Hydropower complementary system transient stability analysis method, system, chip and device

Abstract

The application discloses a water-light complementary system transient stability analysis method, system, chip and equipment, a model of a water-light combined complementary power generation system connected to a flexible direct current sending end converter station is established, the power angle characteristics in the stable condition are analyzed, the power angle characteristics during a short-circuit fault of the water-light complementary power generation connected to the flexible direct current sending end system are analyzed, and a stability enhancement strategy of the water-light complementary power generation connected to the flexible direct current sending end system is provided. The power angle characteristics of the water-light combined complementary power generation system connected to the flexible direct current sending end converter station in different fault conditions are specifically analyzed, and the stability enhancement strategy is provided, thereby providing theoretical guidance for safe and stable operation of the water-light combined power generation system.

Description

Technical Field

[0001] This invention belongs to the field of transient stability analysis technology of new energy power systems, specifically relating to a transient stability analysis method, system, chip and equipment for a water-solar hybrid system. Background Technology

[0002] Due to the inverse distribution of energy and load, most of these new energy sources need to be centrally transmitted over long distances and on a large scale.

[0003] Traditional DC transmission based on grid-commutated converters (LCC-HVDC) lacks voltage support capability and requires grid strength. In contrast, flexible DC transmission technology can self-commutate without relying on the grid, and it does not require AC filters. It also avoids the problem of reactive power excess under conventional DC disturbances, making it more advantageous than traditional DC transmission.

[0004] However, the application of flexible DC transmission technology to scenarios involving large-capacity, long-distance transmission of new energy, especially the safety and stability issues after encountering large disturbances such as short-circuit faults during operation, requires further research using relevant theoretical methods. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a transient stability analysis method, system, chip and equipment for a hydro-solar complementary system, which addresses the shortcomings of the prior art and solves the technical problems of stability judgment and relay protection configuration after an AC fault occurs in the sending end of the hydro-solar complementary power generation system transmitted to the grid via flexible direct current.

[0006] The present invention adopts the following technical solution:

[0007] A method for transient stability analysis of a water-solar hybrid system includes the following steps:

[0008] S1. Establish a system model of the hydro-solar hybrid power generation system connected to the flexible direct transmission converter station, and determine the power angle characteristics of the system model under steady-state conditions;

[0009] S2. Determine the power angle characteristics of the system model obtained in step S1 during short-circuit faults of different fault types and at different fault locations;

[0010] S3. Based on the power angle characteristics of the system model obtained in step S1 under stable conditions and the power angle characteristics of the system model obtained in step S2 during short-circuit faults of different fault types and different fault locations, determine the stability enhancement method for the hydro-solar hybrid power generation system.

[0011] Specifically, in step S1, the power angle characteristics of the system model under steady-state conditions are as follows:

[0012]

[0013] Where, δ hy-vsc ω represents the power angle difference between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. hy-vsc P is the difference in angular velocity between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. mppt P represents the maximum power output of photovoltaic power generation. pv H represents the actual power generated by photovoltaic power generation. vsc H is the inertia constant of the flexible direct-transmission converter. hy Let be the inertia constant of the hydroelectric generator. For the hydraulic turbine to output mechanical power, P hy0 The output power constant of the hydroelectric generator is γ, where γ is the transfer impedance angle between the AC bus of the hydroelectric generator and the AC bus of the flexible direct-feed terminal under steady state. The difference, P hy-vsc This refers to the power transmission limit between the AC bus of the hydroelectric generator and the AC bus of the flexible direct-feed end.

[0014] Furthermore, the dynamic equations of the system model are:

[0015]

[0016] Where, δ vsc ω is the power angle of the AC bus of the flexible direct-transmission converter. vsc ω is the angular velocity of the AC bus of the flexible direct-transmission converter. n The rated angular velocity of the system, This is the power reference value for the flexible direct-transmission converter. K represents the electromagnetic power of the hydroelectric generator. D δ is the damping control coefficient of the grid-type controller for the flexible direct-transmission converter. hy This is the power angle of the hydroelectric generator.

