A method and device for locating voltage sag fault source

Abstract

The present application provides a method and device for locating a voltage sag fault source, comprising: constructing a positive sequence component variation ratio vector function of multiple monitoring points on a line according to electrical parameters of a power grid; the line includes each suspected fault line; devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence component variation ratio scalar function corresponding to each monitoring point; and generating the location of the voltage sag fault source according to the positive sequence component variation ratio scalar function. The present application can determine the location of the voltage sag fault source by constructing a positive sequence component variation ratio function and a corresponding set of equations.

Description

Technical Field

[0001] The present application relates to the field of power fault detection, and specifically to a method and device for locating a voltage sag fault source. Background Art

[0002] Voltage sag is a common phenomenon in power systems. In many cases, voltage sag is caused by short-circuit faults in the power system. Voltage sag can easily affect the normal operation of electronic equipment, causing electronic equipment failures and bringing immeasurable economic losses. By accurately locating the source of the voltage sag fault, not only can the fault be found and the weak links in the power grid be discovered, but it can also help analyze the global voltage sag situation, so as to provide voltage sag on-site compensation devices for power nodes with frequent sags and many sensitive devices, improve the power quality of the power grid, and reduce the economic losses caused by voltage sag.

[0003] The research on the location of voltage sag fault sources has gone through two stages of development. The first stage is to locate the upstream and downstream positions of the voltage sag fault source: determine the location of the sag source based on the changes in system parameters and topological structure before and after the fault; the second stage is to accurately solve the location of the sag source under the premise of simplifying or ignoring the fault type and transition resistance, or derive the transition voltage-independent function of the voltage sag fault source and the fault type based on the sequence component theory to solve the location of the voltage sag fault source.

[0004] The voltage sag fault source fault location method solved by pattern matching has a relatively complex algorithm, which depends on the determination of typical pattern groups, the selection of pattern features, and the accuracy and precision of feature calculation. In addition, the typical pattern group is difficult to cover all fault conditions, the calculation amount is large, the calculation difficulty is high, and the wrong fault source location is often determined, which is difficult to meet the reliability requirements.

[0005] There are also existing technologies that use the method of assuming fault type and transition resistance information to solve the location of the voltage sag fault source in combination with boundary conditions. The voltage sag fault source solved in this way often has large deviations. When the voltage sag fault source location is solved by the pattern matching method based on the positive sequence voltage variable, although the influence of inaccurate fault type and transition resistance information can be avoided, due to the limited number of characteristic modes, the voltage sag fault source solved in this way is difficult to be accurate and unique. Summary of the invention

[0006] In view of the problems in the prior art, the present application provides a method and device for locating a voltage sag fault source, which can determine the location of the voltage sag fault source by constructing a positive sequence component change ratio function.

[0007] In order to solve the above technical problems, this application provides the following technical solutions:

[0008] In a first aspect, the present application provides a method for locating a voltage sag fault source, comprising:

[0009] Constructing a positive sequence component variation ratio vector function of a plurality of monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line;

[0010] Devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence component variation ratio scalar function corresponding to each monitoring point;

[0011] The location of the voltage sag fault source is generated according to the positive sequence component variation ratio scalar function.

[0012] Furthermore, the electrical parameters include: impedance parameters and fault distance; the constructing of a positive sequence component change ratio vector function of multiple monitoring points on the line according to the electrical parameters of the power grid includes:

[0013] Determining an equivalent impedance parameter of the power grid according to the impedance parameter; the equivalent impedance parameter includes an equivalent impedance parameter of each monitoring point from each suspected fault line;

[0014] The positive sequence component variation ratio vector function is determined according to the fault distance and the equivalent impedance parameter.

[0015] Furthermore, the voltage sag fault source location method further includes:

[0016] Select a voltage sag monitoring point with a phase synchronization function, and draw a graph to determine the real part and imaginary part of the positive sequence component variation ratio vector in the positive sequence component variation ratio vector function between two voltage sag monitoring points with a phase synchronization function;

[0017] Determine whether there are multiple suspected voltage sag fault sources in the power grid according to the real part and the imaginary part;

[0018] If it exists, a monitoring point is re-set on the suspected fault line, and a scalar function of the positive sequence component change ratio of the monitoring point is constructed to obtain the location of the voltage sag fault source.

[0019] Furthermore, devectorizing the positive sequence component variation ratio vector function to obtain a scalar function of the positive sequence component variation ratio corresponding to each monitoring point includes:

[0020] Devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence voltage variation ratio;

[0021] A two-variable linear equation is constructed according to the positive-sequence voltage variation ratio, the real part and the imaginary part as a scalar function of the positive-sequence component variation ratio.

