A co-control method and system of a new energy and thermal power bundled direct current external transmission system

Abstract

The application relates to a coordinated control method of a new energy and thermal power bundled direct current external transmission system, which comprises the following steps: controlling the output power of a grid commutated rectifier in the new energy and thermal power bundled direct current external transmission system by using pre-acquired direct current rectifier side power / frequency control parameters; wherein the pre-acquired direct current rectifier side power / frequency control parameters are acquired by testing the direct current rectifier side power / frequency control parameters of a new energy and thermal power bundled direct current external transmission simulation system. The technical scheme provided by the application takes the fluctuant new energy output as the support of traditional direct current output, controls the output power of the grid commutated rectifier based on the direct current rectifier side power / frequency control parameters, improves the reliability and new energy transmission capacity of the system, reduces the influence of the new energy output fluctuation on the thermal power unit speed regulation, and thus reduces the influence of the new energy fluctuation on the direct current external transmission system.

Description

Technical Field

[0001] This invention belongs to the field of power system coordination and control, specifically relating to a coordination and control method and system for a DC transmission system that bundles new energy and thermal power. Background Technology

[0002] With the rapid development of power transmission technology, high voltage direct current (HVDC) transmission has become a very important practical tool for improving the transmission capacity of existing transmission systems. Based on this, large-scale wind power typically uses HVDC (line commutated converter-high voltage direct current, LCC-HVDC) based on grid commutated converters for power transmission.

[0003] When large-scale wind power is connected to the grid using LCC-HVDC, the sending-end LCC-HVDC is considered a passive load. If there is no AC voltage source to support it at the grid connection point, the LCC converter may not be able to commutate normally. Therefore, the idea of ​​bundling new energy with thermal power for transmission has been proposed. A certain number of synchronous thermal power units are configured in the sending-end grid to provide synchronous support, so as to realize the effective transmission of new energy.

[0004] However, the bundled transmission scheme of new energy and thermal power has certain limitations, especially the need to configure a large number of thermal power plants in new energy bases. This means that while developing new energy, a certain amount of installed thermal power capacity must also be provided locally. This scheme has two drawbacks: firstly, fluctuations in the output of new energy power plants affect the frequency of the AC bus on the LCC rectifier side, thus changing the transmission power at the LCC sending end; secondly, the frequency of the AC bus on the LCC rectifier side is related to the speed of the thermal power units. To address the fluctuations in new energy output, the thermal power units need frequent adjustments, and the speed control system of the thermal power units affects their output, increasing the risk of the entire system's operation. Therefore, it is necessary to propose a collaborative control method and system for a bundled DC transmission system of new energy and thermal power to reduce the impact of new energy output fluctuations on the speed control of thermal power units. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a collaborative control method and system for a combined renewable energy and thermal power DC transmission system to reduce the impact of renewable energy output fluctuations on the speed regulation of thermal power units. By utilizing the power / frequency control parameters on the DC rectifier side, the output power of the grid-commutated rectifier in the combined renewable energy and thermal power DC transmission system is controlled, thereby reducing the impact of renewable energy fluctuations on the DC transmission system.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] An improved method for coordinated control of a DC transmission system combining new energy and thermal power, wherein the method includes:

[0008] The output power of the grid-commutated rectifier in the DC power transmission system bundled with new energy and thermal power is controlled by using the pre-acquired power / frequency control parameters on the DC rectifier side.

[0009] The pre-acquired DC rectifier-side power / frequency control parameters are obtained by testing the DC rectifier-side power / frequency control parameters of a simulation system for bundled DC transmission of new energy and thermal power.

[0010] Preferably, the process of obtaining the pre-acquired DC rectifier-side power / frequency control parameters by testing the DC rectifier-side power / frequency control parameters of a simulation system for bundled DC transmission of new energy and thermal power includes:

[0011] Establish a simulation system for bundled DC power transmission of new energy and thermal power;

[0012] The power / frequency control parameters of the DC rectifier side were tested in a simulation system for DC transmission of new energy and thermal power bundled together, and the pre-acquired power / frequency control parameters of the DC rectifier side were obtained.

