Method and system for determining ground wire power loss in AC overhead transmission line

Abstract

The present invention relates to a method and system for determining the amount of electric energy loss of the ground wire in an AC overhead transmission line, the method comprising: obtaining an impedance matrix of a conductor in the AC overhead transmission line; determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the obtained impedance matrix of the conductor in the AC overhead transmission line; determining a circuit model corresponding to the AC overhead transmission line based on the impedance matrix of the conductor in the AC overhead transmission line and the induced electromotive force on the ground wire; and determining the amount of electric energy loss on the ground wire in the conductor of the AC overhead transmission line using the circuit model corresponding to the AC overhead transmission line. The present invention is convenient and flexible, has a wide range of applications, and can conveniently and quickly calculate indicators such as induced electromotive force, induced current, and electric loss of various AC overhead transmission lines under various ground wire connection conditions.

Description

Technical Field

[0001] The invention relates to the field of AC overhead power transmission technology, and in particular to a method and system for determining ground wire power loss in an AC overhead power transmission line. Background Art

[0002] When the line is operating normally, the current flowing in the phase conductor generates an electromagnetic field with a power frequency change in the surrounding space. This changing electromagnetic field is magnetically coupled with the ground wire, generating an induced electromotive force in the ground wire. The schematic diagram of magnetic coupling between the conductor and the ground wire of the high-voltage AC transmission line is shown in Figure 3 As shown; because the ground wire and the earth form a loop, under the trend of this induced electromotive force, an induced current is generated in the ground wire, further generating power loss. In essence, during the operation of the high-voltage AC overhead transmission line, part of the power transmitted in the conductor is transferred to the ground wire through electromagnetic induction, becoming power loss. The schematic diagram of the ground wire induced current is shown in Figure 2 shown.

[0003] In the past, due to the small transmission capacity of the power system and the low voltage level of the power network, and the small proportion of ground wire induction loss in the entire power system transmission capacity, it has received little attention. However, now, with the increase of power transmission capacity and the increase of power network voltage level, the energy loss caused by ground wire loss is getting bigger and bigger. For a 100km double-circuit 750kV AC transmission line on the same tower, assuming that the transmission power of each circuit is 2300MW, the power loss of the ground wire will reach 1197kW, although it only accounts for 0.026% of the transmission power. However, according to the average annual utilization hours of 6500h, the annual energy loss will reach 7.78 million degrees. If the electricity is calculated at 0.3 yuan per degree over the full life cycle of 50 years, the ground wire loss will be as high as 389 million degrees, and the cost will reach 116.7 million yuan. Therefore, from the perspective of developing a low-carbon economy and building environmentally friendly power lines, for high-voltage AC transmission lines, how to calculate the power loss in the ground wire and reduce the ground wire induction loss by improving the ground wire operation mode is a very important research topic in power construction.

[0004] In the prior art, CN104573245B provides a method for calculating ground wire loss in a UHV transmission line, which comprises building an established UHV tower simulation model, a UHV line simulation model and a UHV power frequency power supply simulation model into a total simulation model of the UHV transmission line, and using an electromagnetic transient calculation program and electromagnetic field theory to calculate the ground wire loss values ​​of the total simulation model of the UHV transmission line in a variety of ground wire layout schemes, adjusting parameters to obtain the optimal scheme, and adjusting the ground wire according to the optimal scheme. CN106096161A discloses a simulation calculation method for power frequency induced voltage and current of a transmission line, comprising the following steps: obtaining basic parameters of a transmission line, a ground wire and a transmission tower, soil resistivity along the transmission line and operating parameters of an operating line where the transmission line is located, and transmitting the above parameters to an ATP-EMTP simulation system; building an ATP-EMTP simulation model; setting transmission line parameters; applying a source to the operating line; the calculation of the power frequency induced voltage and current of the transmission line comprises: when calculating the electrostatic induced voltage of the transmission line, the induced transmission line needs to be open at both ends; when calculating the electromagnetic induced voltage of the transmission line, the induced transmission line needs to be grounded at one end and open at the other end; when calculating the electrostatic induced current, the induced transmission line needs to be grounded at one end and open at the other end; when calculating the electromagnetic induced current, the induced transmission line needs to be grounded at one end and open at the other end. CN109165441A proposes a simulation calculation method for induced voltage and current of parallel AC transmission lines based on ATP-EMTP. A model is established through ATP-EMTP simulation software. According to the acquired transmission line parameters, ground wire parameters, transmission pole tower parameters, and soil resistivity parameters along the transmission line, the transmission line related parameters in the ATP-EMTP software are set to establish a line model. According to the acquired operating parameters of the energized transmission line, a voltage source and a current source are established at both ends of the energized transmission line to calculate the electrostatic induced voltage, electrostatic induced current, electromagnetic induced voltage, and electromagnetic induced current of the construction line.

