Power system transient stability real-time emergency control method, system, device and medium

Abstract

The application discloses a power system transient stability real-time emergency control method, system, device and medium, obtains real-time measurement data of a generator terminal PMU after a power system fault; determines whether the power system is transiently unstable based on a system maximum power angle difference change curve, and if so, continues to execute; performs double-machine equivalence on the power system, equivalent to a single-machine infinite system, and then obtains an equivalent power angle characteristic curve of the power system; fits the equivalent power angle characteristic curve of the power system from fault removal to the determination of the transient instability of the power system based on the least square method, then estimates the equivalent power angle characteristic curve after the determination of the transient instability of the power system, and obtains a generator tripping control quantity; calculates the electrical coupling connection degree of a bus node connected with important loads and each generator node of the power system, and obtains an emergency generator tripping control measure. The application makes the transient instability system restore stability while ensuring the power supply capacity of the power system to important loads as much as possible.

Description

Technical Field

[0001] This invention relates to the field of power system control, specifically to a method, system, equipment, and medium for real-time emergency control of transient stability in power systems. Background Technology

[0002] Power system emergency control refers to control measures taken to prevent the instability area from expanding further when the power system experiences transient instability. Accurate and effective emergency control measures play an important role in the stability of my country's power system.

[0003] The commonly adopted emergency control strategy for transient instability both domestically and internationally is "offline decision-making and real-time matching." This strategy primarily involves performing multiple simulations of the system based on the location, type, and operating mode of the power system fault, thereby generating an emergency control strategy table. However, with the construction of large power grids, the introduction of new electrical equipment and renewable energy generation, and the continuous expansion of the power grid scale, it has become increasingly difficult to exhaustively enumerate the system's operating mode and the location and type of the fault during offline calculations. Furthermore, the simulation results inevitably contain biases. Therefore, the "offline decision-making and real-time matching" emergency control strategy cannot meet the requirements for the stable operation of large power grids.

[0004] The development of wide-area measurement systems and phasor measurement units has provided necessary technical support for the "online decision-making and real-time matching" emergency control strategy for transient instability. The "offline decision-making and real-time matching" system emergency control strategy is gradually developing towards "online decision-making and real-time matching." However, existing emergency control methods for transient instability in power systems do not consider the impact of the connection of important loads on emergency control measures. After taking emergency control measures, some components in the power system, such as generators and loads, may be disconnected, which may cause large power losses in generators near the nodes connected to important loads. Usually, it takes a long time for the various components of the system to return to their initial operating state after taking emergency control measures, and the voltage of the nodes connected to important loads is greatly affected by emergency control measures. Summary of the Invention

[0005] The purpose of this invention is to provide a method, system, device, and medium for real-time emergency control of transient stability in power systems. This invention takes into account the access of important loads and realizes the identification of transient instability based on real-time measurement data of PMU. It utilizes the electrical coupling connection degree of each generator in the power system and the real-time measurement data of each generator to realize emergency control measures of the system, reduce the power loss of generators near the nodes connected to important loads, and provide technical support for ensuring the normal power supply of important loads and the stable operation of the power grid as much as possible.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a real-time emergency control method for transient stability of a power system, the method comprising:

[0008] S1: Acquire real-time measurement data of the generator terminal PMU after a power system fault; the real-time PMU measurement data includes generator speed, generator power angle, generator mechanical power and generator electromagnetic power;

[0009] S2: Based on the real-time measurement data of PMU, determine whether the power system has experienced transient instability based on the curve of the change of the maximum power angle difference of the system. If yes, proceed to step S3; otherwise, proceed to step S1.

[0010] S3: Equivalent to a dual-machine power system, the dual-machine system is equivalent to a single-machine infinite system, and then the equivalent power angle characteristic curve of the power system is obtained;

[0011] S4: Based on the least squares method, fit the equivalent power angle characteristic curve of the power system from the fault clearing to the determination of the power system transient instability, and then predict the equivalent power angle characteristic curve after the determination of the power system transient instability, and obtain the tripping control quantity based on the extended equal area method.

[0012] S5: Calculate the electrical coupling connection degree between the bus node connected to the important load and each generator node in the power system, and process the electrical coupling connection degree, real-time measurement data of the generator terminal PMU and the generator tripping control quantity to obtain emergency generator tripping control measures; after taking emergency generator tripping control measures, execute step S1.

