Live-line measurement method and device for zero-sequence distribution parameters of double-circuit line sharing bus at two ends

Abstract

The invention discloses a live-line measurement method and device for zero-sequence distribution parameters of a double-circuit line with double ends sharing a bus, and the method comprises the steps: measuring the power parameters of the double-circuit transmission line with double ends sharing the bus, and enabling the power parameters to be used for at least indicating the operation state of the double-circuit transmission line with double ends sharing the bus; a line impedance parameter matrix and an admittance parameter matrix are constructed based on the electric power parameters of the double-circuit power transmission line with the double ends sharing the bus, the line impedance parameter matrix is used for indicating impedance characteristics of the double-circuit power transmission line with the double ends sharing the bus, and the admittance parameter matrix is used for indicating admittance characteristics of the double-circuit power transmission line with the double ends sharing the bus; zero-sequence parameters, including at least one of zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance, of the double-circuit transmission line sharing the bus at the two ends are determined based on the line impedance parameter matrix and the admittance parameter matrix. According to the invention, live-line measurement of line zero-sequence distribution parameters of double-circuit transmission lines on the same tower or different towers with double ends sharing buses can be effectively realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power system measurement, and in particular to a method and a device for live measurement of zero-sequence distribution parameters of a double-circuit line with a double-end common busbar. Background Art

[0002] The transmission line parameters mainly include resistance, inductance, conductance and capacitance at 50Hz power frequency. Conductance is related to corona loss and insulator leakage resistance, but in order to avoid corona phenomenon during design, the conductance parameters are usually ignored. The phase parameters of the transmission line can be converted into positive-sequence, negative-sequence and zero-sequence parameters by the symmetrical component method. Among them, the zero-sequence parameters include zero-sequence self-impedance, zero-sequence self-admittance, zero-sequence mutual impedance and zero-sequence mutual admittance. These parameters are the basis of numerical analysis of power systems (such as network loss calculation, power flow calculation, short-circuit calculation and relay protection setting). Large calculation errors may cause protection measures to fail or malfunction, affecting the safe and stable operation of the system. Therefore, in the context of increasing requirements for power systems in the new era, it is necessary to pay attention to the accurate measurement of main grid overhead line parameters.

[0003] The construction of new transmission lines has made the transmission corridors more and more crowded. In order to meet the growing demand for electricity, there is a phenomenon of multiple transmission lines being erected in parallel on the same tower or on different towers. There is electromagnetic coupling between these lines. At the same time, nearly 20 UHV lines with a length of more than 600 km are in operation or under construction, and a large number of ultra-high voltage lines are also more than 200 km long. The construction of these new transmission lines has brought new opportunities and challenges to the measurement and research of transmission line parameters. Therefore, studying the measurement theory and methods of transmission line distributed parameters is of vital practical significance to ensure the safe and stable operation of the power system and achieve sustainable development.

[0004] The double-circuit transmission line with a common busbar at both ends is a land-saving and compact tower type that can effectively solve the problem of tight transmission corridors. However, in long-distance transmission, there are errors in the theoretical derivation of centralized model parameters, and the measurement theory of the double-circuit transmission line with a common busbar at both ends on the same tower / not on the same tower based on distributed parameters under live operation conditions is still imperfect. Therefore, there is a technical problem that the line parameters of the double-circuit transmission line with a common busbar at both ends on the same tower / not on the same tower cannot be measured live. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first object of the present invention is to provide a method for measuring the zero-sequence distributed parameters of a double-circuit line with a double-terminal common busbar under power supply conditions, so as to solve the technical problem that the distributed parameters of a double-circuit transmission line cannot be measured under power supply conditions.

[0006] The second object of the present invention is to provide a live measuring device for zero-sequence distributed parameters of a double-circuit line with a double-end common busbar.

[0007] A third object of the present invention is to provide a computer-readable storage medium.

[0008] A fourth object of the present invention is to provide an electronic device.

[0009] To achieve the above object, the present invention is implemented through the following technical solutions:

[0010] A method for measuring zero-sequence distribution parameters of a double-circuit line with a double-terminal common busbar, comprising:

[0011] Measuring power parameters of a double-circuit power transmission line with a double-ended common bus, wherein the power parameters are used to at least indicate the operating state of the double-circuit power transmission line with a double-ended common bus;

[0012] Based on the power parameters of the double-circuit power transmission line with two ends and a common bus, a line impedance parameter matrix and an admittance parameter matrix of the double-circuit power transmission line with two ends and a common bus are constructed, wherein the line impedance parameter matrix is ​​used to indicate the impedance characteristics of the double-circuit power transmission line with two ends and a common bus, and the admittance parameter matrix is ​​used to indicate the admittance characteristics of the double-circuit power transmission line with two ends and a common bus;

[0013] Based on the line impedance parameter matrix and the admittance parameter matrix, the zero-sequence parameter of the double-circuit transmission line with two ends and a common bus is determined, wherein the zero-sequence parameter includes at least one of a zero-sequence resistance, a zero-sequence inductance and a zero-sequence capacitance.

[0014] Preferably, measuring the power parameters of a double-circuit power transmission line with a double-ended common busbar includes:

[0015] Determine multiple measurement methods for each transmission line in the double-circuit transmission line with a double-terminal common busbar;

[0016] When the double-circuit power transmission line with a common bus at both ends is in an energized operation state, the power parameters of each power transmission line in the double-circuit power transmission line with a common bus at both ends are obtained under the multiple measurement modes.