[0013] Furthermore, the simulation system for bundled DC transmission of new energy and thermal power includes: a thermal power plant simulation module, a new energy power plant simulation module, a voltage source converter simulation module, a transformer simulation module, a grid commutation rectifier simulation module, a grid commutation inverter simulation module, and a load center simulation module;

[0014] The thermal power plant simulation module is connected to the input terminal of the power grid commutator simulation module through the transformer simulation module;

[0015] The new energy power plant simulation module is connected to the input terminal of the power grid commutator simulation module in sequence through the voltage source converter simulation module and the transformer simulation module;

[0016] The output of the grid commutated rectifier simulation module is connected to the input of the grid commutated inverter simulation module, and the output of the grid commutated inverter simulation module is connected to the load center simulation module.

[0017] Specifically, the mathematical model for the output power of the power grid commutator simulation module is determined by the following formula:

[0018] P LCCr =P LCCr0 +K f0 (f-f0)

[0019] In the formula, P LCCr P represents the output power of the grid commutator rectifier simulation module. LCCr0 K represents the initial power of the grid commutator rectifier simulation module. f0These are the power / frequency test parameters for the DC rectifier side, where f is the AC bus frequency of the grid commutator rectifier simulation module, and f0 is the rated AC bus frequency of the grid commutator rectifier simulation module.

[0020] Specifically, the mathematical model for the output power of the thermal power plant simulation module is determined by the following formula:

[0021] P g =P g0 +K ω *(ω0-ω)

[0022] In the formula, P g P represents the output power of the thermal power plant simulation module. g0 K represents the initial output power of the thermal power plant simulation module. ω ω represents the slope of the power / speed droop curve; ω represents the speed of the thermal power unit in the thermal power plant simulation module; and ω0 represents the rated speed of the thermal power unit in the thermal power plant simulation module.

[0023] The relationship between ω and the AC bus frequency f of the grid commutator is as follows:

[0024]

[0025] In the formula, p is the number of pole pairs of the thermal power unit.

[0026] Specifically, the mathematical model for the output power of the new energy power station simulation module is determined by the following formula:

[0027] P V =P L C C r -P g

[0028] In the formula, P V P represents the output power of the new energy power plant simulation module. LCCr P represents the output power of the grid commutator rectifier simulation module. g This represents the output power of the thermal power plant simulation module.

[0029] Specifically, the test of the DC rectifier-side power / frequency control parameters of the simulation system for bundled DC transmission of new energy and thermal power, and the acquisition of the pre-acquired DC rectifier-side power / frequency control parameters, includes:

[0030] Continuously adjust the power / frequency test parameters on the DC rectifier side, and adjust the output power of the new energy power plant simulation module to the first initial value P. Vm Second initial value P Vn The output power of the new energy power station simulation module is set to the first initial value P. VmThe corresponding output power P of the thermal power plant simulation module at that time gm The output power of the new energy power plant simulation module is the second initial value P. Vn The corresponding output power P of the thermal power plant simulation module at that time gn The DC rectifier side power / frequency test parameters corresponding to the minimum absolute value of the difference between them are used as the pre-acquired DC rectifier side power / frequency control parameters.

[0031] Specifically, controlling the output power of the grid-commutated rectifier in the DC power transmission system bundled with new energy and thermal power using pre-acquired DC rectifier-side power / frequency control parameters includes:

[0032] The output power P of the grid commutator is determined by the following formula. LCCr ':

[0033] P LCCr '=P LCCr0 '+K f (f'-f0')

[0034] In the formula, P LCCr0 'K' represents the initial power of the grid commutator rectifier. f The power / frequency control parameters for the DC rectifier side are obtained in advance, f' is the AC bus frequency of the grid commutated rectifier, and f0' is the rated AC bus frequency of the grid commutated rectifier.

