Method and device for determining zero-sequence parameters of double-circuit T-type power transmission line

Abstract

The invention discloses a method and a device for determining zero-sequence parameters of a double-circuit T-type power transmission line. The method comprises the steps that electric power parameters of the double-circuit T-type power transmission line are measured, and the electric power parameters are used for at least indicating the power transmission state of the double-circuit T-type power transmission line; based on the electric power parameters, a first transmission model of the double-circuit T-type power transmission line is constructed, and the first transmission model is used for describing the relation between voltage and current in the double-circuit T-type power transmission line; based on the first transmission model, determining a second transmission model of the double-circuit T-type power transmission line, the second transmission model being used for indicating the transmission state of the voltage and / or current of the double-circuit T-type power transmission line; based on the second transmission model, zero-sequence parameters of the double-circuit T-type power transmission line are determined, and the zero-sequence parameters comprise at least one of zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance. The technical problem that the zero-sequence parameters of the double-circuit T-type power transmission line cannot be determined is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power dispatching, and in particular to a method and device for determining zero-sequence parameters of a double-circuit T-type transmission line. Background Art

[0002] At present, the power frequency parameters such as resistance, reactance (i.e. inductance), and earth conductance and susceptance (i.e. capacitance) constitute the cornerstone of the power system model, which is crucial to the accuracy of power flow calculation, relay protection setting, transient stability analysis and fault location, highlighting the importance of obtaining accurate transmission line parameters for the safe and stable operation of the power grid. Therefore, when building a modern power system, the accuracy of measuring transmission line parameters cannot be ignored. With the rapid growth of urbanization, the demand for power supply has risen sharply. The expansion of industry and commerce has prompted the construction of more transmission lines, resulting in large-scale construction of transmission lines and towers. At the same time, the restriction of the land area required for the transmission line corridor has become increasingly prominent, causing tension between power infrastructure construction and land resource utilization. Therefore, balancing economic development with power grid construction and improving the utilization efficiency of transmission corridors have become urgent issues to be solved. In this context, increasing the transmission capacity of the line is one of the solutions. The use of T-type transmission technology not only increases the power supply capacity, but also saves land resources, reduces investment costs, and brings significant social and economic benefits. However, the complex electromagnetic coupling phenomenon in the T-type transmission line makes it a technical challenge to accurately measure its zero-sequence parameters.

[0003] In the related technology, there are some achievements in the research of T-type transmission line parameter measurement. However, most of the research on T-type transmission line parameter measurement currently uses a concentrated parameter model. However, the concentrated parameter model is difficult to overcome the distribution effect and cannot be applied to long-distance T-type transmission lines. Therefore, there is a technical problem that the zero-sequence parameters of double-circuit T-type transmission lines cannot be determined.

[0004] With respect to the above-mentioned technical problem of being unable to determine the zero-sequence parameters of the double-circuit T-type transmission line, no effective solution has been proposed so far. Summary of the invention

[0005] The embodiments of the present invention provide a method and device for determining zero-sequence parameters of a double-circuit T-type transmission line, so as to at least solve the technical problem that the zero-sequence parameters of the double-circuit T-type transmission line cannot be determined.

[0006] According to one aspect of an embodiment of the present invention, a method for determining zero-sequence parameters of a double-circuit T-type transmission line is provided. The method may include: measuring power parameters of the double-circuit T-type transmission line, wherein the power parameters are used to at least indicate the transmission state of the double-circuit T-type transmission line; based on the power parameters, constructing a first transmission model of the double-circuit T-type transmission line, wherein the first transmission model is used to describe the relationship between voltage and current in the double-circuit T-type transmission line; based on the first transmission model, determining a second transmission model of the double-circuit T-type transmission line, wherein the second transmission model is used to indicate the transmission state of the voltage and / or current of the double-circuit T-type transmission line; based on the second transmission model, determining the zero-sequence parameters of the double-circuit T-type transmission line, wherein the zero-sequence parameters include at least one of the following: zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance.

[0007] Optionally, the double-circuit T-type transmission line includes: a first transmission line, a second transmission line and a third transmission line, and measuring the power parameters of the double-circuit T-type transmission line includes: determining multiple connection strategies for each transmission line in the double-circuit T-type transmission line, wherein the connection strategy is used to represent the connection rule of the transmission line; and obtaining the power parameters of each transmission line in the double-circuit T-type transmission line under multiple connection strategies.

[0008] Optionally, the power parameters of each transmission line include at least: the starting zero-sequence voltage and the starting zero-sequence current of the first transmission line and the second transmission line, the terminal zero-sequence voltage and the terminal zero-sequence current of the first transmission line and the second transmission line, and the terminal zero-sequence voltage and the terminal zero-sequence current of the third transmission line.

[0009] Optionally, the multiple connection strategies of each transmission line in the double-circuit T-type transmission line include at least one of the following: the head end of the first transmission line is connected to the power supply and the end of the first transmission line is grounded, the head end and the end of the second transmission line are both connected to the power grid, and the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is grounded; the head end of the first transmission line is connected to the power supply and the end of the first transmission line is in an open circuit state, the head end and the end of the second transmission line are both connected to the power grid, and the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is in an open circuit state; the head end and the end of the first transmission line are both connected to the power grid, the head end of the second transmission line is connected to the power supply and the end of the second transmission line is grounded, and the head end and the end of the third transmission line are both connected to the power grid; the head end and the end of the first transmission line are both connected to the power grid, the head end of the second transmission line is connected to the power supply and the end of the second transmission line is in an open circuit state, and the head end and the end of the third transmission line are connected to the power grid.

[0010] Optionally, the first transmission line and the second transmission line are double-circuit transmission lines, and the third transmission line is a single-circuit transmission line.

[0011] Optionally, based on the power parameters, a transmission equation for a double-circuit T-type transmission line is constructed, including: determining the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line in the double-circuit T-type transmission line based on the power parameters; and generating a first transmission model of the double-circuit T-type transmission line based on the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line.

[0012] According to another aspect of an embodiment of the present invention, a device for determining zero-sequence parameters of a double-circuit T-type transmission line is also provided. The device may include: a measuring unit, used to measure the power parameters of the double-circuit T-type transmission line, wherein the power parameters are used to at least indicate the transmission state of the double-circuit T-type transmission line; a construction unit, used to construct a first transmission model of the double-circuit T-type transmission line based on the power parameters, wherein the first transmission model is used to describe the relationship between voltage and current in the double-circuit T-type transmission line; a first determination unit, used to determine a second transmission model of the double-circuit T-type transmission line based on the first transmission model, wherein the second transmission model is used to indicate the transmission state of the voltage and / or the current of the double-circuit T-type transmission line; a second determination unit, used to determine the zero-sequence parameters of the double-circuit T-type transmission line based on the second transmission model, wherein the zero-sequence parameters include at least one of the following: zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance.

[0013] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the method for determining the zero-sequence parameters of the double-circuit T-type transmission line in an embodiment of the present invention.

[0014] According to another aspect of an embodiment of the present invention, a processor is provided, wherein the processor is used to run a program, wherein when the program is run, the method for determining the zero-sequence parameter of the double-circuit T-type transmission line in the embodiment of the present invention is executed.