[0017] Preferably, the power parameters of each transmission line include at least a head-end zero-sequence voltage and a head-end zero-sequence current of each transmission line, and a terminal zero-sequence voltage and a terminal zero-sequence current of each transmission line.

[0018] Preferably, the double-circuit transmission line with a common bus at both ends includes a first transmission line and a second transmission line, and the multiple measurement methods of each transmission line in the double-circuit transmission line with a common bus at both ends include at least:

[0019] One of the phases at the end of the first transmission line is disconnected for a short time, and then the line is reclosed, and the second transmission line operates normally;

[0020] The other phase at the end of the first transmission line is disconnected for a short time by a circuit breaker, and then the line is reclosed, and the second transmission line operates normally;

[0021] The first transmission line operates normally, and one of the phases at the end of the second transmission line is disconnected for a short time by a circuit breaker, and then the line is reclosed;

[0022] The first transmission line operates normally, and the other phase at the end of the second transmission line disconnects the circuit breaker for a short time and then recloses the line.

[0023] Preferably, based on the power parameters of the double-circuit power transmission line with two ends and a common bus, a line impedance parameter matrix of the double-circuit power transmission line with two ends and a common bus is constructed, including:

[0024] Based on the power parameters of each transmission line in the double-circuit transmission line with a double-ended common busbar, calculate the distributed zero-sequence self-impedance per unit length of each transmission line and the distributed zero-sequence mutual impedance per unit length between the double-circuit transmission lines;

[0025] Based on the distributed zero-sequence self-impedance per unit length and the distributed zero-sequence mutual impedance per unit length of the double-circuit power transmission line with a common bus at both ends, the line impedance parameter matrix of the double-circuit power transmission line with a common bus at both ends is generated.

[0026] Preferably, based on the power parameters of the double-circuit power transmission line with two ends and a common busbar, constructing the admittance parameter matrix of the double-circuit power transmission line with two ends and a common busbar, comprises:

[0027] Based on the power parameters of each transmission line in the double-circuit transmission line with a double-terminal common busbar, calculate the distributed zero-sequence self-admittance per unit length of each transmission line and the distributed zero-sequence mutual admittance per unit length between the double-circuit transmission lines;

[0028] The admittance parameter matrix of the double-circuit transmission line with a common bus at both ends is generated based on the zero-sequence self-admittance per unit length and the distributed zero-sequence mutual-admittance per unit length of the double-circuit transmission line with a common bus at both ends.

[0029] Preferably, determining the zero-sequence parameters of the double-circuit power transmission line with two ends and a common busbar based on the line impedance parameter matrix and the admittance parameter matrix includes:

[0030] Comparing the parameters in the line impedance parameter matrix to obtain a first comparison result of the parameters in the line impedance parameter matrix, and comparing the parameters in the admittance parameter matrix to obtain a second comparison result of the parameters in the admittance parameter matrix;

[0031] Based on the first comparison result, the parameters with equal values ​​in the line impedance parameter matrix are replaced by one of the parameters to obtain a simplified line impedance parameter matrix; and based on the second comparison result, the parameters with equal values ​​in the admittance parameter matrix are replaced by one of the parameters to obtain a simplified admittance parameter matrix;

[0032] Based on the simplified line impedance parameter matrix and the simplified admittance parameter matrix, the zero-sequence parameters of the double-circuit power transmission line with two ends and a common bus are determined.

[0033] In order to achieve the above-mentioned object, the second aspect of the present invention provides a live zero-sequence distributed parameter measuring device for a double-circuit line with a double-terminal common busbar, comprising:

[0034] A measuring unit, used for measuring power parameters of a double-circuit power transmission line with a double-end common bus, wherein the power parameters are used for at least indicating the operating state of the double-circuit power transmission line with a double-end common bus;

[0035] A construction unit, configured to construct a line impedance parameter matrix and an admittance parameter matrix of the double-circuit power transmission line with a double-end common bus based on the power parameters of the double-circuit power transmission line with a double-end common bus, wherein the line impedance parameter matrix is ​​used to indicate the impedance characteristics of the double-circuit power transmission line with a double-end common bus, and the admittance parameter matrix is ​​used to indicate the admittance characteristics of the double-circuit power transmission line with a double-end common bus;

[0036] A determination unit is used to determine the zero-sequence parameters of the double-circuit transmission line with a double-terminal common bus based on the line impedance parameter matrix and the admittance parameter matrix, wherein the zero-sequence parameters include at least one of zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance.

[0037] To achieve the above-mentioned purpose, the third aspect of the present invention provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method for measuring the zero-sequence distributed parameters of a double-circuit line with a double-terminal common busbar is implemented.

[0038] To achieve the above-mentioned purpose, the fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for live measurement of zero-sequence distributed parameters of a double-circuit line with a double-terminal common bus is implemented.

[0039] The present invention has at least the following technical effects:

[0040] The present invention provides a live measurement scheme for zero-sequence distributed parameters of a double-circuit transmission line with a double-ended common bus, specifically measuring the power parameters of a double-circuit transmission line with a double-ended common bus; constructing a line impedance parameter matrix and an admittance parameter matrix of the double-circuit transmission line with a double-ended common bus based on the power parameters of the double-circuit transmission line with a double-ended common bus; and determining the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus based on the line impedance parameter matrix and the admittance parameter matrix. In other words, the present invention can construct a line impedance parameter matrix and an admittance parameter matrix of the double-circuit transmission line with a double-ended common bus through the power parameters of the double-circuit transmission line with a double-ended common bus, solve the line impedance parameter matrix and the admittance parameter matrix by mathematical derivation, and determine the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus, thereby achieving the technical effect of effectively solving the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus, and then solving the technical problem that the line parameters of multi-circuit transmission lines cannot be measured live.

