A method and system for fault location

Abstract

The application provides a fault positioning method and system, the method is applied to a four-terminal transmission line, one end of a fifth branch of the four-terminal transmission line is connected to a first node with a first branch and a second branch, the other end of the fifth branch is connected to a second node with a third branch and a fourth branch, the method comprises the following steps: acquiring positive sequence values corresponding to the first branch to the fourth branch respectively; determining operation calculation values corresponding to the first branch to the fourth branch, the first node and the second node respectively based on the positive sequence values of the first branch to the fourth branch, a commissioning control value and a line impedance value; determining fault positioning values corresponding to the first branch to the fifth branch respectively through a fault positioning calculation formula based on the operation calculation values of the first branch to the fourth branch, the first node and the second node, the commissioning control value and the line impedance value; determining a minimum fault positioning value based on each fault positioning value; determining a fault position based on the value range of the minimum fault positioning value, and the processing efficiency of the power fault is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power systems, and particularly relates to a fault positioning method and system. BACKGROUND

[0002] At present, four-terminal transmission lines have the characteristics of low cost and flexible operation mode, and gradually become an important way of distributed power supply access to the power grid. Four-terminal transmission lines involve five line sections, and have various operation modes. When a fault occurs in the line, the fault point needs to be accurately positioned as soon as possible so as to reduce the fault checking and power supply recovery time. The prior art adopts a double-end distance measurement and a three-terminal distance measurement method to position the line fault, which can only be used for fixed operation modes and is not suitable for the operation mode of four-terminal transmission lines.

[0003] The fault positioning method of the prior art cannot accurately position the fault of the four-terminal transmission line. SUMMARY

[0004] The application embodiment provides a fault positioning method and system, which can solve the problem that the fault of the four-terminal transmission line cannot be accurately positioned.

[0005] In a first aspect, the application embodiment provides a fault positioning method applied to a four-terminal transmission line, the four-terminal transmission line including a first branch, a second branch, a third branch, a fourth branch and a fifth branch, wherein one end of the fifth branch is connected to the first branch and the second branch at a first node, and the other end of the fifth branch is connected to the third branch and the fourth branch at a second node, and the method includes:

[0006] Respective positive sequence values of the first branch, the second branch, the third branch and the fourth branch are acquired;

[0007] Respective operation calculation values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node are determined based on the positive sequence values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch;

[0008] Respective fault positioning values of the first branch, the second branch, the third branch, the fourth branch and the fifth branch are determined through a fault positioning calculation formula based on the operation calculation values, operation control values and line impedance values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node;

[0009] A minimum fault positioning value is determined based on the respective fault positioning values;

[0010] The fault location is determined based on the value range of the minimum fault location value.

[0011] In one embodiment, determining the operation calculation values ​​corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node, and the second node respectively based on the positive sequence values, the commissioning control values, and the line impedance values ​​of the first branch, the second branch, the third branch, and the fourth branch includes:

[0012] Based on the positive sequence values, operation control values, and line impedance values ​​of the first branch, the second branch, the third branch, and the fourth branch, respectively, determining the operation calculation values ​​corresponding to the first branch, the second branch, the third branch, and the fourth branch using a branch operation calculation formula;

[0013] Based on the positive sequence values ​​of the first branch, the second branch, the third branch and the fourth branch, the operation calculation values ​​corresponding to the first node and the second node are respectively determined through a node operation calculation formula.

[0014] In one embodiment, the operation calculation value includes an operation calculation voltage value and an operation calculation current value, the branch operation calculation formula includes a branch operation calculation voltage value calculation formula and a branch operation calculation current value calculation formula, and the positive sequence value includes a positive sequence voltage value and a positive sequence current value;

[0015] The determining of the operation calculation values ​​corresponding to the first branch, the second branch, the third branch, and the fourth branch respectively based on the positive sequence values, the operation control values, and the line impedance values ​​of the first branch, the second branch, the third branch, and the fourth branch by using branch operation calculation formulas includes:

[0016] The operation calculated voltage values ​​corresponding to the first branch, the second branch, the third branch and the fourth branch are determined respectively by using a branch operation calculated voltage value calculation formula based on the positive sequence voltage values, the operation control value and the line impedance value of the first branch, the second branch, the third branch and the fourth branch;

[0017] Based on the positive sequence current value and operation control value of the first branch, the second branch, the third branch and the fourth branch, the operation calculation current values ​​corresponding to the first branch, the second branch, the third branch and the fourth branch are respectively determined by the branch operation calculation current value calculation formula.

[0018] In one embodiment, the branch circuit operation voltage value is calculated as follows:

[0019] U yL_ =β L_iX(U L_i +I L_i XZ L_i )

[0020] wherein, U yL_ is the operation calculation voltage value of the i-th branch, i is 1, 2, 3 or 4;

[0021] β L_i is the operation control value of the i-th branch;

[0022] U L_i is the positive sequence voltage value of the i-th branch;

[0023] I L_i is the positive sequence current value of the i-th branch;

[0024] Z L_i is the line impedance value of the i-th branch;

[0025] The branch operation calculation current value calculation formula is:

[0026] I yL_ = β L_i X I L_i

[0027] wherein, I yL_ is the operation calculation current value of the i-th branch, i is 1, 2, 3 or 4;

[0028] β L_i is the operation control value of the i-th branch;

[0029] I L_i is the positive sequence current value of the i-th branch.