[0015] According to another aspect of the embodiments of the present invention, a computer program product is provided, which includes computer instructions, and when the computer instructions are executed by a processor, the method for determining zero-sequence parameters of a double-circuit T-type transmission line in the embodiments of the present invention is implemented.

[0016] In an embodiment of the present invention, the power parameters of a double-circuit T-type transmission line are measured; according to the power parameters, a first transmission model of the double-circuit T-type transmission line is constructed, wherein the first transmission model is used to describe the relationship between voltage and current in the double-circuit T-type transmission line; according to the first transmission model, a second transmission model of the double-circuit T-type transmission line is determined, wherein the second transmission model is used to indicate the transmission state of the voltage and / or current of the double-circuit T-type transmission line; according to the second transmission model, the zero-sequence parameters of the double-circuit T-type transmission line are determined, wherein the zero-sequence parameters include at least one of the following: zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance. That is, the present invention constructs the first transmission model of the double-circuit T-type transmission line through the power parameters of the double-circuit T-type transmission line, thereby determining the second transmission model according to the first transmission model, and then solving the zero-sequence parameters including zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance according to the second transmission model, thereby solving the technical problem of being unable to determine the zero-sequence parameters of the double-circuit T-type transmission line, and achieving the technical effect of determining the zero-sequence parameters of the double-circuit T-type transmission line. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of a method for determining zero-sequence parameters of a double-circuit T-type transmission line according to an embodiment of the present invention;

[0019] Figure 2 is a physical model diagram of a double-circuit T-type transmission line according to an embodiment of the present invention;

[0020] Figure 3 is a flow chart of a method for measuring zero-sequence distributed parameters of a double-circuit T-type transmission line according to an embodiment of the present invention;

[0021] Figure 4 is a simulation model diagram of a double-circuit T-type transmission line according to an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of a zero-sequence parameter measurement result of a T-type transmission line transformed by a second double-circuit transmission line length according to an embodiment of the present invention;

[0023] Figure 6 It is a schematic diagram of a zero-sequence parameter measurement result of a T-type transmission line transformed by a single-circuit transmission line length according to a third part of an embodiment of the present invention;

[0024] Figure 7 It is a schematic diagram of a device for determining zero-sequence parameters of a double-circuit T-type transmission line according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, functional component or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, functional components or devices.

[0027] According to an embodiment of the present invention, an embodiment of a method for determining zero-sequence parameters of a double-circuit T-type transmission line is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0028] Figure 1 is a flow chart of a method for determining zero-sequence parameters of a double-circuit T-type transmission line according to an embodiment of the present invention, such as Figure 1 As shown, the method may include the following steps:

[0029] Step S101, measuring power parameters of a double-circuit T-type transmission line.

[0030] In the technical solution provided in the above step S101 of the present invention, the power parameter is used to at least indicate the transmission state of the double-circuit T-type transmission line.

[0031] In this embodiment, the power parameters of the double-circuit T-type transmission line are measured, wherein the power parameters may at least include the zero-sequence voltage and zero-sequence current of each transmission line in the double-circuit T-type transmission line.

[0032] Optionally, the double-circuit T-type transmission line includes at least: a first transmission line, a second transmission line and a third transmission line, wherein the first transmission line may also be referred to as line 1, the second transmission line may also be referred to as line 2, and the third transmission line may also be referred to as line 3.

[0033] Optionally, multiple connection modes of each transmission line in the double-circuit T-type transmission line are determined, wherein the connection mode may also be referred to as a measurement mode.

[0034] For example, Figure 2 is a physical model diagram of a double-circuit T-type transmission line according to an embodiment of the present invention, such as Figure 2 As shown, U represents voltage, I represents current, A, B, C, D, E, and F represent different nodes in the line, and the double-circuit T-type transmission line is defined as a T-type transmission line consisting of the first part of the double-circuit transmission line in the first section, the second part of the double-circuit transmission line in the last section, and the third part of the single-circuit transmission line. The head end of the first part of the double-circuit transmission line is the head end of the double-circuit T-type transmission line, the end of the second part of the double-circuit transmission line is one end of the double-circuit T-type transmission line, and the end of the third part of the single-circuit transmission line is the other end of the double-circuit T-type transmission line. The end of the first part of the double-circuit transmission line, the head end of the second part of the double-circuit transmission line, and the head end of the third part of the single-circuit transmission line are the intersection points of the double-circuit T-type transmission line, and the first part of the double-circuit transmission line and the second part of the double-circuit transmission line are at the same height in the vertical plane and have the same conductor material and tower structure. In addition, the two transmission lines of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line are defined as transmission line 1 and transmission line 2, and the third part of the single-circuit transmission line is defined as transmission line 3. Among them, the first measurement method can be: a single-phase power supply is added to the head end of line 1 of the double-circuit T-type transmission line, the end is grounded, line 2 is normally energized, and the end of line 3 is grounded; the second measurement method can be: a single-phase power supply is added to the head end of line 1 of the double-circuit T-type transmission line, the end is open, line 2 is normally energized, and the end of line 3 is open. The third measurement method can be: a single-phase power supply is added to the head end of line 2 of the double-circuit T-type transmission line, the end is grounded, and line 1 and line 3 are normally energized; the fourth measurement method can be: a single-phase power supply is added to the head end of line 2 of the double-circuit T-type transmission line, the end is open, and line 1 and line 3 are normally energized.

[0035] Optionally, after the connection mode is determined, power parameters of each transmission line in the double-circuit T-type transmission line under multiple connection modes are obtained.

[0036] For example, when the line is energized, a synchronous measuring device is used to synchronously measure: the zero-sequence voltage and zero-sequence current at the beginning and end of line 1 under four different measurement methods; the zero-sequence voltage and zero-sequence current at the beginning and end of line 2 under four different measurement methods; the zero-sequence voltage and zero-sequence current at the end of line 3 under four different measurement methods.

[0037] For another example, the zero-sequence voltage at the head end of line 1 under four different measurement methods can be expressed by the following formula (1):

[0038] U k,1,s ,k∈[1,2,3,4](1)

[0039] Among them, U k,1,s To represent the zero-sequence voltage at the head end of line 1 under the kth zero-sequence measurement mode; the zero-sequence voltage at the end of line 1 under four different measurement modes can be represented by the following formula (2):

[0040] U k,1,m ,k∈[1,2,3,4](2)

[0041] Among them, U k,1,m To represent the zero-sequence voltage at the end of line 1 under the kth zero-sequence measurement mode; the zero-sequence current at the head end of line 1 under four different measurement modes can be represented by the following formula (3):

[0042] I k,1,s ,k∈[1,2,3,4](3)

[0043] Among them, I k,1,s To represent the zero-sequence current at the head end of line 1 under the kth zero-sequence measurement mode; the zero-sequence current at the end of line 1 under four different measurement modes can be represented by the following formula (4):

[0044] I k,1,m ,k∈[1,2,3,4](4)

[0045] Among them, I k,1,m To represent the zero-sequence current at the end of line 1 under the kth zero-sequence measurement mode; the zero-sequence voltage at the head end of line 2 under four different measurement modes can be represented by the following formula (5):

