the land on one side of the strait, is used to supply electric energy to the first central station connected thereto, or receive the electric energy returned by the first central station connected thereto;

[0067] The first central station, which is arranged on the land on one side of the strait, is used to collect electric energy from the first three-phase power system, regulate the output voltage of the collected electric energy, and then output it to the traction network and the DC bus connected thereto to supply electric energy to the cross-strait railway electrical equipment and / or the cross-strait railway tunnel power supply system; or receive the electric energy returned by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and regulate the output voltage of the received electric energy and then return it to the first three-phase power system;

[0068] The second three-phase power system, which is arranged on the land on the other side of the strait, is used to supply electric energy to the second central station connected thereto, or receive the electric energy returned by the second central station connected thereto;

[0069] The second central station, which is arranged on the land on the other side of the strait, is used to collect electric energy from the second three-phase power system, regulate the output voltage of the collected electric energy, and then output it to the traction network and the DC bus connected thereto to supply electric energy to the cross-strait railway electrical equipment and / or the cross-strait railway tunnel power supply system; or receive the electric energy returned by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and regulate the output voltage of the received electric energy and then return it to the second three-phase power system;

[0070] The offshore wind power system, which is arranged on the strait, is used to generate electric energy and output the generated electric energy to the DC bus connected thereto to supply electric energy to the cross-strait railway electrical equipment and / or the cross-strait railway tunnel power supply system;

[0071] The cross-strait railway tunnel power supply system, which is arranged on the strait, is used to receive the electric energy transmitted by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and store the received electric energy; or output the stored electric energy to the traction network and the DC bus connected thereto to supply electric energy to the cross-strait railway electrical equipment.

[0072] In this embodiment, after the first three-phase power system A takes power, it is connected to the first central substation M. The first central substation M uses power electronic devices to achieve controllable output voltage. The AC output of the first central substation M is connected to the traction network PA1, and the DC output of the first central substation M is connected to the DC bus PD1. Similarly, after the second three-phase power system B takes power, it is connected to the second central substation T. The AC output of the second central substation T is connected to the traction network PA2, and the DC output of the second central substation M is connected to the DC bus PD2. The traction network and the DC bus supply power to the cross-strait railway tunnel. The outputs of the offshore wind power systems are respectively connected to PW1 and PW2 on the DC bus.

[0073] In an alternative embodiment of the present invention, the cross-strait railway tunnel power supply system specifically includes:

[0074] At least one energy storage device, which is arranged in the cross-strait railway tunnel and is used to store the electric energy transmitted by the DC-DC converter connected to it; or transmit the stored electric energy through the DC-DC converter.

[0075] DC-DC converters, which are set to correspond one-to-one with the storage devices, and are used to collect electric energy from the DC bus connected to them, and after converting the collected electric energy, transmit it to the corresponding energy storage device; or collect electric energy from the corresponding energy storage device, and after converting the collected electric energy, transmit it to the DC bus.

[0076] At least one inverter station, which is arranged in the cross-strait railway tunnel and is used to collect electric energy from the DC bus connected to it, and after converting the collected electric energy, transmit it to the traction network connected to it to provide electric energy for the cross-strait railway electrical equipment; or collect electric energy from the traction network, and after converting the collected electric energy, transmit it to the DC bus.

[0077] In this embodiment, as Figure 2 shown, after the first inverter station N1 in the cross-strait railway tunnel takes power from the DC bus PN1, it is connected to the traction network at point Pn1, and so on. After the nth inverter station Nn in the cross-strait railway tunnel takes power from the DC bus PNn, it is connected to the traction network at point Pnn. After the first energy storage device E1 in the cross-strait railway tunnel undergoes power conversion through the DC-DC converter ZE1, its output is connected to the DC bus PE1, and so on. After the mth energy storage device Em in the cross-strait railway tunnel undergoes power conversion through the DC-DC converter ZEm, its output is connected to the DC bus PEm. The in-line load L1 in the tunnel is connected to the traction network PL1, and so on. The in-line load Lp is connected to the traction network PLp. After the traction network draws current, it supplies power to the cross-strait railway electrical equipment. The cross-strait railway electrical equipment includes cross-strait railway operation trains and / or in-line loads along the cross-strait railway tunnel, thereby ensuring the normal operation of locomotives and in-line loads.

