Fault analysis method based on power network equation and related system

Abstract

The invention belongs to the field of short-circuit current calculation, and discloses a fault analysis method based on a power network equation and a related system.Unified modeling of the overall structure of a power system is achieved by obtaining bus information of the power system and constructing a system topological relation model, and the fault analysis accuracy is improved. The adaptation difficulty caused by different system scales and different wiring modes is avoided, and the universality and the expandability of the method are improved; according to the method, an automatic processing mechanism is introduced into the calculation and decomposition of the admittance matrix, so that the positive sequence admittance matrix, the negative sequence admittance matrix and the zero sequence admittance matrix of the power system can be quickly obtained, manual derivation and gradual simplification processes are reduced, the probability of analysis errors is reduced, and the stability of a calculation result is improved; a three-sequence network equation is uniformly adopted in fault calculation to solve a framework, and a direct coupling relation between an admittance matrix and a short circuit operation condition is utilized, so that key to-be-solved quantities such as fault current and voltage can be quickly and accurately obtained, the calculation process is remarkably shortened, and the analysis efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of short-circuit current calculation, specifically involving a fault analysis method and related system based on power network equations. Background Technology

[0002] In recent years, with the continuous increase in electricity demand in modern society and the widespread integration of distributed power sources, the scale and structure of power systems have become increasingly complex, resulting in a growing workload for short-circuit fault analysis and calculation. This places higher demands on the computational speed and efficiency of simulators. Against this backdrop, developing an accurate and fast practical algorithm for short-circuit faults has significant engineering application value and is of great importance for system planning and operation.

[0003] Currently, the calculation and analysis of complex system faults in engineering mainly rely on corresponding electromagnetic transient simulation software. Although simulation software can calculate the short-circuit current of a system relatively accurately, the simulation difficulty increases with the scale of the system. Facing the complex fault calculation problem of large-scale power grids, the modeling complexity and computational difficulty of using relevant electromagnetic transient simulation software for fault calculation are very high, making it difficult to meet the real-time requirements of short-circuit current engineering calculations and unsuitable for practical engineering calculations of short-circuit currents. Furthermore, traditional complex fault analysis methods suffer from poor versatility and low computational efficiency. Therefore, there is an urgent need to develop an accurate and fast practical algorithm for short-circuit faults. This algorithm needs to be able to accurately solve for the short-circuit current and node voltage of complex power systems under any fault conditions, in order to improve the safety and stability of power systems. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of poor universality and low computational efficiency of traditional complex fault analysis methods, and to provide a fault analysis method and related system based on power network equations.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a fault analysis method based on power network equations, comprising the following steps: Obtain information on all busbars in the power system, obtain component nodes and component parameter values ​​based on the busbar information, construct a system topology model based on the component nodes, and construct the admittance matrix of each node based on the system topology model. Based on the nodal admittance matrix and the component parameter values, the admittance values ​​of different component nodes are calculated. The admittance values ​​of different component nodes are then processed to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix, and zero-sequence admittance matrix of the power system. Obtain the short-circuit operation information that needs to be calculated in the power system, calculate the corresponding three-sequence network equation based on the short-circuit operation information, and determine the faults in the power system through the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

[0006] A further improvement of this invention lies in the following method for obtaining information on all busbars in the power system, obtaining component nodes and component parameter values ​​based on the busbar information, constructing a system topology model based on the component nodes, and constructing the admittance matrix of each node based on the system topology model: Obtain information on all busbars in the power system, and derive component node and component parameter values ​​based on the busbar information; Based on the component nodes, construct the power supply model and the load model; among them, the power supply includes motor-type distributed power supply and converter-type distributed power supply; when constructing the power supply model, the motor-type distributed power supply is equivalent to a voltage source and impedance series model, and the converter-type distributed power supply is equivalent to a constant positive sequence current source; the load includes static load model and dynamic load model; when constructing the load model, a constant impedance model is used to establish the static load model, and an induction motor model is used to establish the dynamic load model. Based on the relationship between the power supply model and the load model, a mathematical model of the power supply and load is constructed as the system topology model. Based on the system topology model, the three-phase unbalanced components of the bus are decomposed into three sets of symmetrical positive-sequence components, negative-sequence components and zero-sequence components, forming a three-sequence network equation; Based on the three-order network equation, the admittance matrix of each node is obtained.