[0013] Among them, PMU stands for Synchronous Phasor Measurement Device.

[0014] Compared with the drawbacks or limitations of existing power grid equivalence methods, the emergency control method proposed in this invention uses electrical coupling connectivity to measure the degree of influence of generators on critical loads, and constructs a comprehensive index that considers the electrical coupling connectivity and mechanical power of generators, providing technical support for ensuring the normal power supply of critical loads and the stable operation of the power grid as much as possible.

[0015] Furthermore, step S2, which determines whether the power system has experienced transient instability based on the curve of the change in the system's maximum power angle difference, includes:

[0016] Define the set of generator nodes in a power system as {A}, and use δ to represent the power angle difference between generator i and generator j in set {A}. ij The maximum power angle difference Δδ of the power system is calculated using the following formula. max :

[0017]

[0018] The system detects in real time whether the maximum power angle difference calculated at the current moment is greater than a preset threshold; if so, the power system is in transient instability; if not, the power system is stable.

[0019] Further, step S3 includes:

[0020] S31: After the power system becomes transiently unstable, the collected power angles of each generator are arranged from smallest to largest, the generator pair with the largest power angle gap is identified, and the generator group in the power system is divided into lagging group B and leading group S before and after this largest power angle gap.

[0021] S32: Based on the measurement data after the failure of the lagging group B and the leading group S, the power system is equivalent to a two-machine system using the following formula:

[0022]

[0023] In the formula: ω i δ i and M i ω represents the angular frequency, power angle, and inertial time constant of generator i, respectively; B δ B and M B Let ω represent the equivalent angular frequency, equivalent work angle, and equivalent inertial time constant of lag group B, respectively; S δ S and M S Let represent the equivalent angular frequency, equivalent power angle, and equivalent inertial time constant of the leading group S, respectively.

[0024] S33: Equivalently converting the two-machine system to a single-machine infinite system, the equivalent power angle characteristic curve of the power system is obtained. The equivalent of the single-machine infinite system is shown in the following formula:

[0025]

[0026] Where: δ d ω is the generator power angle of an equivalent single-machine infinite system. d M is the generator angular frequency of an equivalent single-machine infinite bus system, where ω0 is the initial value of the generator angular frequency; S M is the equivalent inertial time constant of the lag group B; A P is the equivalent inertial time constant of the leading group S; mi P mj P represents the mechanical power of generator i and generator j, respectively; ei P ej P represents the electromagnetic power of generator i and generator j, respectively; dm and P de These represent the mechanical power and electromagnetic power of the generator in an equivalent single-machine infinite system, respectively.

[0027] Further, step S4 includes:

[0028] S41: From the time the power system clears a fault until transient instability is detected, calculate the equivalent single-unit infinite power system generator electromagnetic power at each moment. Based on the collected electromagnetic power data, fit the following formula using the least squares method:

[0029] P de =A + Bsin(δ - C)

[0030] In the formula: P de δ represents the electromagnetic power of the generator in the equivalent single-machine infinite system; δ represents the generator power angle in the equivalent single-machine infinite system; A, B, and C are the parameters to be solved.

[0031] The equivalent power angle characteristic curve after the transient instability of the power system can be predicted using the above formula;

[0032] S42: Calculate the tripping control quantity based on the equivalent power angle characteristic curve and the extended equal area method; the formula for calculating the tripping control quantity is:

[0033]

[0034] In the formula, ΔP m δ0 is the generator tripping control variable of the power system, and δ0 is the equivalent single-unit infinite power system generator's power angle value at the time of power system fault occurrence. c δ is the equivalent power angle value of a single-unit infinite power system generator at the time of power system fault clearing. u ω represents the equivalent single-unit infinite-power system generator's power angle value at the moment when transient instability is detected after a power system fault. du The angular frequency δ of an equivalent single-unit infinite-power system generator is used to detect transient instability in power systems during fault detection. m Δt represents the power angle value at the first unstable equilibrium point of the generator in the equivalent single-unit infinite power system after a power system fault. delay The time delay between detecting transient instability in the power system and implementing emergency control measures; P dm and P de These represent the mechanical power and electromagnetic power of the generator in an equivalent single-machine infinite system, respectively.