[0035] An improvement of a coordinated control system for a new energy and thermal power bundled DC transmission system is that the coordinated control system includes:

[0036] The co-control unit is used to control the output power of the grid commutator in the DC power transmission system bundled with new energy and thermal power using pre-acquired power / frequency control parameters on the DC rectifier side;

[0037] The pre-acquired DC rectifier-side power / frequency control parameters are obtained by testing the DC rectifier-side power / frequency control parameters of a simulation system for bundled DC transmission of new energy and thermal power.

[0038] Preferably, the collaborative control system further includes:

[0039] The building unit is used to build a simulation system for bundled DC power transmission of new energy and thermal power.

[0040] The acquisition unit is used to test the DC rectifier-side power / frequency control parameters of the simulation system for DC transmission of new energy and thermal power bundled together, and to acquire the pre-acquired DC rectifier-side power / frequency control parameters.

[0041] Furthermore, the simulation system for bundled DC transmission of new energy and thermal power includes: a thermal power plant simulation module, a new energy power plant simulation module, a voltage source converter simulation module, a transformer simulation module, a grid commutation rectifier simulation module, a grid commutation inverter simulation module, and a load center simulation module;

[0042] The thermal power plant simulation module is connected to the input terminal of the power grid commutator simulation module through the transformer simulation module;

[0043] The new energy power plant simulation module is connected to the input terminal of the power grid commutator simulation module in sequence through the voltage source converter simulation module and the transformer simulation module;

[0044] The output of the grid commutated rectifier simulation module is connected to the input of the grid commutated inverter simulation module, and the output of the grid commutated inverter simulation module is connected to the load center simulation module.

[0045] Specifically, the mathematical model for the output power of the power grid commutator simulation module is determined by the following formula:

[0046] P LCCr =P LCCr0 +K f0 (f-f0)

[0047] In the formula, P LCCr P represents the output power of the grid commutator rectifier simulation module. LCCr0 K represents the initial power of the grid commutator rectifier simulation module. f0 These are the power / frequency test parameters for the DC rectifier side, where f is the AC bus frequency of the grid commutator rectifier simulation module, and f0 is the rated AC bus frequency of the grid commutator rectifier simulation module.

[0048] Specifically, the mathematical model for the output power of the thermal power plant simulation module is determined by the following formula:

[0049] P g =P g0 +K ω *(ω0-ω)

[0050] In the formula, P g P represents the output power of the thermal power plant simulation module. g0 K represents the initial output power of the thermal power plant simulation module. ω ω represents the slope of the power / speed droop curve; ω represents the speed of the thermal power unit in the thermal power plant simulation module; and ω0 represents the rated speed of the thermal power unit in the thermal power plant simulation module.

[0051] The relationship between ω and the AC bus frequency f of the grid commutator is as follows:

[0052]

[0053] In the formula, p is the number of pole pairs of the thermal power unit.

[0054] Specifically, the mathematical model for the output power of the new energy power station simulation module is determined by the following formula:

[0055] P V =P LCCr -P g

[0056] In the formula, P V P represents the output power of the new energy power plant simulation module. LCCr P represents the output power of the grid commutator rectifier simulation module. g This represents the output power of the thermal power plant simulation module.

[0057] Specifically, the acquisition unit is used for:

[0058] Continuously adjust the power / frequency test parameters on the DC rectifier side, and adjust the output power of the new energy power plant simulation module to the first initial value P. Vm Second initial value P Vn The output power of the new energy power station simulation module is set to the first initial value P. Vm The corresponding output power P of the thermal power plant simulation module at that time gm The output power of the new energy power plant simulation module is the second initial value P. Vn The corresponding output power P of the thermal power plant simulation module at that time gn The DC rectifier side power / frequency test parameters corresponding to the minimum absolute value of the difference between them are used as the pre-acquired DC rectifier side power / frequency control parameters.