[0007] A further improvement of this invention lies in the following method for calculating the admittance values ​​of different component nodes based on the nodal admittance matrix and component parameter values, and processing the admittance values ​​of different component nodes to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix, and zero-sequence admittance matrix of the power system: Obtain the node admittance matrix and combine it with the component parameter values ​​to obtain the position of the element in each node admittance matrix; Traverse all component nodes to obtain the positive and negative order parameters of each component, and calculate the admittance value of each component at different positions based on the positive and negative order parameters of each component. By placing the admittance value of each element at different locations into the corresponding positions of the admittance matrix, the positive-sequence admittance matrix and the negative-sequence admittance matrix of the power system are obtained. To obtain the connection method of the transformer in the power system, disconnect the corresponding terminal in the equivalent circuit of the transformer from the external circuit. Therefore, the admittance value at the corresponding position of the transformer is 0. Use the admittance matrix with an admittance value of 0 as the zero-sequence admittance matrix of the power system.

[0008] A further improvement of this invention lies in obtaining the short-circuit operation information that needs to be calculated in the power system, calculating the corresponding three-sequence network equation based on the short-circuit operation information, and solving for the unknown quantity using the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix, and zero-sequence admittance matrix of the power system. The specific method is as follows: Obtain the short-circuit operation information that needs to be calculated in the power system, obtain the fault port based on the short-circuit operation information, convert the fault port into an equivalent current injection source, and calculate the three-sequence network equation corresponding to the short-circuit operation information based on the current injection source. Obtain the boundary condition equations of the fault ports. Based on the three-sequence network equations corresponding to the short-circuit operation information and the boundary condition equations of the fault ports, obtain the three-sequence components of the voltage of each node and the three-sequence components of the short-circuit current of all fault ports corresponding to the short-circuit operation information. By combining the three-sequence components of the voltage at each node corresponding to the short-circuit operation information and the three-sequence components of the short-circuit current at all fault ports with the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system, the unknown quantity is obtained.

[0009] Secondly, the present invention provides a fault analysis system based on power network equations, comprising: The admittance matrix construction module is used to obtain information on all busbars in the power system, obtain component nodes and component parameter values ​​based on the busbar information, construct a system topology model based on the component nodes, and construct the admittance matrix of each node based on the system topology model. The admittance matrix calculation module is used to calculate the admittance values ​​of different component nodes based on the node admittance matrix and component parameter values, and to process the admittance values ​​of different component nodes to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system. The fault analysis module is used to obtain short-circuit operation information that needs to be calculated in the power system, calculate the corresponding three-sequence network equation based on the short-circuit operation information, and determine the fault in the power system by using the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

[0010] A further improvement of this invention is that the functionality of the admittance matrix construction module is implemented through the following method: Obtain information on all busbars in the power system, and derive component node and component parameter values ​​based on the busbar information; Based on the component nodes, construct the power supply model and the load model; among them, the power supply includes motor-type distributed power supply and converter-type distributed power supply; when constructing the power supply model, the motor-type distributed power supply is equivalent to a voltage source and impedance series model, and the converter-type distributed power supply is equivalent to a constant positive sequence current source; the load includes static load model and dynamic load model; when constructing the load model, a constant impedance model is used to establish the static load model, and an induction motor model is used to establish the dynamic load model. Based on the relationship between the power supply model and the load model, a mathematical model of the power supply and load is constructed as the system topology model. Based on the system topology model, the three-phase unbalanced components of the bus are decomposed into three sets of symmetrical positive-sequence components, negative-sequence components and zero-sequence components, forming a three-sequence network equation; Based on the three-order network equation, the admittance matrix of each node is obtained.

