A method for coordinated control of the sending-end frequency of a hybrid DC system

Abstract

This invention discloses a hybrid DC system sending-end frequency coordination control method, belonging to the field of DC system sending-end frequency coordination control technology. It includes a transmission control system, a hybrid DC station control system, and a frequency coordination control module. The transmission control system is electrically connected to the hybrid DC station control system, which is electrically connected to a transmission monitoring module. The output of the transmission monitoring module is electrically connected to a system frequency modulation analysis module. This hybrid DC system sending-end frequency coordination control method features primary frequency modulation control, which can quickly perform emergency modulation of the DC transmission system, thereby more effectively improving the frequency stability of the DC system sending end. Secondary frequency modulation control can comprehensively coordinate and modulate various DC systems, achieving stable and balanced adaptive frequency modulation, thus improving system frequency stability. Therefore, the cooperation between primary and secondary frequency modulation control makes the control method more effective and flexible, and provides stronger adaptability to power system operating modes.

Description

Technical Field

[0001] This invention relates to the field of frequency coordination control technology for DC system transmitters, specifically a method for frequency coordination control of hybrid DC systems transmitters. Background Technology

[0002] In substations, DC systems provide reliable DC power for control, signaling, protection, automatic devices, and emergency lighting. The sending end refers to the end where electrical energy is output, often also called the high-voltage side. The sending-end grid refers to a regional power grid with abundant power sources that primarily outputs power to the main grid; the sending-end system is generally located in a primary energy source area. The sending end of a hybrid DC system refers to a system that transmits electrical energy from a power plant to a hybrid DC transmission line. Its operation is crucial for ensuring the stable operation of the power grid and the efficiency of power transmission.

[0003] Existing DC system sending-end frequency coordination control methods typically involve directly coordinating and modulating each DC system to alleviate power imbalance after a disturbance in the DC sending-end frequency. This involves a large number of DC systems requiring coordinated control, resulting in a long modulation process. This makes it difficult to quickly perform emergency modulation on the sending end of the hybrid DC system in the first instance, thus limiting the effectiveness of the coordination control method.

[0004] Therefore, in view of this, we study and improve the existing structure and its shortcomings, and propose a hybrid DC system sending-end frequency coordination control method. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for coordinated frequency control at the sending end of a hybrid DC system, which solves the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a hybrid DC system sending-end frequency coordination control method, comprising a transmission control system, a hybrid DC station control system, and a frequency coordination control module. The transmission control system is electrically connected to the hybrid DC station control system, which is electrically connected to a transmission monitoring module. The transmission monitoring module is used to monitor the power parameter data of the hybrid DC station control system in real time to determine the current operating status of the power system. The output of the transmission monitoring module is electrically connected to a system frequency modulation analysis module, which is used to analyze whether to perform system frequency modulation based on the current operating status of the power system. The output of the system frequency modulation analysis module is electrically connected to a frequency coordination control module, which is used to perform frequency coordination control on the DC sending-end system. The frequency coordination control module includes a primary frequency modulation module and a secondary frequency modulation module, with the primary frequency modulation module electrically connected to the secondary frequency modulation module. Both the primary and secondary frequency modulation modules are electrically connected to a modulation execution module, which is electrically connected to a modulation feedback module. The modulation feedback module is also electrically connected to the transmission control system.

[0007] Furthermore, the hybrid DC station control system includes a conventional DC system and a flexible DC system, and both the conventional DC system and the flexible DC system are used for power transmission at the sending end of the power station.

[0008] Furthermore, the primary frequency modulation module includes a disturbance difference calculation module and a power regulation generation module, and the disturbance difference calculation module is electrically connected to the power regulation generation module. The disturbance difference calculation module is used to calculate the difference between the current frequency and the optimal DC frequency when the DC sending end frequency is disturbed. If the difference is less than the difference between the preset frequency peak and the optimal DC frequency, it directly enters the secondary frequency modulation control; otherwise, it continues the primary frequency modulation control. That is, the DC system that needs to be frequency-modulated is selected according to the disturbance difference calculation result. The power regulation generation module is used to generate a power regulation amount according to the preset frequency peak of the sending end system relative to the current DC power modulation amount.