[0041] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The present invention is a flowchart of a method for measuring live zero-sequence distributed parameters of a double-circuit line with a double-ended common busbar according to an embodiment of the present invention.

[0043] Figure 2 The present invention is a flowchart of a method for live measurement of zero-sequence distribution parameters of a double-circuit line with a double-terminal common busbar according to an embodiment of the present invention.

[0044] Figure 3 The diagram is a schematic diagram of a double-circuit line measurement connection with a double-terminal common busbar according to an embodiment of the present invention.

[0045] Figure 4 1 is a schematic diagram of a live zero-sequence distributed parameter measurement device for a double-circuit line with a double-terminal common busbar according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The present embodiment is described in detail below, and examples of the embodiment 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 invention, and should not be construed as limiting the present invention.

[0047] Example 1

[0048] According to an embodiment of the present invention, an embodiment of a live measurement scheme for zero-sequence distributed parameters of a double-circuit line with a double-terminal common bus 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.

[0049] Figure 1 1 is a flow chart of a method for measuring live zero-sequence distributed parameters of a double-circuit line with a double-ended common busbar according to an embodiment of the present invention. Figure 1 As shown, the method may include the following steps:

[0050] Step S101, measuring power parameters of a double-circuit transmission line with a double-end common bus.

[0051] In the technical solution provided in step S101 of the present invention, the power parameters are used to at least indicate the operating status of the double-circuit transmission line with a double-ended common busbar, wherein the power parameters may at least include but are not limited to the zero-sequence voltage and zero-sequence current at the beginning and end of each transmission line.

[0052] In this embodiment, power parameters of a double-circuit power transmission line with a double-terminal common busbar are measured.

[0053] Optionally, multiple measurement methods are determined for each transmission line in a double-circuit transmission line with a double-end common busbar, wherein the power parameters of each transmission line include at least: a zero-sequence voltage and a zero-sequence current at the head end of each transmission line, and a zero-sequence voltage and a zero-sequence current at the end of each transmission line.

[0054] Optionally, the double-circuit transmission line with a double-terminal common busbar includes: a first transmission line and a second transmission line, and a measurement method for the first and last ends of each transmission line in the double-circuit transmission line with a double-terminal common busbar may be defined.

[0055] For example, the first measurement method may be: one of the phases at the end of the first transmission line is short-term disconnected from the circuit breaker, and then the line is reclosed, and the second transmission line operates normally; the second measurement method may be: the other phase at the end of the first transmission line is short-term disconnected from the circuit breaker, and then the line is reclosed, and the second transmission line operates normally; the third measurement method may be: the first transmission line operates normally, and one of the phases at the end of the second transmission line is short-term disconnected from the circuit breaker, and then the line is reclosed; the fourth measurement method may be: the first transmission line operates normally, and the other phase at the end of the second transmission line is short-term disconnected from the circuit breaker, and then the line is reclosed.

[0056] Optionally, after determining multiple measurement methods for each transmission line in a double-circuit transmission line with a double-ended common bus, when the double-circuit transmission line with a double-ended common bus is in an energized operation state, the power parameters of each transmission line in the double-circuit transmission line with a double-ended common bus under multiple measurement methods are obtained. For example, using a synchronous measurement device to synchronously measure the power parameters of each transmission line is only an illustrative example, and the specific method for obtaining the power parameters of each transmission line is not limited.

[0057] For example, a synchronous measuring device is used to synchronously measure the zero-sequence voltage and zero-sequence current at the beginning and end of the first transmission line, and the zero-sequence voltage and zero-sequence current at the beginning and end of the second transmission line.

[0058] In this embodiment, multiple measurement methods for each transmission line in a double-circuit transmission line with a double-end common bus are determined, and when the double-circuit transmission line with a double-end common bus is in an energized operation state, the power parameters of each transmission line in the double-circuit transmission line with a double-end common bus under multiple measurement methods are obtained, and step S102 is executed according to the obtained power parameters of each transmission line.

[0059] Step S102, based on the power parameters of the double-circuit power transmission line with two terminals and a common busbar, construct a line impedance parameter matrix and an admittance parameter matrix of the double-circuit power transmission line with two terminals and a common busbar.

[0060] In the technical solution provided in the above step S102 of the present invention, the line impedance parameter matrix is ​​used to indicate the impedance characteristics of the double-circuit transmission line with a double-terminal common busbar, and the admittance parameter matrix is ​​used to indicate the admittance characteristics of the double-circuit transmission line with a double-terminal common busbar. The line impedance parameter matrix can also be called an impedance matrix, and the admittance parameter matrix can also be called an admittance matrix.

[0061] In this embodiment, according to the power parameters of each transmission line acquired in step S101, a line impedance parameter matrix and an admittance parameter matrix of a double-circuit transmission line with a double-terminal common bus are constructed.

[0062] Optionally, for constructing a line impedance parameter matrix of a double-circuit transmission line with a double-terminal common busbar, the distributed zero-sequence self-impedance per unit length of each transmission line is calculated according to the power parameters of each transmission line in the double-circuit transmission line with a double-terminal common busbar.