[0078] In an alternative embodiment of the present invention, the offshore wind power system specifically includes:

[0079] At least one offshore wind turbine, which is arranged on the strait and is used to generate electric energy and transmit the generated electric energy to a step-up transformer connected thereto;

[0080] A step-up transformer, which is arranged in one-to-one correspondence with the offshore wind turbine and is used to step up and transform the electric energy transmitted by the corresponding offshore wind turbine and then transmit it to the busbar;

[0081] An offshore converter station, which is arranged on the strait and is used to collect electric energy from the busbar, and after performing electric energy conversion on the collected electric energy, output it to a first onshore converter station and a second onshore converter station respectively through two submarine cables;

[0082] A first onshore converter station, which is arranged on the land on one side of the strait and is used to perform electric energy conversion on the electric energy transmitted by the submarine cable and then transmit it to the DC busbar to supply electric energy to the power-consuming equipment of the cross-strait railway and / or the power supply system of the cross-strait railway tunnel;

[0083] A second onshore converter station, which is arranged on the land on the other side of the strait and is used to perform electric energy conversion on the electric energy transmitted by the submarine cable and then transmit it to the DC busbar to supply electric energy to the power-consuming equipment of the cross-strait railway and / or the power supply system of the cross-strait railway tunnel.

[0084] In this embodiment, as Figure 3 shown, the electric energy output by the offshore wind turbine W1 is connected to the busbar through the step-up transformer T1, and so on, the electric energy output by the offshore wind turbine Wo is connected to the busbar through the step-up transformer To; after taking power from the busbar, the offshore converter station CS performs electric energy conversion on it and outputs it in two paths of electric energy. One is to be transmitted to the first onshore converter station CM through the submarine cable LM, and the output of the first onshore converter station CM is connected to the DC busbar at the PW1 point. The other is to be transmitted to the second onshore converter station CT through the submarine cable LT, and the output of the second onshore converter station CT is connected to the DC busbar at the PW2 point.

[0085] Embodiment 2

[0086] As Figure 4 shown, on the basis of a AC-DC hybrid flexible power supply system for a cross-strait railway described in Embodiment 1 of the present invention, an embodiment of the present invention provides a control method applied to the system, including the following steps S1 to S3:

[0087] S1. Obtain the operating conditions of the trains running in the cross-strait railway tunnel;

[0088] S2. Obtain the state of charge of the energy storage device in the cross-strait railway tunnel power supply system;

[0089] S3. According to the operating conditions of the running trains and the state of charge of the energy storage device, coordinate the power supply control and energy allocation for the cross-strait railway electrical equipment by using the first central substation, the second central substation, the offshore wind power system, and the cross-strait railway tunnel power supply system.

[0090] In an alternative embodiment of the present invention, the operating conditions of the running trains specifically include the traction condition and the regenerative braking condition.

[0091] Among them, if the locomotive is in the traction condition, the central substations at both ends of the tunnel, the offshore wind power system, and the energy storage device in the tunnel will coordinate the power supply, and the electric locomotive and the loads along the traction network will draw power from the traction network.

[0092] If the locomotive is in the regenerative braking condition, the central substations at both ends of the tunnel, the offshore wind power system, the energy storage device in the tunnel, and the regenerative braking energy of the train will coordinate the power supply, and the loads along the traction network will draw power from the traction network.

[0093] In an alternative embodiment of the present invention, the state of charge of the energy storage device specifically includes the minimum state of charge, the intermediate state of charge, and the maximum state of charge. In this embodiment, the coordinated control of energy is achieved according to the three states of charge of the energy storage device.

[0094] In an alternative embodiment of the present invention, step S3 specifically includes:

[0095] When the operating condition of the running train is the traction condition, determine whether the output energy of the offshore wind power system is greater than or equal to the energy required by the cross-strait railway electrical equipment;

[0096] If the output energy of the offshore wind power system is greater than or equal to the energy required by the cross-strait railway electrical equipment, determine whether the energy storage device is in the minimum state of charge or the intermediate state of charge;

[0097] If the energy storage device is in the minimum state of charge or the intermediate state of charge, supply the output energy of the offshore wind power system to the cross-strait railway electrical equipment, and store the remaining energy of the offshore wind power system in the energy storage device;

[0098] If the energy storage device is in the maximum state of charge, supply the output energy of the offshore wind power system to the cross-strait railway electrical equipment, and return the remaining energy of the offshore wind power system to the three-phase power system through the nearest central substation;

[0099] If the output energy of the offshore wind power system is less than the energy required by the cross-strait railway electrical equipment, determine whether the energy storage device is in the minimum state of charge;

[0100] If the energy storage device is in the minimum state of charge, supply the output energy of the central substation and the offshore wind power system to the cross-strait railway electrical equipment;

[0101] If the energy storage device is in the intermediate state of charge or the maximum state of charge, the output energy of the energy storage device and the offshore wind power system is supplied to the electrical equipment of the cross-strait railway.