[0009] Furthermore, the primary frequency regulation module also includes a power regulation analysis module and a sensitivity analysis calculation module. The power regulation generation module is electrically connected to the power regulation analysis module, and the power regulation analysis module is electrically connected to the sensitivity analysis calculation module. The power regulation analysis module is used to analyze the number of high-sensitivity DC transmission systems required for frequency regulation based on the calculation results of the power regulation generation module. The sensitivity analysis calculation module is used to calculate the high-sensitivity DC transmission systems in the current hybrid DC station control based on the power system sensitivity analysis algorithm, and sort them in order.

[0010] Furthermore, the primary frequency modulation module also includes a power transmission emergency modulation module. The sensitivity analysis and calculation module is electrically connected to the power transmission emergency modulation module, and the power transmission emergency modulation module is electrically connected to the modulation execution module. The power transmission emergency modulation module is used to select a required number of highly sensitive DC transmission systems for emergency modulation according to the calculation results of the power regulation analysis module and the sensitivity analysis and calculation module, based on the sensitivity analysis ranking.

[0011] Furthermore, the secondary frequency modulation module includes a disturbance difference recalculation module and a coordinated optimization model construction module, and the disturbance difference recalculation module is electrically connected to the coordinated optimization model construction module. The disturbance difference recalculation module is used to recalculate the disturbance difference after the primary frequency modulation control, and the coordinated optimization model construction module is used to construct a coordinated optimization data model for multiple hybrid DC systems.

[0012] Furthermore, the secondary frequency modulation module also includes a coordination optimization calculation module and a power regulation correction module. The coordination optimization model construction module is electrically connected to the coordination optimization calculation module, and the coordination optimization calculation module is electrically connected to the power regulation correction module. The coordination optimization calculation module is used to substitute the difference calculation data from the disturbance difference recalculation module and use the Lagrange multiplier method to coordinate and optimize the parameter settings of each DC frequency control. The power regulation correction module is used to correct the power regulation after excluding faulty DC frequency limiting controllers.

[0013] Furthermore, the secondary frequency modulation module also includes a power transmission coordination modulation module. The power regulation correction module is electrically connected to the power transmission coordination modulation module, and the power transmission coordination modulation module is electrically connected to the modulation execution module. The power transmission coordination modulation module is used to coordinate modulation of each DC system according to the correction result of the power regulation correction module.

[0014] Furthermore, the modulation feedback module is connected to the power transmission system stability assessment module, the modulation execution module is used to perform coordinated control of each DC system through the DC frequency limiting controller, the modulation feedback module is used to feed back the coordinated control results of each DC system to the power transmission control system, and the power transmission system stability assessment module is used to perform stability assessment on the hybrid DC system after adjustment and control.

[0015] Furthermore, the frequency coordination control method includes the following specific steps:

[0016] S1. System Frequency Regulation Analysis: The power parameter data of the hybrid DC station control are monitored in real time by the transmission monitoring module to determine the current operating status of the power system. Then, the system frequency regulation analysis module analyzes whether to perform system frequency regulation based on the current operating status of the power system.

[0017] S2. Primary Frequency Control: The disturbance difference calculation module of the primary frequency control module calculates the difference between the current frequency and the optimal DC frequency when a disturbance occurs at the DC sending end frequency. If the difference is less than the difference between the preset peak frequency and the optimal DC frequency, it directly enters the secondary frequency control; otherwise, it continues the primary frequency control. That is, the DC system that needs to be frequency-modulated is selected based on the disturbance difference calculation result. Then, the power regulation quantity generation module generates the power regulation quantity based on the preset peak frequency of the sending end system relative to the current DC power modulation quantity. Next, the power regulation quantity analysis module analyzes the number of high-sensitivity DC transmission systems required for frequency modulation based on the calculation result of the power regulation quantity generation module. Then, the sensitivity analysis calculation module calculates the high-sensitivity DC transmission systems in the current hybrid DC station control according to the power system sensitivity analysis algorithm and sorts them in order. Finally, the transmission emergency modulation module selects the required number of high-sensitivity DC transmission systems for emergency modulation according to the sensitivity analysis sorting based on the calculation results of the power regulation quantity analysis module and the sensitivity analysis calculation module, and performs coordinated control of each DC system through the modulation execution module.

[0018] S3, Secondary Frequency Control: The disturbance difference after primary frequency control is recalculated by the disturbance difference recalculation module of the secondary frequency control module. Then, the coordinated optimization model construction module constructs a coordinated optimization data model for multiple hybrid DC systems. Next, the coordinated optimization calculation module substitutes the difference calculation data from the disturbance difference recalculation module and uses the Lagrange multiplier method to coordinate and optimize the parameter settings of each DC frequency control. Then, the power regulation correction module corrects the power regulation after excluding the faulty DC frequency limit controller. Finally, the transmission coordinated modulation module performs coordinated modulation on each DC system according to the correction result of the power regulation correction module, and the coordinated control of each DC system is executed by the modulation execution module.

