A method, apparatus, and equipment for solving the static stability limit of a photovoltaic power transmission system.

Abstract

This application relates to a method, apparatus, and equipment for solving the static stability limit of a photovoltaic (PV) power transmission system. The method involves constructing a first simulation model of the PV power transmission system to obtain the reactive power compensation capacity of each collection station under different power transmission rates. Then, a second simulation model of the PV power transmission system is constructed, setting the reactive power compensation capacity of each collection station under different power transmission rates for simulation. This ensures that the voltage of the PV power transmission system remains within a reasonable range during the simulation process until the voltage of the PV power transmission system becomes unstable. Only then can the calculated static stability power limit of the PV power transmission system be accurate, thus solving the technical problem of inaccurate results obtained by existing methods for solving the static stability limit of PV power generation systems.

Description

Technical Field

[0001] This application relates to the field of new energy power system technology, and in particular to a method, apparatus and equipment for solving the static stability limit of a photovoltaic transmission system. Background Technology

[0002] Photovoltaic power transmission systems transmit electricity over long distances from large-scale photovoltaic power plants via AC lines. As the transmitted power level increases, the voltage of the transmission system continuously decreases. When the transmitted power exceeds its power limit, voltage instability occurs, leading to voltage collapse and the inability to maintain stable operation. Therefore, accurately determining the static stability limit power of a photovoltaic power transmission system is of great guiding significance for its engineering design and operation.

[0003] Currently, for traditional power grids that are mainly based on synchronous machines, electromechanical transient simulation is an effective method for solving the static stability limit power of the power grid. However, for photovoltaic power transmission systems that contain a large number of power electronic devices, electromechanical transient simulation cannot accurately reflect their characteristics and it is difficult to obtain accurate results.

[0004] In comparison, electromagnetic transient simulation offers higher computational accuracy, but it cannot directly obtain steady-state power flow results, requiring scientific handling of power flow initialization issues. The approach to solving the static power limit of a photovoltaic power transmission system is to continuously increase the transmitted power until voltage instability occurs; the power at the moment of instability is the static stability limit power. Electromagnetic transient simulation is typically used to initialize the power flow of a power system in the following two ways:

[0005] One approach is to initially initialize the generator as an ideal voltage source. Based on electromechanical transient simulation results, an initial phase angle and initial power flow are assigned to the generator (ideal voltage source state). Once steady state is reached, the generator's excitation and speed control are released, and the power system completes initialization and enters stable operation. However, this method is only suitable for initializing synchronous generators. Photovoltaic power plants have significantly different characteristics from synchronous generators, and it cannot simulate the power rise process of a photovoltaic power plant, nor can it fully simulate the instability process of a photovoltaic power system.

[0006] Another approach is to directly connect photovoltaic (PV) power plants to the grid one by one. For PV power plant simulations, when power levels are low, the PV system has a high stability margin and strong disturbance resistance. When active power or voltage fluctuations occur, the PV system can remain stable, therefore the requirements for the PV system's startup process are not high. However, when used to solve for the static stability limit of a PV system, because the system's disturbance resistance deteriorates near the power limit, it is essential to ensure a smooth startup process and minimize disturbances in order to accurately solve for the static stability limit. Summary of the Invention

[0007] This application provides a method, apparatus, and equipment for solving the static stability limit of a photovoltaic power transmission system, which addresses the technical problem that existing methods for solving the static stability limit of photovoltaic power generation systems yield inaccurate results.

[0008] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0009] A method for solving the static stability limit of a photovoltaic (PV) power transmission system, comprising several collection stations connected by AC lines, each collection station including a PV power plant equipped with dynamic reactive power compensation equipment, the method comprising the following steps:

[0010] Based on the electromechanical transient model of the power system, a first simulation model and a second simulation model are constructed for the photovoltaic transmission system. The first simulation model is used to simulate the photovoltaic transmission system to obtain the maximum power transmission of the photovoltaic transmission system, and the reactive power compensation capacity of each collection station is obtained by simulating the photovoltaic transmission system under the maximum power transmission using the first simulation model, thus obtaining a first reactive power compensation capacity set.

[0011] Based on the first power transmission power, the second power transmission power, the third power transmission power and the fourth power transmission power, the photovoltaic power transmission system is simulated using the first simulation model to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, and the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set and the fifth reactive power compensation capacity set are obtained.

