A method, system, device and medium for evaluating the strength support performance of a superconducting phase modifier system

Abstract

This invention belongs to the field of power system analysis technology, and discloses a method, system, equipment, and medium for evaluating the strength support performance of a superconducting synchronous condenser (SSC). The method includes: acquiring power grid operating parameters and the physical parameters of the connected SSC; calculating the static short-circuit ratio, reflecting the intrinsic strength of the power grid, based on the power grid operating parameters; constructing a dynamic equivalent factor based on the physical parameters of the SSC; and coupling the static short-circuit ratio and the dynamic equivalent factor to construct a dynamic full-process evaluation index that comprehensively reflects the SSC's strength support effect on the power grid system. By introducing a dynamic equivalent factor to correct traditional indicators, a leap from static grid strength to the dynamic support capability of equipment is achieved. Furthermore, a comprehensive dynamic full-process evaluation index, reflecting the SSC's strength support effect on the system throughout the entire fault process, is constructed based on the dynamic equivalent factor, solving the technical problem that traditional indicators cannot accurately quantify the instantaneous dynamic support mechanism.

Description

Technical Field

[0001] This invention belongs to the field of power system analysis technology, specifically relating to a method, system, equipment, and medium for evaluating the strength support performance of a superconducting phase shifter system. Background Technology

[0002] With the large-scale integration of high-proportion renewable energy sources into the power grid, the power system faces severe challenges of decreased system strength and insufficient voltage support. Superconducting synchronous condensers are a new type of equipment developed to address these problems. Compared to traditional synchronous condensers, superconducting condensers utilize the properties of superconducting materials to achieve extremely low subtransient reactance, enabling them to provide stronger and faster reactive current support in the event of a grid fault. This superior dynamic support capability is crucial for improving the transient voltage stability of weak power grids and ensuring the safe operation of renewable energy equipment.

[0003] Existing system strength assessment schemes mainly revolve around the short-circuit ratio (SCR) and its correction forms. For the integration of power electronic equipment such as renewable energy sources and high-voltage direct current (HVDC), researchers have proposed indices such as the generalized short-circuit ratio (GSCR) and multi-infeed short-circuit ratio, attempting to reflect the coupling effects of equipment control characteristics and multi-point integration through mathematical corrections. For example, some studies have proposed a unified effective short-circuit ratio, combining system equivalent impedance and control characteristics to assess strength. Regarding steady-state operation, some schemes utilize the voltage's sensitivity to reactive power to assess the limit of active power delivered by wind farms to the grid. Furthermore, relevant experiments have been conducted to verify the dynamic reactive power characteristics of traditional fast-response synchronous condensers.

[0004] However, existing system strength assessment schemes still have the following limitations: 1. Evaluation methods tend to be static: Existing indicator systems are essentially static or quasi-static evaluation methods.

[0005] 2. Difficulty in capturing dynamic response process: Traditional systems have difficulty in accurately and quantitatively capturing the dynamic response process of a superconducting camera within tens of milliseconds after a fault.

[0006] 3. Insufficient coupling of physical parameters: Existing indicators lack a direct analytical coupling relationship with the extremely low reactance of the core physical characteristics of the superconducting camera.

[0007] 4. Inability to quantify decisive advantages: Existing solutions cannot accurately reflect the decisive advantages of superconducting machines over traditional equipment in instantaneous reactive power support, resulting in the inability to scientifically quantify their dominant role in instantaneous voltage margin.

[0008] Therefore, there is an urgent need for a scientific indicator to accurately evaluate and quantify the actual support effect of the superconducting camera during the entire fault process. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method, system, device, and medium for evaluating the strength support performance of a superconducting camera system. Based on a dynamic equivalent factor, a dynamic full-process comprehensive evaluation index is constructed to comprehensively reflect the strength support effect of the superconducting camera on the system throughout the entire fault process, thus solving the technical problem that traditional indicators are difficult to accurately quantify the instantaneous dynamic support mechanism.

[0010] This invention provides the following technical solution: The first objective of this invention is to provide a method for evaluating the strength support performance of a superconducting camera system, comprising: Acquire the operating parameters of the power grid system and the physical parameters of the connected superconducting phase converter; The static short-circuit ratio, which reflects the intrinsic strength of the power grid, is calculated based on the operating parameters of the power grid system. Dynamic equivalent factors are constructed based on the physical parameters of the superconducting camera. By coupling the static short-circuit ratio with the dynamic equivalent factor, a dynamic full-process evaluation index is constructed that comprehensively reflects the role of superconducting synchronous condensers in supporting the strength of the power grid system.