[0019] S4. Modulation result feedback: After the frequency coordination control module performs modulation on the DC sending system, it feeds back the coordination control results of each DC system to the power transmission control system through the modulation feedback module.

[0020] S5. Stability assessment of DC sending end: Finally, the stability of the hybrid DC system after adjustment and control is assessed through the power transmission system stability assessment module.

[0021] This invention provides a hybrid DC system sending-end frequency coordination control method, which has the following beneficial effects: The primary frequency modulation control of this hybrid DC system can quickly perform emergency modulation on the DC transmission system, thereby more effectively improving the frequency stability of the DC system sending end. The secondary frequency modulation control can comprehensively coordinate and modulate each DC system, achieving stable and balanced adaptive frequency modulation, thereby improving system frequency stability. Therefore, the cooperation between primary and secondary frequency modulation control makes the control method more effective and flexible, and has a stronger adaptability to the power system operation mode.

[0022] 1. The hybrid DC system sending-end frequency coordination control method includes a frequency coordination control module. Both conventional DC systems and flexible DC systems are used for power transmission at the sending end of the power plant. The transmission monitoring module is used to monitor the power parameter data of the hybrid DC station control in real time to determine the current operating status of the power system. The system frequency regulation analysis module is used to analyze whether to perform system frequency regulation based on the current operating status of the power system. The frequency coordination control module is used to perform frequency coordination control on the DC sending-end system. The modulation execution module is used to execute the coordination control of each DC system through the DC frequency limit controller. The modulation feedback module is used to feed back the coordination control results of each DC system to the transmission control system. The transmission system stability assessment module is used to perform stability assessment on the hybrid DC system after adjustment and control.

[0023] 2. The hybrid DC system sending-end frequency coordination control method includes a primary frequency modulation module and a disturbance difference calculation module. The latter calculates the difference between the current frequency and the optimal DC frequency when a disturbance occurs at the DC sending-end frequency. If the difference is less than the difference between the preset peak frequency and the optimal DC frequency, the system directly enters secondary frequency modulation control; otherwise, it continues primary frequency modulation control. This means that the DC system requiring primary frequency modulation is selected based on the disturbance difference calculation result. A power regulation generation module generates a power regulation amount based on the preset peak frequency of the sending-end system relative to the current DC power modulation amount. A power regulation analysis module analyzes the number of high-sensitivity DC transmission systems required for frequency modulation based on the calculation results of the power regulation generation module. A sensitivity analysis calculation module calculates the number of high-sensitivity DC transmission systems in the current hybrid DC station control system using a power system sensitivity analysis algorithm and sorts them sequentially. An emergency transmission modulation module selects the required number of high-sensitivity DC transmission systems for emergency modulation based on the calculation results of the power regulation analysis module and the sensitivity analysis calculation module, according to the sensitivity analysis ranking.

[0024] 3. The hybrid DC system sending-end frequency coordination control method includes a secondary frequency modulation module, a disturbance difference recalculation module for recalculating the disturbance difference after primary frequency modulation control, a coordination optimization model construction module for constructing a coordination optimization data model for multiple hybrid DC systems, a coordination optimization calculation module for substituting the difference calculation data from the disturbance difference recalculation module and using the Lagrange multiplier method to coordinate and optimize the parameter settings of each DC frequency control, a power regulation correction module for correcting the power regulation after excluding faulty DC frequency limiting controllers, and a transmission coordination modulation module for coordinating and modulating each DC system based on the correction results from the power regulation correction module to achieve stable and balanced adaptive frequency modulation, thereby improving system frequency stability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the control system framework for a hybrid DC system sending-end frequency coordination control method according to the present invention;

[0026] Figure 2 This is a schematic diagram of the frequency coordination control module structure of the hybrid DC system sending-end frequency coordination control method of the present invention;

[0027] Figure 3 This is a schematic diagram of the primary frequency modulation module structure of the hybrid DC system sending-end frequency coordination control method of the present invention;

[0028] Figure 4 This is a schematic diagram of the secondary frequency modulation module structure of the hybrid DC system sending-end frequency coordination control method of the present invention;

[0029] Figure 5 This is a schematic diagram of the system flow of a hybrid DC system sending-end frequency coordination control method according to the present invention.