[0035] Further, step S5 includes:

[0036] S51: Calculate the electrical coupling connection degree between the bus nodes connected to important loads and each generator node in the power system;

[0037] S52: Based on the electrical coupling connectivity of each generator in the leading group S and the real-time measurement data of the generator terminal PMU, construct the comprehensive index H of generator i. i for:

[0038] H i=w1D i +w2P m_i

[0039] In the formula, D i P represents the electrical coupling connection degree between generator i and the node connected to the critical load. m_i Let w1 be the mechanical power of generator i, and w2 be the weighting index of the electrical coupling connection degree and mechanical power of generator i, respectively.

[0040] S53: Determine emergency tripping control measures based on the generator's comprehensive index and tripping control quantity; the tripping quantity ΔP of generator i in the power system. i for:

[0041]

[0042] In the formula, ΔP m This refers to the generator tripping control quantity in the power system.

[0043] Furthermore, in step S5, the electrical coupling connectivity D of generator node i... i The calculation formula is:

[0044]

[0045] In the formula, Z ij U represents the equivalent impedance of the two-port network as seen from a generator node i and a node j connected to a critical load. ij and I ij These represent the voltage and current of the two-port network, respectively.

[0046] Secondly, the present invention provides a real-time emergency control system for transient stability of a power system, which uses the aforementioned real-time emergency control method for transient stability of a power system; the system includes:

[0047] The data acquisition unit is used to acquire real-time measurement data of the generator terminal PMU after a power system fault; the real-time PMU measurement data includes generator speed, generator power angle, generator mechanical power and generator electromagnetic power;

[0048] The transient instability judgment unit is used to determine whether the power system has experienced transient instability based on the real-time measurement data of the PMU and the change curve of the maximum power angle difference of the system. If so, proceed to step S3; otherwise, proceed to step S1.

[0049] The equivalent power angle characteristic curve calculation unit is used to convert a two-machine power system into a single-machine infinite system, and then calculate the equivalent power angle characteristic curve of the power system.

[0050] The generator tripping control quantity calculation unit is used to fit the equivalent power angle characteristic curve of the power system from the fault clearing to the determination of the power system transient instability based on the least squares method, and then predict the equivalent power angle characteristic curve after the determination of the power system transient instability, and obtain the generator tripping control quantity based on the extended equal area method.

[0051] The emergency tripping control measure determination unit is used to calculate the electrical coupling connection degree between the bus node connected to the important load and each generator node of the power system, and to process the electrical coupling connection degree, real-time measurement data of the generator terminal PMU and tripping control quantity to obtain emergency tripping control measures.

[0052] Furthermore, the execution process of the emergency machine cut-off control measure determination unit is as follows:

[0053] Calculate the electrical coupling degree between the bus nodes connected to important loads and each generator node in the power system;

[0054] Based on the electrical coupling connectivity of each generator in the leading group S and the real-time measurement data of the generator terminal PMU, a comprehensive index H of generator i is constructed. i for:

[0055] H i =w1D i +w2P m_i

[0056] In the formula, D i P represents the electrical coupling connection degree between generator i and the node connected to the critical load. m_i Let w1 be the mechanical power of generator i, and w2 be the weighting index of the electrical coupling connection degree and mechanical power of generator i, respectively.

[0057] Based on the generator's comprehensive index and tripping control quantity, determine the emergency tripping control measures; the tripping quantity ΔP of generator i in the power system. i for:

[0058]

[0059] In the formula, ΔP m This refers to the generator tripping control quantity in the power system.

[0060] Thirdly, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-mentioned real-time emergency control method for transient stability of power systems.

[0061] Fourthly, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described real-time emergency control method for transient stability of a power system.

[0062] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0063] This invention relates to a real-time emergency control method, system, device, and medium for transient stability of power systems considering the connection of critical loads. It utilizes the determination of whether the maximum power angle difference of the system exceeds a threshold as the initiation means for emergency control. When transient instability is detected, the emergency generator tripping control quantity is calculated based on the extended equal area method, and the electrical coupling connectivity is used to measure the degree of influence of generators on critical loads. A comprehensive index considering the electrical coupling connectivity and mechanical power of generators is constructed, enabling the transiently unstable system to recover stability while reducing power losses of generators near critical load nodes. This enriches the power system stability defense system and provides technical support for ensuring the normal power supply to critical loads and the stable operation of the power grid as much as possible.