[0011] As a further improvement of the present invention, the formula for calculating the static short-circuit ratio is as follows:

[0012] in, This is the static short-circuit ratio. For grid short-circuit capacity, The rated voltage of the grid-connected bus. The equivalent impedance of the power grid. The capacity of power electronic devices connected to the power grid.

[0013] As a further improvement of the present invention, the dynamic full-process evaluation index is the dynamic equivalent short-circuit ratio of the synchronous condenser, which is obtained by coupling and multiplying the static short-circuit ratio and the dynamic equivalent factor. The calculation formula is as follows:

[0014] in, SC-DESCR To synchronize the dynamic equivalent short-circuit ratio of the camera, The rated voltage of the grid-connected bus. For the capacity of power electronic devices connected to the power grid, The equivalent impedance of the power grid. Dynamic equivalent factor.

[0015] As a further improvement of the present invention, the dynamic equivalent factor is a function of the subtransient reactance, transient reactance and excitation control parameters of the superconducting camera, and is used to quantify the dynamic support performance of the superconducting camera for the strength of the power grid system.

[0016] As a further improvement of the present invention, the formula for calculating the dynamic equivalence factor is as follows:

[0017] in, For the subtransient reactance of the superconducting camera, For the transient reactance of the superconducting camera, These are the excitation control parameters for the superconducting camera. The equivalent impedance of the power grid. For the equivalent reactance of the power grid, k This represents the dynamic gain coefficient. By establishing analytical functions for subtransient reactance, transient reactance, and grid impedance, the physical nature of the attenuation of support capacity from the subtransient peak to the transient sustained support is accurately captured. This allows the evaluation index to quantify the decisive impact of the low reactance characteristics of the superconducting phase modulator on system strength, improving the accuracy of the evaluation.

[0018] As a further improvement of the present invention, the excitation control parameters are used to characterize the ability of the superconducting camera to maintain voltage during transient processes, and are calculated from the excitation multiple of the superconducting camera and the direct-axis open-circuit time constant during grid faults.

[0019] As a further improvement of the present invention, the calculation formula for the excitation control parameters is as follows:

[0020] in, The excitation factor is used to characterize the fault support strength of the superconducting camera. is the direct-axis open-circuit time constant, used to characterize the reactive response speed of the superconducting camera.

[0021] The second objective of this invention is to provide a strength support performance evaluation system for a superconducting camera system, used to implement the above-mentioned method, comprising: The parameter acquisition module is used to acquire the operating parameters of the power grid system and the physical parameters of the connected superconducting camera. The static analysis module is used to calculate the static short-circuit ratio, which reflects the intrinsic strength of the power grid, based on the operating parameters of the power grid system. The dynamic modeling module is used to construct dynamic equivalence factors based on the physical parameters of the superconducting camera. The comprehensive evaluation module is used to couple the static short-circuit ratio with the dynamic equivalent factor to construct a dynamic full-process evaluation index that comprehensively reflects the supporting role of the superconducting synchronous condenser in the power grid system.

[0022] 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.

[0023] 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.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: By acquiring power grid operating parameters and synchronous condenser physical parameters, a comprehensive assessment of everything from static grid strength to dynamic support performance of equipment was achieved. The constructed dynamic full-process evaluation index can accurately reflect the true supporting role of superconducting synchronous condensers in the strength of the power grid system throughout the entire fault cycle, solving the problem that traditional indicators cannot quantify millisecond-level dynamic responses.

[0025] The constructed evaluation index is directly linked to subtransient reactance, transient reactance, and excitation control parameters, enabling quantitative analysis of the core characteristic of low reactance of the superconducting phase modulator and highlighting its dominant role in instantaneous reactive power support. Attached Figure Description

[0026] Figure 1 A flowchart of the method for evaluating the strength support performance of a superconducting camera system provided by the present invention; Figure 2 This is a schematic diagram of a traditional synchronous condenser grid topology. Figure 3 This is a schematic diagram of the grid-connected topology for superconducting camera switching. Figure 4 A comparison chart of voltage performance after a three-phase fault; Figure 5 This is a comparison chart of the reactive power output of the synchronous condenser after a three-phase fault. Detailed Implementation

[0027] 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.