[0063] For example, Z 11 The distributed zero-sequence self-impedance per unit length of the first transmission line, Z 22 The distributed zero-sequence self-impedance per unit length of the second transmission line can be represented.

[0064] Optionally, the distributed zero-sequence mutual impedance per unit length between the double-circuit transmission lines with a double-terminal common busbar is calculated according to the power parameters of each transmission line in the double-circuit transmission lines with a double-terminal common busbar.

[0065] For example, Z 12 It can be expressed as the distributed zero-sequence mutual impedance per unit length between the first transmission line and the second transmission line, Z 21 It represents the distributed zero-sequence mutual impedance per unit length between the second transmission line and the first transmission line.

[0066] Optionally, a line impedance parameter matrix of a double-circuit transmission line with a common bus at both ends is generated according to the distributed zero-sequence self-impedance per unit length and the distributed zero-sequence mutual impedance per unit length of each transmission line of the double-circuit transmission line with a common bus at both ends.

[0067] For example, the line impedance parameter matrix Z of a double-circuit transmission line with a double-ended common busbar is:

[0068]

[0069] Optionally, for constructing an admittance parameter matrix of a double-circuit transmission line with a double-terminal common busbar, the distributed zero-sequence self-admittance per unit length of each transmission line is calculated according to the power parameters of each transmission line in the double-circuit transmission line with a double-terminal common busbar.

[0070] For example, Y 11 It can be expressed as the distributed zero-sequence self-admittance per unit length of the first transmission line, Y 22 The distributed zero-sequence self-admittance per unit length of the second transmission line can be represented.

[0071] Optionally, the distributed zero-sequence mutual admittance per unit length between the double-circuit transmission lines with a double-terminal common busbar is calculated according to the power parameters of each transmission line in the double-circuit transmission lines with a double-terminal common busbar.

[0072] For example, Y 12 It can represent the distributed zero-sequence mutual admittance per unit length between the first transmission line and the second transmission line, Y 21 The distributed zero-sequence mutual admittance per unit length between the second transmission line and the first transmission line can be represented.

[0073] Optionally, an admittance parameter matrix of a double-circuit transmission line with a common bus at both ends is generated according to the zero-sequence self-admittance per unit length and the distributed zero-sequence mutual-admittance per unit length of the double-circuit transmission line with a common bus at both ends.

[0074] For example, the admittance parameter matrix Y can be expressed as:

[0075]

[0076] In this embodiment, according to the power parameters of each transmission line in the double-circuit transmission line with two ends and a common bus, the unit length distributed zero-sequence self-impedance of each transmission line and the unit length distributed zero-sequence mutual impedance between each transmission line are calculated, thereby generating a line impedance parameter matrix of the double-circuit transmission line with two ends and a common bus; according to the power parameters of each transmission line in the double-circuit transmission line with two ends and a common bus, the unit length distributed zero-sequence self-admittance of each transmission line and the unit length distributed zero-sequence mutual admittance between each transmission line are calculated, thereby generating an admittance parameter matrix of the double-circuit transmission line with two ends and a common bus. Then, according to the generated line impedance parameter matrix and admittance parameter matrix, step S103 is performed.

[0077] Step S103, determining the zero-sequence parameters of the double-circuit transmission line with a double-terminal common busbar based on the line impedance parameter matrix and the admittance parameter matrix.

[0078] In the technical solution provided in the above step S103 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.

[0079] In this embodiment, after constructing the line impedance parameter matrix and the admittance parameter matrix of the double-circuit transmission line with two terminals and a common busbar in step S102, the zero-sequence parameters of the double-circuit transmission line with two terminals and a common busbar are determined according to the line impedance parameter matrix and the admittance parameter matrix.

[0080] Optionally, each parameter in the line impedance parameter matrix is ​​compared to obtain a first comparison result of each parameter.

[0081] For example, the first comparison result can be expressed by the following first formula:

[0082]

[0083] Optionally, each parameter in the admittance parameter matrix is ​​compared to obtain a second comparison result of each parameter.

[0084] For example, the second comparison result can be expressed by the following second formula:

[0085]

[0086] Optionally, after obtaining the first comparison result, according to the first comparison result, the parameters with equal values ​​in the line impedance parameter matrix are replaced by one of the parameters to obtain a simplified line impedance parameter matrix. 12 =Z 21 When Z 12 Replace Z 21, a simplified line impedance parameter matrix is ​​obtained. This is only an illustrative example and does not limit the specific content of the simplified line impedance parameter matrix.

[0087] For example, the simplified line impedance parameter matrix Z0 can be:

[0088]

[0089] Optionally, after obtaining the second comparison result, according to the second comparison result, the parameters with equal values ​​in the admittance parameter matrix are replaced by one of the parameters to obtain a simplified admittance parameter matrix. 12 =Y 21 When Y 12 Use instead of Y 21 , and a simplified admittance parameter matrix is ​​obtained. This is only an illustrative example and does not limit the specific content of the simplified admittance parameter matrix.

[0090] For example, the simplified admittance parameter matrix Y0 can be:

[0091]

[0092] Optionally, after obtaining a simplified line impedance parameter matrix and a simplified admittance parameter matrix, the zero-sequence parameters of a double-circuit transmission line with a double-terminal common bus are determined according to the simplified line impedance parameter matrix and the simplified admittance parameter matrix.