[0046] U k,2,s ,k∈[1,2,3,4](5)

[0047] Among them, U k,2,s To represent the zero-sequence voltage at the head end of line 2 under the kth zero-sequence measurement mode; the zero-sequence voltage at the end of line 2 under four different measurement modes can be represented by the following formula (6):

[0048] Uk,2,m ,k∈[1,2,3,4](6)

[0049] Among them, U k,2,m To represent the zero-sequence voltage at the end of line 2 under the kth zero-sequence measurement mode; the zero-sequence current at the head end of line 2 under four different measurement modes can be represented by the following formula (7):

[0050] I k,2,s ,k∈[1,2,3,4](7)

[0051] Among them, I k,2,s To represent the zero-sequence current at the head end of line 2 under the kth zero-sequence measurement mode; the zero-sequence current at the end of line 2 under four different measurement modes can be represented by the following formula (8):

[0052] I k,2,m ,k∈[1,2,3,4](8)

[0053] Among them, I k,2,m To represent the zero-sequence current at the end of line 2 under the kth zero-sequence measurement mode; the zero-sequence voltage at the end of line 3 under two different measurement modes can be represented by the following formula (9):

[0054] U k,3,m ,k∈[1,2,3,4](9)

[0055] Among them, U k,3,m To represent the zero-sequence voltage at the end of line 3 under the kth zero-sequence measurement mode; the zero-sequence current at the end of line 3 under two different measurement modes can be represented by the following formula (10):

[0056] I k,3,m ,k∈[1,2,3,4](10)

[0057] Among them, I k,3,m represents the zero-sequence voltage at the end of line 3 in the kth zero-sequence measurement mode.

[0058] Step S102: constructing a first transmission model of a double-circuit T-type transmission line based on power parameters.

[0059] In the technical solution provided in the above step S102 of the present invention, the first transmission model is used to describe the relationship between voltage and current in the double-circuit T-type transmission line. The first transmission model can also be called a transmission equation.

[0060] In this embodiment, the power parameters of the double-circuit T-type transmission line measured in step S101 are used to construct the transmission equation of the double-circuit T-type transmission line.

[0061] Optionally, according to the power parameters, the zero-sequence fundamental voltage and the zero-sequence fundamental current of each transmission line in the double-circuit T-type transmission line are determined.

[0062] For example, the zero-sequence voltage U at the head end of line 1 under the kth zero-sequence measurement mode of the corresponding zero-sequence fundamental component is k,1,s , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the head end of line 1 under the kth zero-sequence measurement mode Zero-sequence voltage U at the end of line 1 under the kth zero-sequence measurement mode k,1,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 1 under the kth zero-sequence measurement mode Zero-sequence current I at the head end of line 1 under the kth zero-sequence measurement mode k,1,s , the Fourier algorithm is used to obtain the zero-sequence fundamental current at the head end of line 1 under the kth zero-sequence measurement mode Zero-sequence voltage I at the end of line 1 under the kth zero-sequence measurement mode k,1,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 1 under the kth zero-sequence measurement mode

[0063] For another example, the zero-sequence voltage U at the head end of line 2 under the kth zero-sequence measurement mode is k,2,s , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the head end of line 2 under the kth zero-sequence measurement mode Zero-sequence voltage U at the end of line 2 under the kth zero-sequence measurement mode k,2,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 2 under the kth zero-sequence measurement mode Zero-sequence current I at the head end of line 2 under the kth zero-sequence measurement mode k,2,s , the Fourier algorithm is used to obtain the zero-sequence fundamental current at the head end of line 2 under the kth zero-sequence measurement mode Zero-sequence voltage I at the end of line 2 under the kth zero-sequence measurement mode k,2,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 2 under the kth zero-sequence measurement mode

[0064] For another example, the zero-sequence voltage U at the end of line 3 under the kth zero-sequence measurement mode is k,3,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 3 under the kth zero-sequence measurement mode Zero-sequence voltage I at the end of line 3 under the kth zero-sequence measurement mode k,3,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 3 under the kth zero-sequence measurement mode Among them, k∈[1,2,3,4].

[0065] Optionally, after the zero-sequence fundamental voltage and the zero-sequence fundamental current of each transmission line are determined, the transmission equation of the double-circuit T-type transmission line is generated according to the zero-sequence fundamental voltage and the zero-sequence fundamental current of each transmission line.

[0066] For example, according to different measurement methods, the voltage and current transmission equations at the beginning and end of a double-circuit T-type transmission line can be expressed by the following formula (11):

[0067]

[0068] Step S103: determining a second transmission model of the double-circuit T-type transmission line based on the first transmission model.

[0069] In the technical solution provided in the above step S103 of the present invention, the second transmission model is used to indicate the transmission state of the voltage and / or current of the double-circuit T-type transmission line. The second transmission model can also be called a transmission matrix.

[0070] In this embodiment, after the transmission equation of the double-circuit T-type transmission line is constructed in step S102, the transmission matrix of the double-circuit T-type transmission line is determined according to the transmission equation.

[0071] For example, the matrix This is the transmission matrix of the first part of the double-circuit transmission line.

[0072] matrix And the matrix is the transmission matrix of the second part of the double-circuit transmission line. And the matrix This is the transmission matrix of the single-circuit transmission line in the third part.

[0073] For another example, the intermediate variables are determined according to the transmission matrix, wherein the intermediate variables can be expressed by the following formulas (12) to (14):

[0074]

[0075] in, It can be used to represent the propagation coefficient of the single-circuit transmission line in the third part, Part III: Wave impedance of single-circuit transmission line. cosh represents the hyperbolic cosine function, and sinh represents the hyperbolic sine function. a is the zero-sequence self-impedance of the first double-circuit transmission line and the second double-circuit transmission line, Z b is the zero-sequence mutual impedance of the first double-circuit transmission line and the second double-circuit transmission line, Y a is the zero-sequence self-admittance of the first double-circuit transmission line and the second double-circuit transmission line, Y bis the zero-sequence mutual admittance of the first double-circuit transmission line and the second double-circuit transmission line. a , rb is a matrix According to the voltage and current transmission equations at the beginning and end of the double-circuit T-type transmission line, the equation for the transmission matrix of the first part of the double-circuit transmission line can be expressed by the above formula (15):

[0076]

[0077] Among them, the intermediate variable A to be found 1 , A 2 , B 1 , B 2 , C 1 , C 2 , A 5 , B 5 and C 5 There are 9 unknowns in total, and only nine equations are needed to solve these nine unknowns. According to the equation of the transmission matrix of the double-circuit transmission line in the first part, the transmission equations of the double-circuit transmission line in the second part and the single-circuit transmission line in the third part can be expressed by the above formula (16):

[0078]

[0079] According to the nine equations in the above formula, nine unknown variables A1, A2, B1, B2, C1, C2, A5, B5 and C5 can be calculated.

[0080] Step S104: determining the zero-sequence parameters of the double-circuit T-type transmission line based on the second transmission model.

[0081] In the technical solution provided in the above step S104 of the present invention, the zero-sequence parameter includes at least one of the following: zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance.

