Experimental verification method and system for broadband oscillation stability control strategy

Abstract

The invention discloses an experimental verification method and system for a broadband oscillation stability control strategy, and the method comprises the steps: building a large-scale new energy access power grid model, and building a broadband oscillation stability control strategy and device closed-loop experimental verification platform; broadband oscillation is excited, and the system overall impedance of the large-scale new energy access power grid model is identified; calculating the overall capacitance and inductance of the system under the oscillation frequency according to the overall impedance of the system; according to the overall capacitance and inductance of the system, broadband oscillation of different frequencies is excited, and experimental verification of a broadband oscillation stability control strategy is achieved; the system comprises a construction module, an identification module, a calculation module and a verification module. The method can be applied to various newly proposed broadband oscillation stability control strategies and closed-loop experiment verification platforms of corresponding control devices, the technical means and platform efficiency of stability control system experiment verification are improved, and a basis is provided for research, development and application of new stability control technologies and new equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power system automation, and particularly to an experimental verification method and system for a wide-frequency oscillation stability control strategy. Background Art

[0002] With the sharp increase in the penetration rate of new energy, the power electronic characteristics of the power system have become increasingly prominent. Compared with traditional power equipment, power electronic equipment has significant differences in physical structure, control mode, dynamic response, interaction with other equipment, etc. The fast and flexible control characteristics of power electronic equipment have had a profound impact on the dynamic behavior of the power system. Due to the influence of internal or external factors, high-proportion new energy and high-proportion power electronic systems cause electrical quantities (such as voltage, current, power, etc.) to fluctuate periodically with time between power electronic equipment and between them and the power grid, and the dynamic process in which the oscillation frequency varies within a wide range is called wide-frequency oscillation of the power system. In recent years, new types of sub- / supra-synchronous oscillation problems caused by variable-flow power sources such as wind power have been very prominent; while the negative resistance characteristics of variable-flow constant-power loads, the phase-locked loop circuit coupling of multiple converters, the participation of converter control in series / parallel resonance on the grid side, and the interaction between static synchronous compensators, high-voltage direct current transmission based on voltage-source converters and weak AC grids have triggered wide-frequency oscillations with frequencies ranging from several hertz to over several thousand hertz. Such wide-band oscillation problems caused by power electronic equipment can cause equipment damage, new energy disconnection from the grid, system outage, and are extremely likely to be transmitted to the user side through cascading failures, resulting in power outages, seriously affecting the stable operation of the power grid and the consumption of new energy.

[0003] At present, initial results have been achieved in the mechanism and suppression measures of wide-frequency oscillation of power systems with new energy participation at home and abroad, and there is a set of mature methods and processes for analyzing wide-frequency oscillation phenomena in specific accidents. However, the experimental verification technology for emergency control-related control technologies and stability control systems for wide-frequency oscillation has not been clarified. It is urgent to explore the reliability of wide-frequency oscillation control systems in large-scale new energy-connected power grids, build a hardware-in-the-loop verification platform for wide-frequency oscillation control systems, improve the technical means and platform efficiency of experimental verification of stability control systems, provide a basis for the research and development and application of new stability control technologies and new equipment, and support the intrinsic safety of stability control systems and the safe and stable operation of the power grid. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide an experimental verification method and system for a wide-frequency oscillation stability control strategy.

[0005] In order to achieve the above technical object and reach the above technical effect, the present invention is realized through the following technical solutions:

[0006] In the first aspect, the present invention provides an experimental verification method for a wide-frequency oscillation stability control strategy, including:

[0007] Build a large-scale new energy grid connection model and set up a closed-loop experimental verification platform for broadband oscillation stability control strategies and devices;

[0008] Excite broadband oscillations and identify the overall impedance of the system of the large-scale new energy grid connection model;

[0009] Calculate the overall capacitance and inductance of the system at the oscillation frequency based on the overall impedance of the system;

[0010] Based on the overall capacitance and inductance of the system, excite broadband oscillations at different frequencies to achieve experimental verification of the broadband oscillation stability control strategy.