[0005] In addition, the literature [1]: Dommel, H., et al., Electromagnetic Transients Program Reference Manual (EMTP Theory Book), 1986 records the calculation method of the parameters such as self-conductor resistance, self-inductance, self-capacitance, mutual resistance, mutual inductance and mutual capacitance between conductors according to the relationship of electromagnetic coupling.

[0006] Reference [2]: AJF Keri (SM) A. Nourai (M) JM Schneider. A method of reducing power loss in ground wire of overhead transmission lines. IEEE Transaction on Power Apparatus and Systems, 1984, PAS-103 (12): 3615-3624, which records the calculation results of the steady-state induced current in the overhead ground wire of an AC single-circuit transmission line when the phase line current is 1000 A.

[0007] Existing technologies all rely on commercial electromagnetic transient simulation software, such as ATP-EMTP and CDEGS, and cannot run independently without these software. In addition, existing technologies cannot solve the complex wiring of ground wires, such as composite impedance between the ground wire and the tower, segmented insulation of the ground wire, ground wire transposition, ground wire open loop, etc. In addition, at present, researchers have proposed various measures to reduce the power loss of the ground wire system by improving the ground wire wiring method, mainly including: composite impedance between the ground wire and the tower, segmented insulation of the ground wire, ground wire transposition, ground wire open loop, etc. These technologies provide important references for reducing ground wire losses, but also make the wiring method of the ground wire system more complicated and the calculation of ground wire losses more complicated. Summary of the invention

[0008] The present application provides a method and system for determining the amount of ground wire power loss in an AC overhead transmission line to at least solve the problems in the related art of relying on commercial electromagnetic transient simulation software, complex ground wire wiring, and complex ground line loss calculation.

[0009] The first embodiment of the present application provides a method for determining the amount of ground wire power loss in an AC overhead transmission line, comprising:

[0010] Obtain the impedance matrix of the conductors in the AC overhead transmission line;

[0011] Determining the induced electromotive force on the ground wire in the conductor of the AC overhead power transmission line according to the acquired impedance matrix of the conductor in the AC overhead power transmission line;

[0012] A circuit model corresponding to the AC overhead power transmission line is determined based on an impedance matrix of conductors in the AC overhead power transmission line and an induced electromotive force on the ground wire.

[0013] The second aspect of the present application provides a system for determining the amount of ground wire power loss in an AC overhead transmission line, comprising:

[0014] An acquisition module, used for acquiring an impedance matrix of a conductor in an AC overhead transmission line;

[0015] A first determination module is used to determine the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the acquired impedance matrix of the conductor in the AC overhead transmission line;

[0016] A second determination module is used to determine a circuit model corresponding to the AC overhead transmission line based on an impedance matrix of conductors in the AC overhead transmission line and an induced electromotive force on the ground wire;

[0017] The third determination module is used to determine the amount of power loss on the ground wire in the conductor of the AC overhead transmission line by using the circuit model corresponding to the AC overhead transmission line.

[0018] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0019] The present invention provides a method and system for determining the amount of electric energy loss on the ground wire in an AC overhead transmission line, the method comprising: obtaining an impedance matrix of a conductor in an AC overhead transmission line; determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the impedance matrix of the conductor in the AC overhead transmission line obtained; determining a circuit model corresponding to the AC overhead transmission line based on the impedance matrix of the conductor in the AC overhead transmission line and the induced electromotive force on the ground wire; and determining the amount of electric energy loss on the ground wire in the conductor of the AC overhead transmission line using the circuit model corresponding to the AC overhead transmission line. The present invention solves the problem of ground wire induction caused by magnetic coupling in AC overhead transmission lines, converts it into a circuit model for solution, and uses the loop current method to solve large-scale electrical network equations, so as to obtain the induced current and loss in the ground wire. The method has sufficient accuracy and is convenient and flexible, and has a wide range of application, and can calculate the various complex ground wire connection situations of single / dual / multi-loop AC overhead transmission lines of various voltage levels.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0022] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0023] Figure 1 It is a flow chart of a method for determining the amount of ground wire power loss in an AC overhead transmission line provided by an embodiment of the present disclosure;