[0022] In a second aspect, the present application provides a voltage sag fault source location device, comprising:

[0023] A vector function determination unit, used to construct a positive sequence component change ratio vector function of multiple monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line;

[0024] A scalar function determination unit, used for devectorizing the positive sequence component variation ratio vector function to obtain a scalar function of the positive sequence component variation ratio corresponding to each monitoring point;

[0025] A positioning unit is used to generate the position of the voltage sag fault source according to the positive sequence component change ratio scalar function.

[0026] Furthermore, the electrical parameters include: impedance parameters and fault distance; the vector function determination unit includes:

[0027] An equivalent impedance determination module, used to determine the equivalent impedance parameters of the power grid according to the impedance parameters; the equivalent impedance parameters include the equivalent impedance parameters of each monitoring point from each suspected fault line;

[0028] A vector function determination module is used to determine the positive sequence component change ratio vector function according to the fault distance and the equivalent impedance parameter.

[0029] Furthermore, the voltage sag fault source locating device further comprises:

[0030] A real and imaginary part determination unit, used for selecting a voltage sag monitoring point with a phase synchronization function, and determining by drawing a graph the real and imaginary parts of the positive sequence component variation ratio vector in the positive sequence component variation ratio vector function between two voltage sag monitoring points with a phase synchronization function;

[0031] A suspected fault judgment unit, used for judging whether there are multiple suspected voltage sag fault sources in the power grid according to the real part and the imaginary part;

[0032] The point resetting unit is used to reset the monitoring point on the suspected fault line when there are multiple suspected voltage sag fault sources, and construct a scalar function of the positive sequence component change ratio of the monitoring point to obtain the position of the voltage sag fault source.

[0033] Furthermore, the scalar function determination unit includes:

[0034] A variation ratio determination module, used for devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence voltage variation ratio;

[0035] The scalar function determination module is used to construct a binary linear equation according to the positive sequence voltage variation ratio, the real part and the imaginary part as a scalar function of the positive sequence component variation ratio.

[0036] In a third aspect, the present application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for locating the source of a voltage sag fault when executing the program.

[0037] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for locating a voltage sag fault source.

[0038] In view of the problems in the prior art, the voltage sag fault source location method and device provided by the present application can construct a set of equations between the voltage sag fault source and the monitoring point based on the positive sequence voltage component change ratio function, and accurately and uniquely determine the fault distance of the voltage sag source by solving the set of equations, thereby determining the location of the voltage sag source, which is simple to calculate and highly reliable. Subsequently, the voltage sag situation of the entire power grid can be obtained based on the solution results of the voltage sag source location and the electrical parameters of the entire power grid, so that the voltage sag can be observed throughout the entire network, laying the foundation for voltage sag assessment and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 This is one of the flow charts of the method for locating the source of a voltage sag fault in an embodiment of the present application;

[0041] Figure 2 A flowchart for determining a vector function in an embodiment of the present application;

[0042] Figure 3 This is the second flow chart of the method for locating the source of a voltage sag fault in an embodiment of the present application;

[0043] Figure 4 A flowchart for determining a scalar function in an embodiment of the present application;

[0044] Figure 5 This is one of the structural diagrams of the voltage sag fault source location device in the embodiment of the present application;

[0045] Figure 6This is a structural diagram of a vector function determination unit in an embodiment of the present application;

[0046] Figure 7 This is the second structural diagram of the voltage sag fault source location device in the embodiment of the present application;

[0047] Figure 8 This is a structural diagram of a scalar function determination unit in an embodiment of the present application;

[0048] Fig. 9 A schematic diagram of the structure of an electronic device in an embodiment of the present application;

[0049] Fig.10 A schematic diagram of a power system failure in an embodiment of the present application;

[0050] Fig.11 This is one of the schematic diagrams in the embodiment of the present application;

[0051] Fig.12 This is the second schematic diagram in the embodiment of the present application;

[0052] Fig.13 This is the third schematic diagram in the embodiment of the present application. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0054] In one embodiment, see Figure 1 In order to determine the location of the voltage sag fault source by constructing a positive sequence component change ratio function, the present application provides a voltage sag fault source location method, including:

[0055] S101: constructing a positive sequence component change ratio vector function of multiple monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line;

[0056] S102: devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence component variation ratio scalar function corresponding to each monitoring point;

[0057] S103: Generate the location of the voltage sag fault source according to the positive sequence component change ratio scalar function.

[0058] It can be understood that when a short circuit fault occurs at any point F in the power system, the schematic diagram of the short circuit fault is shown in Fig.10As shown. Among them, the fault point F is located on the line connecting node A and node B in the power system, and the transition resistance is R f , the line impedance between node A and node B is Z L Assume that the normalized distances from the fault point F to nodes A and B are λ and (1-λ) respectively, then λ satisfies equation (1)

[0059] λ=L AF / L AB (1)

[0060] Where, L AF is the distance from the first node A to the fault point F; L AB is the line length.