[0064] (1) Compared with the prior art, the real-time emergency control method for transient stability of power system proposed in this invention uses electrical coupling connection degree to measure the degree of influence of generator on important loads, and constructs a comprehensive index that considers the electrical coupling connection degree and mechanical power of generator, so that while restoring the transient unstable system to stability, the power supply capacity of the power system to important loads is guaranteed as much as possible.

[0065] (2) This invention acquires generator terminal data in real time through PMU, quantitatively evaluates the transient stability margin of transient unstable systems based on the extended equal area method, and considers the impact of the delay time in the control process from the discovery of transient instability to the implementation of control measures, which helps to improve the effectiveness of emergency control measures. Attached Figure Description

[0066] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0067] Figure 1 This is a flowchart of the real-time emergency control method for transient stability of power systems according to the present invention;

[0068] Figure 2 This is a block diagram of the power system transient stability real-time emergency control system of the present invention. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are only for explaining this invention and are not intended to limit this invention.

[0070] The development of wide-area measurement systems and phasor measurement units has provided necessary technical support for the "online decision-making and real-time matching" emergency control strategy for transient instability. The "offline decision-making and real-time matching" system emergency control strategy is gradually developing towards "online decision-making and real-time matching." However, existing emergency control methods for transient instability in power systems do not consider the impact of the connection of important loads on emergency control measures. After taking emergency control measures, some components in the power system, such as generators and loads, may be disconnected, which may cause large power losses in generators near the nodes connected to important loads. Usually, it takes a long time for the various components of the system to return to their initial operating state after taking emergency control measures, and the voltage of the nodes connected to important loads is greatly affected by emergency control measures.

[0071] Therefore, in the system emergency control measures of "online decision-making and real-time matching," it is necessary to consider the impact of critical load access on emergency control measures, providing technical support for ensuring the normal power supply of critical loads and the stable operation of the power grid as much as possible. This invention designs a real-time emergency control method for power system transient stability that considers critical load access. It judges the transient stability of the power system from real-time measurement data of the power system PMU. For situations where the power system experiences transient instability, it further generates emergency control measures considering the access of critical loads, enabling the transiently unstable system to return to stability while reducing power losses of generators near the nodes connected to critical loads, thus providing technical support for ensuring the normal power supply of critical loads and the stable operation of the power grid as much as possible.

[0072] Compared with the drawbacks or limitations of existing power grid equivalence methods, the emergency control method proposed in this invention uses electrical coupling connectivity to measure the degree of influence of generators on critical loads, and constructs a comprehensive index that considers the electrical coupling connectivity and mechanical power of generators, providing technical support for ensuring the normal power supply of critical loads and the stable operation of the power grid as much as possible.

[0073] Example 1

[0074] like Figure 1 As shown, the present invention provides a real-time emergency control method for transient stability of a power system, the method comprising:

[0075] S1: Acquire real-time measurement data of the generator terminal PMU after a power system fault; the real-time measurement data of the PMU includes generator speed, generator power angle, generator mechanical power and generator electromagnetic power; the PMU is a synchronous phasor measurement device.

[0076] S2: Based on the real-time measurement data of PMU, determine whether the power system has experienced transient instability based on the curve of the change of the maximum power angle difference of the system. If yes, proceed to step S3; otherwise, proceed to step S1.

[0077] Step S2, which determines whether the power system has experienced transient instability based on the curve of the change in the maximum power angle difference, specifically includes:

[0078] Define the set of generator nodes in a power system as {A}, and use δ to represent the power angle difference between generator i and generator j in set {A}. ij The maximum power angle difference Δδ of the power system is calculated using the following formula. max :

[0079]

[0080] The system detects in real time whether the maximum power angle difference calculated at the current moment is greater than a preset threshold; if so, the power system is in transient instability; if not, the power system is stable.

[0081] S3: Equivalent to a dual-machine power system, the dual-machine system is equivalent to a single-machine infinite system, and then the equivalent power angle characteristic curve of the power system is obtained;

[0082] Step S3 specifically includes:

[0083] S31: After the power system becomes transiently unstable, the collected power angles of each generator are arranged from smallest to largest, the generator pair with the largest power angle gap is identified, and the generator group in the power system is divided into lagging group B and leading group S before and after this largest power angle gap.