[0017] Furthermore, ignoring line losses, the power transmitted from the hydro-solar hybrid system to the flexible DC rectifier station is:

[0018]

[0019] in, For the electromagnetic power of the hydro-generator, δ hy The power angle of the hydroelectric generator, δ vsc The power angle of the AC bus of the flexible direct-transmission converter.

[0020] Specifically, in step S2, the power angle characteristics of the system model during short-circuit faults of different fault types and at different fault locations are as follows:

[0021]

[0022] Where, δ hy-vsc ω represents the power angle difference between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. hy-vsc H is the difference in angular velocity between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. vsc H is the inertia constant of the flexible direct-transmission converter. hy Let be the inertia constant of the hydroelectric generator. For the hydraulic turbine to output mechanical power, P mppt P' represents the maximum power output of photovoltaic power generation. hy0 P' represents the constant term of the hydroelectric generator output power during the fault period. vsc0 For the input power constant term of the flexible direct transmission end during the fault period, P' hy-vsc γ' represents the power transmission limit between the hydroelectric generator and the flexible direct-feed terminal during a fault, and γ' is the transfer impedance angle between the AC bus of the hydroelectric generator and the AC bus of the flexible direct-feed terminal during a fault. difference.

[0023] Furthermore, the characteristic curve of the output power of the water-solar hybrid system is as follows:

[0024]

[0025] Among them, P hy-vsc P represents the power transmitted between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. hy0 P' is the output power constant of the hydroelectric generator under steady state. pv P1 represents the output power of the photovoltaic system under fault conditions, and P2 represents the power transmitted from the hydro-photovoltaic hybrid system to the flexible DC rectifier station.

[0026] Specifically, in step S3, the stability enhancement method for the combined hydro-solar power generation system is as follows:

[0027] When a three-phase short-circuit fault occurs at different locations on one of the four transmission lines in a hydro-solar hybrid system, the closer the fault location is to the line midpoint, the faster the protection circuit breaker will clear the fault after the fault clearing time. This is in contrast to fault locations near the line midpoint. a / (l a +l b Compared to a system with a line strength of 0.5, the fault location is at one end of the line (l). a / (l a +l b A system with a first swing of 0.0) cannot maintain synchronous stability and becomes unstable.

[0028] When a single-phase short-circuit fault occurs on one of the four transmission lines in the hydro-solar hybrid system, the protection circuit breaker clears the fault after the fault clearing time, and the system maintains initial swing stability during the single-phase short-circuit fault.

[0029] Secondly, embodiments of the present invention provide a transient stability analysis system for a water-solar hybrid system, comprising:

[0030] Steady-state module: Establish a system model of the hydro-solar hybrid power generation system connected to the flexible direct transmission converter station, and determine the power angle characteristics of the system model under steady-state conditions;

[0031] The fault module determines the power angle characteristics of the system model obtained from the steady-state module during short-circuit faults of different fault types and at different fault locations.

[0032] The analysis module, based on the power angle characteristics of the system model obtained from the steady-state module under steady-state conditions and the power angle characteristics of the system model obtained from the fault module during short-circuit faults of different fault types and different fault locations, determines a stability enhancement method for hydro-solar hybrid power generation systems.

[0033] Thirdly, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method for transient stability analysis of a water-solar hybrid system.

[0034] Fourthly, embodiments of the present invention provide an electronic device, including a chip, which, when executed, implements the steps of the above-described transient stability analysis method for a water-solar complementary system.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] A method for transient stability analysis of a water-solar hybrid system.

[0037] For a system where a hydro-solar hybrid system is connected to a flexible sending-end converter station, a model of the system was obtained by modeling the hydropower station, the photovoltaic power generation system, and the flexible sending-end converter station, and by using impedance model and star-delta transformation for network simplification. This model provides a basis for transient stability analysis in the hydro-solar hybrid scenario.

[0038] Furthermore, based on the model of the water-solar complementary system, the power angle characteristic equation under steady-state conditions was obtained, providing a basis for the stability analysis of the water-solar complementary system.

[0039] Furthermore, ignoring line losses, the power transmitted from the hydro-solar hybrid system to the flexible DC rectifier station was derived. This provides a reference for studying the relationship between the power transmitted from the hydro-solar hybrid system to the flexible DC rectifier and the power angle when the photovoltaic output of the system is different, as well as the relationship between the hydropower output and the power angle. It also provides general rules for subsequent analysis under fault conditions.