[0082] In this embodiment, the zero-sequence parameter of the double-circuit T-type transmission line is determined according to the transmission matrix of the double-circuit T-type transmission line.

[0083] For example, the propagation coefficient and wave impedance of the third part of the single-circuit transmission line can be calculated according to the transmission matrix of the third part of the single-circuit transmission line by the aforementioned formula (17):

[0084]

[0085] According to the propagation coefficient and wave impedance of the third part single-circuit transmission line, the zero-sequence self-resistance, zero-sequence self-inductance and zero-sequence self-capacitance of the third part single-circuit transmission line can be expressed by the above formula (18):

[0086]

[0087] Among them, R3 is the zero-sequence self-resistance of the third part of the single-circuit transmission line, L3 is the zero-sequence self-inductance of the third part of the single-circuit transmission line, and C3 is the zero-sequence self-capacitance of the third part of the single-circuit transmission line.

[0088] For another example, the two characteristic roots r of the matrix T0 are calculated based on the transmission matrix of the double-circuit transmission line in the second part. a 、r b , which can be expressed by the above formula (19):

[0089]

[0090] According to the transmission matrix of the double-circuit transmission line in the second part and the matrix T 0 The two characteristic roots of the first part of the double-circuit transmission line and the zero-sequence self-impedance Z of the second part of the double-circuit transmission line are calculated a , zero sequence mutual impedance Z b , zero-sequence self-admittance Y a and zero-sequence mutual admittance Y b , can be expressed by the above formula (20) and formula (21):

[0091]

[0092]

[0093] According to the zero-sequence self-impedance Z of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line a , zero sequence mutual impedance Z b , zero-sequence self-admittance Y a and zero-sequence mutual admittance Y b The zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line can be calculated by the above formula (22):

[0094]

[0095] Among them, R a is the zero-sequence self-resistance of the first double-circuit transmission line and the second double-circuit transmission line, R b is the zero-sequence mutual resistance of the first double-circuit transmission line and the second double-circuit transmission line, L a is the zero-sequence self-inductance of the first double-circuit transmission line and the second double-circuit transmission line, L b is the zero-sequence mutual inductance of the first double-circuit transmission line and the second double-circuit transmission line, C a is the zero-sequence self-capacitance of the first double-circuit transmission line and the second double-circuit transmission line, C bis the zero-sequence mutual capacitance of the first double-circuit transmission line and the second double-circuit transmission line. The two characteristic roots r of the matrix T0 are calculated based on the transmission matrix of the second double-circuit transmission line. a 、r b , which can be expressed by the above formula (19):

[0096]

[0097] According to the transmission matrix of the double-circuit transmission line in the second part and the matrix T 0 The two characteristic roots of the first part of the double-circuit transmission line and the zero-sequence self-impedance Z of the second part of the double-circuit transmission line are calculated a , zero sequence mutual impedance Z b , zero-sequence self-admittance Y a and zero-sequence mutual admittance Y b , can be expressed by the above formula (20) and formula (21):

[0098]

[0099] According to the zero-sequence self-impedance Z of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line a , zero sequence mutual impedance Z b , zero-sequence self-admittance Y a and zero-sequence mutual admittance Y b The zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line can be calculated by the above formula (22):

[0100]

[0101] Among them, R a is the zero-sequence self-resistance of the first double-circuit transmission line and the second double-circuit transmission line, R b is the zero-sequence mutual resistance of the first double-circuit transmission line and the second double-circuit transmission line, L a is the zero-sequence self-inductance of the first double-circuit transmission line and the second double-circuit transmission line, L b is the zero-sequence mutual inductance of the first double-circuit transmission line and the second double-circuit transmission line, C a is the zero-sequence self-capacitance of the first double-circuit transmission line and the second double-circuit transmission line, C b It is the zero-sequence mutual capacitance of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line.

[0102] It should be noted that the above embodiment can be executed by a device for determining zero-sequence parameters of a double-circuit T-type transmission line.

[0103] In the above steps S101 to S104 of the present invention, the power parameters of the double-circuit T-type transmission line are measured; according to the power parameters, a first transmission model of the double-circuit T-type transmission line is constructed, wherein the first transmission model is used to describe the relationship between the voltage and the current in the double-circuit T-type transmission line; according to the first transmission model, a second transmission model of the double-circuit T-type transmission line is determined, wherein the second transmission model is used to indicate the transmission state of the voltage and / or current of the double-circuit T-type transmission line; according to the second transmission model, the zero-sequence parameters of the double-circuit T-type transmission line are determined, wherein the zero-sequence parameters include at least one of the following: zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance. That is to say, the present invention constructs the first transmission model of the double-circuit T-type transmission line through the power parameters of the double-circuit T-type transmission line, thereby determining the second transmission model according to the first transmission model, and then solving the zero-sequence parameters including zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance according to the second transmission model, thereby solving the technical problem of being unable to determine the zero-sequence parameters of the double-circuit T-type transmission line, and achieving the technical effect of determining the zero-sequence parameters of the double-circuit T-type transmission line.

[0104] The above method of this embodiment is further introduced below.

[0105] As an optional implementation method, a double-circuit T-type transmission line includes: a first transmission line, a second transmission line and a third transmission line. Measuring the power parameters of the double-circuit T-type transmission line includes: determining multiple connection strategies for each transmission line in the double-circuit T-type transmission line, wherein the connection strategy is used to represent the connection rule of the transmission line; and obtaining the power parameters of each transmission line in the double-circuit T-type transmission line under multiple connection strategies.

[0106] In this embodiment, multiple connection strategies for each transmission line in the double-circuit T-type transmission line are determined, and power parameters of each transmission line in the double-circuit T-type transmission line under multiple connection strategies are obtained. The connection strategy may also be referred to as a connection mode.

[0107] Optionally, the first measurement method may be: a single-phase power supply is added to the head end of line 1 of the double-circuit T-type transmission line, the end is grounded, and line 2 is normally energized, that is, line 2 is connected to the power grid, and the end of line 3 is grounded; the second measurement method may be: a single-phase power supply is added to the head end of line 1 of the double-circuit T-type transmission line, the end is open, and line 2 is normally energized, that is, line 2 is connected to the power grid, and the end of line 3 is open. The third measurement method may be: a single-phase power supply is added to the head end of line 2 of the double-circuit T-type transmission line, the end is grounded, and line 1 and line 3 are normally energized, that is, line 1 and line 3 are connected to the power grid; the fourth measurement method may be: a single-phase power supply is added to the head end of line 2 of the double-circuit T-type transmission line, the end is open, and line 1 and line 3 are normally energized, that is, line 1 and line 3 are connected to the power grid.

[0108] As an optional implementation method, the power parameters of each transmission line include at least: the starting zero-sequence voltage and the starting zero-sequence current of the first transmission line and the second transmission line, the terminal zero-sequence voltage and the terminal zero-sequence current of the first transmission line and the second transmission line, and the terminal zero-sequence voltage and the terminal zero-sequence current of the third transmission line.