[0030] In one of the embodiments, the node operation calculation formula comprises a node operation calculation voltage value calculation formula and a node operation calculation current value calculation formula;

[0031] The node operation calculation voltage value calculation formula is:

[0032]

[0033] wherein, U yT is the node operation calculation voltage value;

[0034] U yL_ is the operation calculation voltage value of the i-th branch, i is 1 or 3;

[0035] U L_i+1 is the operation calculation voltage value of the i+1-th branch;

[0036] β L_i is the operation control value of the i-th branch;

[0037] β L_i+1 is the operation and calculation value of the i+1th branch;

[0038] The node operation and calculation current value calculation formula is:

[0039] I yT = I yL_i + I yL_i+1

[0040] Wherein, I yT is the node operation and calculation current value;

[0041] I yL_i is the operation and calculation current value of the i th branch, i is 1 or 3;

[0042] I yL_i+1 is the operation and calculation current value of the i+1th branch.

[0043] In one of the embodiments, the fault location calculation formula includes a first fault location calculation formula, a second fault location calculation formula, a third fault location calculation formula, a fourth fault location calculation formula and a fifth fault location calculation formula, and the operation and calculation value includes an operation and calculation voltage value and an operation and calculation current value;

[0044] Based on the operation and calculation value, the operation and control value and the line impedance value of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node, the fault location value corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch is determined by a fault location calculation formula, including:

[0045] Based on the operation and calculation voltage value and the line impedance value of the first branch, the operation and calculation value and the operation and control value of the second branch, the line impedance value of the fifth branch, the operation and current value of the first node and the operation and calculation value and the operation and control value of the second node, the fault location value of the first branch is determined by the first fault location calculation formula;

[0046] Based on the operation and calculation voltage value and the line impedance value of the second branch, the operation and calculation value and the operation and control value of the first branch, the line impedance value of the fifth branch, the operation and current value of the first node and the operation and calculation value and the operation and control value of the second node, the fault location value of the second branch is determined by the second fault location calculation formula;

[0047] The third fault location value of the third branch is determined by the third fault location calculation formula based on the operating calculation voltage value and line impedance value of the third branch, the operating calculation value and operation control value of the fourth branch, the line impedance value of the fifth branch, the operating current value of the second node, and the operating calculation value and operation control value of the first node;

[0048] The fourth fault location value of the fourth branch is determined by the fourth fault location calculation formula based on the operating calculation voltage value and line impedance value of the fourth branch, the operating calculation value and operation control value of the third branch, the line impedance value of the fifth branch, the operating current value of the second node, and the operating calculation value and operation control value of the first node;

[0049] The fifth fault location value of the fifth branch is obtained by the fifth fault location calculation formula based on the operating calculation value of the first node, the operating calculation value of the second node, and the line impedance value of the fifth branch.

[0050] In one of the embodiments, the first fault location calculation formula is:

[0051]

[0052] wherein, α L_1 is the first fault location value of the first branch;

[0053] U yL_1 is the operating calculation voltage value of the first branch;

[0054] Z L1 is the line impedance value of the first branch;

[0055] β L_2 is the operation control value of the second branch;

[0056] U yL_2 is the operating calculation voltage value of the second branch;

[0057] I yL_2 is the operating calculation current value of the second branch;

[0058] I yT1 is the operating calculation current value of the first node;

[0059] β T2 is the operation control value of the second node;

[0060] U yT2 is the operating calculation voltage value of the second node;

[0061] I yT2 is the operating calculation current value of the second node;

[0062] Z L5 a line impedance value of the fifth branch;

[0063] the second fault location calculation formula is:

[0064]

[0065] wherein, alpha L_2 a fault location value of the second branch; U yL_2 a running calculation voltage value of the second branch; Z L2 a line impedance value of the second branch;

[0066] beta L_1 a commissioning control value of the first branch;

[0067] U yL_1 a running calculation voltage value of the first branch; I yL_1 a running calculation current value of the first branch; I yT1 a running calculation current value of the first node; beta T2 a commissioning control value of the second node;

[0068] U yT2 a running calculation voltage value of the second node; I yT2 a running calculation current value of the second node; Z L5 a line impedance value of the fifth branch;

[0069] the third fault location calculation formula is:

[0070]

[0071] wherein, alpha L_3 a fault location value of the third branch; U yL_3 a running calculation voltage value of the third branch; Z L3 a line impedance value of the third branch;

[0072] beta L_4 a commissioning control value of the fourth branch;

[0073] U yL_4 a running calculation voltage value of the fourth branch; I yL_4 a running calculation current value of the fourth branch; I yT2 a running calculation current value of the second node; beta T1 a commissioning control value of the first node;

[0074] U yT1a running calculation voltage value for the first node;I yT1 a running calculation current value for the first node;Z L5 a line impedance value for the fifth branch;

[0075] The fourth fault location calculation formula is:

[0076]

[0077] wherein, α L_4 a fault location value for the fourth branch;

[0078] U yL_4 a running calculation voltage value for the fourth branch;

[0079] Z L4 a line impedance value for the fourth branch;

[0080] β L_3 a commissioning control value for the third branch;

[0081] U yL_3 a running calculation voltage value for the third branch;

[0082] I yL_3 a running calculation current value for the third branch;

[0083] I yT2 a running calculation current value for the second node;

[0084] β T1 a commissioning control value for the first node;

[0085] U yT1 a running calculation voltage value for the first node;

[0086] I yT1 a running calculation current value for the first node;

[0087] Z L5 a line impedance value for the fifth branch;

[0088] The fifth fault location calculation formula is:

[0089]

[0090] wherein, α L_5 a fault location value for the fifth branch;

[0091] U yT1 a running calculation voltage value for the first node;

[0092] I yT1calculating a voltage value for the operation of the first node;

[0093] U yT2 calculating a voltage value for the operation of the second node;

[0094] I yT2 calculating a current value for the operation of the second node;

[0095] Z L5 calculating a line impedance value for the fifth branch.