[0061] When a short circuit fault occurs at point F on line AB, voltage drops may occur at nodes near the fault point and even at nodes of different voltage levels. For different types of short circuit faults, the node voltages caused by different fault types are not equal due to the different participation of positive sequence, negative sequence and zero sequence in network parameters. A single-phase short circuit fault contains positive sequence components, negative sequence components and zero sequence components, a two-phase short circuit fault contains positive sequence components, negative sequence components and zero sequence components, a two-phase interphase short circuit fault contains positive sequence components and negative sequence components, and a three-phase short circuit fault contains only positive sequence components due to fault symmetry. When the fault in the power system is all phase A, the expressions of the positive sequence component of phase A voltage and phase A voltage under different types of short circuit faults are:

[0062] In case of single-phase grounding fault:

[0063]

[0064]

[0065] Two-phase short circuit

[0066]

[0067]

[0068] Three-phase short circuit

[0069]

[0070]

[0071] Two-phase ground fault

[0072]

[0073]

[0074] In the formula, is the voltage before the fault at monitoring point M; Z MF is the transfer impedance between the monitoring point M and the fault point F; I F is the short-circuit current at fault point F; is the voltage at the fault point; Z FF is the fault point impedance. If the node voltage amplitude is less than 0.9, it is judged that a voltage sag has occurred.

[0075] Among them, Z MF and Z FF The phase components and sequence components are shown in Table 1.

[0076] Table 1Z MF and Z FF The phase and sequence components

[0077]

[0078] According to equations (2)-(9), if the electrical parameters of the power system remain unchanged, the amplitude of the voltage sag depends on the voltage before the fault at the monitoring point, the voltage before the fault at the fault point, the fault distance, the fault type and the transition resistance, that is, the node voltage is a function of the above five variables.

[0079] Construct the positive sequence voltage change ratio monitoring point information of the two monitoring points as in equation (10). This information is only related to the variable Z MF About Z MF Depends on the electrical parameters of the power system and the fault distance.

[0080]

[0081] The ratio of the positive sequence voltage change between different monitoring points is only related to the transfer matrix from the monitoring point to the fault point. The positive sequence transfer impedance matrix is ​​independent of the fault type and transition resistance. Therefore, the monitoring information of the monitoring point is constructed by the ratio of the positive sequence voltage change between the two monitoring points, and the one-to-one correspondence between the monitoring information of the monitoring point where the fault occurs and the fault distance can be constructed. As long as the monitoring information of the required monitoring point and the line where the fault is located are obtained, the fault location can be accurately located. When a system fault occurs, if the positive sequence voltage change of any two monitoring points can be obtained, the fault distance can be determined.

[0082] Based on the above theory, the voltage sag fault source location method provided by the present application can be divided into the following steps: First, according to the electrical parameters of the power grid, construct the positive sequence component change ratio vector function between the two monitoring points for all the lines in the system, and refer to steps S201 to S203 for details; secondly, if there are two or more voltage sag monitoring devices with phase synchronization function in the system, the positive sequence component change ratio vector function of the two monitoring points can be drawn to preliminarily screen out possible fault lines. In this case, the positive sequence component change ratio vector function between the two monitoring points can be constructed only for the suspected fault line.

[0083] Considering that it is difficult for an actual voltage sag monitoring device to achieve phase synchronization, in this step, the positive sequence component variation ratio vector function between each monitoring point is scalarized, and two positive sequence component variation ratio scalar equations are formed for each line to determine the unique solution of the voltage sag fault source or the fault line set. The specific method is shown in steps S401 to S402. If the voltage sag fault source cannot determine a unique solution in the previous step, a third positive sequence component variation ratio scalar equation is determined for each line in the fault line set, and the equation is solved to obtain the fault distance, and the line consistent with the solution of the fault line set is selected. If the line is unique, the voltage sag fault source Determine; if the line is not unique, define the lines with consistent solutions as the secondary fault line set, and the specific method is shown in steps S301 to S303; finally, add a monitoring point information, define the positive sequence component change ratio scalar equation for the lines in the secondary fault line set, solve the equation to obtain the fault distance, and screen out the lines that are consistent with the solution of the secondary fault line set; if the line is unique, the voltage sag fault source is determined; if the line is not unique, if there are still more than one lines in the fault line set, add the positive sequence component change ratio scalar equation or monitoring point, and continue to solve until the fault line is uniquely determined, and the specific method is shown in steps S301 to S303.

[0084] From the above description, it can be seen that the voltage sag fault source location method provided by the present application can construct a set of equations between the voltage sag fault source and the monitoring point based on the positive sequence voltage component change ratio function, and accurately and uniquely determine the fault distance of the voltage sag source by solving the set of equations, thereby determining the location of the voltage sag source, which is simple to calculate and highly reliable. Subsequently, the voltage sag situation of the entire power grid can be obtained based on the solution results of the voltage sag source location and the electrical parameters of the entire power grid, so that the voltage sag can be observed throughout the entire network, laying the foundation for voltage sag assessment and control.