[0011] Further, the excitation of broadband oscillations includes first attempting to excite oscillations by changing the operating speed of the fan and adjusting the impedance characteristics of the fan converter through the fan controller parameters; if not, further incorporate a variable resistor into the monitoring and control branch of the broadband oscillation stability control strategy, and make the power grid near the oscillation risk point by reducing the system resistance, thereby exciting oscillations.

[0012] Further, the overall impedance of the system is expressed as:

[0013]

[0014] where ω 0 represents the oscillation frequency, SYS represents the system, Z represents impedance, R represents resistance, X represents reactance, and j represents an imaginary number.

[0015] Further, the overall capacitance and inductance of the system are calculated according to the following equations:

[0016]

[0017] where L represents inductance and C represents capacitance.

[0018] Further, the excitation of broadband oscillations at different frequencies includes incorporating a variable inductor or capacitor in series in the branch according to the calculated capacitance and inductance, making the power grid near the oscillation risk points at different frequencies by changing the system reactance, and then changing the operating speed of the fan and the fan controller parameters again, thereby exciting broadband oscillations at different frequencies.

[0019] In a second aspect, the present invention provides an experimental verification system for a broadband oscillation stability control strategy, including:

[0020] A construction module for building a large-scale new energy grid connection model and setting up a closed-loop experimental verification platform for broadband oscillation stability control strategies and devices;

[0021] An identification module, which is used to excite broadband oscillations and identify the overall impedance of the system of a large-scale new energy integrated power grid model;

[0022] A calculation module, which is used to calculate the overall capacitance and inductance of the system at the oscillation frequency according to the overall impedance of the system;

[0023] A verification module, which is used to excite broadband oscillations with different frequencies according to the overall capacitance and inductance of the system, and realize the experimental verification of the stable control strategy of broadband oscillations.

[0024] Furthermore, the identification module is specifically used to excite broadband oscillations, including:

[0025] First, try to excite oscillations by changing the operating speed of the fan and adjusting the impedance characteristics of the fan converter by the fan controller parameters; if it fails, further incorporate a variable resistor into the monitoring and control branch of the broadband oscillation stable control strategy, and make the power grid near the oscillation risk point by reducing the system resistance, so as to excite oscillations.

[0026] Furthermore, the identification module is specifically used to identify the overall impedance of the system of a large-scale new energy integrated power grid model, which is expressed as:

[0027]

[0028] where ω 0 represents the oscillation frequency, SYS represents the system, Z represents the impedance, R represents the resistance, X represents the reactance, and j represents the imaginary number.

[0029] Furthermore, the calculation module is specifically used to calculate the overall capacitance and inductance of the system at the oscillation frequency according to the following equations:

[0030]

[0031] where L represents the inductance and C represents the capacitance.

[0032] Furthermore, the verification module is used to excite broadband oscillations with different frequencies according to the overall capacitance and inductance of the system, and realize the experimental verification of the stable control strategy of broadband oscillations,

[0033] Exciting broadband oscillations with different frequencies includes incorporating a variable inductor or capacitor into the branch according to the calculated capacitance and inductance, making the power grid near the oscillation risk points with different frequencies by changing the system reactance, and then changing the operating speed of the fan and the fan controller parameters, so as to excite broadband oscillations with different frequencies.

[0034] In a third aspect, the present invention provides an electronic device, including a memory, a processor, and a program stored on the memory and executable on the processor, which when executed implements the steps of the experimental verification method for the broadband oscillation stability control strategy described above.

[0035] In a fourth aspect, the present invention provides a computer-readable storage medium, hereinafter simply referred to as a storage medium, in which a computer program is stored and designed to implement the steps of the experimental verification method for the broadband oscillation stability control strategy described above when running.