[0096] In one of the embodiments, the determining the minimum fault location value based on the fault location values comprises:

[0097] determining effective fault location values based on the fault location values of the first branch, the second branch, the third branch and the fourth branch;

[0098] determining the minimum fault location value based on the effective fault location values.

[0099] In one of the embodiments, the determining the effective fault location values based on the fault location values of the first branch, the second branch, the third branch and the fourth branch comprises:

[0100] determining the in-service control values of the first branch, the second branch, the third branch and the fourth branch;

[0101] if the in-service control value of a branch is 1, the fault location value corresponding to the branch is a first fault location value;

[0102] if the in-service control value of a branch is 0, the fault location value corresponding to the branch is a second fault location value;

[0103] wherein the first fault location value is an effective fault location value and the second fault location value is an ineffective fault location value.

[0104] In a second aspect, the embodiments of the present application provide a system for fault location, which comprises a fault location device for executing any of the methods for fault location in the first aspect.

[0105] It can be understood that the beneficial effects of the second aspect can be referred to the related description in the first aspect, which will not be repeated here.

[0106] The beneficial effects of the embodiments of the present application compared with the prior art are:

[0107] The method for fault positioning provided in the application is applied to a four-terminal transmission line, the four-terminal transmission line comprising a first branch, a second branch, a third branch, a fourth branch and a fifth branch, wherein one end of the fifth branch is connected to the first branch and the second branch at a first node, and the other end of the fifth branch is connected to the third branch and the fourth branch at a second node, the method comprising: obtaining positive sequence values corresponding to the first branch, the second branch, the third branch and the fourth branch respectively; determining operation calculation values corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node and the second node respectively based on the positive sequence values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch; determining fault positioning values corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch respectively based on the operation calculation values, the operation control values and the line impedance values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node through a fault positioning calculation formula; determining a minimum fault positioning value based on the fault positioning values; and determining a fault position based on a value range of the minimum fault positioning value. Since the fault positioning calculation formula is used to obtain the fault positioning values, the complexity of fault positioning of the four-terminal transmission line is reduced, and the complexity of fault positioning is further reduced and the accuracy of fault positioning is further improved by determining the fault position through the value range of the minimum fault positioning value. BRIEF DESCRIPTION OF DRAWINGS

[0108] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0109] Figure 1 is a schematic diagram of a four-terminal transmission line structure provided by an embodiment of the present application;

[0110] Figure 2 is a flowchart of a method for fault positioning provided by an embodiment of the present application;

[0111] Figure 3 is a flowchart of determining operation calculation values corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node and the second node respectively based on the positive sequence values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch provided by another embodiment of the present application;

[0112] Figure 4is a flowchart of a process provided by another embodiment of the application for determining operation calculation values corresponding to the first branch, the second branch, the third branch and the fourth branch based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch through a branch operation calculation formula;

[0113] Figure 5 is a flowchart of a process provided by another embodiment of the application for determining fault location values corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch based on the operation calculation values, the operation control values and the line impedance values of the first branch, the second branch, the third branch, the fourth branch and the fifth branch through a fault location calculation formula;

[0114] Figure 6 is a flowchart of a process provided by another embodiment of the application for determining a minimum fault location value based on the fault location values;

[0115] Figure 7 is a flowchart of a process provided by another embodiment of the application for determining an effective fault location value based on the fault location values of the first branch, the second branch, the third branch and the fourth branch. DETAILED DESCRIPTION

[0116] In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc., in order to provide a thorough understanding of the embodiments of the application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the application with unnecessary detail.

[0117] It should be understood that the term "comprises" when used in this specification and the appended claims, specifies the presence of stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0118] It should also be understood that the term "and / or" when used in this specification and the appended claims, means any one or more of the associated listed items can be present, and includes multiples of those items that can be present.

[0119] In addition, it should be understood that the terms "first", "second", "third", etc., when used in this specification and the appended claims, are used to distinguish between different features, and are not to be construed as indicating or implying relative importance.

[0120] Reference to "one embodiment" or "some embodiments" or "an embodiment" or "some embodiments" etc. in the present application description means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrases "in one embodiment" or "in some embodiments" or "in other embodiments" or "in additional embodiments" etc. in various places in the description are not necessarily all referring to the same embodiment, although the phrases can be so referred to. The terms "including", "comprising", "having" and their variants mean "including but not limited to", unless otherwise expressly specified.

[0121] The four-terminal transmission line has the characteristics of low cost and flexible operation mode, and gradually becomes an important way for distributed power supply to access the power grid. The four-terminal transmission line involves five line sections and has various operation modes. When a power fault occurs in the four-terminal transmission line, the fault point needs to be quickly and accurately located so as to reduce the time for troubleshooting and restoring power supply.

[0122] However, the prior art uses the double-end distance measurement and three-terminal distance measurement methods to locate the line fault, which can only be used for fixed operation modes and is not suitable for the operation mode of the four-terminal transmission line. The existing fault location method cannot accurately locate the fault of the four-terminal transmission line.

