Method and device for evaluating polymorphic transient voltage stability of power system

Abstract

The invention relates to the technical field of power systems, in particular to a power system polymorphic transient voltage stability assessment method and device, and the method comprises the steps: obtaining the power grid state parameters of a target power system; based on a preset fault set and a preset electromagnetic transient simulation model, performing simulation to obtain a bus transient voltage digital quantity of the target power system under a single fault; and based on the power grid state parameters and the bus transient voltage digital quantity, calculating a multi-form transient voltage stability comprehensive evaluation index of the target power system under a single fault, and further calculating a multi-form transient voltage stability comprehensive evaluation index under multiple faults, so as to obtain a multi-form transient voltage stability comprehensive evaluation result of the target power system. According to the method, a mathematical model and a simulation technology can be combined, complex and changeable voltage instability forms of the double-high power system can be flexibly dealt with, and comprehensive calculation and evaluation of transient voltage stability of the double-high system in multiple forms can be comprehensively and quantitatively realized.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a method and device for evaluating the multi-form transient voltage stability of a power system. Background Art

[0002] With the access of large-scale new energy and power electronic equipment, the dynamic control difficulty of "double high" power system has increased significantly compared with traditional power system, and the voltage stability problem has become more prominent. Affected by the converter control strategy, the transient voltage of the system during fault ride-through and fault recovery is diverse, and transient low voltage, overvoltage, voltage fluctuation and failure to recover may occur during the process, which directly affects the safe and stable operation of the system.

[0003] In the related technology, the transient voltage stability assessment of the power system is mainly realized by using binary tables and short-circuit ratios. Among them, the binary table is a method for quantitatively analyzing the voltage stability of the power system during the transient process by constructing a table containing the binary relationship between voltage and time. After the fault occurs, the change of the system voltage over time is recorded, and a binary table is constructed according to the set threshold. By analyzing the data in the binary table, the voltage stability of the system can be quantitatively evaluated. The short-circuit ratio (SCR) is a key stability assessment indicator in the power system, which mainly reflects the relative relationship between the system short-circuit capacity and the equipment capacity. In the transient voltage stability assessment, the short-circuit ratio is usually used to quantify the system's tolerance to short-circuit faults and to evaluate the system's ability to restore the voltage to a stable state after a short circuit occurs. By comparing the short-circuit ratios under different operating modes or fault scenarios, the voltage stability of the system under different conditions can be evaluated.

[0004] However, the binary table method in the related technology is usually designed and evaluated for specific voltage forms based on static or quasi-static data, so its scope of application is relatively limited. When faced with the complex dynamic characteristics of the transient voltage in the "double-high" power system that is not just a monotonous rise or fall, the accuracy of the transient voltage stability evaluation results of the system is difficult to guarantee; the short-circuit ratio is more used for static voltage stability evaluation, and in the transient process, the operating state of the power system will change rapidly, and the static evaluation method may not be able to accurately capture these changes. Therefore, when using the short-circuit ratio for transient voltage stability evaluation, the evaluation results may be conservative and cannot truly reflect the transient stability of the system, which needs to be solved urgently. Summary of the invention

[0005] The present application provides a method and device for evaluating the multi-form transient voltage stability of an electric power system, in order to solve the problems that the transient voltage stability evaluation method of an electric power system in the related art has a relatively limited scope of application and cannot adapt to the complex dynamic changes of the electric power system. The evaluation results may be conservative and have low accuracy, making it difficult to fully and accurately reflect the morphological changes of the transient voltage of the electric power system and unable to truly reflect the transient stability of the system.

[0006] The first aspect of the present application provides an evaluation method for the multi-form transient voltage stability of an electric power system, comprising the following steps: obtaining grid state parameters of a target electric power system; simulating and obtaining a digital quantity of a bus transient voltage of the target electric power system under a single fault based on a preset fault set and a preset electromagnetic transient simulation model; calculating a comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target electric power system based on the grid state parameters and the digital quantity of the bus transient voltage, and calculating a comprehensive evaluation index of the multi-form transient voltage stability under multiple faults of the target electric power system based on the comprehensive evaluation index of the multi-form transient voltage stability under a single fault, so as to obtain a comprehensive evaluation result of the multi-form transient voltage stability of the target electric power system through the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults.

[0007] Optionally, in one embodiment of the present application, the comprehensive evaluation index of multi-form transient voltage stability under a single fault of the target power system is calculated based on the grid state parameters and the bus transient voltage digital quantity, including: based on the grid state parameters and the bus transient voltage digital quantity, calculating the transient voltage recovery evaluation index, transient overvoltage evaluation index, and transient voltage fluctuation evaluation index of the target power system under a single fault; combining the transient voltage recovery evaluation index, the transient overvoltage evaluation index, the transient voltage fluctuation evaluation index and the corresponding weights to calculate the comprehensive evaluation index of multi-form transient voltage stability under a single fault of the target power system.

[0008] Optionally, in one embodiment of the present application, the comprehensive evaluation index of multi-form transient voltage stability under multiple faults of the target power system is calculated based on the comprehensive evaluation index of multi-form transient voltage stability under single fault, including: based on the comprehensive evaluation index of multi-form transient voltage stability under single fault, combined with the weight corresponding to the single fault, calculating the comprehensive evaluation index of multi-form transient voltage stability under multiple faults.