[0012] Based on the second set of reactive power compensation capacity, the third set of reactive power compensation capacity, the fourth set of reactive power compensation capacity, and the fifth set of reactive power compensation capacity, the photovoltaic power transmission system is simulated in the second simulation model by gradually increasing the power transmission power in the order of the first power transmission power, the second power transmission power, the third power transmission power, and the fourth power transmission power. This ensures that the voltage of the photovoltaic power transmission system remains within a reasonable range during the simulation process until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission power before the voltage of the photovoltaic power transmission system becomes unstable is then obtained as the static stable power limit of the photovoltaic power transmission system.

[0013] Preferably, simulating the photovoltaic power transmission system by gradually increasing the power transmission capacity in the second simulation model based on the second set of reactive power compensation capacity, the third set of reactive power compensation capacity, the fourth set of reactive power compensation capacity, and the fifth set of reactive power compensation capacity includes:

[0014] Parameter data is set on the second simulation model, including first power transmission power, second power transmission power, third power transmission power, fourth power transmission power, second reactive power compensation capacity set, third reactive power compensation capacity set, fourth reactive power compensation capacity set and fifth reactive power compensation capacity set;

[0015] The second simulation model is started to simulate the photovoltaic power transmission system. During the simulation, the photovoltaic power plants of each collection station are unlocked, and the power transmission power of the photovoltaic power transmission system is sequentially increased to the second power transmission power, the third power transmission power, and the fourth power transmission power, and the reactive power compensation capacity of each collection station is switched accordingly.

[0016] During the simulation of the photovoltaic power transmission system in the second simulation model, if the power transmission of the photovoltaic power transmission system increases to a level greater than the fourth power transmission power, then each collection station of the photovoltaic power transmission system is controlled to connect to a dynamic reactive power compensation device with continuous reactive power output, and the operation of the dynamic reactive power compensation device is controlled by the bus voltage of the AC line until the voltage of the photovoltaic power transmission system becomes unstable.

[0017] Preferably, constructing a second simulation model for the photovoltaic power transmission system based on the electromechanical transient model of the power system includes: obtaining the power grid topology and operating parameters of the photovoltaic power transmission system, and constructing a second simulation model based on the first simulation model in combination with the power grid topology and the operating parameters; the operating parameters include the voltage, impedance, capacity and control type of each component in the photovoltaic power transmission system.

[0018] Preferably, the first power supply is 0, the second power supply is 0.3 times the maximum power supply, the third power supply is 0.5 times the maximum power supply, and the fourth power supply is 0.7 times the maximum power supply.

[0019] This application also provides a static stability limit solver for a photovoltaic power transmission system, the photovoltaic power transmission system including a plurality of collection stations connected by AC lines, each of the collection stations including a photovoltaic power station with dynamic reactive power compensation equipment, the static stability limit solver including: a first data acquisition module, a second data acquisition module and a solver module;

[0020] The first data acquisition module is used to construct a first simulation model and a second simulation model for the photovoltaic transmission system based on the electromechanical transient model of the power system, use the first simulation model to simulate the photovoltaic transmission system to obtain the maximum power transmission of the photovoltaic transmission system, and use the first simulation model to simulate the photovoltaic transmission system under the maximum power transmission to obtain the reactive power compensation capacity of each collection station, thereby obtaining a first reactive power compensation capacity set.

[0021] The second data acquisition module is used to simulate the photovoltaic power transmission system based on the first power transmission power, the second power transmission power, the third power transmission power and the fourth power transmission power, using the first simulation model to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, and to obtain the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set and the fifth reactive power compensation capacity set.

[0022] The solution module is used to simulate the photovoltaic power transmission system in the second simulation model by gradually increasing the power transmission power in the order of the first power transmission power, the second power transmission power, the third power transmission power, and the fourth power transmission power, based on the second set of reactive power compensation capacity, the third set of reactive power compensation capacity, the fourth set of reactive power compensation capacity, and the fifth set of reactive power compensation capacity. This ensures that the voltage of the photovoltaic power transmission system remains within a reasonable range during the simulation process until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission power before the voltage of the photovoltaic power transmission system becomes unstable is then obtained as the static stable power limit of the photovoltaic power transmission system.

[0023] Preferably, the solution module includes a model building submodule, a simulation submodule, and a simulation solution submodule;

[0024] The model construction submodule is used to set parameter data on the second simulation model. The parameter data includes a first power transmission power, a second power transmission power, a third power transmission power, a fourth power transmission power, a second reactive power compensation capacity set, a third reactive power compensation capacity set, a fourth reactive power compensation capacity set, and a fifth reactive power compensation capacity set.

[0025] The simulation submodule is used to start the second simulation model to simulate the photovoltaic power transmission system. During the simulation, the photovoltaic power station of each collection station is unlocked, the power transmission power of the photovoltaic power transmission system is sequentially increased to the second power transmission power, the third power transmission power, and the fourth power transmission power, and the reactive power compensation capacity of each collection station is switched accordingly.