[0024] Figure 2 This is a schematic diagram of the ground wire induced current generation;

[0025] Figure 3 It is a schematic diagram of magnetic coupling between the conductor and ground wire of a high voltage AC power transmission line;

[0026] Figure 4 It is a schematic diagram of the spatial layout of the conductors and ground wires of a double-circuit line on the same tower in a method for determining the amount of ground wire power loss in an AC overhead transmission line provided in one embodiment of the present application;

[0027] Figure 5 A ground wire induced current calculation model in a method for determining ground wire power loss in an AC overhead transmission line provided in one embodiment of the present application;

[0028] Figure 6 It is a schematic diagram of the arrangement of conductors and ground wires of a single-circuit transmission line in a method for determining the amount of ground wire power loss in an AC overhead transmission line provided in one embodiment of the present application;

[0029] Figure 7 It is a structural diagram of a system for determining the amount of ground wire power loss in an AC overhead transmission line provided according to an embodiment of the present application;

[0030] Figure 8 It is a structural diagram of a first determination module in a system for determining the amount of ground wire power loss in an AC overhead transmission line provided according to an embodiment of the present application;

[0031] Fig. 9 It is a structural diagram of the third determination module in the system for determining the ground wire power loss amount in the AC overhead transmission line provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0033] The present application proposes a method and system for determining the amount of ground wire electric energy loss in an AC overhead transmission line, the method comprising: obtaining an impedance matrix of conductors in an AC overhead transmission line; determining the induced electromotive force on the ground wire in the conductors of the AC overhead transmission line according to the impedance matrix of the conductors in the AC overhead transmission line obtained; determining a circuit model corresponding to the AC overhead transmission line based on the impedance matrix of the conductors in the AC overhead transmission line and the induced electromotive force on the ground wire; and determining the amount of electric energy loss on the ground wire in the conductors of the AC overhead transmission line using the circuit model corresponding to the AC overhead transmission line. The method realizes the convenient and quick calculation of indicators such as induced electromotive force, induced current and electric loss of various AC overhead transmission lines under various ground wire connection conditions.

[0034] The following describes a method and system for determining the amount of ground wire power loss in an AC overhead transmission line according to an embodiment of the present application with reference to the accompanying drawings.

[0035] Example 1

[0036] Figure 1 A flow chart of a method for determining the amount of ground wire power loss in an AC overhead transmission line provided in an embodiment of the present disclosure, such as Figure 1 Said method comprises:

[0037] Step 1: Obtain the impedance matrix of the conductors in the AC overhead transmission line.

[0038] In an embodiment of the present disclosure, an impedance matrix of conductors in an AC overhead transmission line is calculated based on parameters of conductors and ground wires in the conductors and their spatial position relationship, including self-impedances of all conductors and mutual impedances between every two conductors.

[0039] Figure 4 The schematic diagram of the spatial layout of the conductors and the ground wire of a double-circuit line on the same tower in a method for determining the amount of ground wire power loss in an AC overhead transmission line provided according to an embodiment of the present application, taking a double-circuit line on the same tower as an example, Figure 4 The system includes eight conductors with conductor numbers 1 to 8, and among the eight conductors, conductor numbers 7 and 8 are ground wires. Specifically, conductor number 1 is 1A, conductor number 2 is 1B, conductor number 3 is 1C, conductor number 4 is 2C, conductor number 5 is 2B, conductor number 6 is 2A, conductor number 7 is OPGW (Optical Fiber Composite Overhead Ground Wire), and conductor number 8 is a common ground wire. Figure 4 In addition to self-resistance, self-inductance and self-capacitance, the eight wires also have mutual resistance, mutual inductance and mutual capacitance. The calculation method can be found in reference [1]. These parameters can be calculated by programming based on the relationship of electromagnetic coupling. The calculation method based on programming based on the relationship of electromagnetic coupling is an existing technology and will not be elaborated here.

[0040] It should be noted that Figure 4 The figure only shows the spatial layout diagram of the double-circuit line conductors and the ground wire on the same tower including eight conductors, which does not represent a limitation to the present invention.

[0041] In addition, considering that the mutual capacitance between the wires is very small under the power frequency condition, this application makes an approximate treatment in the solution and ignores it.