[0085] In one embodiment, see Figure 2 , the electrical parameters include: impedance parameters and fault distance; the positive sequence component change ratio vector function of multiple monitoring points on the line is constructed according to the electrical parameters of the power grid, including:

[0086] S201: determining an equivalent impedance parameter of the power grid according to the impedance parameter; the equivalent impedance parameter includes an equivalent impedance parameter of each monitoring point from each suspected fault line;

[0087] S202: Determine the positive sequence component change ratio vector function according to the fault distance and the equivalent impedance parameter.

[0088] It is understandable that in order to overcome the problem of difficulty in accurately obtaining the fault type and transition resistance, the positive sequence voltage change is defined according to the sequence component analysis method. When a short circuit fault occurs in a line l in the actual system, the relationship between the positive sequence voltage change and the fault location and system impedance parameters can be defined as:

[0089]

[0090] This formula is the vector function of the positive sequence component change ratio.

[0091] In the formula, and They represent the monitoring point M in the actual system when a short circuit occurs on line l. i With M j Recorded positive sequence voltage change, f Ml,ij (λ) represents the function of fault distance.

[0092] In other words, node l A and node l B are the two ends of line l, monitoring point M i With M j Not on line l, λ is the distance from the fault point to node l B The distance, also called the fault distance, Z Ml,ilA is the monitoring point M i With node l A The positive sequence mutual impedance or positive sequence transfer impedance between Ml,ilB is the monitoring point M i With node l B The positive sequence mutual impedance or positive sequence transfer impedance between Ml,jlA is the monitoring point M j With node l A The positive sequence mutual impedance or positive sequence transfer impedance between Ml,jlB is the monitoring point M j With node l B The positive-sequence mutual impedance or positive-sequence transfer impedance is between them.

[0093] From the above description, it can be seen that the voltage sag fault source locating method provided in the present application can construct a positive sequence component change ratio vector function between two monitoring points for all lines in the system according to the electrical parameters of the power grid.

[0094] In one embodiment, see Figure 3 , the voltage sag fault source location method further includes:

[0095] S301: selecting a voltage sag monitoring point of a phase synchronization function, and drawing a graph to determine the real part and the imaginary part of the positive sequence component variation ratio vector in the positive sequence component variation ratio vector function between the two monitoring points;

[0096] S302: judging whether there are multiple suspected voltage sag fault sources in the power grid according to the real part and the imaginary part;

[0097] S303: If yes, re-set the monitoring point on the suspected fault line, and construct a scalar function of the positive sequence component change ratio of the monitoring point to obtain the location of the voltage sag fault source.

[0098] It can be understood that in S301, if there are two or more voltage sag monitoring points with phase synchronization function, a plot is drawn to determine the real part and imaginary part of the positive sequence component variation ratio vector in the positive sequence component variation ratio vector function between the two monitoring points.

[0099] In a fault line defined according to the voltage sag monitoring point, in the positive sequence voltage change ratio vector function between two monitoring points, the equation (11) about the fault distance has only one fault distance unknown number λ on the surface, but in fact the premise also includes a hypothetical known fault line l. Therefore, when finding the location of the voltage sag fault source, it is necessary to traverse all the lines in the system. However, due to the uncertainty of the electrical parameters of the power grid, the positive sequence voltage change ratio between different nodes caused by faults at different points on different lines may also be equal, resulting in multiple lines and locations that meet the voltage sag fault source.

[0100] The distribution of positive sequence voltage variation ratio is analyzed by taking the IEEE 30-bus power system as an example. Fig.11 As shown in the figure, the number of nodes is 30 and the number of lines is 37.

[0101] Randomly select two monitoring points 3 and 4 as a group, and monitoring points 4 and 25 as a group. When the vector equation is directly solved, the distribution of the positive sequence voltage change ratio vector of the two monitoring points with respect to the fault location (including the fault line and the fault distance) is as follows: Fig.12 and Fig.13 The horizontal and vertical coordinates are the real and imaginary parts of the positive sequence voltage change ratio vector of the two monitoring points. Lines of different colors represent the changes in the real and imaginary parts of the positive sequence voltage change ratio vector as the fault distance λ changes when different lines fail.

[0102] Depend on Fig.12 and Fig.13It can be seen that the positive sequence voltage variation ratio equation between two voltage sag monitoring points defined based on different line faults may have the same solution. Therefore, the sequence voltage variable ratio vector equation determined by the two monitoring points may determine multiple voltage sag fault source locations, that is, there may be pseudo fault points.

[0103] According to the above analysis, if you want to uniquely determine the location of the voltage sag source, you need at least one pair of positive-sequence voltage variable ratio vector equations between two monitoring points. In the case of a pseudo-fault point, multiple pairs of two-by-two voltage sag monitoring points are required to form multiple positive-sequence voltage variable ratio vector equations to further uniquely determine the location of the voltage sag fault source.