[0123] The fault location method of the application is applied to a four-terminal transmission line, which includes a first branch, a second branch, a third branch, a fourth branch and a fifth branch. One end of the fifth branch is connected to the first branch and the second branch at a first node, and the other end of the fifth branch is connected to the third branch and the fourth branch at a second node. The method includes: obtaining the positive sequence values of the first branch, the second branch, the third branch and the fourth branch respectively; determining the operation calculation values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch; determining the fault location values of the first branch, the second branch, the third branch, the fourth branch and the fifth branch based on the operation calculation values, the operation control values and the line impedance values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node through a fault location calculation formula; determining the minimum fault location value based on the fault location values; and determining the fault location based on the value range of the minimum fault location value. Since the fault location calculation formula is used to obtain the fault location value, the complexity of fault location of the four-terminal transmission line is reduced. The fault location is further determined by the value range of the minimum fault location value, which further reduces the complexity of fault location and further improves the accuracy of fault location, reduces the time for troubleshooting and restoring power supply, and improves the efficiency of power fault handling.

[0124] The technical solutions of the present application are described below through specific embodiments.

[0125] In a first aspect, the present embodiment provides a fault location method, applied to a four-terminal transmission line, as shown in the following figure. Figure 1 As shown in the figure, the four-terminal transmission line includes a first branch, a second branch, a third branch, a fourth branch, and a fifth branch. One end of the fifth branch is connected to the first branch and the second branch at a first node, and the other end of the fifth branch is connected to the third branch and the fourth branch at a second node.

[0126] As shown in the figure, the fault location method includes: Figure 2

[0127] S100, respectively acquiring positive sequence values corresponding to the first branch, the second branch, the third branch, and the fourth branch.

[0128] In one embodiment, the positive sequence values include positive sequence voltage values and positive sequence current values.

[0129] In one embodiment, the fault location master is installed on the first branch, and the fault location slaves are installed on the second branch, the third branch, and the fourth branch. The fault location master and the fault location slaves acquire the positive sequence voltage values and the positive sequence current values of each branch.

[0130] S200, based on the positive sequence values of the first branch, the second branch, the third branch, and the fourth branch, the operation control values, and the line impedance values, respectively determining operation calculation values corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node, and the second node.

[0131] In one embodiment, based on the positive sequence values of the first branch, the second branch, the third branch, and the fourth branch, the operation control values, and the line impedance values, respectively determining operation calculation values corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node, and the second node, thereby obtaining operation information, facilitating fault location.

[0132] In one embodiment, the operation control values of the first branch, the second branch, the third branch, and the fourth branch are set according to their respective operation states. The operation control value of the first node is determined according to the operation control values of the first branch and the second branch using the OR logic. The operation control value of the second node is determined according to the operation control values of the third branch and the fourth branch using the OR logic. The operation control values of each branch and each node are 1 for operation and 0 for shutdown.

[0133] In one embodiment, as shown in the figure, the fault location method includes: Figure 3 ​As shown, based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch, operation calculation values corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node and the second node are determined respectively, including:

[0134] In one embodiment, based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch, operation calculation values corresponding to the first branch, the second branch, the third branch and the fourth branch are determined respectively by the branch operation calculation formula.

[0135] In one embodiment, based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch, operation calculation values corresponding to the first branch, the second branch, the third branch and the fourth branch are determined respectively by the branch operation calculation formula, which facilitates obtaining fault location according to the operation calculation values of the branches and is conducive to improving the accuracy of fault location.

[0136] In one embodiment, the operation calculation values include operation calculation voltage values and operation calculation current values, and the branch operation calculation formula includes a branch operation calculation voltage value calculation formula and a branch operation calculation current value calculation formula.

[0137] In one embodiment, as shown, based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch, operation calculation values corresponding to the first branch, the second branch, the third branch and the fourth branch are determined respectively by the branch operation calculation formula, including: Figure 4

[0138] S211, based on the positive sequence voltage values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch, operation calculation voltage values corresponding to the first branch, the second branch, the third branch and the fourth branch are determined respectively by the branch operation calculation voltage value calculation formula.

[0139] In one embodiment, the branch operation calculation voltage value calculation formula is:

[0140] U yL_i = β L_i × (U L_i + I L_i × Z L_i )

[0141] Wherein, U yL_i is the operation calculation voltage value of the i-th branch, i takes the value of 1, 2, 3 or 4;

[0142] β L_i is the operation control value of the i-th branch;

[0143] U L_i ​a positive sequence voltage value of the i-th branch;

[0144] I L_i a positive sequence current value of the i-th branch;

[0145] Z L_i a line impedance value of the i-th branch.

[0146] S212, based on the positive sequence current values of the first branch, the second branch, the third branch and the fourth branch and the operation control value, determines the operation calculation current values corresponding to the first branch, the second branch, the third branch and the fourth branch respectively by a branch operation calculation current value calculation formula.

[0147] In one embodiment, the branch operation calculation current value calculation formula is:

[0148] I yL_i = β L_i × I L_i

[0149] wherein I yL_i is an operation calculation current value of the i-th branch, i is 1, 2, 3 or 4;

[0150] β L_i is an operation control value of the i-th branch;

[0151] I L_i is a positive sequence current value of the i-th branch.

[0152] S220, based on the positive sequence values of the first branch, the second branch, the third branch and the fourth branch, determines the operation calculation values corresponding to the first node and the second node respectively by a node operation calculation formula.

[0153] In one embodiment, based on the positive sequence values of the first branch, the second branch, the third branch and the fourth branch, the operation calculation values corresponding to the first node and the second node are determined respectively by the node operation calculation formula, which facilitates obtaining the fault location according to the operation calculation values of the nodes and is conducive to improving the accuracy of fault location.