[0042] Furthermore, the conductors of the AC overhead transmission line are written in the form of an impedance matrix, and the impedance calculation formula is as follows:

[0043] Z i,y =R i,y +jωL i,y

[0044] In the above formula, Z i,y R is the impedance of the ith conductor and the yth ground wire in the conductors of the AC overhead transmission line except the ground wire; i,y is the mutual resistance between the ith conductor and the yth ground wire among the conductors of the AC overhead transmission line except the ground wire; L i,y is the mutual inductance between the ith conductor excluding the ground wire and the yth ground wire among the conductors of the AC overhead transmission line.

[0045] In this embodiment, only eight wires are shown, that is, the resistance and inductance of the eight wires are written as an impedance matrix R = [R (i, j)] 8×8 , L=[L(i,j)] 8×8 ,i,j=1,2...8.

[0046] Step 2: Determine the induced electromotive force on the ground wire in the conductor of the AC overhead power transmission line according to the acquired impedance matrix of the conductor in the AC overhead power transmission line.

[0047] In the embodiment of the present disclosure, determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the acquired impedance matrix of the conductor in the AC overhead transmission line includes:

[0048] Respectively obtaining the current flowing through the conductors of the AC overhead transmission line except the ground wire;

[0049] The induced electromotive force on the ground wire among the conductors of the AC overhead transmission line is determined based on the current flowing in the conductors other than the ground wire among the conductors of the AC overhead transmission line and the impedance matrix of the ground wire in the AC overhead transmission line and the conductors other than the ground wire among the conductors of the AC overhead transmission line.

[0050] Further, determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line based on the current flowing in the conductor other than the ground wire in the conductor of the AC overhead transmission line and the impedance matrix of the ground wire in the AC overhead transmission line and the conductor other than the ground wire in the conductor of the AC overhead transmission line includes:

[0051] Determine the induced electromotive force on the yth ground wire in the AC overhead transmission line Induced electromotive force The calculation formula is as follows:

[0052]

[0053] In the formula, is the current flowing through the ith conductor of the AC overhead transmission line except the ground wire, Z i,y =R i,y +jωL i,y , Z i,y is the impedance of the ith conductor and the yth ground wire in the conductors of the AC overhead transmission line except the ground wire, R i,y is the mutual resistance between the ith conductor and the yth ground wire in the conductors of the AC overhead transmission line except the ground wire, L i,y is the mutual inductance between the ith conductor excluding the ground wire and the yth ground wire in the conductors of the AC overhead transmission line, and T is the total number of all conductors excluding the ground wire in the conductors of the AC overhead transmission line.

[0054] For example, using mutual impedance, we can calculate Figure 4 The induced electromotive force on the two ground wires of conductor number 7 and 8 and and The calculation formula is as follows;

[0055]

[0056]

[0057] In the above formula, Respectively represent Figure 4 The current flowing through the conductors numbered 1-6 can be calculated based on the transmission mileage and standard voltage of the line.

[0058] Step 3: Determine a circuit model corresponding to the AC overhead power transmission line based on the impedance matrix of the conductors in the AC overhead power transmission line and the induced electromotive force on the ground wire.

[0059] Step 4: Determine the amount of power loss on the ground wire in the conductor of the AC overhead transmission line using a circuit model corresponding to the AC overhead transmission line.

[0060] In an embodiment of the present disclosure, the determining the amount of power loss on the ground wire in the conductor of the AC overhead transmission line by using the circuit model corresponding to the AC overhead transmission line includes:

[0061] S1: Determine the induced current on each line in the circuit model corresponding to the AC overhead transmission line based on the loop current method.

[0062] In an embodiment of the present disclosure, determining the induced current on each line in the circuit model corresponding to the AC overhead transmission line based on the loop current method in S1 includes:

[0063] Using the loop current method, write the loop current equations corresponding to each loop in the circuit model;

[0064] The loop current equation matrix corresponding to the AC overhead transmission line is written based on the loop current equations corresponding to the various loops, and the loop current equation matrix is ​​solved to obtain the induced current on each line in the circuit model corresponding to the AC overhead transmission line.

[0065] S2: Determine the ground current flowing through the tower of the AC overhead transmission line according to the induced current on each line.

[0066] In an embodiment of the present disclosure, determining the ground current flowing through the tower of the AC overhead transmission line according to the induced current on each line in S2 includes:

[0067] H1: Obtain the induced current on the local lines corresponding to the current tower of the AC overhead transmission line and the induced current on the local lines corresponding to the previous tower of the tower.