[0030] In the diagram: 1. Transmission control system; 2. Hybrid DC station control; 3. Conventional DC system; 4. Flexible DC system; 5. Transmission monitoring module; 6. System frequency modulation analysis module; 7. Frequency coordination control module; 8. Primary frequency modulation module; 801. Disturbance difference calculation module; 802. Power regulation generation module; 803. Power regulation analysis module; 804. Sensitivity analysis calculation module; 805. Transmission emergency modulation module; 9. Secondary frequency modulation module; 901. Disturbance difference recalculation module; 902. Coordination optimization model construction module; 903. Coordination optimization calculation module; 904. Power regulation correction module; 905. Transmission coordinated modulation module; 10. Modulation execution module; 11. Modulation feedback module; 12. Transmission system stability assessment module. Detailed Implementation

[0031] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0032] Please see Figures 1 to 5 This invention provides a technical solution: a method for frequency coordination control at the sending end of a hybrid DC system, comprising a power transmission control system 1, a hybrid DC station control 2, and a frequency coordination control module 7. The power transmission control system 1 is electrically connected to the hybrid DC station control 2, which includes a conventional DC system 3 and a flexible DC system 4. The hybrid DC station control 2 is electrically connected to a power transmission monitoring module 5, and the output of the power transmission monitoring module 5 is electrically connected to a system frequency modulation analysis module 6. The output of the system frequency modulation analysis module 6 is electrically connected to the frequency coordination control module 7. The frequency coordination control module 7 includes a primary frequency modulation module 8 and a secondary frequency modulation module 9, with the primary frequency modulation module 8 electrically connected to the secondary frequency modulation module 9. Both the primary and secondary frequency modulation modules 8 and 9 are electrically connected to a modulation execution module 10, and the modulation execution module 10 is electrically connected to a modulation feedback module 11. The modulation feedback module 11 is also electrically connected to the power transmission control system 1. The modulation feedback module 11 is connected to a power transmission system stability assessment module 12.

[0033] The specific operation is as follows: Conventional DC system 3 and flexible DC system 4 are both used for power transmission in the power plant's sending-end system. Transmission monitoring module 5 is used to monitor the power parameter data of hybrid DC station control 2 in real time to determine the current operating status of the power system. System frequency regulation analysis module 6 is used to analyze whether to perform system frequency regulation based on the current operating status of the power system. Frequency coordination control module 7 is used to perform frequency coordination control on the DC sending-end system. Modulation execution module 10 is used to execute the coordination control of each DC system through the DC frequency limit controller. Modulation feedback module 11 is used to feed back the coordination control results of each DC system to the transmission control system 1. Transmission system stability assessment module 12 is used to perform stability assessment on the hybrid DC system after adjustment and control.

[0034] Please see Figure 2 and Figure 3 The primary frequency modulation module 8 includes a disturbance difference calculation module 801 and a power regulation amount generation module 802, and the disturbance difference calculation module 801 is electrically connected to the power regulation amount generation module 802. The primary frequency modulation module 8 also includes a power regulation amount analysis module 803 and a sensitivity analysis calculation module 804, the power regulation amount generation module 802 is electrically connected to the power regulation amount analysis module 803, and the power regulation amount analysis module 803 is electrically connected to the sensitivity analysis calculation module 804. The primary frequency modulation module 8 also includes a power transmission emergency modulation module 805, the sensitivity analysis calculation module 804 is electrically connected to the power transmission emergency modulation module 805, and the power transmission emergency modulation module 805 is electrically connected to the modulation execution module 10.

[0035] The specific operation is as follows: the disturbance difference calculation module 801 is used to calculate the difference between the current frequency and the optimal DC frequency when the DC sending end frequency is disturbed. If the difference is less than the difference between the preset frequency peak and the optimal DC frequency, it directly enters the secondary frequency modulation control; otherwise, it continues the primary frequency modulation control. That is, the DC system that needs to be frequency-modulated is selected according to the disturbance difference calculation result. The power regulation amount generation module 802 is used to generate the power regulation amount according to the preset frequency peak of the sending end system relative to the current DC power modulation amount. The power regulation amount analysis module 803 is used to analyze the number of high-sensitivity DC transmission systems required for frequency modulation according to the calculation result of the power regulation amount generation module 802. The sensitivity analysis calculation module 804 is used to calculate the high-sensitivity DC transmission systems in the current hybrid DC station control 2 according to the power system sensitivity analysis algorithm and sort them in order. The transmission emergency modulation module 805 is used to select the required number of high-sensitivity DC transmission systems for emergency modulation according to the sensitivity analysis sorting based on the calculation results of the power regulation amount analysis module 803 and the sensitivity analysis calculation module 804.