[0036] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: The present invention solves the problems of unclear oscillation excitation methods and insufficient experimental verification in the closed-loop experimental verification process of the broadband oscillation stability control strategy and device, and gives the oscillation excitation methods of different frequencies for the broadband oscillation simulation model of a large-scale new energy integrated power system; it can be applied to the closed-loop experimental verification platform of various newly proposed broadband oscillation stability control strategies and corresponding control devices, improving the technical means and platform efficiency of the stability control system experimental verification, and providing a basis for the research and development and application of new stability control technologies and new equipment. Description of the Drawings

[0037] Figure 1 is a flowchart of the present invention;

[0038] Figure 2 is a schematic diagram of the closed-loop experimental verification platform for the broadband oscillation stability control strategy and device;

[0039] Figure 3 is a schematic diagram of a simplified system for transmitting power from a large-scale wind farm area. Detailed Embodiments

[0040] The technical solutions of the present invention will be further described below with reference to the drawings. Those skilled in the art will understand that the objectives and advantages that can be achieved by the present invention are not limited to the specific beneficial effects described above, and it will be more clearly understood from the following detailed description that the above and other objectives that the present invention can achieve.

[0041] Those of ordinary skill in the art should understand that the various exemplary components, systems, and methods described in combination with the embodiments disclosed in the present invention can be implemented in hardware, software, or a combination of both. Specifically, whether to implement in hardware or software depends on the specific application and design and tree conditions of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0042] As used herein, the term "embodiment" means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0043] Embodiment 1

[0044] An experimental verification method for a broadband oscillation stability control strategy provided by the present invention, as Figure 1 shown, includes:

[0045] Construct a large-scale new energy integrated power grid model and build a closed-loop experimental verification platform for the broadband oscillation stability control strategy and device.

[0046] Excite broadband oscillations and identify the overall impedance of the system of the large-scale new energy integrated power grid model.

[0047] Calculate the overall capacitance and inductance of the system at the oscillation frequency based on the overall impedance of the system.

[0048] According to the overall capacitance and inductance of the system, excite broadband oscillations at different frequencies to achieve experimental verification of the broadband oscillation stability control strategy.

[0049] First, based on the actual power grid parameters, construct a large-scale new energy integrated power grid model controlled by the broadband oscillation stability control strategy to be experimentally verified on real-time digital simulation software, and build a closed-loop experimental verification platform as Figure 2 shown; then, first try to excite oscillations by changing the operating speed of the fan and adjusting the impedance characteristics of the fan converter by adjusting the fan controller parameters; at the same time, a variable resistor can be further incorporated into the monitoring and control branch of the broadband oscillation stability control strategy, and the power grid can be made near the oscillation risk point by reducing the system resistance, thereby exciting oscillations; then, identify the overall impedance of the system at the oscillation frequency in the branch monitored by the broadband oscillation stability control strategy, and calculate the overall capacitance and inductance of the system at this oscillation frequency; then, insert a variable inductor or capacitor in the branch, and make the power grid near the oscillation risk points at different frequencies by changing the system reactance; finally, change the operating speed of the fan and the fan controller parameters again to excite broadband oscillations at different frequencies to achieve verification of the broadband oscillation stability control strategy for various frequency bands.

[0050] As Figure 3The figure shows a schematic diagram of a simplified system for large-scale new energy access to the power grid. Taking this system as an example, the method of the present invention will be introduced and explained. There are four new energy power stations, namely A, B, C, and D, connected to the new energy grid-connected bus, and are connected to the high-voltage bus through transformers. The new energy stations A, B, C, and D are four different types of new energy clusters respectively, and the new energy clusters under each grid-connected line are new energy units of the same type.

[0051] Build a broadband oscillation simulation model of this simplified system in real-time simulation software. The four new energy power stations are replaced by the standard basic models multiplied by single machines respectively. After the model runs stably, a variable inductor L is connected in series at the low-voltage side of the transformer connecting the new energy grid-connected bus and the high-voltage bus. 0 and a capacitor C 0 , and a variable resistor R is connected in parallel 0 , and their values are all set to zero. Furthermore, a closed-loop experimental verification platform for broadband oscillation stability control strategy and device is constructed.

[0052] Change the operating speed of the fan and adjust the impedance characteristics of the fan converter by adjusting the parameters of the fan controller, and try to see if oscillation can be excited. In this process, the variable resistor R connected in parallel can be further adjusted 0 to reduce the system-side resistance, so that the overall model shows a negative resistance characteristic, thereby exciting the broadband oscillation phenomenon at a certain oscillation frequency ω 0 of the simulation model.