[0009] Optionally, in one embodiment of the present application, before simulating and obtaining the digital value of the bus transient voltage of the target power system under a single fault based on a preset fault set and a preset electromagnetic transient simulation model, it also includes: constructing the preset fault set based on the fault type, fault location and fault duration of the target power system.

[0010] Optionally, in one embodiment of the present application, the calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under a single fault is:

[0011] TVI=α1RI+α2TOVI+α3VFI

[0012] Among them, TVI is the comprehensive evaluation index of multi-form transient voltage stability under the single fault, RI is the transient voltage recovery evaluation index, TOVI is the transient overvoltage evaluation index, VFI is the transient voltage fluctuation evaluation index, α1, α2, α2 are the weight values ​​of the transient voltage recovery evaluation index, the transient overvoltage evaluation index, and the transient voltage fluctuation evaluation index, respectively.

[0013] Optionally, in one embodiment of the present application, the calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under multiple faults is:

[0014]

[0015] Among them, TVIF is the comprehensive evaluation index of transient voltage under multiple faults, M is the number of faults, ω i is the weight value of each fault i, TVI i It is the comprehensive evaluation index of transient voltage under single fault corresponding to each fault i.

[0016] The second aspect of the present application provides an evaluation device for the multi-form transient voltage stability of an electric power system, comprising: a first acquisition module, used to acquire a grid state parameter of a target electric power system; a second acquisition module, used to simulate and acquire a digital value of a bus transient voltage of the target electric power system under a single fault based on a preset fault set and a preset electromagnetic transient simulation model; an evaluation module, used to calculate a comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target electric power system based on the grid state parameter and the digital value of the bus transient voltage, and based on the comprehensive evaluation index of the multi-form transient voltage stability under a single fault, calculate a comprehensive evaluation index of the multi-form transient voltage stability under multiple faults of the target electric power system, so as to obtain a comprehensive evaluation result of the multi-form transient voltage stability of the target electric power system through the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults.

[0017] Optionally, in one embodiment of the present application, the evaluation module includes: a first calculation unit, used to calculate the transient voltage recovery evaluation index, the transient overvoltage evaluation index, and the transient voltage fluctuation evaluation index under a single fault of the target power system based on the grid state parameters and the bus transient voltage digital quantity; a second calculation unit, used to combine the transient voltage recovery evaluation index, the transient overvoltage evaluation index, the transient voltage fluctuation evaluation index and the corresponding weights to calculate the comprehensive evaluation index of multi-form transient voltage stability under a single fault of the target power system.

[0018] Optionally, in one embodiment of the present application, the evaluation module further includes: a third calculation unit, used to calculate the comprehensive evaluation index of multi-form transient voltage stability under multiple faults based on the comprehensive evaluation index of multi-form transient voltage stability under single fault and combined with the weight corresponding to the single fault.

[0019] Optionally, in one embodiment of the present application, it also includes: a construction module, which is used to construct the preset fault set based on the fault type, fault location and fault duration of the target power system before simulating and obtaining the digital value of the bus transient voltage of the target power system under a single fault based on the preset fault set and the preset electromagnetic transient simulation model.

[0020] Optionally, in one embodiment of the present application, the calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under a single fault is:

[0021] TVI=α1RO+α2TOVI+α3VFI

[0022] Among them, TVI is the comprehensive evaluation index of multi-form transient voltage stability under the single fault, RI is the transient voltage recovery evaluation index, TOVI is the transient overvoltage evaluation index, VFI is the transient voltage fluctuation evaluation index, α1, α2, α2 are the weight values ​​of the transient voltage recovery evaluation index, the transient overvoltage evaluation index, and the transient voltage fluctuation evaluation index, respectively.

[0023] Optionally, in one embodiment of the present application, the calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under multiple faults is:

[0024]

[0025] Among them, TVIF is the comprehensive evaluation index of transient voltage under multiple faults, M is the number of faults, ω i is the weight value of each fault i, TVI i It is the comprehensive evaluation index of transient voltage under single fault corresponding to each fault i.

[0026] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for evaluating the multi-morphic transient voltage stability of a power system as described in the above embodiment.

[0027] A fourth aspect of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned method for evaluating the multi-morphological transient voltage stability of a power system.

[0028] A fifth aspect of the present application provides a computer program product, including a computer program, which, when executed, is used to implement the above-mentioned method for evaluating the multi-form transient voltage stability of a power system.

[0029] The embodiment of the present application can calculate the comprehensive evaluation index of the multi-form transient voltage stability under a single fault and the multi-form transient voltage stability under multiple faults of the target power system based on the state parameters of the target power system, the preset fault set and the preset electromagnetic transient simulation model, and finally obtain the comprehensive evaluation result of the multi-form transient voltage stability of the target power system. Thus, the stability index reflecting the transient voltage form such as transient voltage recovery, overvoltage, volatility, etc. is realized, and the application of mathematical models and simulation technology is combined to flexibly respond to the complex and changeable voltage instability form of the "double high" power system, and comprehensively and quantitatively realize the comprehensive calculation and evaluation of the transient voltage stability of the "double high" system under multiple forms. At the same time, it can also enable the power system operation and dispatching personnel to intuitively understand the voltage stability margin of the system under various faults or disturbances, which is helpful to identify potential risks, provide corresponding scientific basis for formulating targeted control measures for system dispatching and optimization, and enhance the safety and stability of the power system. This solves the problems that the power system transient voltage stability assessment method in the related technology has a limited scope of application and cannot adapt to the complex dynamic changes of the power system. The assessment results may be conservative and have low accuracy, making it difficult to fully and accurately reflect the morphological changes of the transient voltage of the power system and unable to truly reflect the transient stability of the system.