[0011] A further improvement of this invention is that the function of the admittance matrix calculation module is implemented through the following method: Obtain the node admittance matrix and combine it with the component parameter values ​​to obtain the position of the element in each node admittance matrix; Traverse all component nodes to obtain the positive and negative order parameters of each component, and calculate the admittance value of each component at different positions based on the positive and negative order parameters of each component. By placing the admittance value of each element at different locations into the corresponding positions of the admittance matrix, the positive-sequence admittance matrix and the negative-sequence admittance matrix of the power system are obtained. To obtain the connection method of the transformer in the power system, disconnect the corresponding terminal in the equivalent circuit of the transformer from the external circuit. Therefore, the admittance value at the corresponding position of the transformer is 0. Use the admittance matrix with an admittance value of 0 as the zero-sequence admittance matrix of the power system.

[0012] A further improvement of this invention is that the function of the fault analysis module is implemented through the following method: Obtain the short-circuit operation information that needs to be calculated in the power system, obtain the fault port based on the short-circuit operation information, convert the fault port into an equivalent current injection source, and calculate the three-sequence network equation corresponding to the short-circuit operation information based on the current injection source. Obtain the boundary condition equations of the fault ports. Based on the three-sequence network equations corresponding to the short-circuit operation information and the boundary condition equations of the fault ports, obtain the three-sequence components of the voltage of each node and the three-sequence components of the short-circuit current of all fault ports corresponding to the short-circuit operation information. By combining the three-sequence components of the voltage at each node corresponding to the short-circuit operation information and the three-sequence components of the short-circuit current at all fault ports with the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system, the unknown quantity is obtained.

[0013] Thirdly, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of a fault analysis method based on power network equations.

[0014] Fourthly, the present invention provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of a fault analysis method based on power network equations.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves unified modeling of the overall power system structure by acquiring bus information and constructing a system topology model, avoiding adaptation difficulties caused by differences in system scale and wiring methods, and improving the universality and scalability of the method. By introducing an automated processing mechanism in the calculation and decomposition of the admittance matrix, this invention can quickly obtain the positive-sequence, negative-sequence, and zero-sequence admittance matrices of the power system, reducing manual derivation and step-by-step simplification processes, lowering the probability of analytical errors, and improving the stability of the calculation results. By uniformly adopting a three-sequence network equation solution framework in fault calculation, and utilizing the direct coupling relationship between the admittance matrix and short-circuit operating conditions, key quantities such as fault current and voltage can be obtained quickly and accurately, significantly shortening the calculation process and improving analytical efficiency. In conclusion, this invention forms a standardized and automated process from bus information input to fault result output, which can meet the rapid response needs of power systems in scenarios such as dispatching operation, protection configuration, and online simulation, providing more efficient and reliable technical support for the safe and stable operation of power systems. Attached Figure Description

[0016] Figure 1 This is a flowchart of the present invention; Figure 2 This is a system diagram of the present invention; Figure 3 This is a structural diagram of the 7-node test case in Example 6; Figure 4 This is a system diagram of Example 7. Detailed Implementation

[0017] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0018] Example 1: See Figure 1 The fault analysis method based on power network equations includes the following steps: S1: Obtain information on all busbars in the power system, obtain component nodes and component parameter values ​​based on the busbar information, construct a system topology model based on the component nodes, and construct the admittance matrix of each node based on the system topology model.

[0019] S2. Based on the node admittance matrix and the component parameter values, calculate the admittance values ​​of different component nodes, process the admittance values ​​of different component nodes, and obtain the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

[0020] S3: Obtain the short-circuit operation information that needs to be calculated in the power system, calculate the corresponding three-sequence network equation based on the short-circuit operation information, and determine the fault of the power system through the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

[0021] Example 2: See Figure 2 A fault analysis system based on power network equations includes: The admittance matrix construction module is used to obtain information on all busbars in the power system, obtain component nodes and component parameter values ​​based on the busbar information, construct a system topology model based on the component nodes, and construct the admittance matrix of each node based on the system topology model.

[0022] The admittance matrix calculation module is used to calculate the admittance values ​​of different component nodes based on the node admittance matrix and component parameter values, and to process the admittance values ​​of different component nodes to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

[0023] The fault analysis module is used to obtain short-circuit operation information that needs to be calculated in the power system, calculate the corresponding three-sequence network equation based on the short-circuit operation information, and determine the faults in the power system through the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

[0024] Example 3: This embodiment, based on the above embodiment, provides a detailed explanation of the functions of step S1 and the admittance matrix construction module: S11: Obtain information on all busbars in the power system, and obtain component node and component parameter values ​​based on the busbar information.