[0040] Furthermore, short-circuit fault scenarios were set up at different fault points, and the power angle characteristic curves were obtained by simulation based on the power angle characteristic equation, providing a detailed and comprehensive reference for the transient stability analysis of the system.

[0041] Furthermore, based on the power angle characteristic analysis under different conditions, a stability enhancement method for hydro-solar hybrid power generation system is proposed, providing a basis for the safe and stable operation of the system.

[0042] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0043] In summary, under the background of building a high proportion of new energy power systems, this invention focuses on the transient stability analysis of hydro-solar hybrid power generation systems. By modeling the new energy system, establishing an impedance model, and employing network simplification methods such as star-delta transformation, the transient stability of the system is analyzed using the power angle characteristic curve. This provides a theoretical reference for the safe and stable operation of hydro-solar hybrid power generation systems under large disturbances.

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] Figure 1 Topology diagram of the system for large disturbance stability analysis;

[0046] Figure 2 This is the equivalent circuit diagram of the system in steady state;

[0047] Figure 3 This is a diagram showing the transfer impedance between nodes of the system in steady state.

[0048] Figure 4 The steady-state power angle characteristic diagram of the system when the photovoltaic output is different (the vertical axis is the active power transmitted to the flexible DC rectifier station);

[0049] Figure 5 A graph showing the steady-state power angle characteristics of the system under different photovoltaic outputs (the vertical axis represents the active power delivered by the hydropower system);

[0050] Figure 6 The equivalent circuit diagram of the system under a short-circuit fault on a single circuit of a transmission line;

[0051] Figure 7 The system star-delta transformation diagram under a short-circuit fault on a single transmission line;

[0052] Figure 8 This is a diagram showing the transfer impedance between nodes in a transmission line under a short-circuit fault on a single circuit.

[0053] Figure 9Power angle characteristic diagrams for faults at different locations in the system;

[0054] Figure 10 Power angle characteristic diagrams for different fault types of the system;

[0055] Figure 11 The transient process diagrams are shown for the system after encountering a three-phase short-circuit fault at different locations on one of the four transmission lines. Among them, (a) is the power angle change curve of the wind-solar hybrid system at different locations, (b) is the angular velocity change curve of the wind-solar hybrid system at different locations, and (c) is the power change curve of the wind-solar hybrid system at different locations.

[0056] Figure 12 The transient process diagrams are shown for the system after encountering a three-phase short circuit fault and a single-phase short circuit fault in one of the four transmission lines. Among them, (a) is the power angle change curve of the wind-solar hybrid system under different fault types, (b) is the angular velocity change curve of the wind-solar hybrid system under different fault types, and (c) is the power change curve of the wind-solar hybrid system under different fault types.

[0057] Figure 13 This is a schematic diagram of the process of the present invention;

[0058] Figure 14 A schematic diagram of a computer device provided in an embodiment of the present invention;

[0059] Figure 15 This is a block diagram of a chip provided according to an embodiment of the present invention. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0062] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0063] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0064] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0065] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0066] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0067] This invention provides a transient stability analysis method for a hydro-solar hybrid power generation system. Through theoretical derivation, a model of the hydro-solar hybrid power generation system connected to a flexible direct-transmission converter station is established. The power angle characteristics of the system under large disturbances such as short-circuit faults, renewable energy disconnection, and flexible direct-transmission blocking are analyzed in hydro-solar hybrid, pure photovoltaic, and pure hydropower scenarios. The transient stability of the hydro-solar hybrid power generation system connected to the flexible direct-transmission converter station is analyzed. Based on this, a stability enhancement strategy for the hydro-solar hybrid power generation system connected to the flexible direct-transmission system is proposed. Specifically, this invention analyzes the power angle characteristics of the hydro-solar hybrid power generation system connected to the flexible direct-transmission converter station under different fault conditions and proposes a stability enhancement strategy, providing theoretical guidance for the safe and stable operation of the hydro-solar hybrid power generation system.