[0030] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0032] Figure 1A flowchart of a method for evaluating multi-form transient voltage stability of a power system provided according to an embodiment of the present application;

[0033] Figure 2 A flowchart of a method for evaluating multi-state transient voltage stability of a power system according to an embodiment of the present application;

[0034] Figure 3 A schematic diagram of the structure of a device for evaluating multi-form transient voltage stability of a power system provided according to an embodiment of the present application;

[0035] Figure 4 It is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application.

[0036] Reference numerals:

[0037] 10-Evaluation device for multi-form transient voltage stability of power system: 100-first acquisition module, 200-second acquisition module and 300-evaluation module; 401-memory, 402-processor and 403-communication interface. DETAILED DESCRIPTION

[0038] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0039] The following describes the evaluation method and device for the multi-form transient voltage stability of the power system of the embodiment of the present application with reference to the accompanying drawings. In view of the fact that the power system transient voltage stability evaluation method in the related art mentioned in the above background technology has a relatively limited scope of application, cannot adapt to the complex dynamic changes of the power system, and the evaluation result may be conservative and have low accuracy, making it difficult to fully and accurately reflect the morphological changes of the transient voltage of the power system, and cannot truly reflect the transient stability of the system, the present application provides a method for evaluating the multi-form transient voltage stability of the power system, in which, based on the state parameters of the target power system, a preset fault set and a preset electromagnetic transient simulation model, the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system and the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults can be calculated, and finally the comprehensive evaluation result of the multi-form transient voltage stability of the target power system is obtained. As a result, the stability indicators reflecting the transient voltage form such as transient voltage recovery, overvoltage, and volatility are realized. Combined with the application of mathematical models and simulation technology, the complex and changeable voltage instability forms of the "double high" power system can be flexibly responded to, and the comprehensive calculation and evaluation of the transient voltage stability of the "double high" system under multiple forms can be fully and quantitatively realized. At the same time, it can also enable the power system operation and dispatching personnel to intuitively understand the voltage stability margin of the system under various faults or disturbances, which is helpful to identify potential risks, and provide corresponding scientific basis for formulating targeted control measures for system dispatching and optimization, and enhance the safety and stability of the power system. As a result, the problems of the limited scope of application of the transient voltage stability evaluation method of the power system in the relevant technology, the inability to adapt to the complex dynamic changes of the power system, the conservative evaluation results and low accuracy, the difficulty in comprehensively and accurately reflecting the form changes of the transient voltage of the power system, and the inability to truly reflect the transient stability of the system are solved.

[0040] Specifically, Figure 1 A flowchart of a method for evaluating multi-form transient voltage stability of a power system provided in an embodiment of the present application.

[0041] like Figure 1 As shown, the evaluation method of the multi-form transient voltage stability of the power system includes the following steps:

[0042] In step S101 , a grid state parameter of a target power system is acquired.

[0043] It can be understood that the target power system here can be understood as a "double-high" power system for multi-modal transient voltage stability assessment. The "double-high" power system refers to a power system with a high proportion of renewable energy access and a high proportion of power electronic equipment application.

[0044] In some embodiments, when evaluating the multi-morphological transient voltage stability of a target power system such as a "dual-high" power system, since the dynamic changes of the "dual-high" power system during a fault are more complex, when evaluating the multi-morphological transient voltage stability of the "dual-high" power system, the present application can first obtain some grid status parameters of the "dual-high" power system.

[0045] The grid state parameters here can be understood as all key parameters required for multi-form transient voltage stability assessment, including but not limited to new energy, reactive power compensation devices, active and reactive output of synchronous generators, basic electrical parameters of transformers and transmission lines, dynamic and static characteristics of loads and their changes over time, etc. In specific applications, the grid state parameters can be set or adjusted by professional and technical personnel in this field according to actual conditions, which is only illustrative here without specific limitation.

[0046] The embodiment of the present application can obtain the grid state parameters of the target power system, thereby improving the accuracy of the multi-form transient voltage stability assessment results of the target power system through the key parameters of the target power system, and providing data support for subsequent processing steps.

[0047] Optionally, in one embodiment of the present application, before simulating and obtaining the digital value of the bus transient voltage of the target power system under a single fault based on a preset fault set and a preset electromagnetic transient simulation model, it also includes: constructing a preset fault set based on the fault type, fault location and fault duration of the target power system.

[0048] In some embodiments, when performing a multi-modal transient voltage stability assessment of a target power system, in addition to obtaining the grid state parameters of the target power system, the present application may also first construct a preset fault set. The preset fault set here can be understood as a fault set pre-constructed based on the fault conditions of the target power system.