[0109] In this embodiment, the first transmission line and the second transmission line have a head-end zero-sequence voltage and a head-end zero-sequence current, the first transmission line and the second transmission line have a terminal zero-sequence voltage and a terminal zero-sequence current, and the terminal zero-sequence voltage and a terminal zero-sequence current of the third transmission line.

[0110] For example, the power parameters of each transmission line include at least: the zero-sequence voltage and zero-sequence current at the beginning and end of line 1 under four different measurement methods; the zero-sequence voltage and zero-sequence current at the beginning and end of line 2 under four different measurement methods; the zero-sequence voltage and zero-sequence current at the end of line 3 under four different measurement methods.

[0111] As an optional implementation method, the multiple connection strategies of each transmission line in the double-circuit T-type transmission line include at least one of the following: the head end of the first transmission line is connected to the power supply and the end of the first transmission line is grounded, the head end and the end of the second transmission line are both connected to the power grid, and the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is grounded; the head end of the first transmission line is connected to the power supply and the end of the first transmission line is in an open circuit state, the head end and the end of the second transmission line are both connected to the power grid, and the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is in an open circuit state; the head end and the end of the first transmission line are both connected to the power grid, the head end of the second transmission line is connected to the power supply and the end of the second transmission line is grounded, and the head end and the end of the third transmission line are both connected to the power grid; the head end and the end of the first transmission line are both connected to the power grid, the head end of the second transmission line is connected to the power supply and the end of the second transmission line is in an open circuit state, and the head end and the end of the third transmission line are connected to the power grid.

[0112] In this embodiment, the head end of the first transmission line is connected to the power supply and the end of the first transmission line is grounded, the head end and the end of the second transmission line are both connected to the power grid, the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is grounded; that is, the head end of line 1 of the double-circuit T-type transmission line is connected to a single-phase power supply and the end is grounded, line 2 is normally energized and operates, and the end of line 3 is grounded.

[0113] Optionally, the head end of the first transmission line is connected to the power supply and the end of the first transmission line is in an open circuit state, the head end and the end of the second transmission line are both connected to the power grid, the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is in an open circuit state; that is, a single-phase power supply is added to the head end of line 1 of the double-circuit T-type transmission line, the end is open circuit, line 2 operates normally with power, and the end of line 3 is open circuit.

[0114] Optionally, the head end and the end of the first transmission line are both connected to the grid, the head end of the second transmission line is connected to the power supply and the end of the second transmission line is grounded, and the head end and the end of the third transmission line are both connected to the grid; that is, the head end of line 2 of the double-circuit T-type transmission line is connected to a single-phase power supply and the end is grounded, and line 1 and line 3 operate normally with power.

[0115] Optionally, the head end and the end of the first transmission line are both connected to the grid, the head end of the second transmission line is connected to the power supply and the end of the second transmission line is in an open circuit state, and the head end and the end of the third transmission line are both connected to the grid; that is, a single-phase power supply is added to the head end of line 2 of the double-circuit T-type transmission line, the end is open circuit, and line 1 and line 3 operate normally with power.

[0116] As an optional implementation manner, the first transmission line and the second transmission line are double-circuit transmission lines, and the third transmission line is a single-circuit transmission line.

[0117] In this embodiment, the first transmission line and the second transmission line are double-circuit transmission lines, and the third transmission line is a single-circuit transmission line.

[0118] For example, Figure 2 As shown, line 2 includes a first portion of double-circuit transmission lines and a second portion of double-circuit transmission lines, and line 3 includes a third portion of single-circuit transmission lines.

[0119] As an optional implementation method, a transmission equation of a double-circuit T-type transmission line is constructed based on power parameters, including: determining the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line in the double-circuit T-type transmission line based on the power parameters; generating a first transmission model of the double-circuit T-type transmission line based on the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line.

[0120] In this embodiment, the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line in the double-circuit T-type transmission line are determined according to the power parameters, so that the transmission equation of the double-circuit T-type transmission line is generated according to the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line.

[0121] Optionally, the specific transmission equations can be referred to as shown in the aforementioned formulas (11) to (16), which will not be repeated here.

[0122] It should be noted that the above embodiment can be executed by a device for determining zero-sequence parameters of a double-circuit T-type transmission line.

[0123] In this embodiment, the power parameters of the double-circuit T-type transmission line are measured; according to the power parameters, a first transmission model of the double-circuit T-type transmission line is constructed, wherein the first transmission model is used to describe the relationship between the voltage and the current in the double-circuit T-type transmission line; according to the first transmission model, a second transmission model of the double-circuit T-type transmission line is determined, wherein the second transmission model is used to indicate the transmission state of the voltage and / or current of the double-circuit T-type transmission line; according to the second transmission model, the zero-sequence parameters of the double-circuit T-type transmission line are determined, wherein the zero-sequence parameters include at least one of the following: zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance. That is to say, the present invention constructs the first transmission model of the double-circuit T-type transmission line through the power parameters of the double-circuit T-type transmission line, thereby determining the second transmission model according to the first transmission model, and then solving the zero-sequence parameters including zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance according to the second transmission model, thereby solving the technical problem of being unable to determine the zero-sequence parameters of the double-circuit T-type transmission line, and achieving the technical effect of determining the zero-sequence parameters of the double-circuit T-type transmission line.

[0124] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0125] At present, the power frequency parameters such as resistance, reactance (i.e. inductance), and earth conductance and susceptance (i.e. capacitance) constitute the cornerstone of the power system model, which is crucial to the accuracy of power flow calculation, relay protection setting, transient stability analysis and fault location, highlighting the importance of obtaining accurate transmission line parameters for the safe and stable operation of the power grid. Therefore, when building a modern power system, the accuracy of measuring transmission line parameters cannot be ignored. With the rapid growth of urbanization, the demand for power supply has risen sharply. The expansion of industry and commerce has prompted the construction of more transmission lines, resulting in large-scale construction of transmission lines and towers. At the same time, the restriction of the land area required for the transmission line corridor has become increasingly prominent, causing tension between power infrastructure construction and land resource utilization. Therefore, balancing economic development with power grid construction and improving the utilization efficiency of transmission corridors have become urgent issues to be solved. In this context, increasing the transmission capacity of the line is one of the solutions. The use of T-type transmission technology not only increases the power supply capacity, but also saves land resources, reduces investment costs, and brings significant social and economic benefits. However, the complex electromagnetic coupling phenomenon in the T-type transmission line makes it a technical challenge to accurately measure its zero-sequence parameters.

[0126] In the related art, there are some achievements in the research on the measurement of T-type transmission line parameters. However, most of the current research on the measurement of T-type transmission line parameters uses a concentrated parameter model. However, the concentrated parameter model is difficult to overcome the distribution effect and cannot be applied to long-distance T-type transmission lines. Therefore, there is a technical problem that the zero-sequence parameters of the double-circuit T-type transmission line cannot be determined. With respect to the above-mentioned technical problem that the zero-sequence parameters of the double-circuit T-type transmission line cannot be determined, no effective solution has been proposed.