[0068] Please see Figure 13 The present invention provides a transient stability analysis method for a water-solar hybrid system, comprising the following steps:

[0069] S1. Establish a model of the combined hydro-solar power generation system connected to the flexible direct transmission converter station, and analyze the power angle characteristics of the model of the combined hydro-solar power generation system connected to the flexible direct transmission converter station under steady-state conditions.

[0070] Please see Figure 1 This diagram illustrates the system topology of a combined, complementary hydropower and photovoltaic (PV) power generation system connected to a flexible direct-feed converter station. In the diagram, bus 1 and bus 2 are the PV output bus and hydropower generator port bus, respectively; bus 3 is the hydropower-PV energy collection bus; and bus 4 is the AC bus of the flexible direct-feed converter station. The flexible direct-feed converter station uses VSG control, and the PV inverters use grid-connected control. The two-stage converter system controls the output power P of the PV power generation system. pv +jQ pv Constant. A hydroelectric power generation system generates electricity by rotating a synchronous machine driven by a hydro turbine. The hydro turbine outputs mechanical power of... ω hy E' is the angular velocity of the hydroelectric generator rotor. hy and X' d X represents the transient internal potential and transient reactance of the hydroelectric generator. Thy and Z lhy =R lhy +jX lhy Z represents the transformer reactance between the hydroelectric generator and the power collection busbar, and the transmission line impedance. pv Z1 is the total impedance between the photovoltaic power generation system and the power collection bus; Z2 is the transmission line impedance between the power collection bus and the port of the flexible direct transmission converter. The hydroelectric generator can be equivalent to the classic generator model.

[0071] The photovoltaic converter station adopts a constant power control strategy to control the constant active and reactive power output of the photovoltaic power generation system. The active power is set to the maximum photovoltaic power signal P output by the MPPT control module. mppt To maximize the efficiency of new energy power generation, the power factor is set to 1 in steady state. Therefore, the reactive power reference value in steady state is 0. Based on the voltage at the water-solar collection point and the power output of the photovoltaic system, the photovoltaic system can be equivalent to a negative impedance model.

[0072]

[0073] Neglecting transmission line resistance, the reactance between the power collection bus and the output bus of the flexible DC rectifier station is X1 (equivalent reactance of four parallel lines). Then, the equivalent circuit of the system in steady state is as follows: Figure 2 As shown.

[0074] The power output of the photovoltaic power generation system is:

[0075] P pv =P mppt (2)

[0076] To obtain the transferred reactance between the hydroelectric generator outlet node and other busbars, based on the star-delta transformation, it is possible to... Figure 2 Transform into Figure 3 The self-impedance Z of the turbine under steady state is obtained by solving for the form. hy-hy And the mutual impedance Z between the turbine and the rectifier station at the flexible direct-feed end. hy-vsc Therefore, the power output of the turbine is:

[0077]

[0078] From equation (3), the dynamic equation of the hydroelectric generator is obtained as follows:

[0079]

[0080] Ignoring line losses, the power transmitted from the hydro-solar hybrid system to the flexible DC rectifier station is:

[0081]

[0082] Therefore, based on the above water-solar complementary system model, the steady-state power angle characteristics of the system can be obtained as follows: Figure 4 and Figure 5 As shown, when the mechanical power of the turbine is the same, the power angle of the system with different photovoltaic outputs is different. The greater the photovoltaic output, the greater the difference in power angle between the nodes.

[0083] The flexible direct-feed rectifier station uses VSG control, and its dynamic equation is:

[0084]

[0085]

[0086] Where, δ vsc ω is the power angle of the AC bus of the flexible direct-transmission converter. vsc ω is the angular velocity of the flexible direct-transmission converter. n The rated angular velocity of the system, H is the power reference value for the flexible direct-transmission converter. vsc P is the inertia constant of the flexible direct-transmission converter. pv The actual power output of the photovoltaic system. K represents the electromagnetic power of the hydroelectric generator. D P is the damping control coefficient of the grid-type controller for the flexible direct-transmission converter. hy0 δ is the output power constant of the hydroelectric generator. hyγ is the power angle of the hydro-generator, and γ is the transfer impedance angle between the AC bus of the hydro-generator and the AC bus of the flexible direct-feed end under steady state. difference.