[0093] For example, the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of a double-circuit transmission line with a double-terminal common busbar can be calculated according to the following third formula.

[0094]

[0095] Among them, R 11 is the distributed zero-sequence self-resistance per unit length of the first transmission line, R 22 is the distributed zero-sequence self-resistance per unit length of the second transmission line, R 12 is the zero-sequence mutual resistance per unit length between the first transmission line and the second transmission line. 11 is the distributed zero-sequence self-inductance per unit length of the first transmission line, L 22 is the distributed zero-sequence self-inductance per unit length of the second transmission line, L 12 is the distributed zero-sequence mutual inductance per unit length between the first transmission line and the second transmission line. C 11 is the distributed zero-sequence self-capacitance per unit length of the first transmission line, C 22 is the distributed zero-sequence self-capacitance per unit length of the second transmission line, C 12is the distributed zero-sequence mutual capacitance per unit length between the first transmission line and the second transmission line, ω is the angular frequency, and j is the imaginary unit.

[0096] For another example, based on Kirchhoff's principle, the simplified line impedance parameter matrix and the simplified admittance parameter matrix are analyzed to determine the zero-sequence distributed parameters of a double-circuit transmission line with a double-terminal common busbar.

[0097] It should be noted that the above embodiment can be implemented by a live zero-sequence distributed parameter measurement device for a double-circuit power transmission line with a double-terminal common busbar.

[0098] The above steps S101 to S103 of the present invention measure the power parameters of the double-circuit transmission line with a double-ended common bus; based on the power parameters of the double-circuit transmission line with a double-ended common bus, construct the line impedance parameter matrix and the admittance parameter matrix of the double-circuit transmission line with a double-ended common bus; based on the line impedance parameter matrix and the admittance parameter matrix, determine the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus. In other words, the present invention can construct the line impedance parameter matrix and the admittance parameter matrix of the double-circuit transmission line with a double-ended common bus through the power parameters of the double-circuit transmission line with a double-ended common bus, solve the line impedance parameter matrix and the admittance parameter matrix by mathematical derivation, and determine the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus, thereby achieving the technical effect of effectively solving the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus, and then solving the technical problem that the line distribution parameters of the double-circuit transmission line cannot be measured live.

[0099] The above method of this embodiment is further introduced below.

[0100] As an optional implementation method, measuring the power parameters of a double-circuit transmission line with a common bus at both ends includes: determining multiple measurement methods for each transmission line in the double-circuit transmission line with a common bus at both ends; when the double-circuit transmission line with a common bus at both ends is in an energized operation state, obtaining the power parameters of each transmission line in the double-circuit transmission line with a common bus at both ends under multiple measurement methods.

[0101] In this embodiment, multiple measurement methods for each transmission line in a double-circuit transmission line with a double-ended common bus are determined. When the double-circuit transmission line with a double-ended common bus is in an energized operation state, the power parameters of each transmission line in the double-circuit transmission line with a double-ended common bus under multiple measurement methods are obtained. For example, the power parameters of each transmission line are synchronously measured using a synchronous measurement device, which is only an illustrative example here, and the specific method for obtaining the power parameters of each transmission line is not limited.

[0102] For example, a synchronous measuring device is used to synchronously measure the zero-sequence voltage and zero-sequence current at the beginning and end of the first transmission line, and the zero-sequence voltage and zero-sequence current at the beginning and end of the second transmission line.

[0103] As an optional implementation manner, the power parameters of each transmission line include at least: the zero-sequence voltage and the zero-sequence current at the head end of each transmission line, and the zero-sequence voltage and the zero-sequence current at the end of each transmission line.

[0104] In this embodiment, each transmission line has dual voltage and terminal zero-sequence current.

[0105] For example, the power parameters of each transmission line include at least: zero-sequence voltage and zero-sequence current at the beginning and end of the first transmission line, and zero-sequence voltage and zero-sequence current at the beginning and end of the second transmission line.

[0106] As an optional implementation method, a double-circuit transmission line with a common bus at both ends includes: a first transmission line, a second transmission line, and multiple measurement methods for each transmission line in the double-circuit transmission line with a common bus at both ends, including at least: one of the phases at the end of the first transmission line is short-term disconnected from the line circuit breaker, and then the line is reclosed, and the second transmission line operates normally; the other phase at the end of the first transmission line is short-term disconnected from the line circuit breaker, and then the line is reclosed, and the second transmission line operates normally; the first transmission line operates normally, and one of the phases at the end of the second transmission line is short-term disconnected from the line circuit breaker, and then the line is reclosed; the first transmission line operates normally, and the other phase at the end of the second transmission line is short-term disconnected from the line circuit breaker, and then the line is reclosed.

[0107] In this embodiment, the first measurement method may be: a circuit breaker of one phase at the end of the first transmission line is disconnected for a short time, and then the line is reclosed, and the second transmission line operates normally.

[0108] Optionally, the second measurement method may be: the other phase at the end of the first transmission line is disconnected for a short time by a circuit breaker, and then the line is reclosed, and the second transmission line operates normally.

[0109] Optionally, the third measurement method may be: the first transmission line operates normally, and one of the phases at the end of the second transmission line is disconnected from the circuit breaker for a short time, and then the line is reclosed.

[0110] Optionally, the fourth measurement method may be: the first transmission line operates normally, and the other phase at the end of the second transmission line is disconnected from the circuit breaker for a short time, and then the line is reclosed.