[0127] However, the embodiment of the present invention proposes a method for measuring zero-sequence distributed parameters of a double-circuit T-type transmission line, which collects original text data and uses the synchronous timing technology of the Beidou system to synchronously measure the zero-sequence voltage and zero-sequence current at both ends of the T-type line under four different measurement modes. Substituting the measured data into the T-type transmission line transmission matrix derived by the present invention, nine zero-sequence parameters including zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance can be solved, thereby solving the technical problem of being unable to determine the zero-sequence parameters of the double-circuit T-type transmission line, and achieving the technical effect of determining the zero-sequence parameters of the double-circuit T-type transmission line.

[0128] The embodiments of the present invention are further described below.

[0129] Figure 3 1 is a flow chart of a method for measuring zero-sequence distributed parameters of a double-circuit T-type transmission line according to an embodiment of the present invention. The method comprises the following steps:

[0130] Step S301, defining the length of the double-circuit T-type transmission line.

[0131] In this embodiment, if Figure 2 As shown, according to the first part double-circuit transmission line length, the second part double-circuit transmission line length and the third part single-circuit transmission line length are defined as the first part transmission line length, the second part transmission line length, the third part transmission line length, the transmission line 1 length, the transmission line 2 length and the transmission line 3 length are defined as line 1 length, line 2 length and line 3 length, and the line 1 length is equal to the line 2 length is equal to the first part transmission line length plus the second part transmission line length, and the line 3 length is equal to the third part transmission line length.

[0132] Optionally, define the length of the first part of the transmission line as l 1 , the length of the second part of the transmission line is l 2 , the length of the third transmission line is l 3 , the length of line 1 is l 1 +l 2 , the length of line 2 is l 1 +l 2 , the length of line 3 is l 3 .

[0133] Step S302, determining a measurement method for a double-circuit T-type transmission line.

[0134] In this embodiment, zero-sequence components of the first part of double-circuit transmission lines, the second part of double-circuit transmission lines and the third part of single-circuit transmission lines are obtained according to four different measurement methods when the lines are energized.

[0135] Optionally, the four different measurement methods include: the first measurement method is: a single-phase power supply is added to the head end of line 1 of the double-circuit T-type transmission line, the end is grounded, line 2 is normally energized, and the end of line 3 is grounded. The second measurement method is: a single-phase power supply is added to the head end of line 1 of the double-circuit T-type transmission line, the end is open, line 2 is normally energized, and the end of line 3 is open. The third measurement method is: a single-phase power supply is added to the head end of line 2 of the double-circuit T-type transmission line, the end is grounded, and line 1 and line 3 are normally energized. The fourth measurement method is: a single-phase power supply is added to the head end of line 2 of the double-circuit T-type transmission line, the end is open, and line 1 and line 3 are normally energized.

[0136] Step S303, obtaining the zero-sequence component of the double-circuit T-type transmission line and calculating the corresponding zero-sequence fundamental component.

[0137] In this embodiment, the zero-sequence components of line 1, line 2 and line 3 are obtained according to four different measurement methods when the line is energized, and the corresponding zero-sequence fundamental components are calculated using the Fourier algorithm based on the obtained zero-sequence components.

[0138] Optionally, a synchronous measuring device is used to synchronously measure the following when the line is energized: the zero-sequence voltage and the zero-sequence current at the beginning and the end of line 1 under four different measurement modes; the zero-sequence voltage and the zero-sequence current at the beginning and the end of line 2 under four different measurement modes; the zero-sequence voltage and the zero-sequence current at the end of line 3 under four different measurement modes; the zero-sequence voltage at the beginning of line 1 under the four different measurement modes can be expressed by the aforementioned formulas (1) to (10), which will not be repeated here.

[0139] Optionally, the zero-sequence voltage U at the head end of line 1 under the kth zero-sequence measurement mode of the corresponding zero-sequence fundamental component k,1,s , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the head end of line 1 under the kth zero-sequence measurement mode Zero-sequence voltage U at the end of line 1 under the kth zero-sequence measurement mode k,1,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 1 under the kth zero-sequence measurement mode Zero-sequence current I at the head end of line 1 under the kth zero-sequence measurement mode k,1,s , the Fourier algorithm is used to obtain the zero-sequence fundamental current at the head end of line 1 under the kth zero-sequence measurement mode Zero-sequence voltage I at the end of line 1 under the kth zero-sequence measurement mode k,1,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 1 under the kth zero-sequence measurement mode Zero-sequence voltage U at the head end of line 2 under the kth zero-sequence measurement mode k,2,s , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the head end of line 2 under the kth zero-sequence measurement mode Zero-sequence voltage U at the end of line 2 under the kth zero-sequence measurement mode k,2,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 2 under the kth zero-sequence measurement mode Zero-sequence current I at the head end of line 2 under the kth zero-sequence measurement mode k,2,s , the Fourier algorithm is used to obtain the zero-sequence fundamental current at the head end of line 2 under the kth zero-sequence measurement mode Zero-sequence voltage I at the end of line 2 under the kth zero-sequence measurement mode k,2,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 2 under the kth zero-sequence measurement mode Zero-sequence voltage U at the end of line 3 under the kth zero-sequence measurement mode k,3,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 3 under the kth zero-sequence measurement mode Zero-sequence voltage I at the end of line 3 under the kth zero-sequence measurement mode k,3,m , the Fourier algorithm is used to obtain the zero-sequence fundamental voltage at the end of line 3 under the kth zero-sequence measurement mode Among them, k∈[1,2,3,4].

[0140] Step S304, determining the voltage and current transmission equations at the beginning and end of the double-circuit T-type transmission line.

[0141] In this embodiment, the voltage and current transmission equations at the beginning and end of the double-circuit T-type transmission line are determined according to the zero-sequence component and the zero-sequence fundamental component of the double-circuit T-type transmission line in step S303.

[0142] Optionally, the voltage and current transmission equations at the head and end of the double-circuit T-type transmission line according to different measurement methods can be expressed by the aforementioned formula (11), which will not be repeated here. is the transmission matrix of the first part of the double-circuit transmission line. And the matrix is the transmission matrix of the second part of the double-circuit transmission line. And the matrix This is the transmission matrix of the single-circuit transmission line in the third part.

[0143] Optionally, the intermediate variables can be expressed by the aforementioned formulas (12) to (14), which will not be described in detail here.

[0144] Optionally, the equation for the transmission matrix of the first part of the double-circuit transmission line obtained according to the voltage and current transmission equations at the beginning and end of the double-circuit T-type transmission line can be expressed by the aforementioned formula (15), which will not be repeated here.

[0145] Optionally, the transmission equations for the second part double-circuit transmission lines and the third part single-circuit transmission lines can be expressed by the aforementioned formula (16) according to the equations of the transmission matrix of the first part double-circuit transmission lines, and will not be repeated here.

[0146] Step S305, calculating the zero-sequence parameters of the third portion of the single-circuit transmission line.

[0147] In this embodiment, the propagation coefficient and wave impedance of the third part of the single-circuit transmission line calculated according to the transmission matrix of the third part of the single-circuit transmission line in step S304 can be expressed by the aforementioned formula (17), which will not be repeated here.

[0148] Optionally, the zero-sequence self-resistance, zero-sequence self-inductance and zero-sequence self-capacitance of the third part of the single-circuit transmission line can be calculated according to the propagation coefficient and wave impedance of the third part of the single-circuit transmission line, which can be expressed by the aforementioned formula (18) and will not be repeated here.