[0026] The simulation solution submodule is used to control each collection station of the photovoltaic power transmission system to connect to a dynamic reactive power compensation device with continuous reactive power output during the simulation of the photovoltaic power transmission system in the second simulation model. The dynamic reactive power compensation device is controlled to operate with the bus voltage of the AC line until the voltage of the photovoltaic power transmission system becomes unstable.

[0027] Preferably, the first data acquisition module is further configured to acquire the grid topology and operating parameters of the photovoltaic transmission system, and construct a second simulation model based on the first simulation model in combination with the grid topology and the operating parameters; the operating parameters include the voltage, impedance, capacity and control type of each component in the photovoltaic transmission system.

[0028] Preferably, the first power supply is 0, the second power supply is 0.3 times the maximum power supply, the third power supply is 0.5 times the maximum power supply, and the fourth power supply is 0.7 times the maximum power supply.

[0029] This application also provides a storage device storing a plurality of program codes adapted to be loaded and run by a processor to execute the static stability limit solution method for the photovoltaic power transmission system described above.

[0030] This application also provides a terminal device, including a processor and a memory;

[0031] The memory is used to store program code and transmit the program code to the processor;

[0032] The processor is configured to execute the static stability limit solution method for the photovoltaic power transmission system described above, according to the instructions in the program code.

[0033] As can be seen from the above technical solutions, the embodiments of this application have the following advantages: the static stability limit solution method, apparatus, and equipment for the photovoltaic power transmission system include constructing a first simulation model and a second simulation model for the photovoltaic power transmission system based on the electromechanical transient model of the power system; using the first simulation model to simulate the photovoltaic power transmission system to obtain the maximum power transmission of the photovoltaic power transmission system; and obtaining the reactive power compensation capacity of each collection station by simulating the photovoltaic power transmission system under the maximum power transmission using the first simulation model, thereby obtaining a first reactive power compensation capacity set; based on the first power transmission, the second power transmission, the third power transmission, and the fourth power transmission... The photovoltaic power transmission system is simulated using a first simulation model to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, resulting in a second, third, fourth, and fifth reactive power compensation capacity set. Based on the second, third, fourth, and fifth reactive power compensation capacity sets, the power transmission power is gradually increased in the second simulation model to simulate the photovoltaic power transmission system until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission power before the voltage instability of the photovoltaic power transmission system at this point is obtained as the static stable power limit of the photovoltaic power transmission system. This method for solving the static stability limit of a photovoltaic (PV) power transmission system involves constructing a first simulation model of the PV power transmission system to obtain the reactive power compensation capacity of each collection station under different power transmission levels. Then, a second simulation model of the PV power transmission system is constructed, setting the reactive power compensation capacity of each collection station under different power transmission levels for simulation. This ensures that the voltage of the PV power transmission system remains within a reasonable range during the simulation process until the voltage of the PV power transmission system becomes unstable. Only then can the static stability power limit of the PV power transmission system be solved accurately, thus solving the technical problem of inaccurate results obtained by existing methods for solving the static stability limit of PV power generation systems. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a flowchart illustrating the steps of the static stability limit solution method for the photovoltaic power transmission system described in this application embodiment;

[0036] Figure 2 This is a framework diagram of the photovoltaic power transmission system in the static stability limit solution method for the photovoltaic power transmission system described in the embodiments of this application;

[0037] Figure 3 This is a framework diagram of the static stability limit solver for the photovoltaic power transmission system according to an embodiment of this application. Detailed Implementation

[0038] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] This application provides a method, apparatus, and equipment for solving the static stability limit of a photovoltaic power transmission system, which solves the technical problem that the results obtained by existing methods for solving the static stability limit of photovoltaic power generation systems are inaccurate.

[0040] Example 1:

[0041] Figure 1 This is a flowchart illustrating the steps of the static stability limit solution method for the photovoltaic power transmission system described in this application embodiment. Figure 2 This is a framework diagram of the photovoltaic power transmission system in the static stability limit solution method of the photovoltaic power transmission system described in the embodiments of this application.

[0042] like Figure 1 As shown in the figure, this application provides a method for solving the static stability limit of a photovoltaic power transmission system, including the following steps:

[0043] S1. Based on the electromechanical transient model of the power system, a first simulation model and a second simulation model are constructed for the photovoltaic transmission system. The first simulation model is used to simulate the photovoltaic transmission system to obtain the maximum power transmission of the photovoltaic transmission system, and the reactive power compensation capacity of each collection station is obtained by simulating the photovoltaic transmission system under the maximum power transmission. Thus, a first reactive power compensation capacity set is obtained.