[0102] Specifically, when the locomotive is in the traction working condition, the locomotive and the loads along the traction network are electrical loads.

[0103] If the output energy EW of the offshore wind power system is greater than or equal to the energy ET and EL required by the locomotive and the loads along the traction network, that is, EW≥ET + EL, and the energy storage device is in the minimum state of charge SOCL or the intermediate state of charge SOCM, the AC-DC hybrid flexible power supply system is in the first working state, specifically: the output energy of the offshore wind power system supplies the locomotive and the loads along the traction network, and the excess energy is stored in the energy storage device; if the output energy EW of the offshore wind power system is greater than or equal to the energy ET and EL required by the locomotive and the loads along the traction network, that is, EW≥ET + EL, and the energy storage device is in the maximum state of charge SOCH, the AC-DC hybrid flexible power supply system is in the second working state, specifically: the output energy of the offshore wind power system supplies the locomotive and the loads along the traction network, and the remaining energy is sent back to the three-phase power grid through the nearest central substation.

[0104] If the output energy EW of the offshore wind power system is less than the energy ET and EL required by the locomotive and the loads along the traction network, that is, EW<ET + EL and the energy storage device is in the minimum state of charge SOCL, the AC-DC hybrid flexible power supply system is in the third working state, specifically: the central substation and the offshore wind power system output energy to supply the locomotive and the loads along the traction network; if the output energy EW of the offshore wind power system is less than the energy ET and EL required by the locomotive and the loads along the traction network, that is, EW<ET + EL and the energy storage device is in the intermediate state of charge SOCM or the maximum state of charge SOCH, the AC-DC hybrid flexible power supply system is in the fourth working state, specifically: the energy storage device in the tunnel and the offshore wind power system output energy to supply the locomotive and the loads along the traction network.

[0105] In an alternative embodiment of the present invention, step S3 specifically includes:

[0106] When the operating condition of the running train is the regenerative braking condition, it is judged whether the output energy of the train regenerative braking system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel;

[0107] If the output energy of the train regenerative braking system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel, it is judged whether the energy storage device is in the minimum state of charge or the intermediate state of charge;

[0108] If the energy storage device is in the minimum state of charge or the intermediate state of charge, the output energy of the train's regenerative braking system is supplied to the loads along the cross-strait railway tunnel, and the remaining energy of the train's regenerative braking system and the output energy of the offshore wind power system are stored in the energy storage device;

[0109] If the energy storage device is in the maximum state of charge, the output energy of the train's regenerative braking system is supplied to the loads along the traction network, and the remaining energy of the train's regenerative braking system and the output energy of the offshore wind power system are sent back to the three-phase power system through the nearest central station;

[0110] If the output energy of the train's regenerative braking system is less than the energy required by the loads along the cross-strait railway tunnel, it is judged whether the sum of the output energy of the train's regenerative braking system and the output energy of the offshore wind power system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel;

[0111] If the sum of the output energy of the train's regenerative braking system and the output energy of the offshore wind power system is greater than or equal to the energy required by the loads along the cross-strait railway tunnel, it is judged whether the energy storage device is in the minimum state of charge or the intermediate state of charge;

[0112] If the energy storage device is in the minimum state of charge or the intermediate state of charge, the output energy of the train's regenerative braking system and the output energy of the offshore wind power system are supplied to the loads along the cross-strait railway tunnel, and the remaining energy of the offshore wind power system is stored in the energy storage device;

[0113] If the energy storage device is in the maximum state of charge, the output energy of the train's regenerative braking system and the output energy of the offshore wind power system are supplied to the loads along the cross-strait railway tunnel, and the remaining energy of the offshore wind power system is sent back to the three-phase power system through the nearest central station;

[0114] If the sum of the output energy of the train's regenerative braking system and the output energy of the offshore wind power system is less than the energy required by the loads along the cross-strait railway tunnel, it is judged whether the energy storage device is in the intermediate state of charge or the maximum state of charge;

[0115] If the energy storage device is in the intermediate state of charge or the maximum state of charge, the output energy of the train's regenerative braking system, the output energy of the offshore wind power system and the output energy of the energy storage device are supplied to the loads along the cross-strait railway tunnel;

[0116] If the energy storage device is in the minimum state of charge, the output energy of the train's regenerative braking system, the output energy of the offshore wind power system and the output energy of the central station are supplied to the loads along the cross-strait railway tunnel.