[0084] S32: Based on the measurement data after the failure of the lagging group B and the leading group S, the power system is equivalent to a two-machine system using the following formula:

[0085]

[0086] In the formula: ω i δ i and M i ω represents the angular frequency, power angle, and inertial time constant of generator i, respectively; B δ B and M B Let ω represent the equivalent angular frequency, equivalent work angle, and equivalent inertial time constant of lag group B, respectively; S δ S and M S Let represent the equivalent angular frequency, equivalent power angle, and equivalent inertial time constant of the leading group S, respectively.

[0087] S33: Equivalently converting the two-machine system to a single-machine infinite system, the equivalent power angle characteristic curve of the power system is obtained. The equivalent of the single-machine infinite system is shown in the following formula:

[0088]

[0089] Where: δ d ω is the generator power angle of an equivalent single-machine infinite system. d M is the generator angular frequency of an equivalent single-machine infinite bus system, where ω0 is the initial value of the generator angular frequency; S M is the equivalent inertial time constant of the lag group B; A P is the equivalent inertial time constant of the leading group S; mi P mj P represents the mechanical power of generator i and generator j, respectively; ei P ej P represents the electromagnetic power of generator i and generator j, respectively; dm and P de These represent the mechanical power and electromagnetic power of the generator in an equivalent single-machine infinite system, respectively.

[0090] Specifically, the generator power angle δ of the equivalent single-machine infinite system d Numerically equal to the equivalent work angle δ of the leading group S S Equivalent work angle δ of lag group B B The difference is the generator angular frequency ω of an equivalent single-machine infinite system. d Numerically equal to the equivalent angular frequency ω of the leading group S S The equivalent angular frequency ω of the hysteresis group B B difference.

[0091] S4: Based on the least squares method, fit the equivalent power angle characteristic curve of the power system from the fault clearing to the determination of the power system transient instability, and then predict the equivalent power angle characteristic curve after the determination of the power system transient instability, and obtain the tripping control quantity based on the extended equal area method.

[0092] Step S4 specifically includes:

[0093] S41: From the time the power system clears a fault until transient instability is detected, calculate the equivalent single-unit infinite power system generator electromagnetic power at each moment. Based on the collected electromagnetic power data, fit the following formula using the least squares method:

[0094] P de =A + Bsin(δ - C)

[0095] In the formula: P deδ represents the electromagnetic power of the generator in the equivalent single-machine infinite system; δ represents the generator power angle in the equivalent single-machine infinite system; A, B, and C are the parameters to be solved.

[0096] The equivalent power angle characteristic curve after the transient instability of the power system can be predicted using the above formula;

[0097] S42: Calculate the tripping control quantity based on the equivalent power angle characteristic curve and the extended equal area method; the formula for calculating the tripping control quantity is:

[0098]

[0099] In the formula, ΔP m δ0 is the generator tripping control variable of the power system, and δ0 is the equivalent single-unit infinite power system generator's power angle value at the time of power system fault occurrence. c δ is the equivalent power angle value of a single-unit infinite power system generator at the time of power system fault clearing. u ω represents the equivalent single-unit infinite-power system generator's power angle value at the moment when transient instability is detected after a power system fault. du The angular frequency δ of an equivalent single-unit infinite-power system generator is used to detect transient instability in power systems during fault detection. m Δt represents the power angle value at the first unstable equilibrium point of the generator in the equivalent single-unit infinite power system after a power system fault. delay The time delay between detecting transient instability in the power system and implementing emergency control measures; P dm and P de These represent the mechanical power and electromagnetic power of the generator in an equivalent single-machine infinite system, respectively.

[0100] S5: Calculate the electrical coupling connection degree between the bus node connected to the important load and each generator node in the power system, and process the electrical coupling connection degree, real-time measurement data of the generator terminal PMU and the generator tripping control quantity to obtain emergency generator tripping control measures; after taking emergency generator tripping control measures, execute step S1.