[0025] S12, Based on the component nodes, construct the power supply model and the load model; where the power supply includes motor-type distributed power supply and converter-type distributed power supply; when constructing the power supply model, the motor-type distributed power supply is equivalent to a voltage source and impedance series model, and the converter-type distributed power supply is equivalent to a constant positive sequence current source; the load includes a static load model and a dynamic load model. When constructing the load model, a constant impedance model is used to establish the static load model, and an induction motor model is used to establish the dynamic load model.

[0026] S13. Based on the relationship between the power supply model and the load model, construct a mathematical model of the power supply and the load as the system topology model.

[0027] S14. Based on the system topology model, the three-phase unbalanced components of the bus are decomposed into three sets of symmetrical positive-sequence components, negative-sequence components, and zero-sequence components, forming a three-sequence network equation.

[0028] S15. Based on the three-order network equation, the admittance matrix of each node is obtained.

[0029] Furthermore, based on the component nodes, power supply and load models are constructed to ensure accurate solutions for the system under short-circuit faults. In terms of power supply modeling, this embodiment considers traditional synchronous generator power supplies and distributed generation (DG) as research objects. DG can be further divided into motor-type DG and converter-type DG. Considering that the short-circuit current characteristics of both synchronous generators and motor-type DG exhibit a transient inrush current at the initial stage of the short-circuit current, gradually transitioning to a steady state after decay, it is generally assumed that synchronous generators and motor-type DG are models with constant internal potential after transient reactance (or subtransient reactance), which can be equivalently represented as a voltage source and impedance series model, satisfying the following form:

[0030] in, This is the terminal voltage of the synchronous motor. This refers to the terminal current of the synchronous motor. The internal potential after transient reactance, For transient reactance, It is the imaginary unit.

[0031] The short-circuit current characteristics of a converter-type distributed generation system are such that it can output a three-phase symmetrical short-circuit current containing only a positive-sequence component under both symmetrical and asymmetrical fault conditions. When a short-circuit fault occurs, the converter-type distributed generation system can be equivalently represented as a constant positive-sequence current source, satisfying the following form:

[0032] in, This refers to the short-circuit current output by the converter-type distributed power source. The allowable overcurrent multiple is typically taken as 1.2 to 1.5; This is the rated current of the converter-type distributed power source.

[0033] In terms of load modeling, this embodiment considers both static and dynamic load models as research objects. When considering a static load model, a constant impedance model can be used. When considering a dynamic load model, an induction motor model can be used. As the most important dynamic load in a power system, the dynamic characteristics of the induction motor can represent the dynamic characteristics of the power load to a certain extent, satisfying the following form:

[0034] in, Indicates stator resistance. This is the equivalent leakage impedance.

[0035] In asymmetrical fault analysis, the symmetrical component method is typically used to decompose the three-phase asymmetrical components into three sets of symmetrical positive-sequence, negative-sequence, and zero-sequence components. When forming the three-sequence network, it is necessary to add an equivalent current source model for the generator-type distributed generation and a constant positive-sequence current source model for the converter-type distributed generation at each generator node, and a static load model and a dynamic load model at each load node. The resulting three-sequence network equations satisfy the following form:

[0036] in, The injected current is for the positive-sequence network. This represents the positive-order admittance matrix formed by the power supply node. The negative-order admittance matrix formed by the power nodes. The zero-sequence admittance matrix formed by the power node. This is the positive-order admittance matrix formed by other elements in the network. This is the negative-order admittance matrix formed by other elements in the network. The zero-order admittance matrix formed by other components in the network. This represents the positive-order admittance matrix formed by the load nodes. The negative-order admittance matrix formed by the load nodes. The zero-order admittance matrix formed by the load nodes. This represents the sum of the admittance matrices of the ascending nodes. The sum of the admittance matrices of the negative-order nodes. This is the sum of the zero-order node admittance matrices.

