A method, system, device, and medium for generating broadband oscillation risk scenarios.

Abstract

This invention belongs to the field of power system automation technology and discloses a method, system, equipment, and medium for generating broadband oscillation risk scenarios. The method includes: based on the broadband oscillation generation mechanism of different access types of new energy units, dividing the power grid into an internal system strongly correlated with oscillations and an external system weakly correlated with oscillations; calculating the equivalent impedance model of each new energy power station in the internal system under different active power output levels through data fitting; performing differentiated equivalent modeling for the internal and external systems respectively; and determining the operating scenarios with broadband oscillation risk based on the equivalent impedance models of each new energy power station, the remaining electrical equipment in the internal system, and the equivalent impedance of the external system. This invention can perform differentiated equivalent modeling of the internal and external systems of the power grid and quickly generate broadband oscillation risk scenarios, balancing the accuracy and efficiency of broadband oscillation analysis, and providing a scenario foundation for dispatching and operation personnel to gain a deeper understanding of the broadband oscillation risk of the power grid.

Description

Technical Field

[0001] This invention belongs to the field of power system automation technology, specifically relating to a method, system, device, and medium for generating wideband oscillation risk scenarios. Background Technology

[0002] High-proportion renewable energy and high-proportion power electronic systems, due to their own or external factors, experience periodic fluctuations in electrical quantities over time due to interactions between power electronic devices and between these devices and the power grid. These oscillations vary over a wide frequency range. Such broadband oscillations caused by power electronic devices can lead to equipment damage, renewable energy disconnection from the grid, system shutdowns, and even cascading failures to the user side, causing power outages and severely impacting the stable operation of the power grid and the absorption of renewable energy.

[0003] Existing electromechanical transient simulations and hybrid simulations are no longer sufficient to analyze broadband oscillations in the power grid. To ensure the safe and stable operation of the power grid and to gain a deeper understanding and effective response to broadband oscillation risks, full electromagnetic transient simulation is required. However, performing full electromagnetic transient simulation on the entire grid is time-consuming, severely impacting the analysis efficiency of personnel. Therefore, it is necessary to perform equivalent modeling of the power grid based on the mechanism of broadband oscillation generation, thereby improving the efficiency of simulation analysis. Furthermore, broadband oscillations are diverse, making it difficult to identify risks using the same set of operating data and the same principles. It is necessary to propose a method for generating oscillation risk scenarios and construct typical operating scenarios that may trigger broadband oscillations. Based on this, full electromagnetic transient simulation analysis can be used to understand the stability characteristics and dominant factors of broadband oscillations of different access types of new energy units, guiding the identification of oscillation risks and the formulation of oscillation suppression measures. However, existing research mainly generates oscillation scenarios based on actual oscillation events or by adjusting the power grid operation mode based on human experience, resulting in low efficiency or even difficulty in generating oscillation scenarios. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method, system, device, and medium for generating broadband oscillation risk scenarios. The method provided by this invention is based on the system equivalent impedance model and the equivalent power grid to quickly generate broadband oscillation risk scenarios, which can balance the accuracy and efficiency of broadband oscillation analysis, and provide a scenario basis for dispatching and operation personnel to gain a deeper understanding of the broadband oscillation risks of the power grid.

[0005] This invention provides the following technical solution:

[0006] The primary objective of this invention is to provide a method for generating broadband oscillation risk scenarios, comprising:

[0007] Based on the broadband oscillation generation mechanism of different access types of new energy units, the power grid is divided into an internal system that is strongly correlated with oscillation and an external system that is weakly correlated with oscillation.

[0008] Calculate the equivalent impedance model of each new energy power station in the internal system under different active power output levels;

[0009] Differential equivalent modeling is performed for the internal and external systems of the power grid, respectively;

[0010] Based on the equivalent impedance model of each new energy power station, the equivalent impedance of the remaining electrical equipment in the internal system and the external system, the operating scenarios with broadband oscillation risk are identified.