[0059] Specifically, the co-control unit is used for:

[0060] The output power P of the grid commutator is determined by the following formula. LCCr ':

[0061] P LCCr '=P LCCr0 '+K f (f'-f0')

[0062] In the formula, P LCCr0 'K' represents the initial power of the grid commutator rectifier. f The power / frequency control parameters for the DC rectifier side are obtained in advance, f' is the AC bus frequency of the grid commutated rectifier, and f0' is the rated AC bus frequency of the grid commutated rectifier.

[0063] Compared with the closest existing technology, the beneficial effects of this invention are reflected in:

[0064] The technical solution provided by this invention aims to mitigate the impact of renewable energy fluctuations on DC power transmission systems. It proposes a collaborative control method and system for renewable energy and thermal power-bearing DC power transmission systems. This method fully utilizes the flexibility of existing long-distance DC transmission lines from thermal power bases and voltage source converters in flexible DC transmission systems. It uses fluctuating renewable energy output as a support for traditional DC power transmission. Based on the power / frequency control parameters of the DC rectifier side, it controls the output power of the grid commutator rectifier, improving system reliability and renewable energy transmission capacity, reducing the impact of renewable energy output fluctuations on the speed regulation of thermal power units, and thus mitigating the impact of renewable energy fluctuations on the DC power transmission system. Attached Figure Description

[0065] Figure 1 This is a flowchart of a collaborative control method for a new energy and thermal power bundled DC transmission system according to an embodiment of the present invention;

[0066] Figure 2 This is a schematic diagram of the structure of the simulation system for bundled DC power transmission of new energy and thermal power in an embodiment of the present invention;

[0067] Figure 3 This is a simulation curve diagram of the DC transmission simulation system for bundled new energy and thermal power in an embodiment of the present invention;

[0068] Figure 4 This is a schematic diagram of the structure of a collaborative control system for a new energy and thermal power bundled DC transmission system in an embodiment of the present invention. Detailed Implementation

[0069] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0070] 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 embodiments of the present invention, not all embodiments. 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.

[0071] This invention provides a collaborative control method for a DC transmission system that bundles new energy and thermal power, such as... Figure 1 As shown, the method includes:

[0072] Establish a simulation system for bundled DC power transmission of new energy and thermal power;

[0073] The power / frequency control parameters of the DC rectifier side are tested in a simulation system for DC transmission of new energy and thermal power bundled together, and the pre-acquired power / frequency control parameters of the DC rectifier side are obtained.

[0074] The output power of the grid-commutated rectifier in the DC power transmission system bundled with new energy and thermal power is controlled by using the pre-acquired power / frequency control parameters on the DC rectifier side.

[0075] Furthermore, the aforementioned simulation system for bundled DC transmission of new energy and thermal power is as follows: Figure 2 As shown, the simulation system includes: a thermal power plant simulation module, a new energy power plant simulation module, a voltage source converter simulation module, a transformer simulation module, a grid commutated rectifier simulation module, a grid commutated inverter simulation module, and a load center simulation module;

[0076] The thermal power plant simulation module is connected to the input terminal of the power grid commutator simulation module through the transformer simulation module;

[0077] The new energy power plant simulation module is connected to the input terminal of the power grid commutator simulation module in sequence through the voltage source converter simulation module and the transformer simulation module;

[0078] The output of the grid commutated rectifier simulation module is connected to the input of the grid commutated inverter simulation module, and the output of the grid commutated inverter simulation module is connected to the load center simulation module.

[0079] Specifically, the mathematical model for the output power of the power grid commutator simulation module is determined by the following formula:

[0080] P LCCr =P LCCr0 +K f0 (f-f0)

[0081] In the formula, P LCCr P represents the output power of the grid commutator rectifier simulation module. LCCr0 K represents the initial power of the grid commutator rectifier simulation module. f0 These are the power / frequency test parameters for the DC rectifier side, where f is the AC bus frequency of the grid commutator rectifier simulation module, and f0 is the rated AC bus frequency of the grid commutator rectifier simulation module.