[0068] Figure 5 A ground wire induced current calculation model in a method for determining ground wire power loss in an AC overhead transmission line provided according to an embodiment of the present application, such as Figure 5 As shown, a loop is called a mesh. According to the loop current method, the following are listed: Figure 5 The loop current equation satisfied by the two meshes in the nth level is:

[0069]

[0070] like Figure 5 As shown, in this model, and Respectively represent the induced electromotive force generated in each gear of the two ground wires; and Respectively represent the impedance value of each level of the two ground wires; R g is the resistance on the corresponding wire; and They represent the voltages of the two lines of ground corresponding to the nth tower. and They represent the induced currents flowing in the two ground wires corresponding to the nth tower, which are the quantities to be determined; represents the ground current of the nth tower, which is the quantity to be determined; and are the induced currents flowing in the two ground wires corresponding to the n-1th tower; and They are respectively the induced currents flowing through the two ground wires corresponding to the (n+1)th tower.

[0071] Furthermore, equation (1) is written in matrix form as follows:

[0072]

[0073] Among them, Then formula (2) can be written as:

[0074]

[0075] Assume that this line has N gears in total, write out the loop current equations satisfied by all meshes, and finally get the total loop current matrix equation as follows:

[0076]

[0077] The left side of equation (4) is the impedance matrix, and the right side is the induced electromotive force matrix. By solving this set of equations, the induced current in the ground wire can be obtained: Then the induced currents in the two ground wires can be obtained respectively and

[0078] H2: The difference between the sum of the induced currents on the local lines corresponding to the previous tower and the sum of the induced currents on the local lines corresponding to the current tower is taken as the ground current flowing through the current tower.

[0079] Specifically, Figure 5 As shown in the figure, the tower ground current in this model is the difference between the currents on both sides of the two ground wires, that is:

[0080]

[0081] There are N lines in the whole line, so there are N+1 towers in total. The ground current of all towers is calculated and written in the form of a matrix:

[0082]

[0083] S3: Determine the amount of power loss on the ground wire in the conductor of the AC overhead power transmission line according to the induced current on each ground wire and the ground current flowing through the iron tower of the AC overhead power transmission line.

[0084] In an embodiment of the present disclosure, determining the amount of power loss on the ground wire in the conductor of the AC overhead transmission line according to the induced current on each ground wire and the ground current flowing through the iron tower of the AC overhead transmission line in S3 includes:

[0085] F1: Obtain the product of the square of the induced current on each line and its corresponding resistance and the product of the square of the ground current flowing through each tower and its corresponding resistance, that is, P = I 2 R;

[0086] F2: Adding the obtained products to obtain the sum of the products, and using the sum as the amount of power loss on the ground wire in the conductor of the AC overhead power transmission line.

[0087] Specifically, the ground wire induction loss is generated by the induced current. The total loss is divided into three parts: OPGW loss, ordinary ground wire loss and tower grounding resistance loss. The three parts of loss are calculated according to the formula: P = I 2 For the sake of convenience, these three parts of loss are collectively referred to as the power loss on the ground wire.

[0088] It should be noted that although the above method for calculating the power loss is based on double circuits on the same tower, it is also applicable to single circuits and multiple circuits on the same tower.

[0089] If the ground wire adopts the technology of single-point grounding and segmented insulation, it is only necessary to add the impedance value representing the insulation at the corresponding position of the equation according to the actual ground wire connection situation: if the ground wire is electrically insulated in the horizontal direction, then its impedance and Add an infinite resistance (10 8 Ω) is enough; if the ground wire is insulated from the ground, then the grounding resistance R g Add an infinite resistance (10 8 Ω) can be used;

[0090] If the two ground wires are swapped, then according to equation (1), it can be seen that it is only necessary to swap the induced electromotive forces generated by the two ground wires.

[0091] This determination method is convenient and flexible, and does not require reliance on electromagnetic transient simulation software. The electromagnetic coupling model can be converted into an ordinary circuit model for solution; it has a wide range of applications: it is applicable to single-circuit, double-circuit and multi-circuit AC overhead transmission lines of all voltage levels; it can solve the problem of complex ground wiring, regardless of whether the ground wire adopts single-point grounding, segmented insulation and transposition technology, it can be converted into a circuit model for solution.

[0092] In particular, it is necessary to verify the results of the above determination method by calculating the steady-state induced current in the overhead ground wire of the AC single-circuit transmission line and comparing it with the results calculated in reference [2].