[0049] For example, the fault set may include, but is not limited to, the fault type (such as single-phase grounding, phase-to-phase short circuit, etc.) of the target power system, the fault location, the fault duration, etc. Furthermore, to facilitate data processing, the embodiment of the present application may also set certain symbols for the elements in the fault set for representation. For example, the fault type can be represented by T, belonging to the fault type set Θ; the fault location is represented by L, belonging to the fault location set Λ; the fault duration is represented by D, belonging to the fault duration set Δ. And, the fault type set Θ, the fault location set Λ and the fault duration set Δ can be further defined as:

[0050] Θ={T1,T2, …,T m} (1)

[0051] Λ={L1,L2, …,Ln} (2)

[0052] Δ={D1,D2, …,D k} (3)

[0053] Among them, T m is the mth fault type, including but not limited to single-phase grounding, two-phase short circuit, two-phase short circuit grounding, three-phase short circuit and other fault types; L n The nth fault location, including but not limited to 35kV, 220kV, 500kV and other line faults; D k is the duration of the kth fault, which can be, but is not limited to, an instantaneous fault (the duration is generally set to 0.1s) or a permanent fault (the duration can be set to 100s).

[0054] The fault set F used for multi-morphological transient voltage assessment can be expressed as:

[0055] F={(T,L,D)|T∈Θ,L∈Λ,D∈Δ} (4)

[0056] It should be noted that the specific contents, symbolic representations and construction process of the preset fault set can be set or adjusted by professional and technical personnel in this field according to actual conditions or actual needs. This is only an example description without specific limitation.

[0057] Step S102: based on a preset fault set and a preset electromagnetic transient simulation model, a digital value of a bus transient voltage of a target power system under a single fault is obtained by simulation.

[0058] In certain embodiments, after constructing a certain fault set, the present application can simulate and obtain the voltage changes of the bus during the fault and recovery period based on the certain fault set and a preset electromagnetic transient simulation model, that is, the digital value of the bus transient voltage of the target power system based on electromagnetic simulation under a single fault.

[0059] The preset electromagnetic transient simulation model here can be understood as a complete electromagnetic transient simulation model built for the target power system based on some electromagnetic transient simulation platforms. After building a certain electromagnetic transient simulation model, a typical fault can be selected from a certain fault set to simulate and obtain the voltage change of the busbar during the fault and recovery period.

[0060] In the embodiment of the present application, the voltage change can be represented by the bus transient voltage digital quantity, but is not limited to it. The process of obtaining the bus transient voltage digital quantity can be represented by discretizing the analog signal, that is, converting the continuous voltage signal into a digital quantity by sampling and quantizing. The expression can be as follows:

[0061] V(x)=V(t)|t=x×Δt (5)

[0062] Among them, V(x) is the actual bus voltage digital value, V(t) is the actual bus voltage, t is time, x is the xth simulation step in the simulation process, and Δt is the time domain simulation calculation step.

[0063] Step S103, based on the grid state parameters and the digital quantity of the bus transient voltage, calculate the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system; based on the comprehensive evaluation index of the multi-form transient voltage stability under a single fault, calculate the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults of the target power system, so as to obtain the comprehensive evaluation result of the multi-form transient voltage stability of the target power system through the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults.

[0064] As a possible implementation method, the comprehensive evaluation result of the multi-form transient voltage stability of the target power system in the embodiment of the present application is mainly obtained by the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults. Among them, the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults can be calculated from the comprehensive evaluation index of the multi-form transient voltage stability under a single fault, and the comprehensive evaluation index of the multi-form transient voltage stability under a single fault can be calculated from the acquired grid state parameters and the bus transient voltage digital quantity.

[0065] In the embodiment of the present application, the transient voltage stability of the target power system can be reflected by the value of the comprehensive evaluation index of multi-form transient voltage stability under multiple faults, but is not limited to the value. The larger the value, the worse the stability. The calculated comprehensive evaluation index of multi-form transient voltage stability under multiple faults is compared with 0, and the comprehensive evaluation result of multi-form transient voltage stability of the target power system can be obtained. The formula can be expressed as follows:

[0066]

[0067] Among them, TVIF is a comprehensive evaluation index of transient voltage stability in multiple forms under multiple faults, and J is the set evaluation discrimination signal. If J=1, it is determined that there is a possibility of transient voltage instability after the fault, and the corresponding evaluation result information (including but not limited to the unstable bus number, possible fault type, fault location, fault duration, etc.) is output; if J=0, it is determined that the possibility of transient voltage instability after the fault is low, and the safety evaluation result is output. At the same time, TVIF characterizes the stability of the system. The larger the negative value of TVIF, the lower the risk of transient instability of the system.

[0068] The embodiment of the present application can calculate the comprehensive evaluation index of multi-form transient voltage stability under multiple faults based on the comprehensive evaluation index of multi-form transient voltage stability under a single fault of the target power system, thereby realizing the comprehensive calculation and evaluation of the transient voltage stability of the target power system under complex forms, and effectively improving the accuracy of the comprehensive evaluation results of multi-form transient voltage stability of the target power system.

[0069] Next, the calculation process of the comprehensive evaluation index of multi-form transient voltage stability under a single fault and the calculation process of the comprehensive evaluation index of multi-form transient voltage stability under multiple faults in the embodiment of the present application are further explained.