[0028] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1As shown, this embodiment provides a method for evaluating the strength support performance of a superconducting camera system, including: Acquire the operating parameters of the power grid system and the physical parameters of the connected superconducting phase converter; The static short-circuit ratio, which reflects the intrinsic strength of the power grid, is calculated based on the operating parameters of the power grid system. Dynamic equivalent factors are constructed based on the physical parameters of the superconducting camera. By coupling the static short-circuit ratio with the dynamic equivalent factor, a dynamic full-process evaluation index is constructed that comprehensively reflects the role of superconducting synchronous condensers in supporting the strength of the power grid system.

[0029] The traditional static short-circuit ratio (SCR) reflects the intrinsic strength of the power grid, which is related to the equivalent reactance at the grid connection point. They have an approximately inverse proportional relationship.

[0030]

[0031] in, For grid short-circuit capacity, The rated voltage of the grid-connected bus. The equivalent impedance of the power grid. The capacity of power electronic devices connected to the power grid.

[0032] When the camera is operating normally, its active power is only used to overcome mechanical losses; therefore, the power angle can be considered as... According to the direct axis voltage quadrature axis voltage ,have , Therefore, the reactive power output of the synchronous modulator is obtained. The calculation formula is:

[0033] in, , These are the direct-axis and quadrature-axis currents, respectively. Reactive power increment during fault for:

[0034] in, This represents the bus voltage increment. This is the bus voltage after the fault. This is the initial current before the fault. This represents the direct-axis current increment. Of the parameters mentioned above, only... The value is determined by adjusting the camera parameters. These are important parameters for determining the reactive power response of a synchronous condenser.

[0035] When a transient fault occurs at the synchronous condenser terminal, the superconducting synchronous condenser stator can generate a strong reactive current in a very short time. Without considering excitation control, the time-varying increment of the direct-axis (d-axis) reactive current is expressed as:

[0036] in, Caused by a short circuit q Shaft pressure drop, its values ​​are ; To adjust the camera's power angle before short-circuiting, it is usually set to 0; To adjust the camera d Secondary transient reactance; Transient reactance; For steady-state reactance; To consider system impedance d The time constant of the axle transient short circuit; The transient short-circuit time constant; To reflect the time constant of the stator winding transient; To adjust the camera's electric angular velocity.

[0037] When the short circuit is considered to be the power angle At that time, the maximum reactive current can be obtained. This value determines the instantaneous reactive power output capability of the synchronous condenser; among which The parameters are related to the type of fault, not determined by the synchronous condenser itself, but by the equivalent grid reactance of different synchronous condensers in the same power grid system. Since it won't change, it's assumed that the impact of different phase shifters on the system voltage is reflected in the phase shifter's subtransient reactance. By linking it with the traditional short static road ratio, we can obtain a quantitative indicator of the improvement in system strength brought about by the access of synchronous condensers.

[0038] Connecting a synchronous condenser is equivalent to injecting additional short-circuit capacity at the grid connection point. This dynamic support effect can be reflected by defining a dynamic equivalent factor, which is a function of the subtransient reactance, transient reactance, and excitation control parameters of the superconducting camera. It is used to quantify the dynamic support performance of superconducting phase modulators for the strength of power grid systems.

[0039] The constructed dynamic full-process evaluation index is the dynamic equivalent short-circuit ratio of the synchronous condenser, which is obtained by coupling and multiplying the static short-circuit ratio and the dynamic equivalent factor. Its calculation formula is as follows:

[0040] in, SC-DESCR To synchronize the dynamic equivalent short-circuit ratio of the camera, The rated voltage of the grid-connected bus. For the capacity of power electronic devices connected to the power grid, The equivalent impedance of the power grid. Dynamic equivalent factor.

[0041] The synchronous condenser emits a strong reactive current. Subsequently, additional reactive power was injected at the grid connection point, thereby increasing the voltage at the grid connection point. U In system strength assessment, this supporting effect is equivalent to increasing the system's short-circuit capacity potential. The relationship between the dynamic equivalent factor and the camera adjustment parameters is as follows:

[0042] When the synchronous condenser is not connected, there is Substituting into the above formula, we get ,have .

[0043] As mentioned above, the change in voltage support after the synchronous condenser is connected is mainly related to the subtransient parameters of the synchronous condenser. Relevant, therefore can be defined ;in, k The dynamic gain coefficient, determined by the excitation control parameters and the transient parameters of the synchronous condenser, plays a role in quantizing the dynamic transition. The calculation formula is as follows:

[0044]

[0045] in, These are the excitation control parameters for the superconducting camera. The excitation factor is used to characterize the fault support strength of the superconducting camera. The direct-axis open-circuit time constant is used to characterize the reactive power response speed of the superconducting phase converter; the ratio of the two represents the excitation voltage rise capability per unit time, which can scientifically characterize the ability of the phase converter to maintain voltage during transient processes.