[0037] For any n In a nodal power system, with the voltage at each node as the unknown variable, according to Kirchhoff's current law, the following equation can be obtained:

[0038] in, A column vector consisting of the injected currents at each node. It is a column vector composed of the voltages of each node. Let be the nodal admittance matrix of the network, satisfying the following form:

[0039] in, ( i =1, , n ) is a node i Self-guided absorbance, n The total number of nodes is equal to the sum of the admittances of the branches connected to that node. ( i ≠ j ;i , j =1, , n ) is a node i With nodes j The mutual admittance between them is equal to the negative of the admittance of the connected branch.

[0040] Example 4: This embodiment, based on the above embodiment, provides a detailed explanation of the functions of step S2 and the admittance matrix calculation module: S21, obtain the node admittance matrix, and combine it with the component parameter values ​​to obtain the position of the element in each node admittance matrix.

[0041] S22, traverse all component nodes to obtain the positive and negative sequence parameters of each component, and calculate the admittance value of each component at different positions based on the positive and negative sequence parameters of each component.

[0042] S23, put the admittance value of each element at different positions into the corresponding positions of the admittance matrix to obtain the positive-sequence admittance matrix and negative-sequence admittance matrix of the power system.

[0043] S24: Obtain the connection method of the transformer in the power system, disconnect the corresponding terminal in the equivalent circuit of the transformer from the external circuit, so the admittance value of the corresponding position of the transformer is 0, which is used as the zero-sequence admittance matrix of the power system.

[0044] Furthermore, the node admittance matrix is ​​obtained, and combined with the component parameter values, the positions of the elements in each node admittance matrix are obtained. This process is repeated for all power component nodes. Based on the positive and negative sequence parameters of each component read from the power system, the admittance values ​​at different positions are calculated and added to the corresponding positions to obtain the positive and negative sequence admittance matrices of the power system. The construction principle of the zero-sequence admittance matrix of the power system is the same as that of the positive and negative sequence admittance matrices. The difference lies in the fact that the construction of the zero-sequence admittance matrix needs to consider the transformer connection method. This is because, under zero-sequence conditions, the sum of the three-phase zero-sequence currents is not equal to zero, therefore they must pass through the neutral point and the ground to form a loop. If the three-phase windings of the transformer are connected in a delta configuration or a star configuration with the neutral point ungrounded, the zero-sequence current cannot flow through the three-phase windings. In this case, it is equivalent to the corresponding endpoints in the transformer's equivalent circuit being disconnected from the external circuit, i.e., the admittance value at the corresponding position is set to 0. The admittance matrix with an admittance value of 0 is taken as the zero-sequence admittance matrix of the power system.

[0045] Example 5: This embodiment, based on the above embodiment, provides a detailed explanation of the functions of step S3 and the fault analysis module: S31: Obtain the short-circuit operation information that needs to be calculated in the power system, obtain the fault port based on the short-circuit operation information, convert the fault port into an equivalent current injection source, and calculate the three-sequence network equation corresponding to the short-circuit operation information based on the current injection source.

[0046] S32, obtain the boundary condition equation of the fault port, and based on the three-sequence network equation corresponding to the short-circuit operation information and the boundary condition equation of the fault port, obtain the three-sequence components of the voltage of each node and the three-sequence components of the short-circuit current of all fault ports corresponding to the short-circuit operation information.

[0047] S33 combines the three-sequence components of the voltage at each node corresponding to the short-circuit operation information and the three-sequence components of the short-circuit current at all fault ports with the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system to obtain the quantity to be determined.

[0048] Furthermore, assuming an asymmetrical fault occurs at a node in the power system, and the fault port is considered equivalent to an injected current source, then in the three-sequence network, the fault point... k Injection current exists in all of them The three-order network under simple faults satisfies the following form:

[0049] in, For faults, give nodes k Injected positive sequence current, For faults, give nodes k Injected negative sequence current, For faults, give nodes k Injected zero-sequence current, For nodes k of n × n identity matrix This represents the positive-sequence voltage column vector of each node in the power system. Includes pre-fault positive sequence voltage and fault positive sequence components Positive sequence voltage before the fault It is obtained from the tri-order network equation that satisfies , This is the column vector of positive sequence currents; The fault negative sequence component of the voltage at each node. For each node voltage, the fault zero-sequence component is the voltage. Since the steady-state solution of the voltage in the negative-sequence and zero-sequence networks is 0 under normal operation, the voltage of each node after a fault only contains the fault component.