[0093] For example, the phase current is 1000A, and the phase and ground wires are arranged as follows: Figure 6 As shown in the figure, the induced current and loss values ​​in the ground wire for the following three ground wire operation modes are calculated respectively, and compared with the results in the literature [2].

[0094] Method 1: Both ground wires are electrically connected and grounded tower by tower;

[0095] Method 2: One ground wire is electrically connected throughout the entire line, and the other ground wire is insulated at each level. Both ground wires are grounded tower by tower;

[0096] Method 3: One ground wire is electrically connected throughout the entire line, and the other ground wire is insulated at each level. Both ground wires are grounded tower by tower, and the two ground wires are swapped every two levels.

[0097] Table 1 shows the comparison between the calculation results of this method and those in reference [2].

[0098] Table 1

[0099]

[0100] As can be seen from Table 1, the calculation results of the induced current by this method are basically consistent with the calculation results in the literature [2], with an error of no more than 5%, which verifies the accuracy of the method described in this application.

[0101] In summary, the present invention provides a method for determining the amount of electric energy loss on the ground wire in an AC overhead transmission line, comprising: obtaining an impedance matrix of a conductor in an AC overhead transmission line; determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the impedance matrix of the conductor in the AC overhead transmission line obtained; determining the circuit model corresponding to the AC overhead transmission line based on the impedance matrix of the conductor in the AC overhead transmission line and the induced electromotive force on the ground wire; and determining the amount of electric energy loss on the ground wire in the conductor of the AC overhead transmission line using the circuit model corresponding to the AC overhead transmission line. The present invention solves the problem of ground wire induction caused by magnetic coupling in AC overhead transmission lines, converts it into a circuit model for solution, and uses the loop current method to solve large-scale electrical network equations, so as to obtain the induced current and loss in the ground wire, and through verification, the method has sufficient accuracy; the method is convenient and flexible, has a wide range of application, and can calculate the various complex ground wire connection situations of single / dual / multi-loop AC overhead transmission lines of various voltage levels.

[0102] Example 2

[0103] Figure 7 A structural diagram of a system for determining ground wire power loss in an AC overhead transmission line provided by an embodiment of the present disclosure, such as Figure 7 As shown, the system comprises:

[0104] An acquisition module 100 is used to acquire an impedance matrix of a conductor in an AC overhead transmission line;

[0105] A first determination module 200 is used to determine the induced electromotive force on the ground wire of the conductor of the AC overhead transmission line according to the acquired impedance matrix of the conductor in the AC overhead transmission line;

[0106] A second determination module 300 is used to determine a circuit model corresponding to the AC overhead transmission line based on an impedance matrix of conductors in the AC overhead transmission line and an induced electromotive force on the ground wire;

[0107] The third determination module 400 is used to determine the amount of power loss on the ground wire in the conductor of the AC overhead transmission line by using the circuit model corresponding to the AC overhead transmission line.

[0108] like Figure 8 As shown, the first determination module 200 includes:

[0109] An acquisition unit 2001 is used to respectively acquire the current flowing through the conductors of the AC overhead transmission line except the ground wire;

[0110] The first determination unit 2002 is used to determine the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line based on the current flowing through the conductor in the conductor of the AC overhead transmission line except the ground wire and the impedance matrix of the ground wire in the AC overhead transmission line and the conductor in the conductor of the AC overhead transmission line except the ground wire.

[0111] In the embodiment of the present disclosure, the second determining module 300 is specifically used for:

[0112] Respectively obtaining the current flowing through the conductors of the AC overhead transmission line except the ground wire;

[0113] The induced electromotive force on the ground wire among the conductors of the AC overhead transmission line is determined based on the current flowing in the conductors other than the ground wire among the conductors of the AC overhead transmission line and the impedance matrix of the ground wire in the AC overhead transmission line and the conductors other than the ground wire among the conductors of the AC overhead transmission line.

[0114] Specifically, the induced electromotive force on the yth ground wire in the AC overhead transmission line is determined by the following formula:

[0115]

[0116] In the formula, is the current flowing through the ith conductor of the AC overhead transmission line except the ground wire, Z i,y =R i,y +jωL i,y , Z i,y is the impedance of the ith conductor and the yth ground wire in the conductors of the AC overhead transmission line except the ground wire, R i,y is the mutual resistance between the ith conductor and the yth ground wire in the conductors of the AC overhead transmission line except the ground wire, L i,y is the mutual inductance between the ith conductor excluding the ground wire and the yth ground wire in the conductors of the AC overhead transmission line, and T is the total number of all conductors excluding the ground wire in the conductors of the AC overhead transmission line.