[0082] Specifically, the mathematical model for the output power of the thermal power plant simulation module is determined by the following formula:

[0083] P g =P g0 +K ω *(ω0-ω)

[0084] In the formula, P g P represents the output power of the thermal power plant simulation module. g0 K represents the initial output power of the thermal power plant simulation module. ωω represents the slope of the power / speed droop curve; ω represents the speed of the thermal power unit in the thermal power plant simulation module; and ω0 represents the rated speed of the thermal power unit in the thermal power plant simulation module.

[0085] The relationship between ω and the AC bus frequency f of the grid commutator is as follows:

[0086]

[0087] In the formula, p is the number of pole pairs of the thermal power unit.

[0088] Specifically, the mathematical model for the output power of the new energy power station simulation module is determined by the following formula:

[0089] P V =P L C C r -P g

[0090] In the formula, P V P represents the output power of the new energy power plant simulation module. LCCr P represents the output power of the grid commutator rectifier simulation module. g This represents the output power of the thermal power plant simulation module.

[0091] Specifically, the test of the DC rectifier-side power / frequency control parameters of the simulation system for bundled DC transmission of new energy and thermal power, and the acquisition of the pre-acquired DC rectifier-side power / frequency control parameters, includes:

[0092] Adjust the DC rectifier side power / frequency test parameters to K f1 And respectively adjust the output power of the new energy power station simulation module to the first initial value P. V1 Second initial value P V2 P V1 The corresponding AC bus frequency of the grid commutator rectifier simulation module is f1, P V1 The corresponding thermal power plant simulation module outputs power P. g1 P V2 The corresponding AC bus frequency of the grid commutator rectifier simulation module is f2, P V2 The corresponding thermal power plant simulation module outputs power P. g2 Adjust the DC rectifier side power / frequency test parameters to K. f2 And K f2 >K f1 The output power of the new energy power station simulation module is adjusted to the first initial value P. V1 Second initial value P V2 P V1The corresponding AC bus frequency of the grid commutator rectifier simulation module is f1', P V1 The corresponding thermal power plant simulation module outputs power P. g1 ', P V2 The corresponding AC bus frequency of the grid commutator rectifier simulation module is f2', P V2 The corresponding thermal power plant simulation module outputs power P. g2 ',like Figure 3 As shown, we can obtain |P g2 '-P g1 '|<|P g2 -P g1 | That is, the change in output power of the new energy power plant simulation module is P V2 —P V1 In this case, increasing the DC rectifier side power / frequency test parameters reduces the change in output power of the thermal power plant simulation module corresponding to the change in output power of the new energy power plant simulation module. Therefore, without causing system power oscillation, the maximum value of the DC rectifier side power / frequency test parameters is taken as the pre-acquired DC rectifier side power / frequency control parameters.

[0093] Specifically, controlling the output power of the grid-commutated rectifier in the DC power transmission system bundled with new energy and thermal power using pre-acquired DC rectifier-side power / frequency control parameters includes:

[0094] The output power P of the grid commutator is determined by the following formula. LCCr ':

[0095] P LCCr '=P LCCr0 '+K f (f'-f0')

[0096] In the formula, P LCCr0 'K' represents the initial power of the grid commutator rectifier. f The power / frequency control parameters for the DC rectifier side are obtained in advance, f' is the AC bus frequency of the grid commutated rectifier, and f0' is the rated AC bus frequency of the grid commutated rectifier.

[0097] Based on the above solution, the present invention also provides a coordinated control system for a new energy and thermal power bundled DC transmission system, such as... Figure 4 As shown, the collaborative control system includes:

[0098] The co-control unit is used to control the output power of the grid commutator in the DC power transmission system bundled with new energy and thermal power using pre-acquired power / frequency control parameters on the DC rectifier side;

[0099] The pre-acquired DC rectifier-side power / frequency control parameters are obtained by testing the DC rectifier-side power / frequency control parameters of a simulation system for bundled DC transmission of new energy and thermal power.

[0100] Furthermore, the collaborative control system also includes:

[0101] The building unit is used to build a simulation system for bundled DC power transmission of new energy and thermal power.