[0050] A power system may experience multiple different types of faults simultaneously. Therefore, the above derivation needs to be slightly extended to accommodate complex faults. Assume the power system has... qIf all nodes fail simultaneously, then you can use q Ports are used to describe this power system. q The three-order network equations under the port satisfy the following form:

[0051] in, For faults, give the node j Injected positive sequence current, For nodes j of n × n identity matrix For faults, give nodes q Injected positive sequence current, For nodes q of n × n identity matrix For faults, give the node j Injected negative sequence current, For faults, give the node q Injected negative sequence current, For faults, give nodes j Injected zero-sequence current, For faults, give the node q Injected zero-sequence current.

[0052] According to the above formula, q The three-order network equations under the port have a total of 3 n Equations and 3 n +3 q There are 10 variables. For each fault port, 3 boundary condition equations can be obtained based on its fault type. q Three faulty ports were added. q Several equations. Clearly, a simultaneous solution... q The three-sequence equations at each port and the boundary condition equations for all fault ports yield the three-sequence components of the voltage at each node and the three-sequence components of the short-circuit current at all fault ports, which can be rearranged to obtain:

[0053] in, Let be the admittance matrix of the entire network. This is the coefficient matrix for each positive-sequence injected current at the fault port. Let be the constraint matrix for the fault port voltage in the boundary conditions. This is the coefficient matrix of the fault port current in the boundary conditions.

[0054] The above equation is the general form of the equation for solving complex faults. By solving the three-sequence components, the three-sequence voltage of the component node and the three-sequence current of the fault port containing all the quantities to be determined can be obtained. The fault of the power system can be determined based on the three-sequence voltage of the component node and the three-sequence current of the fault port.

[0055] Example 6: To verify the correctness and practicality of this invention, this embodiment was tested in a 7-node power system example. The power system structure diagram is shown below. Figure 3 As shown, both simple and complex fault scenarios were considered. A simulation model of this example was built in PSASP (Power System Analysis Software Package), and the correctness of the algorithm was verified through simulation results.

[0056] 1) Simple faults In this embodiment, a three-phase short-circuit fault and a single-phase ground fault are set at node 6. The simulation results and calculation results are shown in Table 1.

[0057] Table 1 Fault Calculation Results for Node 6

[0058] As can be seen from the calculation results in Table 1, the calculation data of the algorithm is the same as the simulation data, which verifies the correctness of the present invention under simple fault conditions.

[0059] 2) Complex faults This embodiment sets up two complex fault scenarios: a single-phase ground fault occurring simultaneously at nodes 6 and 7; and a single-phase ground fault occurring at node 6, while a two-phase short-circuit fault occurs simultaneously at node 7. The simulation results and calculation results are shown in Table 2.

[0060] Table 2 Calculation Results of Complex Faults

[0061] As can be seen from the calculation results in Table 2, the calculation data of the algorithm is the same as the simulation data, which verifies the correctness of the present invention under complex fault conditions.

[0062] Example 7 See Figure 4 The present invention also provides an electronic device 100 based on a fault analysis method for power network equations; the electronic device 100 includes a memory 101, at least one processor 102, a computer program 103 stored in the memory 101 and executable on the at least one processor 102, and at least one communication bus 104.

[0063] The memory 101 can be used to store the computer program 103. The processor 102 implements the steps of the fault analysis method based on power network equations described in Embodiment 1 by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101. The memory 101 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the electronic device 100 (such as audio data), etc. In addition, the memory 101 may include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0064] The at least one processor 102 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 102 may be a microprocessor or any conventional processor. The processor 102 is the control center of the electronic device 100, connecting various parts of the electronic device 100 via various interfaces and lines.