[0101] Step S5 specifically includes:

[0102] S51: Calculate the electrical coupling degree between the bus nodes connected to important loads and each generator node in the power system; the electrical coupling degree D of generator node i. i The calculation formula is:

[0103]

[0104] In the formula, Z ij U represents the equivalent impedance of the two-port network as seen from a generator node i and a node j connected to a critical load. ij and I ijThese represent the voltage and current of the two-port network, respectively.

[0105] S52: Based on the electrical coupling connectivity of each generator in the leading group S and the real-time measurement data of the generator terminal PMU, construct the comprehensive index H of generator i. i for:

[0106] H i =w1D i +w2P m_i

[0107] In the formula, D i P represents the electrical coupling connection degree between generator i and the node connected to the critical load. m_i Let w1 be the mechanical power of generator i, and w2 be the weighting index of the electrical coupling connection degree and mechanical power of generator i, respectively.

[0108] S53: Determine emergency tripping control measures based on the generator's comprehensive index and tripping control quantity; the tripping quantity ΔP of generator i in the power system. i for:

[0109]

[0110] In the formula, ΔP m This refers to the generator tripping control quantity in the power system.

[0111] This invention has the following advantages:

[0112] 1. Compared with the prior art, the real-time emergency control method for transient stability of power system proposed in this invention uses electrical coupling connectivity to measure the degree of influence of generator on important loads, and constructs a comprehensive index that considers the electrical coupling connectivity and mechanical power of generator, so as to restore the transient unstable system to stability while ensuring the power supply capacity of the power system to important loads as much as possible;

[0113] 2. The real-time emergency control method for transient stability of power systems proposed in this invention acquires generator terminal data in real time through the PMU, quantitatively evaluates the transient stability margin of the transient unstable system based on the extended equal area method, and considers the impact of the delay time from the detection of transient instability to the implementation of control measures, which helps to improve the effectiveness of emergency control measures.

[0114] Example 2

[0115] like Figure 2 As shown, the difference between this embodiment and Embodiment 1 is that this embodiment provides a real-time emergency control system for transient stability of a power system. This system uses the real-time emergency control method for transient stability of a power system from Embodiment 1. The system includes:

[0116] The data acquisition unit is used to acquire real-time measurement data of the generator terminal PMU after a power system fault; the real-time PMU measurement data includes generator speed, generator power angle, generator mechanical power and generator electromagnetic power;

[0117] The transient instability judgment unit is used to determine whether the power system has experienced transient instability based on the real-time measurement data of the PMU and the change curve of the maximum power angle difference of the system. If so, proceed to step S3; otherwise, proceed to step S1.

[0118] The equivalent power angle characteristic curve calculation unit is used to convert a two-machine power system into a single-machine infinite system, and then calculate the equivalent power angle characteristic curve of the power system.

[0119] The generator tripping control quantity calculation unit is used to fit the equivalent power angle characteristic curve of the power system from the fault clearing to the determination of the power system transient instability based on the least squares method, and then predict the equivalent power angle characteristic curve after the determination of the power system transient instability, and obtain the generator tripping control quantity based on the extended equal area method.

[0120] The emergency tripping control measure determination unit is used to calculate the electrical coupling connection degree between the bus node connected to the important load and each generator node of the power system, and to process the electrical coupling connection degree, real-time measurement data of the generator terminal PMU and tripping control quantity to obtain emergency tripping control measures.

[0121] As a further implementation, the execution process of the emergency cut-off control measures determination unit is as follows:

[0122] Calculate the electrical coupling degree between the bus nodes connected to important loads and each generator node in the power system;

[0123] Based on the electrical coupling connectivity of each generator in the leading group S and the real-time measurement data of the generator terminal PMU, a comprehensive index H of generator i is constructed. i for:

[0124] H i =w1D i +w2P m_i

[0125] In the formula, D i P represents the electrical coupling connection degree between generator i and the node connected to the critical load. m_i Let w1 be the mechanical power of generator i, and w2 be the weighting index of the electrical coupling connection degree and mechanical power of generator i, respectively.

[0126] Based on the generator's comprehensive index and tripping control quantity, determine the emergency tripping control measures; the tripping quantity ΔP of generator i in the power system. i for:

[0127]

[0128] In the formula, ΔP m This refers to the generator tripping control quantity in the power system.

[0129] The execution process of each unit can be carried out according to the steps of the real-time emergency control method for transient stability of power system in Example 1, and will not be described in detail in this example.