[0102] The acquisition unit is used to test the DC rectifier-side power / frequency control parameters of the simulation system for DC transmission of new energy and thermal power bundled together, and to acquire the pre-acquired DC rectifier-side power / frequency control parameters.

[0103] Specifically, the simulation system for bundled DC transmission of new energy and thermal power includes: a thermal power plant simulation module, a new energy power plant simulation module, a voltage source converter simulation module, a transformer simulation module, a grid commutation rectifier simulation module, a grid commutation inverter simulation module, and a load center simulation module;

[0104] The thermal power plant simulation module is connected to the input terminal of the power grid commutator simulation module through the transformer simulation module;

[0105] The new energy power plant simulation module is connected to the input terminal of the power grid commutator simulation module in sequence through the voltage source converter simulation module and the transformer simulation module;

[0106] The output of the grid commutated rectifier simulation module is connected to the input of the grid commutated inverter simulation module, and the output of the grid commutated inverter simulation module is connected to the load center simulation module.

[0107] Specifically, the mathematical model for the output power of the power grid commutator simulation module is determined by the following formula:

[0108] P LCCr =P LCCr0 +K f0 (f-f0)

[0109] In the formula, P LCCr P represents the output power of the grid commutator rectifier simulation module. LCCr0 K represents the initial power of the grid commutator rectifier simulation module. f0 These are the power / frequency test parameters for the DC rectifier side, where f is the AC bus frequency of the grid commutator rectifier simulation module, and f0 is the rated AC bus frequency of the grid commutator rectifier simulation module.

[0110] Specifically, the mathematical model for the output power of the thermal power plant simulation module is determined by the following formula:

[0111] P g =Pg0 +K ω *(ω0-ω)

[0112] In the formula, P g P represents the output power of the thermal power plant simulation module. g0 K represents the initial output power of the thermal power plant simulation module. ω ω represents the slope of the power / speed droop curve; ω represents the speed of the thermal power unit in the thermal power plant simulation module; and ω0 represents the rated speed of the thermal power unit in the thermal power plant simulation module.

[0113] The relationship between ω and the AC bus frequency f of the grid commutator is as follows:

[0114]

[0115] In the formula, p is the number of pole pairs of the thermal power unit.

[0116] Specifically, the mathematical model for the output power of the new energy power station simulation module is determined by the following formula:

[0117] P V =P LCCr -P g

[0118] In the formula, P V P represents the output power of the new energy power plant simulation module. LCCr P represents the output power of the grid commutator rectifier simulation module. g This represents the output power of the thermal power plant simulation module.

[0119] Specifically, the acquisition unit is used for:

[0120] Continuously adjust the power / frequency test parameters on the DC rectifier side, and adjust the output power of the new energy power plant simulation module to the first initial value P. Vm Second initial value P Vn The output power of the new energy power station simulation module is set to the first initial value P. Vm The corresponding output power P of the thermal power plant simulation module at that time gm The output power of the new energy power plant simulation module is the second initial value P. Vn The corresponding output power P of the thermal power plant simulation module at that time gn The DC rectifier side power / frequency test parameters corresponding to the minimum absolute value of the difference between them are used as the pre-acquired DC rectifier side power / frequency control parameters.

[0121] Specifically, the co-control unit is used for:

[0122] The output power P of the grid commutator is determined by the following formula. LCCr ':

[0123] P LCCr '=P LCCr0 '+K f (f'-f0')

[0124] In the formula, P LCCr0 'K' represents the initial power of the grid commutator rectifier. f The power / frequency control parameters for the DC rectifier side are obtained in advance, f' is the AC bus frequency of the grid commutated rectifier, and f0' is the rated AC bus frequency of the grid commutated rectifier.