[0065] The memory 101 in the electronic device 100 stores multiple instructions to implement a fault analysis method based on power network equations, and the processor 102 can execute the multiple instructions to achieve the following: Obtain information on all busbars in the power system, obtain component nodes and component parameter values ​​based on the busbar information, construct a system topology model based on the component nodes, and construct the admittance matrix of each node based on the system topology model. Based on the nodal admittance matrix and the component parameter values, the admittance values ​​of different component nodes are calculated. The admittance values ​​of different component nodes are then processed to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix, and zero-sequence admittance matrix of the power system. Obtain the short-circuit operation information that needs to be calculated in the power system, calculate the corresponding three-sequence network equation based on the short-circuit operation information, and solve for the unknown quantity by using the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

[0066] Example 8: If the modules / units integrated in the electronic device 100 are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0067] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention 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.

[0068] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0069] 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 1 The function specified in one or more boxes.

[0070] 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.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A fault analysis method based on power network equations, characterized in that, Includes the following steps: Obtain information on all busbars in the power system, obtain component nodes and component parameter values ​​based on the busbar information, construct a system topology model based on the component nodes, and construct the admittance matrix of each node based on the system topology model. Based on the nodal admittance matrix and the component parameter values, the admittance values ​​of different component nodes are calculated. The admittance values ​​of different component nodes are then processed to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix, and zero-sequence admittance matrix of the power system. Obtain the short-circuit operation information that needs to be calculated in the power system, calculate the corresponding three-sequence network equation based on the short-circuit operation information, and determine the faults in the power system through the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

2. The fault analysis method based on power network equations according to claim 1, characterized in that, The specific method for obtaining information on all busbars in the power system, deriving component nodes and parameter values ​​based on the busbar information, constructing a system topology model based on the component nodes, and then constructing the admittance matrix of each node based on the system topology model is as follows: Obtain information on all busbars in the power system, and derive component node and component parameter values ​​based on the busbar information; Based on the component nodes, construct the power supply model and the load model; among them, the power supply includes motor-type distributed power supply and converter-type distributed power supply; when constructing the power supply model, the motor-type distributed power supply is equivalent to a voltage source and impedance series model, and the converter-type distributed power supply is equivalent to a constant positive sequence current source; the load includes static load model and dynamic load model; when constructing the load model, a constant impedance model is used to establish the static load model, and an induction motor model is used to establish the dynamic load model. Based on the relationship between the power supply model and the load model, a mathematical model of the power supply and load is constructed as the system topology model. Based on the system topology model, the three-phase unbalanced components of the bus are decomposed into three sets of symmetrical positive-sequence components, negative-sequence components and zero-sequence components, forming a three-sequence network equation. Based on the three-order network equation, the admittance matrix of each node is obtained.

3. The fault analysis method based on power network equations according to claim 1, characterized in that, The admittance values ​​of different component nodes are calculated based on the nodal admittance matrix and component parameter values. The admittance values ​​of different component nodes are then processed to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix, and zero-sequence admittance matrix of the power system. The specific method for this is as follows: Obtain the node admittance matrix and combine it with the component parameter values ​​to obtain the position of the element in each node admittance matrix; Traverse all component nodes to obtain the positive and negative order parameters of each component, and calculate the admittance value of each component at different positions based on the positive and negative order parameters of each component. By placing the admittance value of each element at different locations into the corresponding positions of the admittance matrix, the positive-sequence admittance matrix and the negative-sequence admittance matrix of the power system are obtained. To obtain the connection method of the transformer in the power system, disconnect the corresponding terminal in the equivalent circuit of the transformer from the external circuit. Therefore, the admittance value at the corresponding position of the transformer is 0. Use the admittance matrix with an admittance value of 0 as the zero-sequence admittance matrix of the power system.

4. The fault analysis method based on power network equations according to claim 1, characterized in that, The specific method for obtaining short-circuit operation information that needs to be calculated in the power system, calculating the corresponding three-sequence network equations based on the short-circuit operation information, and solving for the unknown quantity using the three-sequence network equations and the positive-sequence admittance matrix, negative-sequence admittance matrix, and zero-sequence admittance matrix of the power system is as follows: Obtain the short-circuit operation information that needs to be calculated in the power system, obtain the fault port based on the short-circuit operation information, convert the fault port into an equivalent current injection source, and calculate the three-sequence network equation corresponding to the short-circuit operation information based on the current injection source. Obtain the boundary condition equations of the fault ports. Based on the three-sequence network equations corresponding to the short-circuit operation information and the boundary condition equations of the fault ports, obtain the three-sequence components of the voltage of each node and the three-sequence components of the short-circuit current of all fault ports corresponding to the short-circuit operation information. By combining the three-sequence components of the voltage at each node corresponding to the short-circuit operation information and the three-sequence components of the short-circuit current at all fault ports with the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system, the unknown quantity is obtained.