[0149] Step S306, calculating the zero-sequence parameters of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line.

[0150] In this embodiment, two characteristic roots r of the matrix T0 are calculated based on the transmission matrix of the second part of the double-circuit power transmission line. a 、r b , which can be expressed by the above formula (19) and will not be elaborated here.

[0151] Optionally, according to the transmission matrix of the second part double-circuit transmission line and the matrix T 0 The two characteristic roots of the first part of the double-circuit transmission line and the zero-sequence self-impedance Z of the second part of the double-circuit transmission line are calculated a , zero sequence mutual impedance Z b , zero-sequence self-admittance Y a and zero-sequence mutual admittance Y b , which can be expressed by the above formula (20) and formula (21), will not be repeated here.

[0152] Optionally, according to the zero-sequence self-impedance Z of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line a , zero sequence mutual impedance Z b , zero-sequence self-admittance Y a and zero-sequence mutual admittance Y bThe calculation of the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the first part of the double-circuit transmission line and the second part of the double-circuit transmission line can be expressed by the aforementioned formula (22), which will not be repeated here.

[0153] The following is a further introduction to the zero-sequence distributed parameter measurement method of double-circuit T-type transmission line through a specific example.

[0154] Figure 4 is a simulation model diagram of a double-circuit T-type transmission line according to an embodiment of the present invention, such as Figure 4 A simulation model is established in PSCAD, and the theoretical value of the unit length of the transmission line is shown in Table 1.

[0155] Table 1 Theoretical values ​​of zero-sequence distribution parameters per unit length of T-type transmission line

[0156]

[0157] Optionally, set line parameter l 2 = l 3 = 100km, the first part of the double-circuit T-type transmission line is connected to the double-circuit transmission line length l by the technical solution of the present invention. 1 The simulation was performed when the distance varied from 200 km to 500 km. The measurement results obtained by the measurement method of the present invention are shown in Table 2.

[0158] Table 2 Measured values ​​of zero-sequence parameters of T-type transmission line when the length of double-circuit transmission line changes in the first part

[0159]

[0160] Alternatively, according to the data in Table 2, when the length of the double-circuit parallel transmission line in the first part changes, the measurement error of zero-sequence resistance of the double-circuit transmission line in the T-type transmission line does not exceed 0.4%, the measurement error of zero-sequence inductance does not exceed 0.2%, and the measurement error of zero-sequence capacitance does not exceed 0.9%. In addition, for the single-circuit transmission line in the T-type transmission line, the measurement errors of zero-sequence resistance, inductance and capacitance do not exceed 0.3%, 0.35% and 0.9% respectively, showing high measurement accuracy, and these measurement accuracies are not affected by the change of transmission line length. The progress made in this study is attributed to the adopted distributed parameter model, which deeply considers the distribution effect in the transmission line, enabling it to accurately measure the zero-sequence parameters of transmission lines of different lengths. In addition, by adopting a differentiated processing strategy for the parameters of the double-circuit parallel line and the single-circuit line in the T-type transmission line, the accuracy of the model measurement is further improved. The application of this method not only enhances the reliability of the measurement results, but also provides effective technical support for processing various types of transmission lines.

[0161] Optionally, Figure 5is a schematic diagram of a zero-sequence parameter measurement result of a T-type transmission line transformed by a second double-circuit transmission line length according to an embodiment of the present invention, such as Figure 5 As shown, when the line parameter l 1 =400km, l 3 =100km, the length of the second part of the double-circuit T-type transmission line is l 2 The measurement results obtained by the measurement method of the present invention when the distance changes from 50km to 250km.

[0162] Optionally, Figure 6 is a schematic diagram of a zero-sequence parameter measurement result of a T-type transmission line with a single-circuit transmission line length transformation according to a third part of an embodiment of the present invention, such as Figure 6 As shown, when the line parameter l 1 =400km, l 2 =100km, the length of the third single-circuit transmission line of the double-circuit T-type transmission line is l 3 The measurement results obtained by the measurement method of the present invention when the distance changes from 50km to 250km.

[0163] Optionally, from Figure 5 and Figure 6 It can be seen that the change in the length of the third single-circuit transmission line section and the length of the second double-circuit parallel transmission line has little effect on the error of the zero-sequence parameters of the T-type transmission line. Among them, the maximum error of zero-sequence resistance does not exceed 1.2%, the maximum error of zero-sequence inductance does not exceed 0.8%, and the maximum error of zero-sequence capacitance does not exceed 1.1%, which fully meets the needs of practical engineering applications.

[0164] In this embodiment, by collecting original text data and using the synchronous timing technology of the Beidou system, the zero-sequence voltage and zero-sequence current at both ends of the T-type line are synchronously measured under four different measurement modes. Substituting the measured data into the T-type transmission line transmission matrix derived by the present invention, nine zero-sequence parameters including zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance can be solved, thereby solving the technical problem of being unable to determine the zero-sequence parameters of the double-circuit T-type transmission line, and achieving the technical effect of determining the zero-sequence parameters of the double-circuit T-type transmission line.

[0165] According to an embodiment of the present invention, a device for determining zero-sequence parameters of a double-circuit T-type transmission line is also provided. It should be noted that the device for determining zero-sequence parameters of a double-circuit T-type transmission line can be used to execute the method for determining zero-sequence parameters of a double-circuit T-type transmission line in the method embodiment.

[0166] Figure 7 Schematic diagram of a device for determining zero-sequence parameters of a double-circuit T-type transmission line according to an embodiment of the present invention. Figure 7As shown, the device 700 for determining zero-sequence parameters of the double-circuit T-type transmission line may include: a measuring unit 701 , a constructing unit 702 , a first determining unit 703 , and a second determining unit 704 .

[0167] The measuring unit 701 is used to measure the power parameters of the double-circuit T-type transmission line, wherein the power parameters are used to at least indicate the transmission state of the double-circuit T-type transmission line.

[0168] A construction unit 702 is used to construct a first transmission model of the double-circuit T-type transmission line based on the power parameters, wherein the first transmission model is used to describe the relationship between the voltage and the current in the double-circuit T-type transmission line. A first determination unit 703 is used to determine a second transmission model of the double-circuit T-type transmission line based on the first transmission model, wherein the second transmission model is used to indicate the transmission state of the voltage and / or the current of the double-circuit T-type transmission line.

[0169] The second determining unit 704 is used to determine the zero-sequence parameter of the double-circuit T-type transmission line based on the second transmission model, wherein the zero-sequence parameter includes at least one of the following: zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance.

[0170] Optionally, the measuring unit 701 may include: a first determination module, used to determine multiple connection strategies for each transmission line in the double-circuit T-type transmission line, wherein the connection strategy is used to represent the connection rules of the transmission line; and an acquisition module, used to acquire the power parameters of each transmission line in the double-circuit T-type transmission line under the multiple connection strategies.