[0044] It should be noted that in step S1, firstly, a first simulation model and a second simulation model are constructed; secondly, the constructed first simulation model is used to simulate the photovoltaic power transmission system to obtain the maximum power transmission capacity and the first reactive power compensation capacity set data of the photovoltaic power transmission system. In this embodiment, as... Figure 2 As shown, the photovoltaic power transmission system includes several collecting stations connected by AC lines. Each collecting station includes a photovoltaic power plant equipped with dynamic reactive power compensation equipment, and each collecting station is also connected to dynamic reactive power compensation equipment. The electromechanical transient model is a mature power system simulation technology and will not be elaborated upon here.

[0045] In this embodiment, constructing a second simulation model for the photovoltaic power transmission system based on the electromechanical transient model of the power system includes: obtaining the grid topology and operating parameters of the photovoltaic power transmission system, and constructing a second simulation model based on the first simulation model combined with the grid topology and operating parameters; the operating parameters include the voltage, impedance, capacity, and control type of each component in the photovoltaic power transmission system. The components can be photovoltaic power plants, dynamic reactive power compensation equipment, etc., within the photovoltaic power transmission system.

[0046] It should be noted that the electromechanical transient simulation data in the electromechanical transient model is modeled based on the topology and operating parameters of the design or actual power grid, while the second simulation model can be an electromagnetic transient simulation model, which is constructed based on the electromechanical transient simulation model.

[0047] S2. Based on the first power transmission power, the second power transmission power, the third power transmission power and the fourth power transmission power, the first simulation model is used to simulate the photovoltaic power transmission system to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, and the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set and the fifth reactive power compensation capacity set are obtained.

[0048] It should be noted that in step S2, the first step is to set the power output of the photovoltaic power transmission system during the simulation process. A first simulation model is used to perform power flow calculations on the photovoltaic power transmission system to obtain the reactive power compensation capacity of each collecting station under the corresponding power output. These are denoted as the second, third, fourth, and fifth reactive power compensation capacity sets, providing simulation parameters for solving the static stability power limit in subsequent steps. In this embodiment, performing power flow calculations on the power grid system in the power system simulation model is a very common technique in the field and will not be elaborated upon here. Each reactive power compensation capacity set includes the reactive power compensation capacity of each collecting station of the photovoltaic power transmission system.

[0049] In the embodiments of this application, the first power supply can be selected as 0, the second power supply can be selected as 0.3 times the maximum power supply, the third power supply can be selected as 0.5 times the maximum power supply, and the fourth power supply can be selected as 0.7 times the maximum power supply.

[0050] S3. Based on the second, third, fourth, and fifth reactive power compensation capacity sets, the power transmission capacity is gradually increased in the second simulation model to simulate the photovoltaic power transmission system until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission capacity before the voltage of the photovoltaic power transmission system becomes unstable is then obtained as the static stable power limit of the photovoltaic power transmission system.

[0051] It should be noted that in step S3, the reactive power compensation capacity of each collection station obtained in step S2 is used as the simulation operation parameter of the second simulation model. In the simulation process of the photovoltaic power transmission system in the second simulation model, the power transmission power is gradually increased and the reactive power compensation capacity of each collection station corresponding to the power transmission power is switched until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission power before the voltage of the photovoltaic power transmission system becomes unstable is then obtained as the static stable power limit of the photovoltaic power transmission system.

[0052] This application provides a method for solving the static stability limit of a photovoltaic (PV) power transmission system. The method includes constructing a first simulation model and a second simulation model of the PV power transmission system based on an electromechanical transient model of the power system; using the first simulation model to simulate the PV power transmission system to obtain the maximum power transmission capacity of the PV power transmission system; and using the first simulation model to simulate the PV power transmission system under the maximum power transmission capacity to obtain the reactive power compensation capacity of each collection station, thus obtaining a first reactive power compensation capacity set; based on the first power transmission capacity, the second power transmission capacity, the third power transmission capacity, and the fourth power transmission capacity, using the first simulation model to simulate the PV power transmission system... The power transmission system is simulated to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, resulting in a second set of reactive power compensation capacity, a third set of reactive power compensation capacity, a fourth set of reactive power compensation capacity, and a fifth set of reactive power compensation capacity. Based on the second set of reactive power compensation capacity, the power transmission power is gradually increased in the second simulation model to simulate the photovoltaic power transmission system until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission power before the voltage instability of the photovoltaic power transmission system at this point is obtained as the static stable power limit of the photovoltaic power transmission system. This method for solving the static stability limit of a photovoltaic (PV) power transmission system involves constructing a first simulation model of the PV power transmission system to obtain the reactive power compensation capacity of each collection station under different power transmission levels. Then, a second simulation model of the PV power transmission system is constructed, setting the reactive power compensation capacity of each collection station under different power transmission levels for simulation. This ensures that the voltage of the PV power transmission system remains within a reasonable range during the simulation process until the voltage of the PV power transmission system becomes unstable. Only then can the static stability power limit of the PV power transmission system be solved accurately, thus solving the technical problem of inaccurate results obtained by existing methods for solving the static stability limit of PV power generation systems.