5. A fault analysis system based on power network equations, characterized in that, include: The admittance matrix construction module is used to obtain information on all busbars in the power system, obtain component nodes and component parameter values ​​based on the busbar information, construct a system topology model based on the component nodes, and construct the admittance matrix of each node based on the system topology model. The admittance matrix calculation module is used to calculate the admittance values ​​of different component nodes based on the node admittance matrix and component parameter values, and to process the admittance values ​​of different component nodes to obtain the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system. The fault analysis module is used to obtain short-circuit operation information that needs to be calculated in the power system, calculate the corresponding three-sequence network equation based on the short-circuit operation information, and determine the faults in the power system through the three-sequence network equation and the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system.

6. The fault analysis system based on power network equations according to claim 5, characterized in that, The functionality of the admittance matrix construction module is implemented through the following methods: Obtain information on all busbars in the power system, and derive component node and component parameter values ​​based on the busbar information; Based on the component nodes, construct the power supply model and the load model; among them, the power supply includes motor-type distributed power supply and converter-type distributed power supply; when constructing the power supply model, the motor-type distributed power supply is equivalent to a voltage source and impedance series model, and the converter-type distributed power supply is equivalent to a constant positive sequence current source; the load includes static load model and dynamic load model; when constructing the load model, a constant impedance model is used to establish the static load model, and an induction motor model is used to establish the dynamic load model. Based on the relationship between the power supply model and the load model, a mathematical model of the power supply and load is constructed as the system topology model. Based on the system topology model, the three-phase unbalanced components of the bus are decomposed into three sets of symmetrical positive-sequence components, negative-sequence components and zero-sequence components, forming a three-sequence network equation. Based on the three-order network equation, the admittance matrix of each node is obtained.

7. The fault analysis system based on power network equations according to claim 5, characterized in that, The admittance matrix calculation module is implemented using the following methods: Obtain the node admittance matrix and combine it with the component parameter values ​​to obtain the position of the element in each node admittance matrix; Traverse all component nodes to obtain the positive and negative order parameters of each component, and calculate the admittance value of each component at different positions based on the positive and negative order parameters of each component. By placing the admittance value of each element at different locations into the corresponding positions of the admittance matrix, the positive-sequence admittance matrix and the negative-sequence admittance matrix of the power system are obtained. To obtain the connection method of the transformer in the power system, disconnect the corresponding terminal in the equivalent circuit of the transformer from the external circuit. Therefore, the admittance value at the corresponding position of the transformer is 0. Use the admittance matrix with an admittance value of 0 as the zero-sequence admittance matrix of the power system.

8. The fault analysis system based on power network equations according to claim 5, characterized in that, The fault analysis module's functionality is implemented through the following methods: Obtain the short-circuit operation information that needs to be calculated in the power system, obtain the fault port based on the short-circuit operation information, convert the fault port into an equivalent current injection source, and calculate the three-sequence network equation corresponding to the short-circuit operation information based on the current injection source. Obtain the boundary condition equations of the fault ports. Based on the three-sequence network equations corresponding to the short-circuit operation information and the boundary condition equations of the fault ports, obtain the three-sequence components of the voltage of each node and the three-sequence components of the short-circuit current of all fault ports corresponding to the short-circuit operation information. By combining the three-sequence components of the voltage at each node corresponding to the short-circuit operation information and the three-sequence components of the short-circuit current at all fault ports with the positive-sequence admittance matrix, negative-sequence admittance matrix and zero-sequence admittance matrix of the power system, the unknown quantity is obtained.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the fault analysis method based on power network equations as described in any one of claims 1 to 4.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the fault analysis method based on power network equations as described in any one of claims 1 to 4.

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