[0117] Specifically, when the locomotive is in the regenerative braking mode, the loads along the traction network are power-consuming loads at this time.

[0118] If the regenerative braking energy ER of the train is greater than or equal to the energy EL required by the loads along the traction network, i.e., ER≥EL, and the energy storage device is in the minimum state of charge SOCL or the intermediate state of charge SOCM, the AC-DC hybrid flexible power supply system is in the fifth working state, specifically: the energy output by the regenerative braking train supplies the loads along the traction network, and the remaining regenerative braking energy and the energy of the offshore wind power system are stored in the energy storage device; if the regenerative braking energy ER of the train is greater than or equal to the energy EL required by the loads along the traction network, i.e., ER≥EL, and the energy storage device is in the maximum state of charge SOCH, the AC-DC hybrid flexible power supply system is in the sixth working state, specifically: the energy output by the regenerative braking train supplies the loads along the traction network, and the remaining regenerative braking energy and the energy of the offshore wind power system are sent back to the three-phase power grid through the nearest substation center.

[0119] If the regenerative braking energy ER of the train is less than the energy EL required by the loads along the traction network and the sum of the regenerative braking energy ER of the train and the power generation energy EW of the offshore wind power system is greater than or equal to the energy EL required by the loads along the traction network, i.e., ER<EL&ER+EW≥EL, and the energy storage device is in the minimum state of charge SOCL or the intermediate state of charge SOCM, the AC-DC hybrid flexible power supply system is in the seventh working state, specifically: the regenerative braking train and the offshore wind power system output energy to supply the loads along the traction network, and the remaining energy is stored in the energy storage device; if the regenerative braking energy ER of the train is less than the energy EL required by the loads along the traction network and the sum of the regenerative braking energy ER of the train and the power generation energy EW of the offshore wind power system is greater than the energy EL required by the loads along the traction network, i.e., ER<EL&ER+EW≥EL, and the energy storage device is in the maximum state of charge SOCH, the AC-DC hybrid flexible power supply system is in the eighth working state, specifically: the regenerative braking train and the offshore wind power system output energy to supply the loads along the traction network, and the remaining energy is sent back to the three-phase power grid through the nearest substation center.

[0120] If the regenerative braking energy ER of the train is less than the energy EL required by the loads along the traction network and the sum of the regenerative braking energy ER of the train and the power generation energy EW of the offshore wind power system is less than the energy EL required by the loads along the traction network, that is, ER < EL & ER + EW < EL, and the energy storage device is in the intermediate state of charge SOCM or the maximum state of charge SOCH, at this time, the AC-DC hybrid flexible power supply system is in the ninth working state, specifically: the regenerative braking train, the offshore wind power system and the energy storage device output energy to supply the loads along the traction network; If the regenerative braking energy ER of the train is less than the energy EL required by the loads along the traction network and the sum of the regenerative braking energy ER of the train and the power generation energy EW of the offshore wind power system is less than the energy EL required by the loads along the traction network, that is, ER < EL & ER + EW < EL, and the energy storage device is in the minimum state of charge SOCL, at this time, the AC-DC hybrid flexible power supply system is in the tenth working state, specifically: the regenerative braking train, the offshore wind power system and the central station output energy to supply the loads along the traction network.

[0121] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0122] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0123] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0124] In the present invention, specific embodiments are used to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only for helping to understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

[0125] Those of ordinary skill in the art will realize that the embodiments described herein are for helping the reader understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not depart from the essence of the present invention according to these technical revelations disclosed by the present invention, and these deformations and combinations are still within the protection scope of the present invention.