[0125] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for coordinated control of a DC transmission system combining new energy and thermal power, characterized in that, The method includes: The output power of the grid-commutated rectifier in the DC power transmission system bundled with new energy and thermal power is controlled by using the pre-acquired power / frequency control parameters on the DC rectifier side. The pre-acquired DC rectifier-side power / frequency control parameters are obtained by testing the DC rectifier-side power / frequency control parameters of a simulation system for bundled DC transmission of new energy and thermal power. The process of obtaining the pre-acquired DC rectifier-side power / frequency control parameters by testing the DC rectifier-side power / frequency control parameters of a simulation system for bundled DC transmission of new energy and thermal power includes: Establish a simulation system for bundled DC power transmission of new energy and thermal power; The power / frequency control parameters of the DC rectifier side are tested in a simulation system for DC transmission of new energy and thermal power bundled together, and the pre-acquired power / frequency control parameters of the DC rectifier side are obtained. Continuously adjust the power / frequency test parameters on the DC rectifier side, and respectively adjust the output power of the new energy power plant simulation module in the new energy and thermal power bundled DC transmission simulation system to the first initial value. Second initial value The output power of the new energy power plant simulation module is set to the first initial value. The time corresponds to the output power of the thermal power plant simulation module in the aforementioned simulation system for bundled DC transmission of new energy and thermal power. The output power of the new energy power plant simulation module is the second initial value. The corresponding output power of the thermal power plant simulation module The DC rectifier side power / frequency test parameters corresponding to the minimum absolute value of the difference between them are used as the pre-acquired DC rectifier side power / frequency control parameters. The mathematical model for the output power of the new energy power plant simulation module in the new energy and thermal power bundled DC transmission simulation system is determined by the following formula: In the formula, The output power of the new energy power plant simulation module. The output power of the grid commutator rectifier simulation module. The output power of the thermal power plant simulation module; The mathematical model for the output power of the grid commutator simulation module in the new energy and thermal power bundled DC transmission simulation system is determined by the following formula: In the formula, The output power of the grid commutator rectifier simulation module. P LCCr 0 The initial power of the grid commutator rectifier simulation module is given. K f 0 These are the power / frequency test parameters for the DC rectifier side. f This refers to the AC bus frequency of the power grid commutator rectifier simulation module. f 0 represents the rated AC bus frequency of the power grid commutator rectifier simulation module; The mathematical model for the output power of the thermal power plant simulation module in the new energy and thermal power bundled DC transmission simulation system is determined by the following formula: In the formula, The output power of the thermal power plant simulation module. P g0 This represents the initial output power of the thermal power plant simulation module. The slope of the power / speed droop curve; This refers to the rotational speed of thermal power units in the thermal power plant simulation module. The rated speed of the thermal power unit in the thermal power plant simulation module; in, AC bus frequency of the grid commutator f The relationship is: In the formula, p This represents the number of pole pairs in a thermal power unit.

2. The method as described in claim 1, characterized in that, The simulation system for bundled DC transmission of new energy and thermal power includes: a thermal power plant simulation module, a new energy power plant simulation module, a voltage source converter simulation module, a transformer simulation module, a grid commutated rectifier simulation module, a grid commutated inverter simulation module, and a load center simulation module. The thermal power plant simulation module is connected to the input terminal of the power grid commutator simulation module through the transformer simulation module; The new energy power plant simulation module is connected to the input terminal of the power grid commutator simulation module in sequence through the voltage source converter simulation module and the transformer simulation module; The output of the grid commutated rectifier simulation module is connected to the input of the grid commutated inverter simulation module, and the output of the grid commutated inverter simulation module is connected to the load center simulation module.

3. The method as described in claim 1, characterized in that, The method of controlling the output power of the grid-commutated rectifier in the DC power transmission system bundled with new energy and thermal power using pre-acquired DC rectifier-side power / frequency control parameters includes: The output power of the grid commutator rectifier is determined by the following formula. : In the formula, This represents the initial power of the grid commutator rectifier. For the pre-acquired power / frequency control parameters on the DC rectifier side, This refers to the AC bus frequency of the power grid commutator rectifier. This is the rated AC bus frequency of the power grid commutator.