[0130] Meanwhile, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-mentioned real-time emergency control method for transient stability of power systems.

[0131] Meanwhile, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned real-time emergency control method for transient stability of power systems.

[0132] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0133] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0134] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0135] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0136] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. 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 real-time emergency control method for transient stability of a power system, characterized in that, The method includes: S1: Acquire real-time measurement data of the generator terminal PMU after a power system fault; the real-time measurement data of the PMU includes generator speed, generator power angle, generator mechanical power and generator electromagnetic power; S2: Based on the real-time measurement data of the PMU, determine whether the power system has experienced transient instability based on the curve of the change of the maximum power angle difference of the system. If yes, proceed to step S3; otherwise, proceed to step S1. S3: Equivalent to a dual-machine power system, the dual-machine system is equivalent to a single-machine infinite system, and then the equivalent power angle characteristic curve of the power system is obtained; S4: Based on the least squares method, fit the equivalent power angle characteristic curve of the power system from the fault clearing to the determination of the power system transient instability, and then predict the equivalent power angle characteristic curve after the determination of the power system transient instability, and obtain the tripping control quantity based on the extended equal area method. S5: Calculate the electrical coupling connection degree between the bus node connected to the important load and each generator node in the power system, and process the electrical coupling connection degree, real-time measurement data of the generator terminal PMU and the generator tripping control quantity to obtain emergency generator tripping control measures; after taking the emergency generator tripping control measures, execute step S1; Step S5 includes: S51: Calculate the electrical coupling connection degree between the bus nodes connected to important loads and each generator node in the power system; S52: Based on the electrical coupling connectivity of each generator in the leading group S and the real-time measurement data of the generator terminal PMU, construct the comprehensive index H of generator i. i for: ； In the formula, D i P represents the electrical coupling connection degree between generator i and the node connected to the critical load. m_i Let w1 be the mechanical power of generator i, and w2 be the weighting index of the electrical coupling connection degree and mechanical power of generator i, respectively. S53: Determine emergency tripping control measures based on the generator's comprehensive index and the tripping control quantity; tripping quantity of generator i in the power system. for: ； In the formula, ΔP m This refers to the generator tripping control quantity in the power system.

2. The real-time emergency control method for transient stability of power systems according to claim 1, characterized in that, Step S2, which determines whether the power system has experienced transient instability based on the curve of the change in the maximum power angle difference of the system, includes: Define the set of generator nodes in a power system as {A}, and use δ to represent the power angle difference between generator i and generator j in set {A}. ij The maximum power angle difference of the power system is calculated using the following formula. : ; The system detects in real time whether the maximum power angle difference calculated at the current moment is greater than a preset threshold; if so, the power system is in transient instability; if not, the power system is stable.

3. The real-time emergency control method for transient stability of a power system according to claim 1, characterized in that, Step S3 includes: S31: After the power system becomes transiently unstable, the collected power angles of each generator are arranged from smallest to largest, the generator pair with the largest power angle gap is identified, and the generator group in the power system is divided into lagging group B and leading group S before and after this largest power angle gap. S32: Based on the measurement data after the failure of the lagging group B and the leading group S, the power system is equivalent to a two-machine system using the following formula: ； In the formula: ω i δ i and M i ω represents the angular frequency, power angle, and inertial time constant of generator i, respectively; B δ B and M B Let ω represent the equivalent angular frequency, equivalent work angle, and equivalent inertial time constant of lag group B, respectively; S δ S and M S Let represent the equivalent angular frequency, equivalent power angle, and equivalent inertial time constant of the leading group S, respectively. S33: Equivalently converting the two-machine system to a single-machine infinite system, thereby obtaining the equivalent power angle characteristic curve of the power system. The equivalent of the single-machine infinite system is shown in the following formula: ； Where: δ d ω is the generator power angle of an equivalent single-machine infinite system. d M is the generator angular frequency of an equivalent single-machine infinite bus system, where ω0 is the initial value of the generator angular frequency; S M is the equivalent inertial time constant of the lag group B; A P is the equivalent inertial time constant of the leading group S; mi P mj P represents the mechanical power of generator i and generator j, respectively; ei P ej P represents the electromagnetic power of generator i and generator j, respectively; dm and P de These represent the mechanical power and electromagnetic power of the generator in an equivalent single-machine infinite system, respectively.