[0104] Specifically, if the voltage sag fault source is not uniquely located in the previous step, for each line in the fault line set, the third positive sequence voltage change ratio scalar equation is formed based on equation (14) using the information of two monitoring points, as shown in equation (15).

[0105] a l,jk λ 2 +b l,jk λ+b l,jk =0 (15)

[0106] Where l is the line number in the fault line set.

[0107] The method for determining the above scalar equation is detailed in the description of step S401 to step S402.

[0108] Solve the scalar equation of the positive sequence voltage change ratio of all lines in the fault line set one by one, and check λ l,jk The solution corresponding to the faulty line concentration line λ l,ij If there is only one line l that satisfies λ l,jk =λ l,ij , then the line l and the corresponding solution λ l,jk This is the location of the voltage sag fault source. If there are still multiple lines whose solutions are the same as the solution calculated in step 2, define these lines as the secondary fault line set and record the corresponding solutions.

[0109] Specifically, if the voltage sag fault source is not uniquely located in the previous step, a monitoring point m is added to the line in the secondary fault line concentration, and the fourth positive sequence voltage change ratio scalar equation is defined, as shown in formula (16).

[0110] a l,im λ 2 +b l,im λ+b l,im =0 (16)

[0111] The method for determining the above scalar equation is detailed in the description of step S401 to step S402.

[0112] Traverse the set of secondary fault lines solved in the previous step and solve the scalar equation of the positive sequence component change ratio of equation (16). If there is a unique line whose solution of equation (16) corresponds to the fault distance solved in step 3, the line is determined to be the corresponding fault line and the solution is the corresponding fault distance.

[0113] If the corresponding line-fault distance is still not unique, continue to add the positive sequence component change ratio scalar equation, as shown in equation (17).

[0114]

[0115] Continue to solve the equation and screen the fault line until the fault line and fault distance are uniquely determined.

[0116] The method for determining the above scalar equation is detailed in the description of step S401 to step S402.

[0117] It can be seen from the above description that the voltage sag fault source locating method provided in the present application can determine the location of the voltage sag fault source.

[0118] In one embodiment, see Figure 4 , devectorizing the positive sequence component variation ratio vector function to obtain a scalar function of the positive sequence component variation ratio corresponding to each monitoring point, including:

[0119] S401: Devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence voltage variation ratio;

[0120] S402: constructing a two-variable linear equation according to the positive-sequence voltage change ratio, the real part and the imaginary part as a scalar function of the positive-sequence component change ratio.

[0121] It is understandable that since it is difficult for most voltage sag monitoring devices in actual systems to achieve synchronous phase measurement, the vector equation is difficult to solve, so it is necessary to convert the vector equation into a scalar equation, as shown in equation (12).

[0122]

[0123] In the formula, R 11,ijl for The real part, X 11,ijl for The imaginary part of R 12,ijl =Z M1A -Z M1B ), X 12,ijl for The imaginary part of R21,ijl for The real part, X 21,ijl for The imaginary part of R 22,ijl for The real part, X 22,ijl for The imaginary part of .

[0124] Let the positive sequence voltage change ratio be d, and the scalar equation is:

[0125]

[0126] The solution is:

[0127]

[0128] Define two positive sequence voltage change ratio scalar equations, as shown in equation (14).

[0129]

[0130] Traverse all routes l and solve the two equations for the corresponding routes. If there is only one route l that satisfies λ l,ij =λ l,ik , then the line l and the corresponding solution λ l,ij and λ l,ik That is, the location of the voltage sag fault source. If there are multiple lines that satisfy the same solutions to the two equations, these lines are defined as a fault line set, and the corresponding solutions are recorded. For details, please refer to the description of steps S301 to S303.

[0131] When a short circuit fault occurs in the power system and causes a voltage sag, the method provided in the present application can easily and quickly lock the location of the voltage sag source or narrow the possible locations of the voltage sag source to the maximum extent.

[0132] From the above description, it can be seen that the voltage sag fault source locating method provided in the present application can devectorize the positive-sequence component change ratio vector function to obtain the positive-sequence component change ratio scalar function corresponding to each monitoring point.

[0133] To summarize the above, the embodiments of the present application have the following features:

[0134] ① For all lines in the system, a vector function of the positive sequence component change ratio between any two monitoring points is constructed based on the electrical parameters of the power grid and the monitoring point data.

[0135] ② Considering that it is difficult to achieve phase synchronization in actual voltage sag monitoring devices, the positive-sequence component change ratio vector function between each monitoring point is scalarized, and two positive-sequence component change ratio scalar equations are formed for each suspected fault line or system screened out by vector drawing to determine the unique solution of the voltage sag fault source or the set of fault lines.

[0136] ③ For each line in the fault line set, determine the scalar equation of the third positive sequence component change ratio, solve the equation to obtain the fault distance, and screen out the lines that are consistent with the solution in ②. If the line is unique, the source of the voltage sag fault is determined. If the line is not unique, the lines with consistent solutions are defined as the secondary fault line set.