4. A coordinated control system for a new energy and thermal power bundled DC transmission system, characterized in that, The collaborative control system includes: The co-control unit is used to control the output power of the grid commutator in the DC power transmission system bundled with new energy and thermal power using pre-acquired power / frequency control parameters on the DC rectifier side; The pre-acquired DC rectifier-side power / frequency control parameters are obtained by testing the DC rectifier-side power / frequency control parameters of a simulation system for bundled DC transmission of new energy and thermal power. The collaborative control system also includes: The building unit is used to build a simulation system for bundled DC power transmission of new energy and thermal power. The acquisition unit is used to test the DC rectifier-side power / frequency control parameters of the simulation system for DC transmission of new energy and thermal power bundled together, and to acquire the pre-acquired DC rectifier-side power / frequency control parameters. The acquisition unit is specifically used for: Continuously adjust the power / frequency test parameters on the DC rectifier side, and respectively adjust the output power of the new energy power plant simulation module in the new energy and thermal power bundled DC transmission simulation system to the first initial value. Second initial value The output power of the new energy power plant simulation module is set to the first initial value. The time corresponds to the output power of the thermal power plant simulation module in the aforementioned simulation system for bundled DC transmission of new energy and thermal power. The output power of the new energy power plant simulation module is the second initial value. The corresponding output power of the thermal power plant simulation module The DC rectifier side power / frequency test parameters corresponding to the minimum absolute value of the difference between them are used as the pre-acquired DC rectifier side power / frequency control parameters. The mathematical model for the output power of the new energy power plant simulation module in the new energy and thermal power bundled DC transmission simulation system is determined by the following formula: In the formula, The output power of the new energy power plant simulation module. The output power of the grid commutator rectifier simulation module. The output power of the thermal power plant simulation module; The mathematical model for the output power of the grid commutator simulation module in the new energy and thermal power bundled DC transmission simulation system is determined by the following formula: In the formula, The output power of the grid commutator rectifier simulation module. P LCCr 0 The initial power of the grid commutator rectifier simulation module is given. K f 0 These are the power / frequency test parameters for the DC rectifier side. f This refers to the AC bus frequency of the power grid commutator rectifier simulation module. f 0 represents the rated AC bus frequency of the power grid commutator rectifier simulation module; The mathematical model for the output power of the thermal power plant simulation module in the new energy and thermal power bundled DC transmission simulation system is determined by the following formula: In the formula, The output power of the thermal power plant simulation module. P g0 This represents the initial output power of the thermal power plant simulation module. The slope of the power / speed droop curve; This refers to the rotational speed of thermal power units in the thermal power plant simulation module. The rated speed of the thermal power unit in the thermal power plant simulation module; in, AC bus frequency of the grid commutator f The relationship is: In the formula, p This represents the number of pole pairs in a thermal power unit.

5. The collaborative control system as described in claim 4, characterized in that, The simulation system for bundled DC transmission of new energy and thermal power includes: a thermal power plant simulation module, a new energy power plant simulation module, a voltage source converter simulation module, a transformer simulation module, a grid commutated rectifier simulation module, a grid commutated inverter simulation module, and a load center simulation module. The thermal power plant simulation module is connected to the input terminal of the power grid commutator simulation module through the transformer simulation module; The new energy power plant simulation module is connected to the input terminal of the power grid commutator simulation module in sequence through the voltage source converter simulation module and the transformer simulation module; The output of the grid commutated rectifier simulation module is connected to the input of the grid commutated inverter simulation module, and the output of the grid commutated inverter simulation module is connected to the load center simulation module.

6. The collaborative control system as described in claim 4, characterized in that, The co-control unit is specifically used for: The output power of the grid commutator rectifier is determined by the following formula. : In the formula, This represents the initial power of the grid commutator rectifier. For the pre-acquired power / frequency control parameters on the DC rectifier side, This refers to the AC bus frequency of the power grid commutator rectifier. This is the rated AC bus frequency of the power grid commutator.

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