[0087] S2. Analyze the power angle characteristics of the model of the combined hydro-solar power generation system connected to the flexible direct transmission converter station obtained in step S1 during the short-circuit fault of the combined hydro-solar power generation system.

[0088] During system failures, the photovoltaic power generation system converter control generates a certain amount of reactive power. Based on the voltage at the water-solar convergence point and the power generated by the photovoltaic system, the photovoltaic system can be equivalent to a negative impedance model.

[0089] Consider the equivalent circuit of the system when a fault occurs in one circuit of the AC transmission line, such as Figure 6 As shown, the distance from the fault point to the hydroelectric power collection bus is l a Depending on the type of fault, an additional grounding impedance X is connected at the fault point in the positive sequence network. Δ .

[0090] The transfer reactance between the hydroelectric generator outlet node and other busbars is re-solved based on the star-delta transformation, such as... Figure 6 As shown. The star-delta transformation of the system under a short-circuit fault on a single transmission line, as follows: Figure 7 As shown in the diagram. A schematic diagram of the impedance transfer between nodes in a transmission line under a single-circuit short-circuit fault is shown below. Figure 8 As shown.

[0091] Combination Figure 7 and Figure 8 The transfer impedance Z' is obtained. hy-pv Z' pv-vsc Z' hy-vsc Self-impedance Z' hy-hy Z' vsc-vsc and mutual impedance Z' hy-vsc The power output of the turbine during the fault can be calculated as follows:

[0092]

[0093] The output power of the hydropower complementary system is:

[0094]

[0095] The power output of the flexible DC converter station during the fault was:

[0096]

[0097] According to equation (10), the state equation of the hydroelectric generator is:

[0098]

[0099] The flexible direct-feed rectifier station uses VSG control, and its dynamic equation is:

[0100]

[0101] To investigate the transient synchronization stability between the AC bus of the hydroelectric generator and the AC bus of the outlet of the rectifier at the flexible direct-transmission end, by combining (4) and (6), the system power-power angle difference equation under steady state is expressed by the following equation.

[0102]

[0103] Combining (11) and (12), the system power-power angle difference equation during the fault is expressed by the following equation.

[0104]

[0105] Study the output power characteristic curve of the water-solar hybrid system:

[0106]

[0107] Figure 9 and Figure 10 This diagram illustrates the relationship between power transmitted to the rectifier station at the flexible direct-transmission end and the power angle when the system encounters faults at different locations and of different types. For short-circuit faults occurring on a single-circuit line, the closer the fault is to the line's electrical center, the smaller the system acceleration area and the smaller the power angle deviation for the same fault clearing time, resulting in a more stable system. Three-phase short-circuit faults at the same location have a larger acceleration area and a larger power angle deviation than single-phase faults, leading to poorer stability. The most effective response after a system fault occurs is to disconnect the faulty line using line fault protection devices. If the deceleration area is greater than the acceleration area, the system is transiently stable.

[0108] S3. Based on the power angle characteristics of the system model obtained in step S1 under stable conditions and the power angle characteristics of the system model obtained in step S2 during short-circuit faults of different fault types and different fault locations, determine the stability enhancement strategy for the hydro-solar hybrid power generation system.

[0109] After a three-phase short-circuit fault occurs at different locations on one of the four transmission lines in a hydro-solar hybrid system, the closer the fault location is to the midpoint of the line, the smaller the power difference between the hydro-solar hybrid system and the new energy base during the fault period, the slower the acceleration of the angular frequency difference between the AC side of the new energy base and the AC side of the flexible direct transmission end, and the slower the increase of the power angle difference. After the fault clearing time, the protection circuit breaker clears the fault, and the fault location is closer to the midpoint of the line (l a / (l a +l b Compared to a system with a ratio of 0.5, the fault location is at one end of the line (l). a / (l a +lb A system with a fault clearance time of 0.0% cannot maintain initial swing synchronization stability. After the fault is cleared, the power angle difference between the two sides of the sending-end system continues to increase, leading to system instability. The only solution is to reduce the fault clearing time and improve the relay protection speed to mitigate the risk of instability.