[0053] In one embodiment of this application, simulating the photovoltaic power transmission system by gradually increasing the power transmission capacity in the second simulation model based on the second set of reactive power compensation capacity, the third set of reactive power compensation capacity, the fourth set of reactive power compensation capacity, and the fifth set of reactive power compensation capacity includes:

[0054] Parameter data is set on the second simulation model. The parameter data includes the first power transmission power, the second power transmission power, the third power transmission power, the fourth power transmission power, the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set, and the fifth reactive power compensation capacity set.

[0055] The second simulation model is started to simulate the photovoltaic power transmission system. During the simulation, the photovoltaic power plants of each collection station are unlocked, and the power transmission power of the photovoltaic power transmission system is increased to the second power transmission power, the third power transmission power, and the fourth power transmission power in sequence, and the reactive power compensation capacity of each collection station is switched accordingly.

[0056] During the simulation of the photovoltaic power transmission system in the second simulation model, if the power transmission of the photovoltaic power transmission system increases to a level greater than the fourth power transmission power, then each collection station of the photovoltaic power transmission system is controlled to connect to a dynamic reactive power compensation device with continuous reactive power output, and the operation of the dynamic reactive power compensation device is controlled by the bus voltage of the AC line until the voltage of the photovoltaic power transmission system becomes unstable.

[0057] In this embodiment, at time T0, the initial time of the second simulation model simulating the photovoltaic power transmission system, the reactive power compensation capacity of each collection station of the photovoltaic power transmission system is set according to the second reactive power compensation capacity set, and the inverters of the photovoltaic power plants connected to the collection stations are controlled to be in a locked state, i.e., the active power of the photovoltaic power plants is 0. Then, the reactive power compensation capacity of each collection station of the photovoltaic power transmission system is set according to the third reactive power compensation capacity set, and the power transmission capacity of the photovoltaic power transmission system at time T1 is set to the second power transmission capacity. The second simulation model is then started to simulate the photovoltaic power transmission system. Between times T0 and T1, the photovoltaic power plants use DC voltage control. After unlocking the inverters of the photovoltaic power plants, the power transmission capacity of the photovoltaic power transmission system rapidly increases to the second power transmission capacity, and simultaneously, the reactive power compensation capacity of each collection station is switched to the reactive power compensation capacity corresponding to the third reactive power compensation capacity set. Then, the power transmission capacity of the photovoltaic power transmission system is slowly increased from the second power transmission capacity to the fourth power transmission capacity. During the increase in power transmission capacity, to ensure that the voltage remains within a reasonable range, the reactive power compensation capacity setting of the photovoltaic power transmission system is switched twice. Specifically, when the power transmission capacity reaches the third and fourth power transmission capacities, the system switches to the fourth and fifth reactive power compensation capacity sets respectively. If the power transmission capacity continues to increase, and the increased power exceeds the fourth power transmission capacity, each collection station of the photovoltaic power transmission system is connected to a dynamic reactive power compensation device with continuous reactive power output. The operation of the dynamic reactive power compensation device is controlled by the bus voltage of the AC line until the voltage of the photovoltaic power transmission system becomes unstable.

[0058] It should be noted that the power transmission capacity of the photovoltaic (PV) power transmission system is controlled by adjusting the illuminance. If the power transmission capacity continues to increase beyond the fourth power level, the demand for reactive power compensation will also increase, and the system's disturbance rejection capability will decrease, leading to significant errors in the simulation results. Therefore, in the second simulation model, when the power transmission capacity of the PV system exceeds the fourth power level, each collecting station is connected to a dynamic reactive power compensation device. The control target of the dynamic reactive power compensation device is the AC bus voltage. As the power transmission capacity of the PV system increases, the dynamic reactive power compensation device continuously outputs reactive power, preventing the system's disturbance rejection capability from deteriorating and causing significant errors in the simulation results.