[0036] Please see Figure 2 and Figure 4 The secondary frequency modulation module 9 includes a disturbance difference recalculation module 901 and a coordination optimization model construction module 902, and the disturbance difference recalculation module 901 is electrically connected to the coordination optimization model construction module 902. The secondary frequency modulation module 9 also includes a coordination optimization calculation module 903 and a power regulation correction module 904, and the coordination optimization model construction module 902 is electrically connected to the coordination optimization calculation module 903, and the coordination optimization calculation module 903 is electrically connected to the power regulation correction module 904. The secondary frequency modulation module 9 also includes a transmission coordination modulation module 905, and the power regulation correction module 904 is electrically connected to the transmission coordination modulation module 905, and the transmission coordination modulation module 905 is electrically connected to the modulation execution module 10.

[0037] The specific operations are as follows: the disturbance difference recalculation module 901 is used to recalculate the disturbance difference after the first frequency modulation control; the coordinated optimization model construction module 902 is used to construct a coordinated optimization data model for multiple hybrid DC systems; the coordinated optimization calculation module 903 is used to substitute the difference calculation data from the disturbance difference recalculation module 901 and use the Lagrange multiplier method to coordinate and optimize the parameter settings of each DC frequency control; the power regulation correction module 904 is used to correct the power regulation after excluding faulty DC frequency limit controllers; and the transmission coordinated modulation module 905 is used to coordinate and modulate each DC system according to the correction result of the power regulation correction module 904.

[0038] In summary, the hybrid DC system sending-end frequency coordination control method, when in use, firstly, the transmission control system 1 transmits power to the power station sending-end system through the conventional DC system 3 and flexible DC system 4 of the hybrid DC station control 2. During this process, the power parameter data of the hybrid DC station control 2 are monitored in real time by the transmission monitoring module 5 to determine the current operating status of the power system. Then, the system frequency regulation analysis module 6 analyzes whether to perform system frequency regulation based on the current operating status of the power system. When DC system modulation is required, the disturbance difference calculation module 801 of the primary frequency regulation module 8 first calculates the difference between the current frequency and the optimal DC frequency when the DC sending-end frequency is disturbed. If the difference is less than the difference between the preset peak frequency and the optimal DC frequency, the secondary frequency regulation control is directly entered; otherwise, the primary frequency regulation control continues. That is, the frequency regulation is selected based on the disturbance difference calculation result. The system selects the DC system requiring frequency modulation. Then, the power regulation generation module 802 generates a power regulation value based on the preset frequency peak value of the sending-end system relative to the current DC power modulation value. Next, the power regulation analysis module 803 analyzes the number of high-sensitivity DC transmission systems required for frequency modulation based on the calculation results of the power regulation generation module 802. Then, the sensitivity analysis calculation module 804 calculates the number of high-sensitivity DC transmission systems in the current hybrid DC station control 2 using a power system sensitivity analysis algorithm and sorts them sequentially. Finally, the emergency modulation module 805 selects the required number of high-sensitivity DC transmission systems for emergency modulation according to the sensitivity analysis ranking based on the calculation results of the power regulation analysis module 803 and the sensitivity analysis calculation module 804, and executes the coordinated control of each DC system through the modulation execution module 10.

[0039] In the secondary frequency modulation control process, the disturbance difference after the primary frequency modulation control is first recalculated by the disturbance difference recalculation module 901 of the secondary frequency modulation module 9. Then, the coordinated optimization model construction module 902 constructs a coordinated optimization data model for multiple hybrid DC systems. Next, the coordinated optimization calculation module 903 substitutes the difference calculation data from the disturbance difference recalculation module 901 and uses the Lagrange multiplier method to coordinate and optimize the parameter settings of each DC frequency control. Then, the power regulation correction module 904 corrects the power regulation after eliminating the faulty DC frequency limit controller. Finally, the transmission coordinated modulation module 905 performs coordinated modulation on each DC system according to the correction result of the power regulation correction module 904, and executes the coordinated control of each DC system through the modulation execution module 10. Then, the modulation feedback module 11 feeds back the coordinated control results of each DC system to the transmission control system 1. Then, the stability evaluation module 12 of the transmission system performs a stability evaluation on the hybrid DC system after adjustment and control. This completes the entire process of using the hybrid DC system sending-end frequency coordinated control method.