Claims

1. An AC / DC hybrid flexible power supply system for a cross-strait railway, characterized in that: include: A first three-phase power system is arranged on the land on one side of the strait and is used to provide electric energy to the first center connected thereto or receive electric energy returned by the first center connected thereto; The first central station is arranged on the land on one side of the strait, and is used to collect electric energy from the first three-phase power system, and output the collected electric energy to the traction network and DC bus connected thereto after adjusting the output voltage, and provide electric energy to the cross-strait railway power equipment and / or the cross-strait railway tunnel power supply system; or receive the electric energy returned by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and return the received electric energy to the first three-phase power system after adjusting the output voltage; A second three-phase power system is provided on the land on the other side of the strait and is used to provide electric energy to a second center connected thereto or to receive electric energy returned thereto by a second center connected thereto; The second center is located on the land on the other side of the strait, and is used to collect electric energy from the second three-phase power system, and output the collected electric energy to the traction network and DC bus connected thereto after adjusting the output voltage, and provide electric energy to the cross-strait railway power equipment and / or the cross-strait railway tunnel power supply system; or receive the electric energy returned by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and return the received electric energy to the second three-phase power system after adjusting the output voltage; An offshore wind power system, which is arranged on a strait and is used to generate electric energy, and output the generated electric energy to a DC bus connected thereto to provide electric energy to cross-strait railway power equipment and / or a cross-strait railway tunnel power supply system; The cross-strait railway tunnel power supply system is set up on the strait and is used to receive the electric energy transmitted by the offshore wind power system through the DC bus, and / or receive the electric energy returned by the train regenerative braking system through the traction network, and store the received electric energy; or output the stored electric energy to the traction network and DC bus connected to it to provide electric energy to the cross-strait railway electrical equipment.

2. The AC / DC hybrid flexible power supply system for cross-strait railway according to claim 1 is characterized in that: The cross-strait railway tunnel power supply system specifically includes: At least one energy storage device, which is arranged in the cross-channel railway tunnel and is used to store the electric energy transmitted by the DC-DC converter connected thereto; or to transmit the stored electric energy through the DC-DC converter; A DC-DC converter, which is arranged to correspond one-to-one with a storage device, is used to collect electric energy from a DC bus connected thereto, and transmit the collected electric energy to a corresponding energy storage device after performing electric energy conversion; or collect electric energy from a corresponding energy storage device, and transmit the collected electric energy to a DC bus after performing electric energy conversion; At least one inverter station is arranged in the cross-strait railway tunnel, which is used to collect electric energy from the DC bus connected to it, and transmit the collected electric energy to the traction network connected to it after power conversion to provide electric energy to the cross-strait railway electrical equipment; or collect electric energy from the traction network, and transmit the collected electric energy to the DC bus after power conversion.

3. The AC / DC hybrid flexible power supply system for cross-strait railway according to claim 1 is characterized in that: The offshore wind power system specifically includes: at least one offshore wind turbine, which is disposed on the strait and is used to generate electric energy and transmit the generated electric energy to a step-up transformer connected thereto; A step-up transformer, which is arranged to correspond to each offshore wind turbine one by one, and is used to step up and transform the electric energy transmitted by the corresponding offshore wind turbine and then transmit it to the busbar; The offshore converter station is arranged on the strait, and is used to collect electric energy from the busbar, and then convert the collected electric energy into electric energy and output it to the first onshore converter station and the second onshore converter station through two submarine cables respectively; The first onshore converter station is located on the land on one side of the strait and is used to convert the electric energy transmitted by the submarine cable and transmit it to the DC bus to provide electric energy to the cross-strait railway power equipment and / or the cross-strait railway tunnel power supply system; The second onshore converter station is located on the other side of the strait and is used to convert the electric energy transmitted by the submarine cable and transmit it to the DC bus to provide electric energy to the cross-strait railway electrical equipment and / or the cross-strait railway tunnel power supply system.

4. The AC / DC hybrid flexible power supply system for cross-strait railway according to claim 1, characterized in that: The cross-strait railway electrical equipment specifically includes: Loads along trains operating on the cross-channel railway and / or along the cross-channel railway tunnel.

5. A control method for an AC / DC hybrid flexible power supply system for a cross-strait railway as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Obtaining the operating conditions of trains running in a cross-strait railway tunnel; S2, obtaining the charge state of the energy storage device in the cross-strait railway tunnel power supply system; S3. Based on the acquired operating conditions of the running train and the charge state of the energy storage device, the first center, the second center, the offshore wind power system and the cross-strait railway tunnel power supply system are used to coordinate power supply control and energy allocation for the cross-strait railway electrical equipment.