[0059] In the embodiments of this application, the static stability limit solution method for the photovoltaic power transmission system obtains the static stability power limit of the photovoltaic power transmission system. When the power transmission of the photovoltaic power transmission system exceeds the fourth power transmission power, dynamic reactive power compensation is added as a compensation means to provide continuous reactive power output for the photovoltaic power transmission system. This avoids drastic fluctuations in reactive power due to capacitor input or untimely capacitor input, which could lead to voltage instability in the photovoltaic power transmission system, thereby ensuring the accuracy of the obtained static stability power limit.

[0060] In this embodiment of the application, the static stability limit solution method of the photovoltaic power transmission system further includes obtaining the reactive power compensation capacity of all collection stations corresponding to the power transmission capacity before voltage instability when obtaining the power transmission capacity of the photovoltaic power transmission system before voltage instability, which is denoted as the sixth reactive power compensation capacity set.

[0061] It should be noted that the reactive power compensation capacity of the sixth reactive power compensation capacity set can provide a basis for selecting the amount of reactive power compensation capacity for photovoltaic power transmission systems.

[0062] Example 2:

[0063] Figure 3 This is a flowchart illustrating the framework of the static stability limit solver for the photovoltaic power transmission system described in this application.

[0064] like Figure 3 As shown in the figure, this application provides a static stability limit solver for a photovoltaic power transmission system. The photovoltaic power transmission system includes several collection stations connected by AC lines. Each collection station includes a photovoltaic power station with dynamic reactive power compensation equipment. The static stability limit solver includes: a first data acquisition module 10, a second data acquisition module 20, and a solver module 30.

[0065] The first data acquisition module 10 is used to construct a first simulation model and a second simulation model for the photovoltaic transmission system based on the electromechanical transient model of the power system. The first simulation model is used to simulate the photovoltaic transmission system to obtain the maximum power transmission of the photovoltaic transmission system, and the first simulation model is used to simulate the photovoltaic transmission system under the maximum power transmission to obtain the reactive power compensation capacity of each collection station, thereby obtaining the first reactive power compensation capacity set.

[0066] The second data acquisition module 20 is used to simulate the photovoltaic power transmission system based on the first power transmission power, the second power transmission power, the third power transmission power and the fourth power transmission power, and to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, so as to obtain the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set and the fifth reactive power compensation capacity set.

[0067] The solver module 30 is used to simulate the photovoltaic power transmission system by gradually increasing the power transmission capacity in the second simulation model based on the second set of reactive power compensation capacity, the third set of reactive power compensation capacity, the fourth set of reactive power compensation capacity, and the fifth set of reactive power compensation capacity, until the voltage of the photovoltaic power transmission system becomes unstable, and to obtain the power transmission capacity before the voltage of the photovoltaic power transmission system becomes unstable at this time as the static stable power limit of the photovoltaic power transmission system.

[0068] In this embodiment of the application, the solver module 30 includes a model building submodule, a simulation submodule, and a simulation solver submodule;

[0069] The model building submodule is used to set parameter data on the second simulation model. The parameter data includes the first power transmission power, the second power transmission power, the third power transmission power, the fourth power transmission power, the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set, and the fifth reactive power compensation capacity set.

[0070] The simulation submodule is used to start the second simulation model to simulate the photovoltaic power transmission system. During the simulation, the photovoltaic power station of each collection station is unlocked, and the power transmission power of the photovoltaic power transmission system is increased to the second power transmission power, the third power transmission power, and the fourth power transmission power in sequence, and the reactive power compensation capacity of each collection station is switched accordingly.

[0071] The simulation solution submodule is used to control each collection station of the photovoltaic power transmission system to connect to a dynamic reactive power compensation device with continuous reactive power output during the simulation of the photovoltaic power transmission system in the second simulation model. The dynamic reactive power compensation device is controlled to operate with the bus voltage of the AC line until the voltage of the photovoltaic power transmission system becomes unstable.

[0072] In this embodiment, the first data acquisition module is further used to acquire the grid topology and operating parameters of the photovoltaic transmission system, and to construct a second simulation model based on the first simulation model and the grid topology and operating parameters; the operating parameters include the voltage, impedance, capacity and control type of each component in the photovoltaic transmission system.

[0073] In the embodiments of this application, the first power supply is 0, the second power supply is 0.3 times the maximum power supply, the third power supply is 0.5 times the maximum power supply, and the fourth power supply is 0.7 times the maximum power supply.

[0074] It should be noted that the modules in the device of Embodiment 2 correspond to the steps in the method of Embodiment 1. The content of the static stability limit solution method of the photovoltaic power transmission system has been described in detail in Embodiment 1, and the content of the modules in the device will not be described in detail in this Embodiment 2.