[0110] When a single-phase short-circuit fault occurs on one of the four transmission lines of a hydro-solar hybrid system, compared to a three-phase short circuit, the smaller the power difference between the hydro-solar hybrid system and the new energy base after a single-phase short circuit, the slower the acceleration of the angular frequency difference between the AC side of the new energy base and the AC side of the flexible direct transmission end, and the slower the increase of the power angle difference. After the fault clearing time, the protection circuit breaker clears the fault, and the single-phase short-circuit fault system can maintain the stability of the first swing.

[0111] In another embodiment of the present invention, a transient stability analysis system for a water-solar hybrid system is provided. This system can be used to implement the above-mentioned transient stability analysis method for a water-solar hybrid system. Specifically, the transient stability analysis system for a water-solar hybrid system includes a steady-state module, a fault module, and an analysis module.

[0112] Among them, the steady-state module establishes a system model of the hydro-solar hybrid power generation system connected to the flexible direct transmission converter station, and determines the power angle characteristics of the system model under steady-state conditions;

[0113] The fault module determines the power angle characteristics of the system model obtained from the steady-state module during short-circuit faults of different fault types and at different fault locations.

[0114] The analysis module, based on the power angle characteristics of the system model obtained from the steady-state module under steady-state conditions and the power angle characteristics of the system model obtained from the fault module during short-circuit faults of different fault types and different fault locations, determines a stability enhancement method for hydro-solar hybrid power generation systems.

[0115] In another embodiment of the present invention, a terminal device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used for the operation of a transient stability analysis method for a water-solar hybrid system, including:

[0116] A system model of a hydro-solar hybrid power generation system connected to a flexible direct transmission converter station is established, and the power angle characteristics of the system model under steady-state conditions are determined. The power angle characteristics of the system model during short-circuit faults of different fault types and at different fault locations are also determined. Based on the power angle characteristics of the system model under steady-state conditions and the power angle characteristics of the system model during short-circuit faults of different fault types and at different fault locations, a stability enhancement method for the hydro-solar hybrid power generation system is determined.

[0117] Please see Figure 14 The terminal device is a computer device. In this embodiment, the computer device 60 includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When executed by the processor 61, the computer program 63 implements the fluid composition calculation method in the reservoir stimulation wellbore of this embodiment. To avoid repetition, details are omitted here. Alternatively, when executed by the processor 61, the computer program 63 implements the functions of each model / unit in the transient stability analysis system of the water-solar hybrid system of this embodiment. To avoid repetition, details are omitted here.

[0118] Computer device 60 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. Computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will understand that... Figure 14This is merely an example of computer device 60 and does not constitute a limitation on computer device 60. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0119] The processor 61 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0120] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or RAM of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on the computer device 60.

[0121] Furthermore, the memory 62 may include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0122] Please see Figure 15 The terminal device is a chip. In this embodiment, the chip 600 includes a processor 622, which may be one or more, and a memory 632 for storing computer programs executable by the processor 622. The computer program stored in the memory 632 may include one or more modules, each corresponding to a set of instructions. Furthermore, the processor 622 may be configured to execute the computer program to perform the aforementioned transient stability analysis method for the water-solar hybrid system.

[0123] Additionally, chip 600 may also include a power supply component 626 and a communication component 650. The power supply component 626 can be configured to perform power management of chip 600, and the communication component 650 can be configured to enable communication of chip 600, such as wired or wireless communication. Furthermore, chip 600 may also include an input / output (I / O) interface 658. Chip 600 can operate on an operating system stored in memory 632.

[0124] In another embodiment of the present invention, a storage medium is also provided, specifically a computer-readable storage medium (memory). This computer-readable storage medium is a memory device in a terminal device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and extended storage media supported by the terminal device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device.

[0125] One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the transient stability analysis method for the water-solar complementary system in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor in the following steps:

[0126] A system model of a hydro-solar hybrid power generation system connected to a flexible direct transmission converter station is established, and the power angle characteristics of the system model under steady-state conditions are determined. The power angle characteristics of the system model during short-circuit faults of different fault types and at different fault locations are also determined. Based on the power angle characteristics of the system model under steady-state conditions and the power angle characteristics of the system model during short-circuit faults of different fault types and at different fault locations, a stability enhancement method for the hydro-solar hybrid power generation system is determined.