[0011] As a further improvement of the present invention, the broadband oscillation generation mechanism based on different access types of new energy units divides the power grid into an internal system strongly correlated with oscillations and an external system weakly correlated with oscillations, including:

[0012] Identify the access type of new energy units. The access types include direct-drive wind turbines via AC lines without series compensation, doubly-fed wind turbines via AC lines with series compensation, and new energy units transmitted via flexible direct transmission.

[0013] For the case where direct-drive wind turbines transmit power through AC lines without series compensation, take any one of the direct-drive wind farms as the starting point, and use topology search to find the 500kV or 750kV transmission line of the wind farm. Define the network consisting of the transmission line and all new energy power plants, transmission lines and transformers below the sending end of the line as the internal system, and the rest as the external system.

[0014] For the case where the doubly fed wind turbine is transmitted through an AC line with series compensation, the network consisting of the series compensation line and all new energy power plants, transmission lines and transformers below the sending end of the line is defined as the internal system, and the rest is defined as the external system.

[0015] For the case of new energy being transmitted via flexible DC transmission, the flexible DC transmission and all new energy generating units, transmission lines and transformers in the power grid at the sending end of the flexible DC transmission are defined as the internal system, and the power grid at the receiving end of the flexible DC transmission is defined as the external system.

[0016] The bus connecting the internal system and the external system is defined as a boundary node.

[0017] The broadband oscillation generation mechanisms of the three new energy unit access types mentioned above are the same. By incorporating the key equipment and surrounding networks with strong oscillation correlation into the internal system and classifying the weakly correlated regions as the external system, redundant modeling is avoided, the scale of simulation verification is reduced, and the efficiency of simulation analysis is improved. Clearly defining the boundary nodes ensures that the short-circuit capacity of the boundary nodes before and after equivalent modeling is consistent, avoiding equivalent modeling errors caused by boundary ambiguity and improving the accuracy of equivalent modeling.

[0018] As a further improvement of the present invention, the equivalent impedance model for each new energy power station in the internal system under different active power output levels includes:

[0019] The equivalent impedance value of a single new energy unit at a certain active power output level and frequency is obtained by analytical derivation or model identification method.

[0020] Based on the equivalent impedance value of a single new energy unit, the impedance of the corresponding transformer and collector line, and the internal topology of the new energy power station, the equivalent impedance value of the new energy power station at some active power output levels and frequencies is calculated.

[0021] Based on the equivalent impedance values ​​of the active power output level and frequency of the new energy power station, the equivalent impedance model of the new energy power station under different active power output levels is obtained by using the data fitting method.

[0022] As a further improvement of the present invention, the differentiated equivalent modeling of the internal and external power grid systems includes:

[0023] For the internal power grid system, we perform equivalent modeling of various types of new energy units in each new energy power station, equivalent modeling of the collection lines and box-type substations in each new energy power station, and detailed modeling of the remaining electrical equipment.

[0024] For external systems of the power grid, the multi-port Thevenin equivalent method is used for equivalent modeling.

[0025] The internal system employs equivalent modeling for renewable energy power plants, ensuring that the equivalent impedance remains unchanged before and after equivalence. Detailed modeling is used for remaining electrical equipment to ensure the dynamic characteristics of the core broadband oscillation region are not lost, guaranteeing the accuracy of oscillation risk analysis. The external system utilizes multi-port Thevenin equivalent modeling, simplifying the complex external network into equivalent electromotive force and equivalent impedance while maintaining consistent short-circuit capacity at boundary nodes, significantly reducing model complexity and computational load. This differentiated modeling strategy balances accuracy and efficiency, significantly shortening the time required for broadband oscillation analysis and meeting the efficiency requirements of power grid operators for simulation analysis.

[0026] As a further improvement of the present invention, equivalent modeling is performed on the new energy generating units, transformer substations, and collector lines within the power grid system, including:

[0027] For the same type of new energy generating units, the single-unit multiplication method is used for equivalent modeling. Based on the number of new energy generating units in each type, the equivalent impedance model of each type of new energy generating unit is obtained.

[0028] Based on the impedance of the transformer substation corresponding to each type of new energy unit and the number of each type of new energy unit, the impedance of the transformer substation after the equivalent is calculated.