[0111] As an optional implementation method, based on the power parameters of a double-circuit transmission line with a double-ended common bus, a line impedance parameter matrix of the double-circuit transmission line with a double-ended common bus is constructed, including: based on the power parameters of each transmission line in the double-circuit transmission line with a double-ended common bus, calculating the unit length distributed zero-sequence self-impedance of each transmission line, and based on the power parameters of each transmission line in the double-circuit transmission line with a double-ended common bus, calculating the unit length distributed zero-sequence mutual impedance of the double-circuit transmission line with a double-ended common bus; based on the unit length distributed zero-sequence self-impedance and unit length distributed zero-sequence mutual impedance of the double-circuit transmission line with a double-ended common bus, generating a line impedance parameter matrix of the double-circuit transmission line with a double-ended common bus.

[0112] In this embodiment, the distributed zero-sequence self-impedance per unit length of each transmission line is calculated according to the power parameters of each transmission line in the double-circuit transmission line with a double-terminal common busbar. The method of calculating the distributed zero-sequence self-impedance per unit length of each transmission line according to the power parameters of each transmission line in the double-circuit transmission line with a double-terminal common busbar can refer to the introduction of the aforementioned step S102, which will not be repeated here.

[0113] Similarly, based on the power parameters of the double-circuit transmission line with a double-terminal common busbar, the admittance parameter matrix of the double-circuit transmission line with a double-terminal common busbar is constructed.

[0114] As an optional implementation method, based on the line impedance parameter matrix and the admittance parameter matrix, the zero-sequence parameters of the double-circuit transmission line with a common bus at both ends are determined, including: comparing the parameters in the line impedance parameter matrix to obtain a first comparison result of the parameters, and comparing the parameters in the admittance parameter matrix to obtain a second comparison result of the parameters; based on the first comparison result, replacing the parameters with equal values ​​in the line impedance parameter matrix with one of the parameters to obtain a simplified line impedance parameter matrix, and based on the second comparison result, replacing the parameters with equal values ​​in the admittance parameter matrix with one of the parameters to obtain a simplified admittance parameter matrix; based on the simplified line impedance parameter matrix and the simplified admittance parameter matrix, the zero-sequence parameters of the double-circuit transmission line with a common bus at both ends are determined.

[0115] In this embodiment, the parameters in the line impedance parameter matrix are compared to obtain the first comparison results of the parameters; the parameters in the admittance parameter matrix are compared to obtain the second comparison results of the parameters. After obtaining the first comparison result, the parameters with equal values ​​in the line impedance parameter matrix are replaced by one of the parameters according to the first comparison result to obtain a simplified line impedance parameter matrix. For example, when Z 12 =Z 21 When Z 12 Use instead of Z 21, and obtain the simplified line impedance parameter matrix. Similarly, after obtaining the second comparison result, according to the second comparison result, the parameters with equal values ​​in the admittance parameter matrix are replaced by one of the parameters to obtain the simplified admittance parameter matrix. For example, when Y 12 =Y 21 When Y 12 Use instead of Y 21 , and obtain a simplified admittance parameter matrix. The method of determining the simplified line impedance matrix and the simplified admittance parameter matrix can refer to the introduction of the aforementioned step S103, which will not be repeated here.

[0116] As an optional implementation method, based on a simplified line impedance parameter matrix and a simplified admittance parameter matrix, the zero-sequence parameters of a double-circuit transmission line with a common bus at both ends are determined, including: according to Kirchhoff's principle, the simplified line impedance parameter matrix and the simplified admittance parameter matrix are analyzed to determine the zero-sequence parameters of the double-circuit transmission line with a common bus at both ends.

[0117] In this embodiment, according to Kirchhoff's principle, the simplified line impedance parameter matrix and the simplified admittance parameter matrix are analyzed to determine the zero-sequence parameters of the double-circuit transmission line with a double-terminal common busbar.

[0118] For example, by analyzing the simplified line impedance parameter matrix and the simplified admittance parameter matrix, the line transmission line equation can be determined as:

[0119]

[0120]

[0121] In the formula, is the zero-sequence fundamental voltage at the head end of the first transmission line, is the zero-sequence fundamental voltage at the head end of the second transmission line. is the zero-sequence fundamental current at the head end of the first transmission line, is the zero-sequence fundamental current at the head end of the second transmission line.

[0122] The voltage matrix of the matrix form line transmission line equation is calculated according to the fourth formula below and the current matrix And write the line transmission line equation in matrix form;

[0123] Among them, the fourth formula is:

[0124]

[0125] The transmission line equation in matrix form is:

[0126]

[0127] According to the impedance parameter matrix and the admittance parameter matrix, the intermediate parameter matrix P can be obtained:

[0128]

[0129] Among them, P1, P2, P3, and P4 are the parameters in the intermediate parameter matrix P respectively;

[0130] Based on the second-order derivative form of the transmission line equation in matrix form, the fifth formula can be obtained;

[0131] Among them, the fifth formula is:

[0132]

[0133] Convert the fifth formula into the seventh formula according to the sixth formula;

[0134] Among them, the sixth formula is:

[0135]

[0136] Wherein, f(x) represents the original function, F(s) or L[f(x)] represents the image function of f(x), L[f″(x)] represents the Laplace transform of the time domain function in the square brackets, s=σ+jω represents a frequency in complex form, abbreviated as complex frequency, where the real part σ is always positive, and the imaginary part ω can be positive, negative, or zero.