[0070] Optionally, in one embodiment of the present application, based on the grid state parameters and the bus transient voltage digital quantity, calculating the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system includes: calculating the transient voltage recovery evaluation index, transient overvoltage evaluation index, and transient voltage fluctuation evaluation index under a single fault of the target power system based on the grid state parameters and the bus transient voltage digital quantity; combining the transient voltage recovery evaluation index, transient overvoltage evaluation index, and transient voltage fluctuation evaluation index with the corresponding weights to calculate the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system. Among them, the calculation formula of the comprehensive evaluation index of the multi-form transient voltage stability under a single fault can be expressed as:

[0071] TVI=α1RI+α2TOVI+α3VFI

[0072] Among them, TVI is the comprehensive evaluation index of multi-form transient voltage stability under single fault, RI is the transient voltage recovery evaluation index, TOVI is the transient overvoltage evaluation index, VFI is the transient voltage fluctuation evaluation index, α1, α2, α2 are the weight values ​​of transient voltage recovery evaluation index, transient overvoltage evaluation index, and transient voltage fluctuation evaluation index respectively.

[0073] In the actual implementation process, the comprehensive evaluation index of multi-form transient voltage stability under single fault of the target power system in this application is mainly but not limited to the comprehensive calculation of evaluation indicators such as transient voltage recovery, transient overvoltage and transient voltage fluctuation obtained based on grid state parameters and bus transient voltage digital quantities.

[0074] Among them, the calculation process of transient voltage recovery evaluation index, transient overvoltage evaluation index and transient voltage fluctuation evaluation index can be expressed as follows:

[0075] ① Transient voltage recovery evaluation index

[0076] After a large disturbance fault occurs in the target power system, the bus voltages of the target power system may be offset. The duration of the bus voltage being lower than the limit value after the fault is removed and whether it can be restored to a steady-state level are the key to measuring the transient voltage stability of the target power system. The transient voltage recovery evaluation index in the embodiment of the present application can be understood here as an evaluation index that describes the voltage recovery capability of the target power system after a fault.

[0077] The transient voltage recovery evaluation index RI in the embodiment of the present application includes but is not limited to a penalty function and an integral. The penalty function is represented by RL. The penalty value can be, but is not limited to, determined by the product of the difference between the time when the actual bus voltage is lower than the voltage limit value and the time limit value, and the difference between the actual bus voltage and the voltage limit value. When the standard requirements are met, the penalty value is close to 0. When the standard requirements are not met, the penalty value is greater than 0, and the larger the product of the two differences, the larger the penalty term; the integral term represents the area enclosed by the time axis when the actual bus voltage is lower than the voltage limit value. Based on this, the transient voltage recovery evaluation index formula can be expressed as:

[0078]

[0079] The penalty term RL function can be expressed as:

[0080]

[0081] in,

[0082]

[0083] Among them, RI is the transient voltage recovery evaluation index, RL is the penalty function, V(t) is the actual bus voltage, V crR is the voltage limit value, t crR is the duration limit of the bus voltage being lower than the voltage limit value, t 0R is the starting time when the bus voltage is lower than the voltage limit value, t R The fault node voltage is lower than V crR duration.

[0084] Using the digital value of bus transient voltage obtained by time domain simulation, the transient voltage recovery evaluation index formula can be expressed as:

[0085]

[0086] The penalty term RL function formula can be expressed as:

[0087]

[0088] in,

[0089]

[0090] Among them, Δt is the time domain simulation calculation step, V(x) is the actual bus voltage digital value, V crR is the voltage limit value, t crR N is the duration limit of the bus voltage being lower than the voltage limit value. R The bus voltage digital value is lower than V crR The number of data points.

[0091] If multiple voltage limit values ​​and corresponding duration limit values ​​are set, the transient voltage recovery evaluation index formula can be expressed as:

[0092]

[0093] The penalty term RL function can be expressed as:

[0094]

[0095] in,

[0096]

[0097] Among them, Δt is the time domain simulation calculation step, V(x) is the actual bus voltage digital value, V crRj is the jth voltage limit value, t crR N is the duration limit of the bus voltage being lower than the voltage limit value. Rj The bus voltage digital value is lower than V crRj The number of data points.

[0098] ② Transient overvoltage assessment indicators

[0099] During the target power system fault recovery period, new energy equipment and reactive power compensation devices will cause reactive power surplus due to control delay. This reactive power surplus will cause the voltage of the target power system to rise, and then produce overvoltage phenomenon, which may cause new energy to be disconnected from the grid, posing a potential threat to the stability of power equipment and the target power system. Therefore, it is necessary to establish a transient overvoltage assessment index for the target power system to assess whether the overvoltage meets the requirements. Among them, the transient overvoltage assessment index formula can be expressed as:

[0100]

[0101] The penalty term TOVL function can be expressed as:

[0102]

[0103] in,

[0104]

[0105] Among them, TOVI is the transient voltage recovery evaluation index, TOVL is the penalty function, V(t) is the actual bus voltage, V crh is the overvoltage limit (usually 1.3), t0 is the starting time when the bus voltage is higher than the voltage limit, t h The fault node voltage is higher than V crh duration.

[0106] The digital value of bus transient voltage obtained by time domain simulation can be expressed as:

[0107]

[0108] The penalty term RL function can be expressed as:

[0109]

[0110] in,

[0111]

[0112] Among them, Δt is the time domain simulation calculation step, V(x) is the actual bus voltage digital value, N h The bus voltage digital value is higher than V crh The number of data points.