[0040] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A hybrid DC system sender-end frequency coordination control system, characterized in that, The system includes a power transmission control system (1), a hybrid DC station control system (2), and a frequency coordination control module (7). The power transmission control system (1) is electrically connected to the hybrid DC station control system (2). The hybrid DC station control system (2) is electrically connected to a power transmission monitoring module (5). The power transmission monitoring module (5) is used to monitor the power parameter data of the hybrid DC station control system (2) in real time to determine the current operating status of the power system. The output of the power transmission monitoring module (5) is electrically connected to a system frequency regulation analysis module (6). The system frequency regulation analysis module (6) is used to analyze whether to perform system frequency regulation based on the current operating status of the power system. The output of the system frequency modulation analysis module (6) is electrically connected to the frequency coordination control module (7), and the frequency coordination control module (7) is used to perform frequency coordination control on the DC transmission system. The frequency coordination control module (7) includes a primary frequency modulation module (8) and a secondary frequency modulation module (9), and the primary frequency modulation module (8) is electrically connected to the secondary frequency modulation module (9). Both the primary frequency modulation module (8) and the secondary frequency modulation module (9) are electrically connected to the modulation execution module (10), and the modulation execution module (10) is electrically connected to the modulation feedback module (11). The modulation feedback module (11) is connected to the power transmission control module. The system (1) is electrically connected. The primary frequency modulation module (8) includes a disturbance difference calculation module (801) and a power regulation generation module (802). The disturbance difference calculation module (801) is electrically connected to the power regulation generation module (802). The disturbance difference calculation module (801) is used to calculate the difference between the current frequency and the optimal DC frequency when the DC sending end frequency is disturbed. If the difference is less than the difference between the preset frequency peak and the optimal DC frequency, it directly enters the secondary frequency modulation control. Otherwise, it continues the primary frequency modulation control. That is, the DC system that needs to be frequency-modulated is selected according to the disturbance difference calculation result. The power regulation generation module (802) is used to generate a power regulation amount based on the preset frequency peak value of the sending system relative to the current DC power modulation amount. The secondary frequency modulation module (9) includes a disturbance difference recalculation module (901) and a coordination optimization model construction module (902). The disturbance difference recalculation module (901) is electrically connected to the coordination optimization model construction module (902). The disturbance difference recalculation module (901) is used to recalculate the disturbance difference after the primary frequency modulation control. The coordination optimization model construction module (902) is used to construct a coordination optimization data model for multiple hybrid DC systems.

2. The hybrid DC system transmitter frequency coordination control system according to claim 1, characterized in that, The hybrid DC station control (2) includes a conventional DC system (3) and a flexible DC system (4), and both the conventional DC system (3) and the flexible DC system (4) are used for power transmission at the sending end of the power station.

3. The hybrid DC system transmitter frequency coordination control system according to claim 1, characterized in that, The primary frequency regulation module (8) further includes a power regulation analysis module (803) and a sensitivity analysis calculation module (804). The power regulation generation module (802) is electrically connected to the power regulation analysis module (803), and the power regulation analysis module (803) is electrically connected to the sensitivity analysis calculation module (804). The power regulation analysis module (803) is used to analyze the number of high-sensitivity DC transmission systems required for frequency regulation based on the calculation results of the power regulation generation module (802). The sensitivity analysis calculation module (804) is used to calculate the high-sensitivity DC transmission systems in the current hybrid DC station control (2) according to the power system sensitivity analysis algorithm, and sort them in order.

4. The hybrid DC system transmitter frequency coordination control system according to claim 3, characterized in that, The primary frequency modulation module (8) further includes a power transmission emergency modulation module (805). The sensitivity analysis calculation module (804) is electrically connected to the power transmission emergency modulation module (805), and the power transmission emergency modulation module (805) is electrically connected to the modulation execution module (10). The power transmission emergency modulation module (805) is used to select the required number of highly sensitive DC transmission systems for emergency modulation according to the calculation results of the power regulation analysis module (803) and the sensitivity analysis calculation module (804) in accordance with the order of sensitivity analysis.