[0154] In one embodiment, the node operation calculation formula includes a node operation calculation voltage value calculation formula and a node operation calculation current value calculation formula.

[0155] In one embodiment, the node operation calculation voltage value calculation formula is:

[0156]

[0157] wherein U yT is a node operation calculation voltage value;

[0158] U yL_iThe running calculation voltage value for the i-th branch, i being 1 or 3;

[0159] U yL_i+1 The running calculation voltage value for the i+1-th branch;

[0160] β L_i The running control value for the i-th branch;

[0161] β L_i+1 The running control value for the i+1-th branch;

[0162] In one embodiment, the node running calculation current value calculation formula is:

[0163] I yT = I yL_i + I yL_i+1

[0164] wherein I yT is the node running calculation current value;

[0165] I yL_i is the running calculation current value for the i-th branch, i being 1 or 3;

[0166] I yL_i+1 is the running calculation current value for the i+1-th branch.

[0167] In one embodiment, the first node running calculation voltage value calculation formula is:

[0168]

[0169] wherein U yT1 is the first node running calculation voltage value;

[0170] U yL_1 is the running calculation voltage value for the first branch;

[0171] U yL_2 is the running calculation voltage value for the second branch;

[0172] β L_1 is the running control value for the first branch;

[0173] β L_2 is the running control value for the second branch;

[0174] The first node running calculation current value calculation formula is:

[0175] I yT1 = I yL_1 + I yL_2

[0176] wherein I yT1 is the first node running calculation current value;

[0177] I yL_1 calculating the current value for the operation of the first branch;

[0178] I yL_2 calculating the current value for the operation of the second branch.

[0179] S300, based on the operation calculation value, the operation control value and the line impedance value of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node, determining the fault location value corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch through the fault location calculation formula respectively.

[0180] In one embodiment, based on the operation calculation value, the operation control value and the line impedance value of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node, the fault location value corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch is determined through the fault location calculation formula respectively, since the fault location value of each branch is introduced, the fault location calculation formula is simplified, the calculation amount of fault location is reduced, and the complexity of fault location is reduced, thereby reducing the time of power fault troubleshooting and power restoration and improving the processing efficiency of power fault.

[0181] In one embodiment, the fault location calculation formula includes a first fault location calculation formula, a second fault location calculation formula, a third fault location calculation formula, a fourth fault location calculation formula and a fifth fault location calculation formula.

[0182] In one embodiment, as shown in Figure 5 based on the operation calculation value, the operation control value and the line impedance value of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node, the fault location value corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch is determined through the fault location calculation formula respectively, including:

[0183] S310, based on the operation calculation voltage value and the line impedance value of the first branch, the operation calculation value and the operation control value of the second branch, the line impedance value of the fifth branch, the operation current value of the first node and the operation calculation value and the operation control value of the second node, the fault location value of the first branch is determined through the first fault location calculation formula.

[0184] In one embodiment, the first fault location calculation formula is:

[0185]

[0186] wherein, α L_1 is the fault location value of the first branch;

[0187] U yL_1a running calculation voltage value for the first branch;

[0188] Z L1 a line impedance value for the first branch;

[0189] β L_2 a running control value for the second branch;

[0190] U yL_2 a running calculation voltage value for the second branch;

[0191] I yL_2 a running calculation current value for the second branch;

[0192] I yT1 a running calculation current value for the first node;

[0193] β T2 a running control value for the second node;

[0194] U yT2 a running calculation voltage value for the second node;

[0195] I yT2 a running calculation current value for the second node;

[0196] Z L5 a line impedance value for the fifth branch.

[0197] S320, determining a fault location value of the second branch by a second fault location calculation formula based on the running calculation voltage value and the line impedance value of the second branch, the running calculation value and the running control value of the first branch, the line impedance value of the fifth branch, the running current value of the first node and the running calculation value and the running control value of the second node.

[0198] In one embodiment, the second fault location calculation formula is:

[0199]

[0200] wherein α L_2 a fault location value of the second branch;

[0201] U yL_2 a running calculation voltage value for the second branch;

[0202] Z L2 a line impedance value for the second branch;

[0203] β L_1 a running control value for the first branch;

[0204] U yL_1 a running calculation voltage value for the first branch;

[0205] I yL_1 calculating the current value for the operation of the first branch;

[0206] I yT1 calculating the current value for the operation of the first node;

[0207] β T2 the commissioning control value for the second node;

[0208] U yT2 calculating the voltage value for the operation of the second node;

[0209] I yT2 calculating the current value for the operation of the second node;

[0210] Z L5 the line impedance value of the fifth branch.

[0211] S330, determining the fault location value of the third branch by a third fault location calculation formula based on the voltage value and the line impedance value calculated for the operation of the third branch, the value calculated for the operation and the commissioning control value of the fourth branch, the line impedance value of the fifth branch, the current value for the operation of the second node and the value calculated for the operation and the commissioning control value of the first node.

[0212] In one embodiment, the third fault location calculation formula is:

[0213]

[0214] wherein α L_3 the fault location value of the third branch;

[0215] U yL_3 the voltage value calculated for the operation of the third branch;

[0216] Z L3 the line impedance value of the third branch;

[0217] β L_4 the commissioning control value of the fourth branch;

[0218] U yL_4 the voltage value calculated for the operation of the fourth branch;

[0219] I yL_4 the current value calculated for the operation of the fourth branch;

[0220] I yT2 the current value calculated for the operation of the second node;

[0221] β T1 the commissioning control value of the first node;

[0222] U yT1 the voltage value calculated for the operation of the first node;

[0223] I yT1 a running calculation current value of the first node;

[0224] Z L5 a line impedance value of the fifth branch.