[0113] ③ Transient voltage fluctuation evaluation index

[0114] During the fault ride-through process of the new energy system, especially the low voltage ride-through and high voltage ride-through stages, the control strategy and power output adjustment may also have a certain impact on the grid voltage, thereby causing the transient voltage to continue to fluctuate significantly, which may exceed the standard requirements. Considering that this new phenomenon may occur, the embodiment of the present application can be described by, but not limited to, the transient voltage volatility assessment index of the "double high" power system, and the formula can be expressed as:

[0115]

[0116] The penalty term VFL function can be expressed as:

[0117]

[0118] in,

[0119]

[0120] Among them, VFI is the transient voltage fluctuation evaluation index, VFL is the penalty function, V(x) is the actual bus voltage digital value, V N is the voltage rating (the per-unit value can be taken as 1), NF It is the number of digital quantities obtained by sampling when the bus voltage fluctuation amplitude remains almost unchanged for a period of time after a fault.

[0121] After obtaining the transient voltage recovery evaluation index, the overvoltage evaluation index, and the voltage fluctuation evaluation index, the embodiment of the present application can select different weight values ​​for the transient voltage recovery evaluation index, the overvoltage evaluation index, and the voltage fluctuation evaluation index, respectively, to obtain a multi-form target power system transient voltage comprehensive evaluation index under a single fault, and the formula can be expressed as:

[0122] TVI=α1RI+α2TOVI+α3VFI (25)

[0123] in,

[0124] α1+α2+α3=1 (26)

[0125] Among them, RI is the transient voltage recovery assessment index, TOVI is the transient overvoltage assessment index, VFI is the transient voltage fluctuation assessment index, α1, α2, and α3 are the weight values ​​of the transient voltage recovery assessment index, the transient overvoltage assessment index, and the transient voltage fluctuation assessment index, respectively.

[0126] It should be noted that the specific weight value allocation and selection can be adjusted by professional and technical personnel in this field according to actual conditions, and this application does not impose any specific restrictions.

[0127] Optionally, in one embodiment of the present application, based on the comprehensive evaluation index of multi-form transient voltage stability under a single fault, the comprehensive evaluation index of multi-form transient voltage stability under multiple faults of the target power system is calculated, including: based on the comprehensive evaluation index of multi-form transient voltage stability under a single fault, combined with the weight corresponding to the single fault, the comprehensive evaluation index of multi-form transient voltage stability under multiple faults is calculated. Among them, the calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under multiple faults is:

[0128]

[0129] Among them, TVIF is the comprehensive evaluation index of transient voltage under multiple faults, M is the number of faults, ω i is the weight value of each fault i, TVI i It is the comprehensive evaluation index of transient voltage under single fault corresponding to each fault i.

[0130] In other embodiments, after obtaining the comprehensive evaluation index of multi-form transient voltage stability under a single fault of the target power system, the present application can calculate the comprehensive evaluation index of multi-form transient voltage stability under multiple faults based on the comprehensive evaluation index of multi-form transient voltage stability under a single fault combined with the weight corresponding to the single fault.

[0131] Simply put, after calculating the comprehensive evaluation index of multi-form transient voltage stability under a single fault, the comprehensive evaluation index of multi-form transient voltage stability under multiple faults is obtained by weighting the calculation results of the comprehensive evaluation index of multi-form transient voltage stability under a single fault according to the weight of the single fault, and adding them up.

[0132] Among them, the weight corresponding to a single fault in the embodiment of the present application can be selected or adjusted according to, but not limited to, the weight of a single fault in a preset fault set. It can be specifically set or adjusted by professional and technical personnel in this field according to actual conditions. This is only an example description without specific limitation.

[0133] For example, the present application can select M typical faults from a certain fault set, and the weight values ​​assigned to different faults are ω1, ω2, ..., ω M , the comprehensive evaluation index of transient voltage of the "double high" system considering multiple forms under multiple faults at a certain node can be expressed as:

[0134]

[0135] in,

[0136]

[0137] Among them, TVIF is the comprehensive evaluation index of transient voltage under multiple faults, M is the number of faults, ω i is the weight value of each fault i, TVI i It is the comprehensive evaluation index of transient voltage under single fault corresponding to each fault i.

[0138] The present application is described in detail with reference to a specific embodiment below.

[0139] Figure 2 This is a flow chart of a method for evaluating multi-form transient voltage stability of a power system according to an embodiment of the present application, such as Figure 2 As shown:

[0140] Step 201: Obtaining grid state parameters for multi-modal transient voltage stability assessment and constructing a fault set;

[0141] Step 202: Obtaining a digital value of bus transient voltage based on electromagnetic simulation under a single fault;

[0142] Step 203: Calculate the comprehensive evaluation index of multi-form transient voltage stability under single fault;

[0143] Step 204: Calculate the comprehensive evaluation index of transient voltage stability in multiple forms under multiple faults;

[0144] Step 205: Obtain comprehensive evaluation results of multi-form transient voltage stability of the “double-high” power system.