[0137] ④Add a monitoring point information, define the positive sequence component change ratio scalar equation for the lines in the secondary fault line concentration, solve the equation to obtain the fault distance, and screen out the lines consistent with the solution in ③. If the line is unique, the voltage sag fault source is determined. If the line is not unique, if there are still more than one lines in the fault line concentration, add the positive sequence component change ratio scalar equation or monitoring point, and continue to solve until the fault line is uniquely determined.

[0138] The present invention locates the source of voltage sag caused by a short circuit fault, and can accurately obtain the location of the source of voltage sag by solving analytical equations. The calculation is simple and the reliability is strong, which lays an important foundation for subsequent evaluation and control of voltage sag.

[0139] Based on the same inventive concept, the embodiments of the present application also provide a device for locating a voltage sag fault source, which can be used to implement the method described in the above embodiments, as described in the following embodiments. Since the principle of solving the problem by the device for locating a voltage sag fault source is similar to that of the method for locating a voltage sag fault source, the implementation of the device for locating a voltage sag fault source can refer to the implementation of the method for determining the software performance benchmark, and the repeated parts will not be repeated. As used below, the terms "unit" or "module" can be a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation in hardware, or a combination of software and hardware, is also possible and conceivable.

[0140] In one embodiment, see Figure 5 In order to determine the location of a voltage sag fault source by constructing a positive sequence component variation ratio function, the present application provides a voltage sag fault source locating device, comprising:

[0141] A vector function determination unit 501 is used to construct a positive sequence component change ratio vector function of multiple monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line;

[0142] A scalar function determination unit 502 is used to devectorize the positive sequence component variation ratio vector function to obtain a scalar function of the positive sequence component variation ratio corresponding to each monitoring point;

[0143] The positioning unit 503 is used to generate the location of the voltage sag fault source according to the positive sequence component change ratio scalar function.

[0144] In one embodiment, see Figure 6 , the electrical parameters include: impedance parameters and fault distance; the vector function determination unit 501 includes:

[0145] An equivalent impedance determination module 601 is used to determine an equivalent impedance parameter of the power grid according to the impedance parameter; the equivalent impedance parameter includes an equivalent impedance parameter of each monitoring point from each suspected fault line;

[0146] The vector function determination module 602 is used to determine the positive sequence component variation ratio vector function according to the fault distance and the equivalent impedance parameter.

[0147] In one embodiment, see Figure 7 , the voltage sag fault source locating device further comprises:

[0148] A real and imaginary part determining unit 701 is used for determining the real and imaginary parts of the positive sequence component variation ratio vector in the positive sequence component variation ratio vector function by plotting;

[0149] A suspected fault judgment unit 702 is used to judge whether there are multiple suspected voltage sag fault sources in the power grid according to the real part and the imaginary part;

[0150] The point resetting unit 703 is used to reset the monitoring point on the suspected fault line when there are multiple suspected voltage sag fault sources, and construct a scalar function of the positive sequence component change ratio of the monitoring point to obtain the position of the voltage sag fault source.

[0151] In one embodiment, see Figure 8 , the scalar function determining unit 502 comprises:

[0152] A variation ratio determination module 801 is used to devectorize the positive sequence component variation ratio vector function to obtain a positive sequence voltage variation ratio;

[0153] The scalar function determination module 802 is used to construct a two-variable linear equation according to the positive-sequence voltage change ratio, the real part and the imaginary part as a scalar function of the positive-sequence component change ratio.

[0154] From a hardware perspective, in order to determine the location of a voltage sag fault source by constructing a positive sequence component variation ratio function, the present application provides an embodiment of an electronic device for implementing all or part of the contents of the voltage sag fault source location method, and the electronic device specifically includes the following contents:

[0155] Processor, memory, communication interface and bus; wherein the processor, memory and communication interface communicate with each other through the bus; the communication interface is used to realize information transmission between the voltage sag fault source locating device and related devices such as core business systems, user terminals and related databases; the logic controller can be a desktop computer, a tablet computer and a mobile terminal, etc., but the present embodiment is not limited thereto. In the present embodiment, the logic controller can be implemented with reference to the embodiment of the voltage sag fault source locating method and the embodiment of the voltage sag fault source locating device in the embodiment, and the contents thereof are incorporated herein, and the repeated parts are not repeated.

[0156] It is understandable that the user terminal may include a smart phone, a tablet electronic device, a network set-top box, a portable computer, a desktop computer, a personal digital assistant (PDA), a vehicle-mounted device, a smart wearable device, etc. Among them, the smart wearable device may include smart glasses, a smart watch, a smart bracelet, etc.

[0157] In practical applications, part of the voltage sag fault source location method can be performed on the electronic device side as described above, or all operations can be completed in the client device. The specific selection can be based on the processing capability of the client device and the limitations of the user's usage scenario. This application does not limit this. If all operations are completed in the client device, the client device may also include a processor.