[0075] Example 3:

[0076] This application provides a storage device storing multiple lines of program code, characterized in that the program code is adapted to be loaded and run by a processor to execute the above-described method for solving the static stability limit of a photovoltaic power transmission system.

[0077] Example 4:

[0078] This application provides a terminal device, including a processor and a memory;

[0079] Memory is used to store program code and transfer the program code to the processor;

[0080] The processor is used to execute the static stability limit solution method for the photovoltaic power transmission system as described above, according to the instructions in the program code.

[0081] It should be noted that the processor is used to execute the steps in the above-described embodiment of the static stability limit solution method for a photovoltaic power transmission system according to the instructions in the program code. Alternatively, when the processor executes the computer program, it implements the functions of each module / unit in the above-described system / device embodiments.

[0082] For example, a computer program can be divided into one or more modules / units, one or more of which are stored in memory and executed by a processor to complete this application. One or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in a terminal device.

[0083] Terminal devices can be computing devices such as desktop computers, laptops, handheld computers, and cloud servers. Terminal devices may include, but are not limited to, processors and memory. Those skilled in the art will understand that this does not constitute a limitation on the terminal device, which may include more or fewer components than illustrated, or combinations of certain components, or different components. For example, a terminal device may also include input / output devices, network access devices, buses, etc.

[0084] The processor referred to can 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 can be a microprocessor or any conventional processor.

[0085] Memory can be an internal storage unit of a terminal device, such as a hard drive or RAM. Memory can also be an external storage device, such as a plug-in hard drive, SmartMedia Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, memory can include both internal and external storage units. Memory is used to store computer programs and other programs and data required by the terminal device. Memory can also be used for temporary storage of data that has been output or will be output.

[0086] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0087] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of 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 an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0088] 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.

[0089] Furthermore, the functional units in the various embodiments of this application 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.

[0090] If the integrated 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, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0091] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for solving the static stability limit of a photovoltaic power transmission system, the photovoltaic power transmission system comprising a plurality of collecting stations connected by AC lines, each collecting station comprising a photovoltaic power station equipped with dynamic reactive power compensation equipment, characterized in that, The static stability limit solution method includes the following steps: Based on the electromechanical transient model of the power system, a first simulation model and a second simulation model are constructed for the photovoltaic transmission system. The first simulation model is used to simulate the photovoltaic transmission system to obtain the maximum power transmission of the photovoltaic transmission system, and the reactive power compensation capacity of each collection station is obtained by simulating the photovoltaic transmission system under the maximum power transmission using the first simulation model, thus obtaining a first reactive power compensation capacity set. Based on the first power transmission power, the second power transmission power, the third power transmission power and the fourth power transmission power, the photovoltaic power transmission system is simulated using the first simulation model to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, and the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set and the fifth reactive power compensation capacity set are obtained. Based on the second set of reactive power compensation capacity, the third set of reactive power compensation capacity, the fourth set of reactive power compensation capacity, and the fifth set of reactive power compensation capacity, the photovoltaic power transmission system is simulated in the second simulation model by gradually increasing the power transmission power in the order of the first power transmission power, the second power transmission power, the third power transmission power, and the fourth power transmission power. This ensures that the voltage of the photovoltaic power transmission system remains within a reasonable range during the simulation process until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission power before the voltage of the photovoltaic power transmission system becomes unstable is then obtained as the static stable power limit of the photovoltaic power transmission system. Wherein, the first power supply is 0, the second power supply is 0.3 times the maximum power supply, the third power supply is 0.5 times the maximum power supply, and the fourth power supply is 0.7 times the maximum power supply.

2. The method for solving the static stability limit of a photovoltaic power transmission system according to claim 1, characterized in that, Based on the second set of reactive power compensation capacity, the third set of reactive power compensation capacity, the fourth set of reactive power compensation capacity, and the fifth set of reactive power compensation capacity, the simulation of the photovoltaic power transmission system in the second simulation model by gradually increasing the power transmission capacity includes: Parameter data is set on the second simulation model, including first power transmission power, second power transmission power, third power transmission power, fourth power transmission power, second reactive power compensation capacity set, third reactive power compensation capacity set, fourth reactive power compensation capacity set and fifth reactive power compensation capacity set; The second simulation model is started to simulate the photovoltaic power transmission system. During the simulation, the photovoltaic power plants of each collection station are unlocked, and the power transmission power of the photovoltaic power transmission system is sequentially increased to the second power transmission power, the third power transmission power, and the fourth power transmission power, and the reactive power compensation capacity of each collection station is switched accordingly. During the simulation of the photovoltaic power transmission system in the second simulation model, if the power transmission of the photovoltaic power transmission system increases to a level greater than the fourth power transmission power, then each collection station of the photovoltaic power transmission system is controlled to connect to a dynamic reactive power compensation device with continuous reactive power output, and the operation of the dynamic reactive power compensation device is controlled by the bus voltage of the AC line until the voltage of the photovoltaic power transmission system becomes unstable.