4. The real-time emergency control method for transient stability of a power system according to claim 1, characterized in that, Step S4 includes: S41: From the time the power system clears a fault until transient instability is detected, calculate the equivalent single-unit infinite power system generator electromagnetic power at each moment. Based on the collected electromagnetic power data, fit the following formula using the least squares method: ； In the formula: P de δ represents the electromagnetic power of the generator in the equivalent single-machine infinite system; δ represents the generator power angle in the equivalent single-machine infinite system; A, B, and C are the parameters to be solved. The equivalent power angle characteristic curve after the transient instability of the power system can be predicted using the above formula; S42: Based on the equivalent power angle characteristic curve, calculate the tripping control quantity using the extended equal area method; the calculation formula for the tripping control quantity is: ； In the formula, ΔP m δ0 is the generator tripping control variable of the power system, and δ0 is the equivalent single-unit infinite power system generator's power angle value at the time of power system fault occurrence. c δ is the equivalent power angle value of a single-unit infinite power system generator at the time of power system fault clearing. u ω represents the equivalent single-unit infinite-power system generator's power angle value at the moment when transient instability is detected after a power system fault. du The angular frequency δ of an equivalent single-unit infinite-power system generator is used to detect transient instability in power systems during fault detection. m Δt represents the power angle value at the first unstable equilibrium point of the generator in the equivalent single-unit infinite power system after a power system fault. delay The time delay between detecting transient instability in the power system and implementing emergency control measures; P dm and P de These represent the mechanical power and electromagnetic power of the generator in an equivalent single-machine infinite system, respectively.

5. The real-time emergency control method for transient stability of a power system according to claim 1, characterized in that, The electrical coupling degree D of generator node i in step S5 i The calculation formula is: ； In the formula, Z ij U represents the equivalent impedance of the two-port network as seen from a generator node i and a node j connected to a critical load. ij and I ij These represent the voltage and current of the two-port network, respectively.

6. A real-time emergency control system for transient stability of a power system, characterized in that, The system includes: The data acquisition unit is used to acquire real-time measurement data of the generator terminal PMU after a power system fault; the real-time measurement data of the PMU includes generator speed, generator power angle, generator mechanical power and generator electromagnetic power; The transient instability judgment unit is used to determine whether the power system has experienced transient instability based on the real-time measurement data of the PMU and the change curve of the maximum power angle difference of the system. If so, step S3 is performed; otherwise, step S1 is performed. The equivalent power angle characteristic curve calculation unit is used to convert a two-machine power system into a single-machine infinite system, and then calculate the equivalent power angle characteristic curve of the power system. The generator tripping control quantity calculation unit is used to fit the equivalent power angle characteristic curve of the power system from the fault clearing to the determination of the power system transient instability based on the least squares method, and then predict the equivalent power angle characteristic curve after the determination of the power system transient instability, and obtain the generator tripping control quantity based on the extended equal area method. The emergency generator tripping control measure determination unit is used to calculate the electrical coupling connection degree between the bus node connected to the important load and each generator node of the power system, and to process the electrical coupling connection degree, real-time measurement data of the generator terminal PMU and the generator tripping control quantity to obtain the emergency generator tripping control measures. The execution process of the emergency machine cut-off control measure determination unit is as follows: Calculate the electrical coupling degree between the bus nodes connected to important loads and each generator node in the power system; Based on the electrical coupling connectivity of each generator in the leading group S and the real-time measurement data of the generator terminal PMU, a comprehensive index H of generator i is constructed. i for: ； In the formula, D i P represents the electrical coupling connection degree between generator i and the node connected to the critical load. m_i Let w1 be the mechanical power of generator i, and w2 be the weighting index of the electrical coupling connection degree and mechanical power of generator i, respectively. Based on the generator's comprehensive index and the aforementioned generator tripping control quantity, determine the emergency generator tripping control measures; the generator tripping quantity of generator i in the power system. for: ； In the formula, ΔP m This refers to the generator tripping control quantity in the power system.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the real-time emergency control method for transient stability of the power system as described in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the real-time emergency control method for transient stability of the power system as described in any one of claims 1 to 5.

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