[0225] S340, based on the running calculation voltage value and the line impedance value of the fourth branch, the running calculation value and the operation control value of the third branch, the line impedance value of the fifth branch, the running calculation current value of the second node and the running calculation value and the operation control value of the first node, determining the fault location value of the fourth branch through a fourth fault location calculation formula.

[0226] In one embodiment, the fourth fault location calculation formula is:

[0227]

[0228] wherein, α L_4 a fault location value of the fourth branch;

[0229] U yL_4 a running calculation voltage value of the fourth branch;

[0230] Z L4 a line impedance value of the fourth branch;

[0231] β L_3 an operation control value of the third branch;

[0232] U yL_3 a running calculation voltage value of the third branch;

[0233] I yL_3 a running calculation current value of the third branch;

[0234] I yT2 a running calculation current value of the second node;

[0235] β T1 an operation control value of the first node;

[0236] U yT1 a running calculation voltage value of the first node;

[0237] I yT1 a running calculation current value of the first node;

[0238] Z L5 a line impedance value of the fifth branch.

[0239] S350, based on the running calculation value of the first node, the running calculation value of the second node and the line impedance value of the fifth branch, obtaining the fault location value of the fifth branch through a fifth fault location calculation formula.

[0240] In one embodiment, the fifth fault location calculation formula is:

[0241]

[0242] wherein α L_5 is the fault location value of the fifth branch;

[0243] U yT1 is the operating calculation voltage value of the first node;

[0244] I yT1 is the operating calculation current value of the first node;

[0245] U yT2 is the operating calculation voltage value of the second node;

[0246] I yT2 is the operating calculation current value of the second node;

[0247] Z L5 is the line impedance value of the fifth branch.

[0248] S400, determining the minimum fault location value based on each fault location value.

[0249] In one embodiment, the minimum fault location value is determined based on each fault location value, which facilitates locating the fault through the fault location value, reduces the complexity of fault location, and improves the efficiency of fault location.

[0250] In one embodiment, as shown in Figure 6 , determining the minimum fault location value based on each fault location value comprises:

[0251] S410, determining the effective fault location value based on the fault location values of the first branch, the second branch, the third branch, and the fourth branch.

[0252] In one embodiment, as shown in Figure 7 , determining the effective fault location value based on the fault location values of the first branch, the second branch, the third branch, and the fourth branch comprises:

[0253] S411, determining the in-service control value in the first branch, the second branch, the third branch, and the fourth branch.

[0254] S412, if the in-service control value of a branch is 1, the fault location value corresponding to the branch is the first fault location value, and the first fault location value is the effective fault location value.

[0255] S413, if the in-service control value of a branch is 0, the fault location value corresponding to the branch is the second fault location value, and the second fault location value is the invalid fault location value.

[0256] S420, determining a minimum fault location value based on each effective fault location value.

[0257] In one embodiment, the minimum fault location value is determined by taking the minimum value among the effective fault location values.

[0258] S500, determining the fault location based on the value range of the minimum fault location value.

[0259] In one embodiment, the minimum fault location value is α min , if 0≦α min <1, the branch corresponding to the minimum fault location value α min is the fault branch; if α min =1, the node of the branch corresponding to the minimum fault location value α min is the fault node; if α min >1, the fifth branch is the fault branch, and α min =α L_5 .

[0260] After the step of determining the fault location based on the value range of the minimum fault location value, the method further comprises:

[0261] if α min ≠1, determining the fault branch ranging based on the fault location.

[0262] In one embodiment, when the fault location is the fifth branch, the fault branch ranging is determined based on the fault location, and the starting point of the fault branch ranging is the first node T1.

[0263] In one embodiment, the fault ranging calculation formula is:

[0264] L 故障支路测距 =α min ×L 故障支路长度

[0265] wherein, L 故障支路长度 is the overall length of the fault branch.

[0266] It should be understood that the size of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0267] Compared with the prior art, the embodiment has the beneficial effects that:

[0268] The fault positioning method of the embodiment is applied to a four-terminal transmission line, the four-terminal transmission line includes a first branch, a second branch, a third branch, a fourth branch and a fifth branch, one end of the fifth branch is connected to the first node with the first branch and the second branch, the other end of the fifth branch is connected to the second node with the third branch and the fourth branch, the method includes: obtaining the positive sequence values corresponding to the first branch, the second branch, the third branch and the fourth branch respectively; determining the operation calculation values corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node and the second node respectively based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch; determining the fault positioning values corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch respectively through a fault positioning calculation formula based on the operation calculation values, the operation control values and the line impedance values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node; determining the minimum fault positioning value based on the fault positioning values; determining the fault position based on the value range of the minimum fault positioning value, since the fault positioning calculation formula is used to obtain the fault positioning value, the complexity of fault positioning of the four-terminal transmission line is reduced, and the complexity of fault positioning is further reduced by determining the fault position through the value range of the minimum fault positioning value, the accuracy of fault positioning is further improved, the time of power fault troubleshooting and power supply recovery is reduced, and the processing efficiency of power fault is improved.

[0269] The fault positioning method of the embodiment is also applicable to fault positioning when the four-terminal transmission line is operated in a two-terminal or three-terminal mode, can accurately position the fault position under the working conditions of metallic fault, high-resistance fault, weakly fed side fault and the like, and further improves the efficiency of power fault processing.