[0029] Based on the topology of each new energy unit in the new energy power station, the equivalent impedance model of each type of new energy unit before and after equivalence, the impedance of the corresponding transformer before and after equivalence for each type of new energy unit, and the impedance of the collector line before equivalence, the impedance of the collector line after equivalence is calculated.

[0030] For the same type of generating unit, a single-unit multiplication equivalent model is adopted. This significantly reduces the number of nodes and computational load within the internal system while ensuring the consistency of the dynamic characteristics of the new energy generating units, without losing the impedance characteristics of the unit cluster, thus balancing modeling complexity and accuracy. The equivalent transformer impedance is calculated based on the number of generating units and the impedance of a single transformer, and the equivalent impedance of the collector lines is calculated in conjunction with the topology. This ensures that the equivalent models of key equipment within the power station accurately reflect actual operating characteristics, avoiding oscillation analysis errors caused by equipment simplification. The modeling method is adaptable to different numbers, types, and access methods of new energy generating units, enabling flexible internal system equivalent modeling to accommodate various new energy power station configurations.

[0031] As a further improvement of the present invention, the determination of operating scenarios with broadband oscillation risk based on the equivalent impedance model of each new energy power station, the remaining electrical equipment in the internal system, and the equivalent impedance of the external system includes:

[0032] The equivalent impedance model of the internal system is calculated based on the equivalent impedance model of each new energy power station and the equivalent impedance of the remaining electrical equipment in the internal system.

[0033] The equivalent impedance model of the internal system is superimposed in series with the equivalent impedance of the external system to calculate the equivalent impedance model of the entire power grid system.

[0034] With the objective that the equivalent reactance of the entire power grid system is less than a threshold value, a genetic algorithm is used to generate candidate combinations of active power output for each new energy power station.

[0035] Combinations with equivalent resistance less than zero are selected from the candidate combinations as operating scenarios with the risk of wideband oscillation.

[0036] As a further improvement of the present invention, the system based on differentiated equivalent modeling is used to verify the operation scenario with broadband oscillation risk through full electromagnetic transient simulation software. If the time domain simulation results show that there is an oscillation risk, the obtained active power output combination is taken as the broadband oscillation risk scenario. Otherwise, the threshold value of the equivalent impedance is reduced, and the active power output combination of each new energy power station is regenerated until the active power output combination of the new energy power station with broadband oscillation risk is obtained.

[0037] The second objective of this invention is to provide an oscillation risk scenario generation system for implementing the above-mentioned method, comprising:

[0038] The power grid partitioning module is configured to divide the power grid into an internal system strongly correlated with oscillations and an external system weakly correlated with oscillations, based on the broadband oscillation generation mechanism of different access types of new energy units.

[0039] The equivalent impedance model calculation module is configured to calculate the equivalent impedance model of each new energy power station in the internal system under different active power output levels.

[0040] The equivalent modeling module is configured to perform differentiated equivalent modeling of the internal and external systems of the power grid, reducing the scale of full electromagnetic transient simulation verification and improving simulation analysis efficiency.

[0041] The risk scenario generation module is configured to: determine the operating scenarios with broadband oscillation risk based on the equivalent impedance model of each new energy power station, the remaining electrical equipment in the internal system, and the equivalent impedance of the external system.

[0042] A third objective of this invention is to provide a computer device comprising at least one processing unit and at least one storage unit, wherein the storage unit stores a computer program, and when the program is executed by the processing unit, the processing unit performs the aforementioned method.

[0043] A fourth objective of this invention is to provide a computer-readable storage medium storing a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the above-described method.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] Based on the broadband oscillation generation mechanism of different access types of new energy units, the power grid is divided into an internal system strongly correlated with oscillation and an external system weakly correlated with oscillation. The equivalent impedance model of each new energy power station in the internal system under different active power output levels is calculated by data fitting method. Differentiated equivalent modeling is performed for the internal and external systems. Broadband oscillation risk scenarios can be quickly generated based on the system equivalent impedance model. This can balance the accuracy and efficiency of broadband oscillation analysis and provide a scenario basis for dispatching and operation personnel to deeply understand the broadband oscillation risk of the power grid.