5. The hybrid DC system transmitter frequency coordination control system according to claim 1, characterized in that, The secondary frequency modulation module (9) further includes a coordination optimization calculation module (903) and a power regulation correction module (904). The coordination optimization model construction module (902) is electrically connected to the coordination optimization calculation module (903), and the coordination optimization calculation module (903) is electrically connected to the power regulation correction module (904). The coordination optimization calculation module (903) is used to substitute the difference calculation data of the disturbance difference recalculation module (901) and use the Lagrange multiplier method to coordinate and optimize the parameter settings of each DC frequency control. The power regulation correction module (904) is used to correct the power regulation after excluding the faulty DC frequency limit controller.

6. The hybrid DC system transmitter frequency coordination control system according to claim 5, characterized in that, The secondary frequency modulation module (9) further includes a power transmission coordination modulation module (905). The power regulation correction module (904) is electrically connected to the power transmission coordination modulation module (905), and the power transmission coordination modulation module (905) is electrically connected to the modulation execution module (10). The power transmission coordination modulation module (905) is used to coordinate modulation of each DC system according to the correction result of the power regulation correction module (904).

7. The hybrid DC system transmitter frequency coordination control system according to claim 1, characterized in that, The modulation feedback module (11) is connected to the power transmission system stability assessment module (12). The modulation execution module (10) is used to perform coordinated control of each DC system through the DC frequency limit controller. The modulation feedback module (11) is used to feed back the coordinated control results of each DC system to the power transmission control system (1). The power transmission system stability assessment module (12) is used to perform stability assessment on the hybrid DC system after adjustment and control.

8. A control method for a hybrid DC system sending-end frequency coordination control system according to any one of claims 1-7, characterized in that, The frequency coordination control method includes the following specific steps: S1. System frequency regulation analysis: The power parameter data of the hybrid DC station control (2) are monitored in real time by the power transmission monitoring module (5) to determine the current power system operating status. Then, the system frequency regulation analysis module (6) analyzes whether to perform system frequency regulation based on the current power system operating status. S2, Primary Frequency Modulation Control: The disturbance difference calculation module (801) of the primary frequency modulation module (8) calculates the difference between the current frequency and the optimal DC frequency when the DC sending end frequency is disturbed. If the difference is less than the difference between the preset frequency peak and the optimal DC frequency, it directly enters the secondary frequency modulation control; otherwise, it continues the primary frequency modulation control. That is, the DC system that needs to be frequency-modulated is selected according to the disturbance difference calculation result. Then, the power regulation amount generation module (802) generates the power regulation amount according to the preset frequency peak of the sending end system relative to the current DC power modulation amount. Then, the power regulation amount analysis module (803) generates the power regulation amount according to the power regulation amount. The calculation results of the module (802) are analyzed to determine the number of high-sensitivity DC transmission systems required for frequency regulation. Then, the sensitivity analysis calculation module (804) calculates the high-sensitivity DC transmission systems in the current hybrid DC station control (2) according to the power system sensitivity analysis algorithm and sorts them in order. Finally, the transmission emergency modulation module (805) is used to select the required number of high-sensitivity DC transmission systems for emergency modulation according to the calculation results of the power regulation analysis module (803) and the sensitivity analysis calculation module (804) and the sorting of sensitivity analysis, and executes the coordinated control of each DC system through the modulation execution module (10). S3, Secondary Frequency Control: The disturbance difference after the primary frequency control is recalculated by the disturbance difference recalculation module (901) of the secondary frequency control module (9). Then, the coordinated optimization model construction module (902) constructs a coordinated optimization data model for multiple hybrid DC systems. Next, the coordinated optimization calculation module (903) substitutes the difference calculation data of the disturbance difference recalculation module (901) into the data and uses the Lagrange multiplier method to coordinate and optimize the parameter setting values ​​of each DC frequency control. Then, the power regulation correction module (904) corrects the power regulation after eliminating the faulty DC frequency limit controller. Finally, the power transmission coordinated modulation module (905) performs coordinated modulation on each DC system according to the correction result of the power regulation correction module (904) and executes the coordinated control of each DC system through the modulation execution module (10). S4. Modulation result feedback: After the frequency coordination control module (7) performs modulation on the DC sending system, it feeds back the coordination control results of each DC system to the power transmission control system (1) through the modulation feedback module (11). S5. Stability assessment of DC sending end: Finally, the stability of the hybrid DC system after adjustment and control is assessed by the power transmission system stability assessment module (12).

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