[0137] The seventh formula is:

[0138]

[0139] represents the image function of the zero-sequence fundamental voltage of the first section of the first transmission line, represents the image function of the zero-sequence fundamental voltage of the first section of the second transmission line, represents the zero-sequence fundamental voltage at the end of the first transmission line, Represents the zero-sequence fundamental voltage at the end of the second transmission line.

[0140] Convert the seventh formula into the eighth formula;

[0141] Among them, the eighth formula is:

[0142]

[0143] represents the zero-sequence fundamental current at the end of the first transmission line, Represents the zero-sequence fundamental current at the end of the second transmission line.

[0144] According to the intermediate parameter matrix P, the parameter matrix Q can be obtained:

[0145]

[0146] Among them, the determinant of the parameter matrix Q is:

[0147]

[0148] r1 and r2 are intermediate parameters.

[0149] Convert the eighth formula into the ninth formula;

[0150] Among them, the ninth formula is:

[0151]

[0152] Taking Laplace transform of the ninth formula, we get the tenth formula;

[0153] Among them, the tenth formula is:

[0154]

[0155] In the formula, Represents the zero-sequence fundamental voltage at the head end of the first transmission line and Equivalent, The zero-sequence fundamental voltage at the head end of the second transmission line is Equivalently, A1-A4 and B1-B4 are all intermediate variables.

[0156] Among them, the intermediate variables A1-A4, B1-B4 are:

[0157]

[0158] Wherein, x=l, l is the length of the double-circuit transmission line with a double-ended common busbar.

[0159] Based on the second-order derivative form of the matrix transmission line equation and the derivation process of the tenth formula, the eleventh formula can be obtained as follows:

[0160]

[0161] in, Represents the zero-sequence fundamental current at the head end of the first transmission line and Equivalent, Represents the zero-sequence fundamental current at the head end of the second transmission line and Equivalently, C1-C4 and D1-D4 are intermediate variables, and D1-D4 is:

[0162]

[0163] Substituting the tenth and eleventh formulas into the boundary condition x=l, we can get the thirteenth formula;

[0164] The thirteenth formula is:

[0165]

[0166] Expand the thirteenth formula into the fourteenth formula;

[0167] The fourteenth formula is:

[0168]

[0169] In the formula, superscripts 1, 2, 3, and 4 represent four different measurement methods.

[0170] Solving the fourteenth formula yields the fifteenth formula;

[0171] The fifteenth formula is:

[0172]

[0173] According to the determinant of Q and the intermediate variables A1, A2, A3, A4, we can get the sixteenth formula;

[0174] Formula 16;

[0175]

[0176] Solve the sixteenth formula to obtain the intermediate variables r1 and r2.

[0177] According to the expressions of intermediate variables A1, A2, A3, A4, r1, r2, the intermediate parameter matrix P is solved.

[0178] According to the expressions of intermediate variables B1, B2, B3, B4, r1, r2 and the intermediate parameter matrix P, the zero-sequence impedance Z of the double-circuit transmission line with two terminals and a common busbar is obtained. 11 ,Z 22 ,Z 12 .

[0179] According to the intermediate parameter matrix P and the zero-sequence impedance Z of the double-circuit transmission line with two-terminal common busbar 11 ,Z 22 ,Z 12 , we can get the zero-sequence admittance Y of the double-circuit transmission line with two terminals and a common busbar: 11 ,Y 22 ,Y 12 .

[0180] According to the seventeenth formula, the zero-sequence parameters of the double-circuit transmission line with a double-ended common busbar can be obtained;

[0181] The seventeenth formula is:

[0182]

[0183] Optionally, the calculation of the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the double-circuit power transmission line with a double-terminal common busbar may refer to the introduction of the aforementioned step S103, which will not be repeated here.

[0184] It should be noted that the above embodiment can be implemented by a device for determining zero-sequence parameters of a double-circuit power transmission line with a double-terminal common busbar.

[0185] In this embodiment, the power parameters of the double-circuit transmission line with a double-ended common bus are measured; based on the power parameters of the double-circuit transmission line with a double-ended common bus, the line impedance parameter matrix and the admittance parameter matrix of the double-circuit transmission line with a double-ended common bus are constructed; based on the line impedance parameter matrix and the admittance parameter matrix, the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus are determined. In other words, the present invention can construct the line impedance parameter matrix and the admittance parameter matrix of the double-circuit transmission line with a double-ended common bus through the power parameters of the double-circuit transmission line with a double-ended common bus, solve the line impedance parameter matrix and the admittance parameter matrix by mathematical derivation, and determine the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus, thereby achieving the technical effect of effectively solving the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus, and then solving the technical problem that the line parameters of the double-circuit transmission line cannot be measured live.

[0186] Example 2

[0187] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0188] The line parameters of the transmission line mainly include: resistance, inductance, conductance and capacitance at 50Hz power frequency. Conductance is related to corona loss and insulator leakage resistance, but in order to avoid corona phenomenon during design, the conductance parameters are usually ignored. The phase parameters of the transmission line can be converted into positive sequence, negative sequence and zero sequence parameters by the symmetrical component method, among which the zero sequence parameters include self-impedance, self-admittance, mutual impedance and mutual admittance. These parameters are the basis of numerical analysis of power systems (for example: network loss calculation, power flow calculation, short-circuit calculation and relay protection setting). Calculation errors may cause the protection measures to fail or malfunction, affecting the safe and stable operation of the system. Therefore, in the context of increasing requirements for power systems in the new era, it is necessary to attach importance to the measurement of main grid overhead line parameters.