[0158] The client device may have a communication module (i.e., a communication unit) that can communicate with a remote server to achieve data transmission with the server. The server may include a server on the task scheduling center side, and other implementation scenarios may also include a server on an intermediate platform, such as a server on a third-party server platform that has a communication link with the task scheduling center server. The server may include a single computer device, or a server cluster consisting of multiple servers, or a server structure of a distributed device.

[0159] Fig. 9 FIG. 9 is a schematic block diagram of the system structure of the electronic device 9600 according to an embodiment of the present application. Fig. 9As shown, the electronic device 9600 may include a central processor 9100 and a memory 9140; the memory 9140 is coupled to the central processor 9100. It is worth noting that Fig. 9 is exemplary; other types of structures may also be used to supplement or replace this structure to implement telecommunication functions or other functions.

[0160] In one embodiment, the voltage sag fault source location method function may be integrated into the central processor 9100. The central processor 9100 may be configured to perform the following control:

[0161] S101: constructing a positive sequence component change ratio vector function of multiple monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line;

[0162] S102: devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence component variation ratio scalar function corresponding to each monitoring point;

[0163] S103: Generate the location of the voltage sag fault source according to the positive sequence component change ratio scalar function.

[0164] From the above description, it can be seen that the voltage sag fault source location method provided by the present application can construct a set of equations between the voltage sag fault source and the monitoring point based on the positive sequence voltage component change ratio function, and accurately and uniquely determine the fault distance of the voltage sag source by solving the set of equations, thereby determining the location of the voltage sag source, which is simple to calculate and highly reliable. Subsequently, the voltage sag situation of the entire power grid can be obtained based on the solution results of the voltage sag source location and the electrical parameters of the entire power grid, so that the voltage sag can be observed throughout the entire network, laying the foundation for voltage sag assessment and control.

[0165] In another embodiment, the voltage sag fault source locating device can be configured separately from the central processing unit 9100. For example, the data composite transmission device voltage sag fault source locating device can be configured as a chip connected to the central processing unit 9100, and the function of the voltage sag fault source locating method can be implemented through the control of the central processing unit.

[0166] like Fig. 9 As shown, the electronic device 9600 may also include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It is worth noting that the electronic device 9600 does not necessarily have to include Fig. 9 In addition, the electronic device 9600 may also include Fig. 9 For components not shown, reference may be made to the prior art.

[0167] like Fig. 9As shown, the central processing unit 9100 is sometimes also referred to as a controller or an operation control, and may include a microprocessor or other processor device and / or logic device. The central processing unit 9100 receives input and controls the operation of various components of the electronic device 9600.

[0168] The memory 9140 may be, for example, one or more of a cache, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory or other suitable devices. The above-mentioned information related to the failure may be stored, and a program for executing the relevant information may also be stored. The CPU 9100 may execute the program stored in the memory 9140 to implement information storage or processing, etc.

[0169] The input unit 9120 provides input to the central processing unit 9100. The input unit 9120 is, for example, a key or a touch input device. The power supply 9170 is used to provide power to the electronic device 9600. The display 9160 is used to display display objects such as images and texts. The display may be, for example, an LCD display, but is not limited thereto.

[0170] The memory 9140 may be a solid-state memory, such as a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It may also be a memory that saves information even when the power is off, can be selectively erased, and is provided with more data, examples of which are sometimes referred to as EPROMs, etc. The memory 9140 may also be some other type of device. The memory 9140 includes a buffer memory 9141 (sometimes referred to as a buffer). The memory 9140 may include an application / function storage unit 9142, which is used to store application programs and function programs or processes for executing the operation of the electronic device 9600 through the central processor 9100.

[0171] The memory 9140 may also include a data storage unit 9143 for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 9144 of the memory 9140 may include various drivers for communication functions of the electronic device and / or for executing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0172] The communication module 9110 is a transmitter / receiver 9110 that sends and receives signals via an antenna 9111. The communication module (transmitter / receiver) 9110 is coupled to the central processor 9100 to provide input signals and receive output signals, which may be the same as the case of a conventional mobile communication terminal.

[0173] Based on different communication technologies, multiple communication modules 9110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module and / or a wireless LAN module. The communication module (transmitter / receiver) 9110 is also coupled to a speaker 9131 and a microphone 9132 via an audio processor 9130 to provide an audio output via the speaker 9131 and receive an audio input from the microphone 9132, thereby realizing a common telecommunication function. The audio processor 9130 may include any suitable buffer, decoder, amplifier, etc. In addition, the audio processor 9130 is also coupled to the central processor 9100, so that recording can be performed on the local machine through the microphone 9132, and the sound stored on the local machine can be played through the speaker 9131.