[0117] In the embodiment of the present disclosure, the third determination module 400 is specifically used to:

[0118] B1: Determine the induced current on each line in the circuit model corresponding to the AC overhead transmission line based on the loop current method;

[0119] B2: determining the ground current flowing through the tower of the AC overhead transmission line according to the induced current on each line;

[0120] B3: Determine the amount of power loss on the ground wire in the conductor of the AC overhead power transmission line based on the induced current on each ground wire and the ground current flowing through the iron tower of the AC overhead power transmission line.

[0121] like Fig. 9 As shown, the third determination module 400 includes:

[0122] The second determining unit 4001 is used to determine the induced current on each line in the circuit model corresponding to the AC overhead transmission line based on the loop current method;

[0123] A third determining unit 4002 is used to determine the ground current flowing through the tower of the AC overhead transmission line according to the induced current on the local lines;

[0124] The fourth determining unit 4003 is used to determine the amount of power loss on the ground wire in the conductor of the AC overhead transmission line according to the induced current on the ground wire and the ground current flowing through the iron tower of the AC overhead transmission line.

[0125] Further, the second determining unit 4001 is specifically configured to:

[0126] Using the loop current method, write the loop current equations corresponding to each loop in the circuit model;

[0127] The loop current equation matrix corresponding to the AC overhead transmission line is written based on the loop current equations corresponding to the various loops, and the loop current equation matrix is ​​solved to obtain the induced current on each line in the circuit model corresponding to the AC overhead transmission line.

[0128] The third determining unit 4002 is specifically configured to:

[0129] Obtaining the induced current on each line corresponding to the current iron tower of the AC overhead transmission line and the induced current on each line corresponding to the previous iron tower of the iron tower;

[0130] The difference between the sum of the induced currents on the local wires corresponding to the previous tower of the tower and the sum of the induced currents on the local wires corresponding to the current tower is taken as the ground current flowing through the current tower.

[0131] The fourth determining unit 4003 is specifically configured to:

[0132] Obtaining the product of the square of the induced current on each wire and its corresponding resistance and the product of the square of the ground current flowing through each tower and its corresponding resistance;

[0133] The obtained products are added together to obtain the sum of the products, and the sum is used as the amount of power loss on the ground wire in the conductor of the AC overhead power transmission line.

[0134] In summary, a system for determining ground wire power loss in an AC overhead transmission line provided according to an embodiment of the present disclosure realizes calculation of various complex ground wire connection situations of single / dual / multi-circuit AC overhead transmission lines of various voltage levels.

[0135] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0136] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0137] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for determining the amount of ground wire power loss in an AC overhead transmission line, characterized in that: The method comprises: Obtain the impedance matrix of the conductors in the AC overhead transmission line; Determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the acquired impedance matrix of the conductor in the AC overhead transmission line; Determining a circuit model corresponding to the AC overhead transmission line based on an impedance matrix of conductors in the AC overhead transmission line and an induced electromotive force on the ground wire; Determine the amount of power loss on the ground wire in the conductor of the AC overhead power transmission line by using a circuit model corresponding to the AC overhead power transmission line; The step of determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the acquired impedance matrix of the conductor in the AC overhead transmission line comprises: Respectively obtaining the current flowing through the conductors of the AC overhead transmission line except the ground wire; Determining an induced electromotive force on the ground wire among the conductors of the AC overhead transmission line based on the current flowing through the conductors other than the ground wire among the conductors of the AC overhead transmission line and the impedance matrix of the ground wire among the conductors of the AC overhead transmission line and the conductors other than the ground wire among the conductors of the AC overhead transmission line; The method of determining the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line based on the current flowing through the conductor other than the ground wire in the conductor of the AC overhead transmission line and the impedance matrix of the ground wire in the AC overhead transmission line and the conductor other than the ground wire in the conductor of the AC overhead transmission line comprises: The induced electromotive force on the yth ground wire in the AC overhead transmission line is determined by the following formula: : In the formula, is the current flowing through the ith conductor of the AC overhead transmission line except the ground wire, , is the impedance of the ith conductor and the yth ground wire in the conductors of the AC overhead transmission line excluding the ground wire, is the mutual resistance between the ith conductor excluding the ground wire and the yth ground wire in the conductors of the AC overhead transmission line, is the mutual inductance between the ith conductor and the yth ground wire of the AC overhead transmission line except the ground wire, It is the total number of all conductors in the AC overhead transmission line except the ground wire.