[0127] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0128] The transient stability analysis method of the hydro-solar hybrid power generation system connected to the flexible direct transmission converter station described in the embodiments of the present invention was experimentally verified.

[0129] Figure 11 The figure illustrates the transient process after a three-phase short-circuit fault occurs at different locations on one of the four transmission lines. It shows that the closer the fault location is to the line midpoint, the smaller the power difference between the hydro-solar hybrid power base and the AC side of the flexible direct transmission line during the fault period. The acceleration of the angular frequency difference between the AC side of the power base and the AC side of the flexible direct transmission line is slower, and the increase in the power angle difference is also slower. After the fault clearing time, the protection circuit breaker clears the fault. This is consistent with the situation where the fault location is at the line midpoint (l...). a / (l a +l b Compared to a system with a line strength of 0.5, the fault location is at one end of the line (l). a / (l a +l b A system with a fault clearance time of 0.0% cannot maintain initial swing synchronization stability. After the fault is cleared, the power angle difference between the two sides of the sending-end system continues to increase, leading to system instability. The only solution is to reduce the fault clearing time and improve the relay protection speed to mitigate the risk of instability.

[0130] Figure 12 The figure illustrates the transient processes of the system after one of the four transmission lines encounters a three-phase short-circuit fault and a single-phase short-circuit fault. As can be seen from the figure, compared to a three-phase short circuit, the smaller the power difference of the hydro-solar hybrid new energy base after encountering a single-phase short-circuit fault, the slower the acceleration of the angular frequency difference between the AC side of the new energy base and the AC side of the flexible direct transmission end, and the slower the increase of the power angle difference. After the fault clearing time, the protection circuit breaker clears the fault. The system stabilizes during the first swing of the single-phase short-circuit fault, while the system becomes synchronously unstable during the three-phase short-circuit fault.

[0131] Figure 11 and Figure 12 The effectiveness of the stability enhancement strategy for dealing with short-circuit faults in the water-solar hybrid system was verified.

[0132] In summary, this invention provides a transient stability analysis method, system, chip, and device for a hydro-solar hybrid power generation system. Through theoretical derivation, it models the hydro-solar hybrid power generation system and analyzes its power angle characteristics under large disturbances such as short-circuit faults, renewable energy disconnection, and flexible DC transmission blocking in hydro-solar hybrid, pure photovoltaic, and pure hydropower scenarios. The transient stability of the hydro-solar hybrid power generation system connected to the flexible DC transmission converter station is analyzed. Based on this, a stability enhancement strategy for the hydro-solar hybrid power generation system is further proposed. This stability analysis method is expected to provide theoretical guidance for the stable operation of new power systems dominated by renewable energy sources.

[0133] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0134] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0135] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0136] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0137] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0138] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0139] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random-access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0140] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0141] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0142] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0143] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A transient stability analysis method for a combined hydro-solar power generation system, characterized in that, Includes the following steps: S1. Establish a system model of the hydro-solar hybrid power generation system connected to the flexible direct transmission converter, and determine the power angle characteristics of the system model under steady-state conditions. The power angle characteristics of the system model under steady-state conditions are as follows: in, The power angle difference between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. The difference in angular velocity between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. This represents the maximum power output of photovoltaic power generation. This represents the actual power output of photovoltaic power generation. Let be the inertia constant of the flexible direct-transmission converter. Let be the inertia constant of the hydroelectric generator. To output mechanical power for the hydroelectric generator, This is the constant term for the output power of the hydroelectric generator. The transfer impedance angle between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end under steady state and The difference, This is the power transmission limit between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end; The dynamic equations of the system model are: in, The power angle of the AC bus of the flexible direct-feed converter. The angular velocity of the AC bus of the flexible direct-feed converter. The rated angular velocity of the system, This is the power reference value for the flexible direct-transmission converter. For the electromagnetic power of the hydroelectric generator, The damping control coefficient for the grid-type controller of the flexible direct-transmission converter. The power angle of the hydroelectric generator; S2. Determine the power angle characteristics of the system model obtained in step S1 during short-circuit faults of different fault types and at different fault locations; S3. Based on the power angle characteristics of the system model obtained in step S1 under stable conditions and the power angle characteristics of the system model obtained in step S2 during short-circuit faults of different fault types and different fault locations, determine the stability enhancement method for the hydro-solar hybrid power generation system.