[0046] The internal system employs equivalent modeling for renewable energy power plants, ensuring that the equivalent impedance remains unchanged before and after equivalence. Detailed modeling is used for remaining electrical equipment to ensure the dynamic characteristics of the core broadband oscillation region are not lost, guaranteeing the accuracy of oscillation risk analysis. The external system utilizes multi-port Thevenin equivalent modeling, simplifying the complex external network into equivalent electromotive force and equivalent impedance while maintaining consistent short-circuit capacity at boundary nodes, significantly reducing model complexity and computational load. This differentiated modeling strategy balances accuracy and efficiency, significantly shortening the time required for broadband oscillation analysis and meeting the efficiency requirements of power grid operators for simulation analysis. Attached Figure Description

[0047] Figure 1 A flowchart of a method for generating broadband oscillation risk scenarios provided by the present invention;

[0048] Figure 2 A schematic diagram showing the radial connection of various new energy units within a new energy power station;

[0049] Figure 3 An equivalent modeling diagram of the radial connection of various new energy units within a new energy power station;

[0050] Figure 4 A schematic diagram showing the trunk line connection of various new energy units within a new energy power station;

[0051] Figure 5 An equivalent modeling diagram of the trunk line connection between various new energy units in a new energy power station. Detailed Implementation

[0052] 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.

[0053] The present invention will now be described in further detail with reference to the accompanying drawings:

[0054] like Figure 1 As shown, this embodiment provides a method for generating broadband oscillation risk scenarios, including:

[0055] Based on the broadband oscillation generation mechanism of different access types of new energy units, the power grid is divided into an internal system strongly correlated with oscillations and an external system weakly correlated with oscillations; specific division methods include:

[0056] Identify the access type of new energy units. The access types include direct-drive wind turbines via AC lines without series compensation, doubly-fed wind turbines via AC lines with series compensation, and new energy units transmitted via flexible direct transmission.

[0057] For the case where direct-drive wind turbines transmit power through AC lines without series compensation, take any one of the direct-drive wind farms as the starting point, and use topology search to find the 500kV or 750kV transmission line of the wind farm. Define the network consisting of the transmission line and all new energy power plants, transmission lines and transformers below the sending end of the line as the internal system, and the rest as the external system.

[0058] For the case where the doubly fed wind turbine is transmitted through an AC line with series compensation, the network consisting of the series compensation line and all new energy power plants, transmission lines and transformers below the sending end of the line is defined as the internal system, and the rest is defined as the external system.

[0059] For the case of new energy being transmitted via flexible DC transmission, the flexible DC transmission and all new energy generating units, transmission lines and transformers in the power grid at the sending end of the flexible DC transmission are defined as the internal system, and the power grid at the receiving end of the flexible DC transmission is defined as the external system.

[0060] The bus connecting the internal system and the external system is defined as a boundary node.

[0061] The broadband oscillation generation mechanism of the above three types of new energy unit access is the same: when the imaginary part of the sum of the overall equivalent impedance of the system is 0 and the real part at the corresponding frequency is negative, the new energy grid-connected system is at risk of broadband oscillation. By incorporating the key equipment and surrounding networks with strong oscillation correlation into the internal system and classifying the weakly correlated areas as the external system, redundant modeling is avoided, the scale of simulation verification is reduced, and the efficiency of simulation analysis is improved. Furthermore, the definition of boundary nodes is clearly defined to ensure that the short-circuit capacity of boundary nodes is consistent before and after equivalence, avoiding equivalence errors caused by boundary ambiguity and improving the accuracy of equivalence modeling.

[0062] The equivalent impedance models for each renewable energy power station within the internal system are calculated under different active power output levels, including:

[0063] For new energy generator units with known control structures and control parameters, the equivalent impedance value of a single new energy generator unit at a certain active power output level and frequency can be obtained through analytical derivation; for new energy generator units with unknown control structures and control parameters, the equivalent impedance value of a single new energy generator unit at a certain active power output level and frequency can be obtained through existing model identification methods.

[0064] Assuming that the active power output of the new energy units in the same new energy power station is consistent, based on the equivalent impedance value of a single new energy unit, the impedance of the transformer and the collector line, and the internal topology of the new energy power station, the equivalent impedance value of the new energy power station at some active power output levels and frequencies is calculated.