[0171] Optionally, the first determination module may include: a first connection submodule, used for connecting the head end of the first transmission line to the power supply and the end of the first transmission line to the ground, the head end and the end of the second transmission line are both connected to the grid, and the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is grounded; a second connection submodule, used for connecting the head end of the first transmission line to the power supply and the end of the first transmission line is in an open circuit state, the head end and the end of the second transmission line are both connected to the grid, the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is in an open circuit state; a third connection submodule, used for connecting the head end and the end of the first transmission line to the grid, the head end of the second transmission line to the power supply and the end of the second transmission line is grounded, and the head end and the end of the third transmission line are both connected to the grid; a fourth connection submodule, used for connecting the head end and the end of the first transmission line to the grid, the head end of the second transmission line to the power supply and the end of the second transmission line is in an open circuit state, and the head end and the end of the third transmission line are connected to the grid.

[0172] Optionally, the first determination unit 703 may include: a second determination module, used to determine the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line in the double-circuit T-type transmission line based on power parameters; a generation module, used to generate a first transmission model of the double-circuit T-type transmission line based on the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line.

[0173] In this embodiment, the power parameters of the double-circuit T-type transmission line are measured; according to the power parameters, a first transmission model of the double-circuit T-type transmission line is constructed, wherein the first transmission model is used to describe the relationship between the voltage and the current in the double-circuit T-type transmission line; according to the first transmission model, a second transmission model of the double-circuit T-type transmission line is determined, wherein the second transmission model is used to indicate the transmission state of the voltage and / or current of the double-circuit T-type transmission line; according to the second transmission model, the zero-sequence parameters of the double-circuit T-type transmission line are determined, wherein the zero-sequence parameters include at least one of the following: zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance. That is to say, the present invention constructs the first transmission model of the double-circuit T-type transmission line through the power parameters of the double-circuit T-type transmission line, thereby determining the second transmission model according to the first transmission model, and then solving the zero-sequence parameters including zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance according to the second transmission model, thereby solving the technical problem of being unable to determine the zero-sequence parameters of the double-circuit T-type transmission line, and achieving the technical effect of determining the zero-sequence parameters of the double-circuit T-type transmission line.

[0174] According to an embodiment of the present invention, there is further provided a computer-readable storage medium, the storage medium comprising a stored program, wherein the program executes the method for determining the zero-sequence parameters of a double-circuit T-type transmission line in the method embodiment.

[0175] According to an embodiment of the present invention, a processor is further provided, the processor being used to run a program, wherein when the program is run, the method for determining the zero-sequence parameters of a double-circuit T-type transmission line in the method embodiment is executed.

[0176] According to an embodiment of the present invention, a computer program product is also provided. The computer program product includes computer instructions. When the computer instructions are executed by a processor, the method for determining the zero-sequence parameters of the double-circuit T-type transmission line in the method embodiment is implemented.

[0177] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0178] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0179] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0180] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0181] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0182] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent functional component, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software functional component, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk, etc., which can store program codes.

[0183] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining zero-sequence parameters of a double-circuit T-type transmission line, characterized in that: include: Measuring a power parameter of a double-circuit T-type transmission line, wherein the power parameter is used to at least indicate a power transmission state of the double-circuit T-type transmission line; Based on the power parameters, construct a first transmission model of the double-circuit T-type transmission line, wherein the first transmission model is used to describe the relationship between voltage and current in the double-circuit T-type transmission line; Based on the first transmission model, determining a second transmission model of the double-circuit T-type transmission line, wherein the second transmission model is used to indicate a transmission state of the voltage and / or the current of the double-circuit T-type transmission line; Based on the second transmission model, a zero-sequence parameter of the double-circuit T-type transmission line is determined, wherein the zero-sequence parameter includes at least one of the following: zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance.

2. The method according to claim 1, characterized in that The double-circuit T-type transmission line includes: a first transmission line, a second transmission line and a third transmission line. Measuring the power parameters of the double-circuit T-type transmission line includes: Determining a plurality of connection strategies for each transmission line in the double-circuit T-type transmission line, wherein the connection strategy is used to represent a connection rule of the transmission line; Under the multiple connection strategies, the power parameters of each transmission line in the double-circuit T-type transmission line are obtained.

3. The method according to claim 2, characterized in that The power parameters of each transmission line include at least: the head end zero-sequence voltage and the head end zero-sequence current of the first transmission line and the second transmission line, the terminal zero-sequence voltage and the terminal zero-sequence current of the first transmission line and the second transmission line, and the terminal zero-sequence voltage and the terminal zero-sequence current of the third transmission line.

4. The method according to claim 2, characterized in that: The multiple connection strategies of each transmission line in the double-circuit T-type transmission line include at least one of the following: The first end of the first transmission line is connected to a power source and the end of the first transmission line is grounded, the first end and the end of the second transmission line are both connected to a power grid, the first end of the third transmission line is connected to the first transmission line and the end of the third transmission line is grounded; The head end of the first transmission line is connected to a power source and the end of the first transmission line is in an open circuit state, the head end and the end of the second transmission line are both connected to the power grid, the head end of the third transmission line is connected to the first transmission line and the end of the third transmission line is in the open circuit state; The first end and the terminal of the first transmission line are both connected to the power grid, the first end of the second transmission line is connected to a power source and the terminal of the second transmission line is grounded, and the first end and the terminal of the third transmission line are connected to the power grid; The first end and the end of the first transmission line are both connected to the power grid, the first end of the second transmission line is connected to the power supply and the end of the second transmission line is in the open circuit state, and the first end and the end of the third transmission line are both connected to the power grid.

5. The method according to claim 2, characterized in that: The first transmission line and the second transmission line are double-circuit transmission lines, and the third transmission line is a single-circuit transmission line.

6. The method according to any one of claims 1 to 5, characterized in that: Based on the power parameters, a first transmission model of the double-circuit T-type transmission line is constructed, including: Based on the power parameters, determining the zero-sequence fundamental voltage and zero-sequence fundamental current of each transmission line in the double-circuit T-type transmission line; The first transmission model of the double-circuit T-type transmission line is generated based on the zero-sequence fundamental voltage and the zero-sequence fundamental current of each of the transmission lines.

7. A device for determining zero-sequence parameters of a double-circuit T-type transmission line, characterized in that: include: A measuring unit, used for measuring a power parameter of a double-circuit T-type transmission line, wherein the power parameter is used for at least indicating a power transmission state of the double-circuit T-type transmission line; A construction unit, configured to construct a first transmission model of the double-circuit T-type transmission line based on the power parameter, wherein the first transmission model is used to describe the relationship between voltage and current in the double-circuit T-type transmission line; A first determining unit, configured to determine a second transmission model of the double-circuit T-type transmission line based on the first transmission model, wherein the second transmission model is used to indicate a transmission state of the voltage and / or the current of the double-circuit T-type transmission line; The second determination unit is used to determine the zero-sequence parameter of the double-circuit T-type transmission line based on the second transmission model, wherein the zero-sequence parameter includes at least one of the following: zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the method according to any one of claims 1 to 6.

9. A processor, characterized in that: The processor is used to run a program, wherein the program executes the method according to any one of claims 1 to 6 when running.

10. A computer program product, characterized in that The computer program product comprises computer instructions, which implement the method according to any one of claims 1 to 6 when executed by a processor.

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