[0145] According to the evaluation method of the multi-form transient voltage stability of the power system proposed in the embodiment of the present application, the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system and the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults can be calculated based on the state parameters of the target power system, the preset fault set and the preset electromagnetic transient simulation model, and finally the comprehensive evaluation result of the multi-form transient voltage stability of the target power system is obtained. Thus, the stability index reflecting the transient voltage form such as transient voltage recovery, overvoltage, volatility, etc. is realized, and the application of mathematical models and simulation technology is combined to flexibly respond to the complex and changeable voltage instability form of the "double high" power system, and the comprehensive calculation and evaluation of the transient voltage stability of the "double high" system under multiple forms is realized comprehensively and quantitatively. At the same time, it can also enable the power system operation and dispatching personnel to intuitively understand the voltage stability margin of the system under various faults or disturbances, which is helpful to identify potential risks, provide corresponding scientific basis for formulating targeted control measures for system dispatching and optimization, and enhance the safety and stability of the power system. This solves the problems that the power system transient voltage stability assessment method in the related technology has a limited scope of application and cannot adapt to the complex dynamic changes of the power system. The assessment results may be conservative and have low accuracy, making it difficult to fully and accurately reflect the morphological changes of the transient voltage of the power system and unable to truly reflect the transient stability of the system.

[0146] Next, a device for evaluating multi-form transient voltage stability of a power system proposed in an embodiment of the present application will be described with reference to the accompanying drawings.

[0147] Figure 3 It is a structural schematic diagram of an apparatus for evaluating multi-form transient voltage stability of a power system according to an embodiment of the present application.

[0148] like Figure 3 As shown, the power system multi-form transient voltage stability evaluation device 10 includes: a first acquisition module 100 , a second acquisition module 200 and an evaluation module 300 .

[0149] Wherein, the first acquisition module 100 is used to acquire the grid state parameters of the target power system;

[0150] The second acquisition module 200 is used to simulate and acquire the digital value of the bus transient voltage of the target power system under a single fault based on a preset fault set and a preset electromagnetic transient simulation model;

[0151] The evaluation module 300 is used to calculate the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system based on the grid state parameters and the digital quantity of the bus transient voltage, and calculate the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults based on the comprehensive evaluation index of the multi-form transient voltage stability under a single fault, so as to obtain the comprehensive evaluation result of the multi-form transient voltage stability of the target power system through the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults.

[0152] Optionally, in one embodiment of the present application, the evaluation module 300 includes: a first calculation unit and a second calculation unit.

[0153] The first calculation unit is used to calculate the transient voltage recovery evaluation index, transient overvoltage evaluation index, and transient voltage fluctuation evaluation index of the target power system under a single fault based on the grid state parameters and the bus transient voltage digital quantity;

[0154] The second calculation unit is used to calculate the comprehensive evaluation index of multi-form transient voltage stability under a single fault of the target power system by combining the transient voltage recovery evaluation index, the transient overvoltage evaluation index, the transient voltage fluctuation evaluation index and the corresponding weights.

[0155] Optionally, in one embodiment of the present application, the evaluation module 300 includes:

[0156] The third calculation unit is used to calculate the comprehensive evaluation index of multi-form transient voltage stability under multiple faults based on the transient voltage recovery evaluation index under a single fault and the weight corresponding to the single fault.

[0157] Optionally, in one embodiment of the present application, it further includes:

[0158] A construction module is used to construct a preset fault set based on the fault type, fault location and fault duration of the target power system before simulating and obtaining the digital value of the bus transient voltage of the target power system under a single fault based on the preset fault set and the preset electromagnetic transient simulation model.

[0159] Optionally, in one embodiment of the present application, the calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under a single fault may be, but is not limited to, expressed as:

[0160] TVI=α1RI+α2TOVI+α3VFI

[0161] Among them, TVI is the comprehensive evaluation index of multi-form transient voltage stability under single fault, RI is the transient voltage recovery evaluation index, TOVI is the transient overvoltage evaluation index, VFI is the transient voltage fluctuation evaluation index, α1, α2, α2 are the weight values ​​of transient voltage recovery evaluation index, transient overvoltage evaluation index, and transient voltage fluctuation evaluation index respectively.

[0162] Optionally, in one embodiment of the present application, the calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under multiple faults may be, but is not limited to, expressed as:

[0163]

[0164] Among them, TVIF is the comprehensive evaluation index of transient voltage under multiple faults, M is the number of faults, ω i is the weight value of each fault i, TVI i It is the comprehensive evaluation index of transient voltage under single fault corresponding to each fault i.

[0165] It should be noted that the above explanation of the embodiment of the method for evaluating the multi-morphological transient voltage stability of a power system is also applicable to the device for evaluating the multi-morphological transient voltage stability of a power system of this embodiment, and will not be repeated here.

[0166] According to the evaluation device of the multi-form transient voltage stability of the power system proposed in the embodiment of the present application, the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system and the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults can be calculated based on the state parameters of the target power system, the preset fault set and the preset electromagnetic transient simulation model, and finally the comprehensive evaluation result of the multi-form transient voltage stability of the target power system is obtained. Thus, the stability index reflecting the transient voltage form such as transient voltage recovery, overvoltage, volatility, etc. is realized, and the application of mathematical models and simulation technology is combined to flexibly respond to the complex and changeable voltage instability form of the "double high" power system, and the comprehensive calculation and evaluation of the transient voltage stability of the "double high" system under multiple forms is realized comprehensively and quantitatively. At the same time, it can also enable the power system operation and dispatching personnel to intuitively understand the voltage stability margin of the system under various faults or disturbances, which is helpful to identify potential risks, provide corresponding scientific basis for formulating targeted control measures for system dispatching and optimization, and enhance the safety and stability of the power system. This solves the problems that the power system transient voltage stability assessment method in the related technology has a limited scope of application and cannot adapt to the complex dynamic changes of the power system. The assessment results may be conservative and have low accuracy, making it difficult to fully and accurately reflect the morphological changes of the transient voltage of the power system and unable to truly reflect the transient stability of the system.