[0065] The equivalent impedance model of the renewable energy power station under different active power output levels was calculated using a data fitting method. The calculation formula is:

[0066]

[0067] in, For complex frequency domain variables; The oscillation frequency; , These are the orders of the denominator and numerator of the equivalent impedance model, respectively. , The coefficients of the polynomials in the denominator and numerator are respectively used for fitting, and the following formula is used:

[0068]

[0069] Differential equivalent modeling is performed for the internal and external systems of the power grid, including:

[0070] For the internal power grid system, we perform equivalent modeling of various types of new energy units in each new energy power station, equivalent modeling of the collection lines and box-type substations in each new energy power station, and detailed modeling of the remaining electrical equipment.

[0071] For external systems of the power grid, the multi-port Thevenin equivalent method is used for equivalent modeling.

[0072] For the internal system of the power grid, equivalent modeling includes:

[0073] The types of new energy units in new energy power stations are statistically analyzed. Considering that the control parameters of new energy units of the same type are consistent, that is, the equivalent impedance is consistent, the same type of new energy units are used for equivalent modeling by multiplying the single unit. Therefore, if there are K types of units in a new energy power station, it is equivalent to K new energy units.

[0074] Based on the impedance of the transformer substation corresponding to each type of new energy unit, and the number of each type of new energy unit, the equivalent impedance of the transformer substation is calculated using the following formula:

[0075]

[0076] in, For the first Equivalent impedance of the transformer substation corresponding to new energy generation units; For the first The impedance of the transformer substation corresponding to the new energy generation unit (assuming that the impedance parameters of the transformer substation connected to the same type of new energy generation unit are consistent). For the first The number of new energy generating units;

[0077] like Figure 2 and Figure 3 As shown, if the new energy units in a new energy power station adopt a radial topology, the formula for calculating the equivalent impedance of the collector lines is:

[0078]

[0079] in, For the first The active power output of the new energy-type generating units is The equivalent impedance of the collector line at that time; For the first The active power output of the new energy-type generating units is Equivalent impedance model at time; For the first equivalence The first of the new energy units The impedance of the collector lines of the new energy unit;

[0080] like Figure 4 and Figure 5 As shown, if each new energy unit in a new energy power station adopts a trunk-line topology, the formula for calculating the equivalent impedance of the collector lines is:

[0081]

[0082] in, Contributing to the development of new energy power units The equivalent impedance of the current collector line; Contributing to the development of new energy power units Equivalent impedance model of new energy power stations.

[0083] Based on the equivalent impedance model of each new energy power station, the equivalent impedance of the remaining electrical equipment in the internal system, and the equivalent impedance of the external system, operating scenarios with broadband oscillation risk are identified, including:

[0084] The equivalent impedance model of the internal system is calculated based on the equivalent impedance model of each new energy power station and the equivalent impedance of the remaining electrical equipment in the internal system. The equivalent impedance model of the internal system is then superimposed in series with the equivalent impedance of the external system to obtain the equivalent impedance model of the entire power grid system.

[0085] The equivalent impedance model of the entire power grid system is expressed as:

[0086]

[0087] in, The equivalent impedance model for the entire power grid system; The equivalent impedance model of the internal system; The equivalent impedance of the external system;

[0088] With the objective that the equivalent reactance of the entire power grid system is less than a threshold value, a genetic algorithm is used to generate candidate combinations of active power output for each new energy power station.

[0089] Combinations with equivalent resistance less than zero are selected from the candidate combinations as operating scenarios with the risk of wideband oscillation.

[0090] Based on the system after differentiated equivalent modeling, the operation scenario with broadband oscillation risk is verified by full electromagnetic transient simulation software. If the time domain simulation results show that there is an oscillation risk, the obtained active power output combination is taken as the broadband oscillation risk scenario. Otherwise, the threshold value of equivalent impedance is reduced, and the active power output combination of each new energy power station is regenerated until the active power output combination of the new energy power station with broadband oscillation risk is obtained.