6. The control method according to claim 5, characterized in that: The operating conditions of the running train specifically include: Traction and regenerative braking conditions.

7. The control method according to claim 6, characterized in that: The charge state of the energy storage device specifically includes: Minimum state of charge, intermediate state of charge, and maximum state of charge.

8. The control method according to claim 7, characterized in that: Step S3 specifically includes: When the operating condition of the running train is the traction condition, it is determined whether the output energy of the offshore wind power system is greater than or equal to the energy required by the cross-strait railway power equipment; If the output energy of the offshore wind power system is greater than or equal to the energy required by the cross-strait railway electrical equipment, it is determined whether the energy storage device is in a minimum charge state or an intermediate charge state; If the energy storage device is in a minimum charge state or an intermediate charge state, the output energy of the offshore wind power system is supplied to the cross-channel railway power equipment, and the remaining energy of the offshore wind power system is stored in the energy storage device; If the energy storage device is in the maximum charge state, the output energy of the offshore wind power system is supplied to the cross-channel railway power equipment, and the remaining energy of the offshore wind power system is returned to the three-phase power system through the nearest center; If the output energy of the offshore wind power system is less than the energy required by the cross-channel railway electrical equipment, it is determined whether the energy storage device is in a minimum charge state; If the energy storage device is in the minimum charge state, the output energy of the center and the offshore wind power system will be supplied to the cross-strait railway power equipment; If the energy storage device is in an intermediate state of charge or a maximum state of charge, the output energy of the energy storage device and the offshore wind power system will be supplied to the cross-channel railway electrical equipment.

9. The control method according to claim 8, characterized in that: Step S3 specifically includes: When the operating condition of the running train is the regenerative braking condition, judging whether the output energy of the train regenerative braking system is greater than or equal to the energy required by the load along the cross-strait railway tunnel; If the output energy of the train regenerative braking system is greater than or equal to the energy required by the load along the cross-strait railway tunnel, it is determined whether the energy storage device is in a minimum charge state or an intermediate charge state; If the energy storage device is in a minimum state of charge or an intermediate state of charge, the output energy of the train regenerative braking system is supplied to the loads along the cross-channel railway tunnel, and the remaining energy of the train regenerative braking system and the output energy of the offshore wind power system are stored in the energy storage device; If the energy storage device is in the maximum charge state, the output energy of the train regenerative braking system is supplied to the loads along the traction network, and the remaining energy of the train regenerative braking system and the output energy of the offshore wind power system are returned to the three-phase power system through the nearest center; If the output energy of the train regenerative braking system is less than the energy required by the load along the cross-strait railway tunnel, then determine whether the sum of the output energy of the train regenerative braking system and the output energy of the offshore wind power system is greater than or equal to the energy required by the load along the cross-strait railway tunnel; If the sum of the output energy of the train regenerative braking system and the output energy of the offshore wind power system is greater than or equal to the energy required by the load along the cross-strait railway tunnel, it is determined whether the energy storage device is in a minimum charge state or an intermediate charge state; If the energy storage device is in a minimum state of charge or an intermediate state of charge, the output energy of the train regenerative braking system and the output energy of the offshore wind power system are supplied to the loads along the cross-channel railway tunnel, and the remaining energy of the offshore wind power system is stored in the energy storage device; If the energy storage device is in the maximum charge state, the output energy of the train regenerative braking system and the output energy of the offshore wind power system are supplied to the loads along the cross-strait railway tunnel, and the remaining energy of the offshore wind power system is returned to the three-phase power system through the nearest center; If the sum of the output energy of the train regenerative braking system and the output energy of the offshore wind power system is less than the energy required by the load along the cross-strait railway tunnel, it is determined whether the energy storage device is in an intermediate state of charge or a maximum state of charge; If the energy storage device is in an intermediate state of charge or a maximum state of charge, the output energy of the train regenerative braking system, the output energy of the offshore wind power system and the output energy of the energy storage device are supplied to the loads along the cross-strait railway tunnel; If the energy storage device is in a minimum charge state, the output energy of the train regenerative braking system, the output energy of the offshore wind power system and the output energy of the center will be supplied to the loads along the cross-strait railway tunnel.

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