[0167] Figure 4A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0168] Memory 401 , processor 402 , and a computer program stored in the memory 401 and executable on the processor 402 .

[0169] When the processor 402 executes the program, the method for evaluating the multi-state transient voltage stability of the power system provided in the above embodiment is implemented.

[0170] Furthermore, the electronic device further comprises:

[0171] The communication interface 403 is used for communication between the memory 401 and the processor 402 .

[0172] The memory 401 is used to store computer programs that can be executed on the processor 402 .

[0173] The memory 401 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0174] If the memory 401, the processor 402 and the communication interface 403 are implemented independently, the communication interface 403, the memory 401 and the processor 402 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 4 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0175] Optionally, in a specific implementation, if the memory 401, the processor 402 and the communication interface 403 are integrated on a chip, the memory 401, the processor 402 and the communication interface 403 can communicate with each other through an internal interface.

[0176] The processor 402 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0177] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for evaluating the multi-form transient voltage stability of a power system.

[0178] An embodiment of the present application also provides a computer program product, including a computer program, which can run computer instructions. When the computer instructions are executed by a processor, the method for evaluating the multi-form transient voltage stability of the power system provided in the embodiment of the present application is implemented.

[0179] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0180] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0181] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0182] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0183] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented by hardware, as in another embodiment, it can be implemented by any one or a combination of multiple of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0184] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0185] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0186] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for evaluating multi-state transient voltage stability of a power system, characterized in that: The following steps are involved: Obtaining grid state parameters of the target power system; Based on a preset fault set and a preset electromagnetic transient simulation model, a digital value of a bus transient voltage of the target power system under a single fault is obtained by simulation; Based on the grid state parameters and the digital quantity of the bus transient voltage, the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system is calculated; based on the comprehensive evaluation index of the multi-form transient voltage stability under a single fault, the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults of the target power system is calculated, so as to obtain the comprehensive evaluation result of the multi-form transient voltage stability of the target power system through the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults.

2. The method according to claim 1, characterized in that The calculating, based on the grid state parameter and the bus transient voltage digital quantity, a comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system comprises: Based on the grid state parameters and the bus transient voltage digital quantity, calculating the transient voltage recovery evaluation index, transient overvoltage evaluation index, and transient voltage fluctuation evaluation index of the target power system under single fault; The transient voltage recovery evaluation index, the transient overvoltage evaluation index, the transient voltage fluctuation evaluation index and the corresponding weights are combined to calculate a comprehensive evaluation index of multi-form transient voltage stability under a single fault of the target power system.

3. The method according to claim 1, characterized in that The step of calculating the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults of the target power system based on the comprehensive evaluation index of the multi-form transient voltage stability under single faults includes: Based on the comprehensive evaluation index of multi-form transient voltage stability under a single fault and in combination with the weight corresponding to the single fault, the comprehensive evaluation index of multi-form transient voltage stability under multiple faults is calculated.

4. The method according to claim 1, characterized in that: Before simulating and obtaining the digital value of the bus transient voltage of the target power system under a single fault based on the preset fault set and the preset electromagnetic transient simulation model, the method further includes: The preset fault set is constructed based on the fault type, fault location and fault duration of the target power system.

5. The method according to claim 1, characterized in that The calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under single fault is: TVI=α1RI+α2TPVI+α3VEI Among them, TVI is the comprehensive evaluation index of multi-form transient voltage stability under the single fault, RI is the transient voltage recovery evaluation index, TOVI is the transient overvoltage evaluation index, VFI is the transient voltage fluctuation evaluation index, α1, α2, α2 are the weight values ​​of the transient voltage recovery evaluation index, the transient overvoltage evaluation index, and the transient voltage fluctuation evaluation index, respectively.

6. The method according to claim 1, characterized in that The calculation formula of the comprehensive evaluation index of multi-form transient voltage stability under multiple faults is: Among them, TVIF is the comprehensive evaluation index of transient voltage under multiple faults, M is the number of faults, ω i is the weight value of each fault i, TVI i It is the comprehensive evaluation index of transient voltage under single fault corresponding to each fault i.

7. An evaluation device for multi-state transient voltage stability of a power system, characterized in that: include: A first acquisition module, used to acquire the grid state parameters of the target power system; A second acquisition module is used to simulate and acquire the digital value of the bus transient voltage of the target power system under a single fault based on a preset fault set and a preset electromagnetic transient simulation model; An evaluation module is used to calculate the comprehensive evaluation index of the multi-form transient voltage stability under a single fault of the target power system based on the grid state parameters and the digital quantity of the bus transient voltage, and to calculate the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults of the target power system based on the comprehensive evaluation index of the multi-form transient voltage stability under a single fault, so as to obtain the comprehensive evaluation result of the multi-form transient voltage stability of the target power system through the comprehensive evaluation index of the multi-form transient voltage stability under multiple faults.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for evaluating the multi-morphological transient voltage stability of an electric power system as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the method for evaluating multi-form transient voltage stability of a power system as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed, it is used to implement the method for evaluating multi-form transient voltage stability of a power system as described in any one of claims 1 to 6.

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