[0270] In a second aspect, the embodiment provides a fault positioning system, the system includes a fault positioning device, the fault positioning device is used to execute any fault positioning method in the first aspect.

[0271] The fault positioning device includes:

[0272] An obtaining module is configured to obtain the positive sequence values corresponding to the first branch, the second branch, the third branch and the fourth branch respectively;

[0273] A first determining module is configured to determine the operation calculation values corresponding to the first branch, the second branch, the third branch, the fourth branch, the first node and the second node respectively based on the positive sequence values, the operation control values and the line impedance values of the first branch, the second branch, the third branch and the fourth branch;

[0274] The second determining module is configured to determine fault locating values corresponding to the first branch, the second branch, the third branch, the fourth branch and the fifth branch respectively based on the operation calculation values, the commissioning control values and the line impedance values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node through a fault locating calculation formula;

[0275] The third determining module is configured to determine a minimum fault locating value based on the fault locating values.

[0276] The fourth determining module is configured to determine the fault location based on a value range of the minimum fault locating value.

[0277] It should be noted that the information interaction and execution process between the above-described devices / modules are based on the same concept as the method embodiments of the present application, and the specific functions and technical effects can be referred to the method embodiments part, which will not be described here.

[0278] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be realized in the form of hardware or software function unit. In addition, the specific name of each functional unit and module is only for easy distinction, and does not limit the protection scope of the present application. The specific working process of the unit and module in the above system can be referred to the corresponding process in the foregoing method embodiments, which will not be described here.

[0279] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0280] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method of fault location, characterized by, The application is applied to a four-terminal transmission line, the four-terminal transmission line includes a first branch, a second branch, a third branch, a fourth branch and a fifth branch, one end of the fifth branch is connected to the first branch and the second branch at a first node, the other end of the fifth branch is connected to the third branch and the fourth branch at a second node, and the method comprises: Respective positive sequence values of the first branch, the second branch, the third branch and the fourth branch are obtained; Based on the positive sequence values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch, respective operation calculation values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node are determined; Based on the operation calculation values, operation control values and line impedance values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node, respective fault positioning values of the first branch, the second branch, the third branch, the fourth branch and the fifth branch are determined through a fault positioning calculation formula; A minimum fault positioning value is determined based on the fault positioning values; A fault position is determined based on a value range of the minimum fault positioning value.

2. The method of claim 1, wherein, The determination of the operation calculation values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node based on the positive sequence values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch comprises: Respective operation calculation values of the first branch, the second branch, the third branch and the fourth branch are determined based on the positive sequence values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch through a branch operation calculation formula; Respective operation calculation values of the first node and the second node are determined based on the positive sequence values of the first branch, the second branch, the third branch and the fourth branch through a node operation calculation formula.

3. The method of claim 2, wherein, The operation calculation values include operation calculation voltage values and operation calculation current values, the branch operation calculation formula includes a branch operation calculation voltage value calculation formula and a branch operation calculation current value calculation formula, and the positive sequence values include positive sequence voltage values and positive sequence current values; The determination of the operation calculation values of the first branch, the second branch, the third branch and the fourth branch based on the positive sequence values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch through a branch operation calculation formula comprises: Respective operation calculation voltage values of the first branch, the second branch, the third branch and the fourth branch are determined based on the positive sequence voltage values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch through a branch operation calculation voltage value calculation formula; Respective operation calculation voltage values of the first branch, the second branch, the third branch and the fourth branch are determined based on the positive sequence voltage values, operation control values and line impedance values of the first branch, the second branch, the third branch and the fourth branch through a branch operation calculation voltage value calculation formula; The positive sequence current values and the operation control values of the first branch, the second branch, the third branch and the fourth branch are determined by branch operation calculation current value calculation formulas respectively to obtain operation calculation current values of the first branch, the second branch, the third branch and the fourth branch.

4. The method of claim 3, wherein, The branch operation calculation voltage value calculation formula is: U yL_i = β L_i × (U L_i + I L_i × Z L_i ) wherein U yL_i is the operating voltage value of the i-th branch, i being 1, 2, 3 or 4; β L_i the on-line control value for the i-th branch; U L_i Vdi is the positive sequence voltage value for the ith branch; I L_i Ii is the positive sequence current value for the i-th branch; Z L_i Zi line impedance value for the ith branch; The branch operation calculation current value calculation formula is: I yL_i = β L_i × I L_i where I yL_i is the operating current value of the i-th branch, i taking the values 1, 2, 3 or 4; β L_i the on-off control value for the i-th branch; I L_i Ii is the positive sequence current value for the i-th branch.

5. The method of claim 3, wherein, The node operation calculation formula includes a node operation calculation voltage value calculation formula and a node operation calculation current value calculation formula; The node operation calculation voltage value calculation formula is: wherein U yT running the voltage value for the node; U yL_i Calculate the voltage value for the operation of the i-th branch, i taking the values 1 or 3; U L_i+1 Calculate the voltage value for the operation of the (i+1)th branch; β L_i the on-line control value for the i-th branch; β L_i+1 the on control value for the i+1th branch; The node operation calculation current value calculation formula is: I yT = I yL_i + I yL_i+1 I = I + I yT Run the calculation current value for the node; I yL_i Calculate the current value for the operation of the i-th branch, i taking the values 1 or 3; I yL_i+1 Calculate the current value for the operation of the i+1 branch.