[0046] As time progresses, the current-supporting capacity will change from that of the subtransient reactance. The determined peak value decays to the value determined by the transient reactance. The ability to sustain a decision in a transient state. k As a dynamic gain coefficient, the subtransient reactance The resulting instantaneous potential is corrected to a support strength that remains effective throughout the entire transient phase. Transient reactance A larger value means a greater current attenuation and poorer current continuity, which is reflected in the specifications as... SC-DESCRA larger value indicates worse performance. Therefore, the formula for the dynamic full-process evaluation index is as follows:

[0047]

[0048] The feasibility of the dynamic full-process evaluation index constructed in this invention is verified through experimental simulation. The non-adjustable phase converter, the conventional phase converter, and the superconducting phase converter are all placed in the same circuit topology system (the grid-connected topology of the conventional phase converter is as follows). Figure 2 As shown, the superconducting camera grid-connected topology is as follows: Figure 3 As shown in the figure, the voltage support capability corresponding to the three operating conditions is evaluated using the index constructed in this invention, that is, to verify whether the higher the index value, the stronger the support performance of the power grid during faults.

[0049] in, , , To simplify calculations, no-excitation parameters are used, that is, let Calculate the index values ​​under the three working conditions respectively: 1. Calculation of camera parameters without adjustment (at this time) ):

[0050] 2. Traditional synchronous condenser index calculation: Subtransient reactance of traditional phase converter The subtransient reactance is 0.0772 pu. It is 0.126 pu;

[0051] 3. Calculation of superconducting camera specifications: Subtransient reactance of superconducting camera The transient reactance is 0.117 pu. It is 0.608 pu;

[0052] against Figure 2 , Figure 3 The topology shown is used to simulate a three-phase short-circuit fault at the grid connection point. Experiments are conducted and analyzed under three conditions: no synchronous condenser, connection of a traditional synchronous condenser, and connection of a superconducting synchronous condenser. The voltage performance after the three-phase short-circuit fault is compared as follows: Figure 4 As shown, the reactive power output of the synchronous condenser is as follows: Figure 5 As shown; the specific analysis results are as follows: 1. Voltage support capability during faults (1.5s-1.6s).

[0053] During a short-circuit fault, the voltage waveform showed that the voltage drop was deepest without a synchronous condenser, while the drop became shallower after the synchronous condenser was connected. This fully verifies the synchronous condenser's ability to support the grid during transient reactive power outages. During this period, the instantaneous voltage drop depth at the synchronous condenser terminals mainly depends on the secondary transient synchronous reactance. Equivalent impedance to the power grid The ratio is directly related to the calculation principle of the dynamic short-circuit ratio index.

[0054] Because the superconducting phase converter has extremely low subtransient reactance, it has the strongest instantaneous current injection capability. Therefore, the voltage drop at the terminal of the superconducting phase converter is the smallest under operating conditions, which verifies the advantage brought by the improvement of the index value, that is, whether the index value can accurately reflect the depth of voltage drop.

[0055] 2. System stability after fault clearing (1.6s-2.0s).

[0056] After the fault was cleared in 1.6 seconds, the system's reactive power and voltage dynamic recovery characteristics showed significant differences: In a system without a synchronous condenser, the voltage cannot be restored and remains stagnant at a low level for an extended period, indicating a voltage collapse. This closely matches theoretical predictions that under low performance parameters, the system is unable to support reactive power demand and loses voltage stability.

[0057] Configuration of the synchronous condenser system: Regardless of whether a traditional or superconducting synchronous condenser is configured, the system can restore the voltage to its rated value after a period of time. Among these, the voltage recovery speed and post-recovery stability of the superconducting synchronous condenser are significantly better than those of the traditional synchronous condenser. This directly demonstrates the superior voltage stability provided by the high index 11.1, indicating that the dynamic full-process evaluation index constructed in this invention can quantify the strength support performance of the superconducting synchronous condenser for the power grid system.

[0058] Traditional static short-circuit ratio (SCR) metrics, when measuring grid support performance, primarily focus on the equivalent impedance of the power grid, neglecting the internal physical parameters of the synchronous condenser. This makes it impossible to differentiate the grid support roles of different devices and explain why, for devices of the same capacity, a superconducting synchronous condenser can prevent grid voltage collapse while a traditional one cannot. Furthermore, most existing solutions are static or quasi-static, while the crucial role of a superconducting synchronous condenser manifests within tens of milliseconds after a fault, a momentary, dominant effect that existing metrics cannot capture.