2. The method according to claim 1, characterized in that The method of determining the amount of power loss on the ground wire in the conductor of the AC overhead transmission line by using the circuit model corresponding to the AC overhead transmission line comprises: Determine the induced current on each line in the circuit model corresponding to the AC overhead transmission line based on the loop current method; Determine the ground current flowing through the iron tower of the AC overhead transmission line according to the induced current on each local line; The amount of electric energy loss on the ground wire in the conductor of the AC overhead power transmission line is determined according to the induced current on each ground wire and the ground current flowing through the iron tower of the AC overhead power transmission line.

3. The method according to claim 2, characterized in that The method of determining the induced current on each line in the circuit model corresponding to the AC overhead transmission line based on the loop current method includes: Using the loop current method, write the loop current equations corresponding to each loop in the circuit model; The loop current equation matrix corresponding to the AC overhead transmission line is written based on the loop current equations corresponding to the various loops, and the loop current equation matrix is ​​solved to obtain the induced current on each line in the circuit model corresponding to the AC overhead transmission line.

4. The method according to claim 2, characterized in that The method of determining the ground current flowing through the iron tower of the AC overhead transmission line according to the induced current on each local line includes: Obtaining the induced current on each line corresponding to the current iron tower of the AC overhead transmission line and the induced current on each line corresponding to the previous iron tower of the iron tower; The difference between the sum of the induced currents on the local wires corresponding to the previous tower of the tower and the sum of the induced currents on the local wires corresponding to the current tower is taken as the ground current flowing through the current tower.

5. The method according to claim 2, characterized in that The method of determining the amount of electric energy loss on the ground wire in the conductor of the AC overhead transmission line according to the induced current on each ground wire and the ground current flowing through the iron tower of the AC overhead transmission line comprises: Obtaining the product of the square of the induced current on each wire and its corresponding resistance and the product of the square of the ground current flowing through each tower and its corresponding resistance; The obtained products are added together to obtain the sum of the products, and the sum is used as the amount of power loss on the ground wire in the conductor of the AC overhead power transmission line.

6. A system for determining the amount of ground wire power loss in an AC overhead transmission line, characterized in that: The system comprises: An acquisition module, used for acquiring an impedance matrix of a conductor in an AC overhead transmission line; A first determination module is used to determine the induced electromotive force on the ground wire in the conductor of the AC overhead transmission line according to the acquired impedance matrix of the conductor in the AC overhead transmission line; A second determination module is used to determine a circuit model corresponding to the AC overhead transmission line based on an impedance matrix of conductors in the AC overhead transmission line and an induced electromotive force on the ground wire; A third determination module is used to determine the amount of power loss on the ground wire in the conductor of the AC overhead transmission line by using a circuit model corresponding to the AC overhead transmission line; The first determining module includes: An acquisition unit, used for respectively acquiring currents flowing through the conductors of the AC overhead transmission line except the ground wire; a first determining unit, configured to determine an induced electromotive force on a ground wire in the conductor of the AC overhead transmission line based on a current flowing in a conductor other than a ground wire in the conductor of the AC overhead transmission line and an impedance matrix between the ground wire in the AC overhead transmission line and the conductor other than the ground wire in the conductor of the AC overhead transmission line; The induced electromotive force on the yth ground wire in the AC overhead transmission line is determined by the following formula: : In the formula, is the current flowing through the ith conductor of the AC overhead transmission line except the ground wire, , is the impedance of the ith conductor and the yth ground wire in the conductors of the AC overhead transmission line excluding the ground wire, is the mutual resistance between the ith conductor excluding the ground wire and the yth ground wire in the conductors of the AC overhead transmission line, is the mutual inductance between the ith conductor and the yth ground wire of the AC overhead transmission line except the ground wire, It is the total number of all conductors in the AC overhead transmission line except the ground wire.

7. The system according to claim 6, characterized in that The third determining module comprises: A second determining unit is used to determine the induced current on each line in the circuit model corresponding to the AC overhead transmission line based on a loop current method; A third determining unit, configured to determine the ground current flowing through the iron tower of the AC overhead transmission line according to the induced current on each local line; The fourth determining unit is used to determine the amount of power loss on the ground wire in the conductor of the AC overhead transmission line according to the induced current on the ground wire and the ground current flowing through the iron tower of the AC overhead transmission line.

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