3. The method for solving the static stability limit of a photovoltaic power transmission system according to claim 1, characterized in that, The construction of a second simulation model for the photovoltaic power transmission system based on the electromechanical transient model of the power system includes: obtaining the power grid topology and operating parameters of the photovoltaic power transmission system, and constructing a second simulation model based on the first simulation model in combination with the power grid topology and the operating parameters; the operating parameters include the voltage, impedance, capacity and control type of each component in the photovoltaic power transmission system.

4. A static stability limit solver for a photovoltaic power transmission system, characterized in that, The photovoltaic power transmission system includes several collection stations connected by AC lines, each collection station including a photovoltaic power station with dynamic reactive power compensation equipment. The static stability limit solver includes: a first data acquisition module, a second data acquisition module and a solver module. The first data acquisition module is used to construct a first simulation model and a second simulation model for the photovoltaic transmission system based on the electromechanical transient model of the power system, use the first simulation model to simulate the photovoltaic transmission system to obtain the maximum power transmission of the photovoltaic transmission system, and use the first simulation model to simulate the photovoltaic transmission system under the maximum power transmission to obtain the reactive power compensation capacity of each collection station, thereby obtaining a first reactive power compensation capacity set. The second data acquisition module is used to simulate the photovoltaic power transmission system based on the first power transmission power, the second power transmission power, the third power transmission power and the fourth power transmission power, using the first simulation model to obtain the reactive power compensation capacity of each collection station under the corresponding power transmission power, and to obtain the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set and the fifth reactive power compensation capacity set. The solution module is used to simulate the photovoltaic power transmission system in the second simulation model by gradually increasing the power transmission power in the order of the first power transmission power, the second power transmission power, the third power transmission power, and the fourth power transmission power, based on the second reactive power compensation capacity set, the third reactive power compensation capacity set, the fourth reactive power compensation capacity set, and the fifth reactive power compensation capacity set. This ensures that the voltage of the photovoltaic power transmission system remains within a reasonable range during the simulation process until the voltage of the photovoltaic power transmission system becomes unstable. The power transmission power before the voltage of the photovoltaic power transmission system becomes unstable is then obtained as the static stable power limit of the photovoltaic power transmission system. Wherein, the first power supply is 0, the second power supply is 0.3 times the maximum power supply, the third power supply is 0.5 times the maximum power supply, and the fourth power supply is 0.7 times the maximum power supply.

5. The static stability limit solver for a photovoltaic power transmission system according to claim 4, characterized in that, The solution module includes a model building submodule, a simulation submodule, and a simulation solution submodule; The model construction submodule is used to set parameter data on the second simulation model. The parameter data includes a first power transmission power, a second power transmission power, a third power transmission power, a fourth power transmission power, a second reactive power compensation capacity set, a third reactive power compensation capacity set, a fourth reactive power compensation capacity set, and a fifth reactive power compensation capacity set. The simulation submodule is used to start the second simulation model to simulate the photovoltaic power transmission system. During the simulation, the photovoltaic power station of each collection station is unlocked, the power transmission power of the photovoltaic power transmission system is sequentially increased to the second power transmission power, the third power transmission power, and the fourth power transmission power, and the reactive power compensation capacity of each collection station is switched accordingly. The simulation solution submodule is used to control each collection station of the photovoltaic power transmission system to connect to a dynamic reactive power compensation device with continuous reactive power output during the simulation of the photovoltaic power transmission system in the second simulation model. The dynamic reactive power compensation device is controlled to operate with the bus voltage of the AC line until the voltage of the photovoltaic power transmission system becomes unstable.

6. The static stability limit solver for a photovoltaic power transmission system according to claim 4, characterized in that, The first data acquisition module is also used to acquire the grid topology and operating parameters of the photovoltaic transmission system, and construct a second simulation model based on the first simulation model in combination with the grid topology and the operating parameters; the operating parameters include the voltage, impedance, capacity and control type of each component in the photovoltaic transmission system.

7. A storage device storing a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by a processor to perform the static stability limit solution method for a photovoltaic power transmission system as described in any one of claims 1-3.

8. A terminal device, characterized in that, Including the processor and memory; The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the static stability limit solution method for the photovoltaic power transmission system as described in any one of claims 1-3, according to the instructions in the program code.

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