2. The transient stability analysis method for a combined hydro-solar power generation system according to claim 1, characterized in that, Ignoring line losses, the power transmitted from the hydro-solar hybrid power generation system to the flexible direct-transmission converter is: in, For the electromagnetic power of the hydroelectric generator, The power angle of the hydroelectric generator. The power angle of the AC bus of the flexible direct-transmission converter.

3. The transient stability analysis method for a combined hydro-solar power generation system according to claim 1, characterized in that, In step S2, the power angle characteristics of the system model during short-circuit faults of different fault types and at different fault locations are as follows: in, The power angle difference between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. The difference in angular velocity between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. Let be the inertia constant of the flexible direct-transmission converter. Let be the inertia constant of the hydroelectric generator. To output mechanical power for the hydroelectric generator, This represents the maximum power output of photovoltaic power generation. This is the constant term for the output power of the hydroelectric generator during the fault period. This is the input power constant term for the flexible direct-feed converter during a fault. This represents the maximum power transmission limit between the hydroelectric generator and the AC busbar at the flexible direct-feed end during a fault. The transfer impedance angle between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end during the fault period and difference.

4. The transient stability analysis method for a combined hydro-solar power generation system according to claim 3, characterized in that, The characteristic curve of the output power of the combined hydro-solar power generation system is as follows: in, This refers to the power transmission limit between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. This is the constant term for the output power of the hydroelectric generator. This represents the actual power generated by the photovoltaic system under fault conditions. The power transmitted from the hydro-solar hybrid power generation system to the flexible direct-transmission converter.

5. The transient stability analysis method for a combined hydro-solar power generation system according to claim 1, characterized in that, In step S3, the stability enhancement method for the combined hydro-solar power generation system is as follows: When a hydro-solar hybrid power generation system encounters a three-phase short-circuit fault at a different location on one of the four transmission lines, the closer the fault location is to the midpoint of the line, the more likely the protection circuit breaker will clear the fault after the fault clearing time. When a single-phase short-circuit fault occurs on one of the four transmission lines of the hydro-solar hybrid power generation system, the protection circuit breaker clears the fault after the fault clearing time, and the system maintains initial stability during the single-phase short-circuit fault.

6. A transient stability analysis system for a combined hydro-solar power generation system, characterized in that, include: In the steady-state module, a system model is established connecting the hydro-solar hybrid power generation system to the flexible direct-transmission converter. The power angle characteristics of the system model under steady-state conditions are determined as follows: in, The power angle difference between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. The difference in angular velocity between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end. This represents the maximum power output of photovoltaic power generation. This represents the actual power output of photovoltaic power generation. Let be the inertia constant of the flexible direct-transmission converter. Let be the inertia constant of the hydroelectric generator. To output mechanical power for the hydroelectric generator, This is the constant term for the output power of the hydroelectric generator. The transfer impedance angle between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end under steady state and The difference, This is the power transmission limit between the AC busbar of the hydroelectric generator and the AC busbar of the flexible direct-feed end; The dynamic equations of the system model are: in, The power angle of the AC bus of the flexible direct-feed converter. The angular velocity of the AC bus of the flexible direct-feed converter. The rated angular velocity of the system, This is the power reference value for the flexible direct-transmission converter. For the electromagnetic power of the hydroelectric generator, The damping control coefficient for the grid-type controller of the flexible direct-transmission converter. The power angle of the hydroelectric generator; The fault module determines the power angle characteristics of the system model obtained from the steady-state module during short-circuit faults of different fault types and at different fault locations. The analysis module, based on the power angle characteristics of the system model obtained from the steady-state module under steady-state conditions and the power angle characteristics of the system model obtained from the fault module during short-circuit faults of different fault types and different fault locations, determines a stability enhancement method for hydro-solar hybrid power generation systems.

7. A chip, characterized in that, A memory having a computer program stored thereon; a processor for executing the computer program in the memory to implement the steps of the method according to any one of claims 1-5.

8. An electronic device, characterized in that, Includes the chip as described in claim 7.

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