[0091] The method provided in this embodiment is based on the broadband oscillation generation mechanism of different access types of new energy units. It divides the power grid into an internal system that is strongly correlated with the oscillation and an external system that is weakly correlated with the oscillation. It calculates the equivalent impedance model of each new energy power station in the internal system under different active power output levels through data fitting. It performs differentiated equivalent modeling of the internal and external systems. Based on the system equivalent impedance model, it uses a genetic algorithm to quickly generate broadband oscillation risk scenarios. It can balance the accuracy and efficiency of broadband oscillation analysis and provide a scenario basis for dispatching and operation personnel to deeply understand the broadband oscillation risk of the power grid.

[0092] The internal system employs equivalent modeling for renewable energy power plants, ensuring that the equivalent impedance remains unchanged before and after equivalence. Detailed modeling is used for remaining electrical equipment to ensure the dynamic characteristics of the core broadband oscillation region are not lost, guaranteeing the accuracy of oscillation risk analysis. The external system utilizes multi-port Thevenin equivalent modeling, simplifying the complex external network into equivalent electromotive force and equivalent impedance while maintaining consistent short-circuit capacity at boundary nodes, significantly reducing model complexity and computational load. This differentiated modeling strategy balances accuracy and efficiency, significantly shortening the time required for broadband oscillation analysis and meeting the efficiency requirements of power grid operators for simulation analysis.

[0093] This embodiment provides an oscillation risk scenario generation system for implementing the above method, including:

[0094] The power grid partitioning module is configured to divide the power grid into an internal system strongly correlated with oscillations and an external system weakly correlated with oscillations, based on the broadband oscillation generation mechanism of different access types of new energy units.

[0095] The equivalent impedance model calculation module is configured to calculate the equivalent impedance model of each new energy power station in the internal system under different active power output levels.

[0096] The equivalent modeling module is configured to perform differentiated equivalent modeling of the internal and external systems of the power grid, reducing the scale of full electromagnetic transient simulation verification and improving simulation analysis efficiency.

[0097] The risk scenario generation module is configured to: determine the operating scenarios with broadband oscillation risk based on the equivalent impedance model of each new energy power station, the remaining electrical equipment in the internal system, and the equivalent impedance of the external system.

[0098] This embodiment provides a computer device, including at least one processing unit and at least one storage unit, wherein the storage unit stores a computer program, and when the program is executed by the processing unit, the processing unit performs the above-described method.

[0099] This embodiment provides a computer-readable storage medium storing a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the above-described method.

[0100] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for generating broadband oscillation risk scenarios, characterized in that, include: Based on the broadband oscillation generation mechanism of different access types of new energy units, the power grid is divided into an internal system that is strongly correlated with oscillation and an external system that is weakly correlated with oscillation. Calculate the equivalent impedance model of each new energy power station in the internal system under different active power output levels; Differential equivalent modeling is performed for the internal and external systems of the power grid, respectively; Based on the equivalent impedance model of each new energy power station, the remaining electrical equipment in the internal system, and the equivalent impedance of the external system, the operating scenarios with broadband oscillation risk are identified. include: The equivalent impedance model of the internal system is calculated based on the equivalent impedance model of each new energy power station and the equivalent impedance of the remaining electrical equipment in the internal system. The equivalent impedance model of the internal system is superimposed in series with the equivalent impedance of the external system to calculate the equivalent impedance model of the entire power grid system. With the objective that the equivalent reactance of the entire power grid system is less than a threshold value, a genetic algorithm is used to generate candidate combinations of active power output for each new energy power station. Combinations with equivalent resistance less than zero are selected from the candidate combinations as operating scenarios with the risk of wideband oscillation.