[0053] According to the broadband oscillation frequency-domain impedance principle and the calculation formula of line reactance calculate the overall inductance 0 of the system at the oscillation frequency ω and capacitance Furthermore, in combination with the calculated system inductance and capacitance parameters, adjust the parameters of the variable inductor L 0 or capacitor C 0 to change the system reactance so that the power grid is near the oscillation risk points at different frequencies.

[0054] Adjust the operating conditions and control parameters of the new energy units again to excite broadband oscillations at different frequencies.

[0055] Embodiment 2

[0056] In addition, based on the same inventive concept, the embodiment of the present invention also provides a new energy distributed trading system for a distribution network under an energy sharing framework, including:

[0057] A construction module for constructing a model of large-scale new energy access to the power grid and building a closed-loop experimental verification platform for broadband oscillation stability control strategy and device;

[0058] An identification module, which is used to excite broadband oscillation and identify the overall impedance of the system of a large-scale new energy integrated power grid model;

[0059] A calculation module, which is used to calculate the overall capacitance and inductance of the system at the oscillation frequency according to the overall impedance of the system;

[0060] A verification module, which is used to excite broadband oscillations of different frequencies according to the overall capacitance and inductance of the system, and realize the experimental verification of the stable control strategy of broadband oscillation.

[0061] The identification module is specifically used to excite broadband oscillation, including:

[0062] First, try to excite oscillation by changing the operating speed of the fan and adjusting the impedance characteristics of the fan converter by the fan controller parameters; if not, further incorporate a variable resistor into the monitoring and control branch of the broadband oscillation stable control strategy, and make the power grid near the oscillation risk point by reducing the system resistance, so as to excite oscillation.

[0063] The identification module is specifically used to identify the overall impedance of the system of a large-scale new energy integrated power grid model, expressed as:

[0064]

[0065] where ω 0 represents the oscillation frequency, SYS represents the system, Z represents the impedance, R represents the resistance, X represents the reactance, and j represents the imaginary number.

[0066] The calculation module is specifically used to calculate the overall capacitance and inductance of the system at the oscillation frequency according to the following equations:

[0067]

[0068] where L represents the inductance and C represents the capacitance.

[0069] Furthermore, the verification module is used to excite broadband oscillations of different frequencies according to the overall capacitance and inductance of the system, and realize the experimental verification of the stable control strategy of broadband oscillation,

[0070] Exciting broadband oscillations of different frequencies includes, according to the calculated capacitance and inductance, connecting a variable inductance or capacitance in series in the branch, making the power grid near the oscillation risk points of different frequencies by changing the system reactance, and then changing the operating speed of the fan and the fan controller parameters, so as to excite broadband oscillations of different frequencies.

[0071] Embodiment III

[0072] In addition, based on the same inventive concept, an embodiment of the present invention further provides an electronic device, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, the steps of the experimental verification method for the broadband oscillation stability control strategy are implemented.

[0073] It should be understood that each part of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following well-known technologies in the art can be used: discrete logic circuits with logic gate circuits for implementing logic functions on data signals, application-specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0074] Embodiment 4

[0075] In addition, based on the same inventive concept, an embodiment of the present invention further provides a storage medium storing a computer program, and the computer program is designed to implement the steps of the experimental verification method for the broadband oscillation stability control strategy when running.

[0076] Those of ordinary skill in the art of the present technology can understand that all or part of the steps carried by the method in the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0077] In addition, in each embodiment of the present invention, each functional unit can be integrated in a processing module, or each unit can exist physically alone, or two or more units can be integrated in a module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0078] The above-mentioned computer-readable storage medium can be a tangible storage medium, such as a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, floppy disk, hard disk, removable storage disk, CD-ROM, or any other form of storage medium well-known in the art.