6. The method of claim 1, wherein, The fault location calculation formula includes a first fault location calculation formula, a second fault location calculation formula, a third fault location calculation formula, a fourth fault location calculation formula and a fifth fault location calculation formula, and the operation calculation values include operation calculation voltage values and operation calculation current values; The operation calculation values, the operation control values and the line impedance values of the first branch, the second branch, the third branch, the fourth branch, the first node and the second node are determined by fault location calculation formulas respectively to obtain fault location values of the first branch, the second branch, the third branch, the fourth branch and the fifth branch, including: The operation calculation voltage values and the line impedance values of the first branch, the operation calculation values and the operation control values of the second branch, the line impedance values of the fifth branch, the operation current value of the first node and the operation calculation values and the operation control values of the second node are determined by the first fault location calculation formula to obtain the fault location value of the first branch; The operation calculation voltage values and the line impedance values of the second branch, the operation calculation values and the operation control values of the first branch, the line impedance values of the fifth branch, the operation current value of the first node and the operation calculation values and the operation control values of the second node are determined by the second fault location calculation formula to obtain the fault location value of the second branch; The operation calculation voltage values and the line impedance values of the third branch, the operation calculation values and the operation control values of the fourth branch, the line impedance values of the fifth branch, the operation current value of the second node and the operation calculation values and the operation control values of the first node are determined by the third fault location calculation formula to obtain the fault location value of the third branch; The operation calculation voltage values and the line impedance values of the fourth branch, the operation calculation values and the operation control values of the third branch, the line impedance values of the fifth branch, the operation current value of the second node and the operation calculation values and the operation control values of the first node are determined by the fourth fault location calculation formula to obtain the fault location value of the fourth branch; The operation calculation values of the first node, the operation calculation values of the second node and the line impedance values of the fifth branch are determined by the fifth fault location calculation formula to obtain the fault location value of the fifth branch.

7. The method of claim 6, wherein, The first fault location calculation formula is: wherein a L_1 is the fault location value of the first branch; U yL_1 calculating a voltage value for operation of the first branch; Z L1 Z is the line impedance value for the first branch; β L_2 is the on-stream control value for the second branch; U yL_2 calculating a voltage value for the operation of the second branch; I yL_2 calculating a current value for the operation of the second branch; I yT1 calculating a current value for the operation of the first node; β T2 calculating a control value for the operation of the second node; U yT2 calculating a voltage value for operation of the second node;I yT2 calculating a current value for operation of the second node;Z L5 a line impedance value for the fifth branch; The second fault location calculation formula is: wherein, a L_2 is the fault location value of the second branch; U yL_2 is the operating calculation voltage value of the second branch; Z L2 is the line impedance value of the second branch; β L_1 is the in-service control value for the first branch; U yL_1 calculating a voltage value for the operation of the first branch; I yL_1 calculating a current value for the operation of the first branch; I yT1 calculating a current value for the operation of the first node; β T2 calculating a control value for the operation of the second node; U yT2 a voltage value for operation of the second node;I yT2 a current value for operation of the second node;Z L5 a line impedance value for the fifth branch; The third fault location calculation formula is: wherein, α L_3 is the fault location value of the third branch; U yL_3 is the operating calculation voltage value of the third branch; Z L3 is the line impedance value of the third branch; β L_4 is the on control value for the fourth branch; U yL_4 calculating a voltage value for the operation of the fourth branch; I yL_4 calculating a current value for the operation of the fourth branch; I yT2 calculating a current value for the operation of the second node; β T1 a commissioning control value for the first node; U yT1 a voltage value for operation of the first node;I yT1 a current value for operation of the first node;Z L5 a line impedance value for the fifth branch; The fourth fault location calculation formula is: The fourth fault location calculation formula is: wherein, α L_4 is the fault location value of the fourth branch; U yL_4 is the operating calculation voltage value of the fourth branch; Z L4 is the line impedance value of the fourth branch; β L_3 is the on control value for the third branch; U yL_3 calculating a voltage value for the operation of the third branch; I yL_3 calculating a current value for the operation of the third branch; I yT2 calculating a current value for the operation of the second node; β T1 calculating a control value for the operation of the first node; U yT1 a voltage value for operation of the first node;I yT1 a current value for operation of the first node;Z L5 a line impedance value for the fifth branch; The fifth fault location calculation formula is: wherein a L_5 is the fault location value of the fifth branch; U yT1 calculating a voltage value for operation of the first node; I yT1 calculating a current value for operation of the first node; U yT2 calculating a voltage value for operation of the second node; I yT2 calculating a current value for operation of the second node; Z L5 is the line impedance value for the fifth branch.

8. The method of claim 1, wherein, The minimum fault location value is determined based on the fault location values of the first branch, the second branch, the third branch and the fourth branch. The effective fault location values are determined based on the fault location values of the first branch, the second branch, the third branch and the fourth branch. The minimum fault location value is determined based on the effective fault location values.

9. The method of claim 8, wherein, The effective fault location values are determined based on the fault location values of the first branch, the second branch, the third branch and the fourth branch. The in-service control values of the first branch, the second branch, the third branch and the fourth branch are determined. If the in-service control value of a branch is 1, the fault location value corresponding to the branch is a first fault location value. If the in-service control value of a branch is 0, the fault location value corresponding to the branch is a second fault location value. The first fault location value is an effective fault location value, and the second fault location value is an ineffective fault location value.

10. A system for fault location, characterized by The system comprises a fault location device for performing the method of any one of claims 1 to 9.

Images