2. The method according to claim 1, characterized in that, The broadband oscillation generation mechanism based on different access types of new energy units divides the power grid into an internal system strongly correlated with oscillations and an external system weakly correlated with oscillations, including: Identify the access type of new energy units. The access types include direct-drive wind turbines via AC lines without series compensation, doubly-fed wind turbines via AC lines with series compensation, and new energy units transmitted via flexible direct transmission. For the case where direct-drive wind turbines transmit power through AC lines without series compensation, take any one of the direct-drive wind farms as the starting point, and use topology search to find the 500kV or 750kV transmission line of the wind farm. Define the network consisting of the transmission line and all new energy power plants, transmission lines and transformers below the sending end of the line as the internal system, and the rest as the external system. For the case where the doubly fed wind turbine is transmitted through an AC line with series compensation, the network consisting of the series compensation line and all new energy power plants, transmission lines and transformers below the sending end of the line is defined as the internal system, and the rest is defined as the external system. For the case of new energy being transmitted via flexible DC transmission, the flexible DC transmission and all new energy generating units, transmission lines and transformers in the power grid at the sending end of the flexible DC transmission are defined as the internal system, and the power grid at the receiving end of the flexible DC transmission is defined as the external system. The bus connecting the internal system and the external system is defined as a boundary node.

3. The method according to claim 1, characterized in that, The equivalent impedance model for each new energy power station in the internal calculation system under different active power output levels includes: The equivalent impedance value of a single new energy unit at a certain active power output level and frequency is obtained by analytical derivation or model identification method. Based on the equivalent impedance value of a single new energy unit, the impedance of the corresponding transformer and collector line, and the internal topology of the new energy power station, the equivalent impedance value of the new energy power station at some active power output levels and frequencies is calculated. Based on the equivalent impedance values ​​of the active power output level and frequency of the new energy power station, the equivalent impedance model of the new energy power station under different active power output levels is obtained by using the data fitting method.

4. The method according to claim 1, characterized in that, The differentiated equivalent modeling of the internal and external power grid systems includes: For the internal power grid system, we perform equivalent modeling of various types of new energy units in each new energy power station, equivalent modeling of the collection lines and box-type substations in each new energy power station, and detailed modeling of the remaining electrical equipment. For external systems of the power grid, the multi-port Thevenin equivalent method is used for equivalent modeling.

5. The method according to claim 4, characterized in that, Equivalent modeling is performed on new energy generating units, transformer substations, and collector lines in the internal power grid system's new energy power stations, including: For the same type of new energy generating units, the single-unit multiplication method is used for equivalent modeling. Based on the number of new energy generating units in each type, the equivalent impedance model of each type of new energy generating unit is obtained. Based on the impedance of the transformer substation corresponding to each type of new energy unit and the number of each type of new energy unit, the impedance of the transformer substation after the equivalent is calculated. Based on the topology of each new energy unit in the new energy power station, the equivalent impedance model of each type of new energy unit before and after equivalence, the impedance of the corresponding transformer before and after equivalence for each type of new energy unit, and the impedance of the collector line before equivalence, the impedance of the collector line after equivalence is calculated.

6. The method according to claim 1, characterized in that, Based on the system after differentiated equivalent modeling, the operation scenario with broadband oscillation risk is verified by full electromagnetic transient simulation software. If the time domain simulation results show that there is an oscillation risk, the obtained active power output combination is taken as the broadband oscillation risk scenario. Otherwise, the threshold value of equivalent impedance is reduced, and the active power output combination of each new energy power station is regenerated until the active power output combination of the new energy power station with broadband oscillation risk is obtained.

7. A broadband oscillation risk scenario generation system, used to implement the method as described in any one of claims 1 to 6, characterized in that, include: The power grid partitioning module is configured to divide the power grid into an internal system strongly correlated with oscillations and an external system weakly correlated with oscillations, based on the broadband oscillation generation mechanism of different access types of new energy units. The equivalent impedance model calculation module is configured to calculate the equivalent impedance model of each new energy power station in the internal system under different active power output levels. The equivalent modeling module is configured to perform differentiated equivalent modeling for the internal and external systems of the power grid, respectively. The risk scenario generation module is configured to: determine the operating scenarios with broadband oscillation risk based on the equivalent impedance model of each new energy power station, the remaining electrical equipment in the internal system, and the equivalent impedance of the external system.

8. A computer device, characterized in that, The method includes at least one processing unit and at least one storage unit, wherein the storage unit stores a computer program that, when executed by the processing unit, causes the processing unit to perform the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, It stores a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the method as described in any one of claims 1 to 6.

Images