[0059] In summary, this invention, by introducing a dynamic equivalent factor to correct traditional indicators, achieves a leap from static grid strength to dynamic support capability of equipment. Furthermore, based on the dynamic equivalent factor, it constructs a dynamic full-process comprehensive evaluation index that comprehensively reflects the support effect of the superconducting phase converter on the system strength throughout the entire fault process, thus solving the technical problem that traditional indicators are difficult to accurately quantify the instantaneous dynamic support mechanism.

[0060] This embodiment provides a strength support performance evaluation system for a superconducting camera system, used to implement the above method, including: The parameter acquisition module is used to acquire the operating parameters of the power grid system and the physical parameters of the connected superconducting camera. The static analysis module is used to calculate the static short-circuit ratio, which reflects the intrinsic strength of the power grid, based on the operating parameters of the power grid system. The dynamic modeling module is used to construct dynamic equivalence factors based on the physical parameters of the superconducting camera. The comprehensive evaluation module is used to couple the static short-circuit ratio with the dynamic equivalent factor to construct a dynamic full-process evaluation index that comprehensively reflects the supporting role of the superconducting synchronous condenser in the power grid system.

[0061] 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.

[0062] 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.

[0063] 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 evaluating the strength support performance of a superconducting camera system, characterized in that, include: Acquire the operating parameters of the power grid system and the physical parameters of the connected superconducting phase converter; The static short-circuit ratio, which reflects the intrinsic strength of the power grid, is calculated based on the operating parameters of the power grid system. Dynamic equivalent factors are constructed based on the physical parameters of the superconducting camera. By coupling the static short-circuit ratio with the dynamic equivalent factor, a dynamic full-process evaluation index is constructed that comprehensively reflects the role of superconducting synchronous condensers in supporting the strength of the power grid system.

2. The method according to claim 1, characterized in that, The formula for calculating the static short-circuit ratio is: in, This is the static short-circuit ratio. For grid short-circuit capacity, The rated voltage of the grid-connected bus. The equivalent impedance of the power grid. The capacity of power electronic devices connected to the power grid.

3. The method according to claim 1, characterized in that, The dynamic full-process evaluation index is the dynamic equivalent short-circuit ratio of the synchronous condenser, which is obtained by coupling and multiplying the static short-circuit ratio and the dynamic equivalent factor. The calculation formula is as follows: in, SC-DESCR To synchronize the dynamic equivalent short-circuit ratio of the camera, The rated voltage of the grid-connected bus. For the capacity of power electronic devices connected to the power grid, The equivalent impedance of the power grid. Dynamic equivalent factor.

4. The method according to claim 1, characterized in that, The dynamic equivalent factor is a function of the subtransient reactance, transient reactance, and excitation control parameters of the superconducting phase converter, and is used to quantify the dynamic support performance of the superconducting phase converter for the strength of the power grid system.

5. The method according to claim 4, characterized in that, The formula for calculating the dynamic equivalence factor is as follows: in, For the subtransient reactance of the superconducting camera, For the transient reactance of the superconducting camera, These are the excitation control parameters for the superconducting camera. The equivalent impedance of the power grid. For the equivalent reactance of the power grid, k This is the dynamic gain coefficient.

6. The method according to claim 4, characterized in that, The excitation control parameters are used to characterize the ability of the superconducting phase converter to maintain voltage during transient processes, and are calculated from the excitation multiple of the superconducting phase converter and the direct-axis open-circuit time constant during grid faults.

7. The method according to claim 6, characterized in that, The calculation formula for the excitation control parameters is as follows: in, The excitation factor is used to characterize the fault support strength of the superconducting camera. is the direct-axis open-circuit time constant, used to characterize the reactive response speed of the superconducting camera.

8. A strength support performance evaluation system for a superconducting camera system, used to implement the method described in any one of claims 1 to 7, characterized in that, include: The parameter acquisition module is used to acquire the operating parameters of the power grid system and the physical parameters of the connected superconducting camera. The static analysis module is used to calculate the static short-circuit ratio, which reflects the intrinsic strength of the power grid, based on the operating parameters of the power grid system. The dynamic modeling module is used to construct dynamic equivalence factors based on the physical parameters of the superconducting camera. The comprehensive evaluation module is used to couple the static short-circuit ratio with the dynamic equivalent factor to construct a dynamic full-process evaluation index that comprehensively reflects the supporting role of the superconducting synchronous condenser in the power grid system.

9. A computer device, characterized in that, It 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 7.

10. 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 7.

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