[0174] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all the steps of the method for locating a voltage sag fault source in the above embodiment, where the execution subject is a server or a client. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, all the steps of the method for locating a voltage sag fault source in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0175] S101: constructing a positive sequence component change ratio vector function of multiple monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line;

[0176] S102: devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence component variation ratio scalar function corresponding to each monitoring point;

[0177] S103: Generate the location of the voltage sag fault source according to the positive sequence component change ratio scalar function.

[0178] From the above description, it can be seen that the voltage sag fault source location method provided by the present application can construct a set of equations between the voltage sag fault source and the monitoring point based on the positive sequence voltage component change ratio function, and accurately and uniquely determine the fault distance of the voltage sag source by solving the set of equations, thereby determining the location of the voltage sag source, which is simple to calculate and highly reliable. Subsequently, the voltage sag situation of the entire power grid can be obtained based on the solution results of the voltage sag source location and the electrical parameters of the entire power grid, so that the voltage sag can be observed throughout the entire network, laying the foundation for voltage sag assessment and control.

[0179] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented 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.

[0180] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (apparatus), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0181] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0182] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0183] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for locating a voltage sag fault source, characterized in that: include: Constructing a positive sequence component variation ratio vector function of a plurality of monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line; Devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence component variation ratio scalar function corresponding to each monitoring point; Generating the location of the voltage sag fault source according to the positive sequence component variation ratio scalar function; The method further includes: selecting a voltage sag monitoring point with a phase synchronization function, drawing a graph to determine the real part and imaginary part of the positive sequence component variation ratio vector in the positive sequence component variation ratio vector function between two voltage sag monitoring points with a phase synchronization function; judging whether there are multiple suspected voltage sag fault sources in the power grid according to the real part and the imaginary part; If it exists, a monitoring point is re-set on the suspected fault line, and a scalar function of the positive sequence component change ratio of the monitoring point is constructed to obtain the location of the voltage sag fault source.

2. The method for locating a voltage sag fault source according to claim 1, characterized in that: The electrical parameters include: impedance parameters and fault distance; the positive sequence component change ratio vector function of multiple monitoring points on the line is constructed according to the electrical parameters of the power grid, including: Determining an equivalent impedance parameter of the power grid according to the impedance parameter; the equivalent impedance parameter includes an equivalent impedance parameter of each monitoring point from each suspected fault line; The positive sequence component variation ratio vector function is determined according to the fault distance and the equivalent impedance parameter.

3. The method for locating a voltage sag fault source according to claim 1, characterized in that: Devectorizing the positive sequence component variation ratio vector function to obtain a scalar function of the positive sequence component variation ratio corresponding to each monitoring point includes: Devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence voltage variation ratio; A two-variable linear equation is constructed according to the positive-sequence voltage variation ratio, the real part and the imaginary part as a scalar function of the positive-sequence component variation ratio.

4. A voltage sag fault source location device, characterized in that: include: A vector function determination unit, used to construct a positive sequence component change ratio vector function of multiple monitoring points on a line according to electrical parameters of the power grid; the line includes each suspected fault line; A scalar function determination unit, used for devectorizing the positive sequence component variation ratio vector function to obtain a scalar function of the positive sequence component variation ratio corresponding to each monitoring point; A positioning unit, used for generating the location of the voltage sag fault source according to the positive sequence component variation ratio scalar function; The device further comprises: A real and imaginary part determination unit, used for selecting a voltage sag monitoring point with a phase synchronization function, and determining by drawing a graph the real and imaginary parts of the positive sequence component variation ratio vector in the positive sequence component variation ratio vector function between two voltage sag monitoring points with a phase synchronization function; A suspected fault judgment unit, used for judging whether there are multiple suspected voltage sag fault sources in the power grid according to the real part and the imaginary part; The point resetting unit is used to reset the monitoring point on the suspected fault line when there are multiple suspected voltage sag fault sources, and construct a scalar function of the positive sequence component change ratio of the monitoring point to obtain the position of the voltage sag fault source.

5. The voltage sag fault source location device according to claim 4, characterized in that: The electrical parameters include: impedance parameters and fault distance; the vector function determination unit includes: An equivalent impedance determination module, used to determine the equivalent impedance parameters of the power grid according to the impedance parameters; the equivalent impedance parameters include the equivalent impedance parameters of each monitoring point from each suspected fault line; A vector function determination module is used to determine the positive sequence component change ratio vector function according to the fault distance and the equivalent impedance parameter.

6. The voltage sag fault source location device according to claim 4, characterized in that: The scalar function determination unit comprises: A variation ratio determination module, used for devectorizing the positive sequence component variation ratio vector function to obtain a positive sequence voltage variation ratio; The scalar function determination module is used to construct a binary linear equation according to the positive sequence voltage variation ratio, the real part and the imaginary part as a scalar function of the positive sequence component variation ratio.

7. An electronic 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 program, the steps of the method for locating the voltage sag fault source according to any one of claims 1 to 3 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for locating a voltage sag fault source as claimed in any one of claims 1 to 3 are implemented.

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