[0079] The specific description above further elaborates on the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An experimental verification method for a broadband oscillation stabilization control strategy, characterized in that: include: Construct a large-scale renewable energy access grid model, and build a broadband oscillation stability control strategy and device closed-loop experimental verification platform; Stimulate broadband oscillations and identify the overall system impedance of large-scale renewable energy access grid models; The overall capacitance and inductance of the system at the oscillation frequency are calculated based on the overall impedance of the system; According to the overall capacitance and inductance of the system, broadband oscillations of different frequencies are excited to achieve experimental verification of the broadband oscillation stability control strategy.

2. The experimental verification method of the wide-band oscillation stabilization control strategy according to claim 1 is characterized in that: The exciting broadband oscillation includes first trying to stimulate oscillation by changing the operating speed of the wind turbine and adjusting the impedance characteristics of the wind turbine converter by changing the wind turbine controller parameters; if it fails, further incorporating a variable resistor into the broadband oscillation stability control strategy monitoring control branch, reducing the system resistance so that the power grid is near the oscillation risk point, thereby exciting oscillation.

3. The experimental verification method of the wide-band oscillation stabilization control strategy according to claim 1 is characterized in that: The overall impedance of the system is expressed as: Among them, ω0 represents the oscillation frequency, SYS represents the system, Z represents the impedance, R represents the resistance, X represents the reactance, and j represents the imaginary number.

4. The experimental verification method of the wide-band oscillation stabilization control strategy according to claim 1 is characterized in that: The overall capacitance and inductance of the system are calculated according to the following set of equations: Among them, L represents inductance and C represents capacitance.

5. The experimental verification method of the wide-band oscillation stabilization control strategy according to claim 1 is characterized in that: The method of exciting broadband oscillations of different frequencies includes inserting a variable inductor or capacitor in series in the branch according to the calculated capacitance and inductance, changing the system reactance so that the power grid is near the oscillation risk point of different frequencies, and once again changing the wind turbine operating speed and wind turbine controller parameters to stimulate broadband oscillations of different frequencies.

6. An experimental verification system for a wide-band oscillation stability control strategy, characterized in that: include: Construction module, used to build a large-scale renewable energy access grid model, and to build a broadband oscillation stability control strategy and device closed-loop experimental verification platform; Identification module, used to stimulate broadband oscillation and identify the overall system impedance of large-scale renewable energy access grid models; A calculation module, used to calculate the overall capacitance and inductance of the system at the oscillation frequency according to the overall impedance of the system; The verification module is used to excite broadband oscillations of different frequencies according to the overall capacitance and inductance of the system, and to realize experimental verification of the broadband oscillation stability control strategy.

7. The experimental verification system of the wide-band oscillation stabilization control strategy according to claim 6 is characterized in that: The identification module is specifically used to excite broadband oscillation and includes: First, try to stimulate oscillation by changing the wind turbine operating speed and adjusting the wind turbine converter impedance characteristics by changing the wind turbine controller parameters. If not, further add a variable resistor to the wide-band oscillation stability control strategy monitoring control branch to reduce the system resistance so that the grid is near the oscillation risk point, thereby stimulating oscillation.

8. The experimental verification system of the wide-band oscillation stabilization control strategy according to claim 6 is characterized in that: The identification module is specifically used to identify the overall system impedance of a large-scale renewable energy access grid model, which is expressed as: Among them, ω0 represents the oscillation frequency, SYS represents the system, Z represents the impedance, R represents the resistance, X represents the reactance, and j represents the imaginary number.

9. The experimental verification system of the wide-band oscillation stabilization control strategy according to claim 6, characterized in that: The calculation module is specifically used to calculate the overall capacitance and inductance of the system at the oscillation frequency according to the following set of equations: Among them, L represents inductance and C represents capacitance.

10. The experimental verification system of the wide-band oscillation stabilization control strategy according to claim 6, characterized in that: The verification module is used to excite broadband oscillations of different frequencies according to the overall capacitance and inductance of the system, and to realize experimental verification of the broadband oscillation stability control strategy. Exciting broadband oscillations of different frequencies includes inserting variable inductance or capacitance in series in the branch according to the calculated capacitance and inductance, changing the system reactance so that the power grid is near the oscillation risk point of different frequencies, and once again changing the wind turbine operating speed and wind turbine controller parameters to excite broadband oscillations of different frequencies.

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