[0189] In related technologies, with economic growth and the expansion of the power grid, a large number of new transmission lines have been built. Especially in economically developed areas with tight land resources, the contradiction between the demand for transmission corridors and land resources has become increasingly severe. In order to make full use of existing land and transmission corridors, the method of installing the same tower on the existing transmission corridors has been adopted, resulting in the common use of double-circuit transmission lines on the same tower with a common busbar at both ends, and a complex installation method has emerged. As the number of lines increases, the electromagnetic coupling phenomenon between parallel lines becomes more complicated, which brings greater challenges to the solution of line parameters.

[0190] The construction of new transmission lines has made the transmission corridors more and more crowded. In order to meet the growing demand for electricity, multiple transmission lines have been erected in parallel on the same tower, and there is electromagnetic coupling between these lines. At the same time, nearly 20 UHV lines with a length of more than 600 km are in operation or under construction, and a large number of ultra-high voltage lines are more than 200 km long. The construction of these new transmission lines has brought new opportunities and challenges to the measurement and research of transmission line parameters. Therefore, studying the measurement theory and methods of transmission line distributed parameters is of vital practical significance to ensure the safe and stable operation of the power system and achieve sustainable development.

[0191] However, an embodiment of the present invention proposes a method for measuring the zero-sequence distributed parameters of a double-circuit line with a double-end common busbar under energization, by measuring the zero-sequence voltage and zero-sequence current at the beginning and end of each transmission line in the double-circuit transmission line with a double-end common busbar, and then constructing a line impedance parameter matrix and an admittance parameter matrix according to the zero-sequence voltage and zero-sequence current at the beginning and end of each transmission line, and then mathematically deriving and solving the line impedance parameter matrix and the admittance parameter matrix to obtain the zero-sequence distributed parameters of the double-circuit transmission line with a double-end common busbar, which can achieve the technical effect of effectively solving the zero-sequence parameters of the double-circuit transmission line with a double-end common busbar, and then solve the technical problem that the line parameters of the double-circuit transmission line cannot be measured under energization.

[0192] The embodiments of the present invention are further described below.

[0193] In this embodiment, the operating voltages of the first transmission line and the second transmission line of the double-circuit transmission line with a double-terminal common busbar are consistent.

[0194] Optionally, the measurement method includes the steps of: defining four different measurement methods based on the first transmission line and the second transmission line, and obtaining the first-end voltage value, the terminal voltage value, the first-end current value and the terminal current value of the first transmission line and the second transmission line according to the four different measurement methods when the line is energized, and then further calculating the intermediate parameter matrix. Calculate the eigenvalue of the intermediate parameter matrix; calculate the propagation coefficient of the differential equation according to the eigenvalue of the intermediate parameter matrix; calculate the intermediate variable according to the propagation coefficient. Calculate the adjoint matrix according to the propagation coefficient and the intermediate variable; calculate the line impedance parameter matrix and the admittance parameter matrix based on the adjoint matrix; calculate the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the double-circuit transmission line with a double-terminal common bus based on the line impedance parameter matrix and the admittance parameter matrix.

[0195] Optionally, the four different measurement methods include: a first measurement method, the first measurement method is to short-term disconnect the circuit breaker of one phase at the end of the first transmission line, and then reclose the line, and the second transmission line operates normally; a second measurement method, the second measurement method is to short-term disconnect the circuit breaker of another phase at the end of the first transmission line, and then reclose the line, and the second transmission line operates normally; a third measurement method, the third measurement method is that the first transmission line operates normally, and one phase at the end of the second transmission line is short-term disconnected from the circuit breaker, and then reclosed the line; a fourth measurement method, the fourth measurement method is that the first transmission line operates normally, and the other phase at the end of the second transmission line is short-term disconnected from the circuit breaker, and then reclosed the line.

[0196] Optionally, a synchronous measuring device is used to synchronously measure the following when the line is in an energized operation state: zero-sequence voltage and zero-sequence current at the beginning and end of the first transmission line under four different measurement modes; zero-sequence voltage and zero-sequence current at the beginning and end of the second transmission line under four different measurement modes;

[0197] Optionally, the intermediate parameter matrix of the double-circuit transmission line with a double-ended common busbar is a second-order matrix. The line impedance parameter matrix and the admittance parameter matrix thereof can be described in the above-mentioned step S102, which will not be described again here.

[0198] Optionally, the operating voltages of the first transmission line and the second transmission line are consistent. The parameters of the transmission line are simplified according to the first formula.

[0199] Optionally, the method of determining the simplified line impedance parameter matrix and the simplified admittance parameter matrix may refer to the introduction of the aforementioned step S103, which will not be described in detail here.

[0200] Optionally, since corona phenomenon does not occur in normal operation lines, the susceptance parameter is ignored. The zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the double-circuit transmission line with double-terminal common busbar are calculated according to the third formula, see the introduction of the above step S103, which will not be repeated here.

[0201] Optionally, ignoring high-order infinitesimals, the line transmission line equation can be determined according to Kirchhoff's theorem. The determination of the line transmission line equation according to Kirchhoff's theorem can refer to the above introduction and will not be repeated here.

[0202] Optionally, the calculation of the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the double-circuit transmission line with a double-terminal common busbar may refer to the introduction of the aforementioned step S103, which will not be repeated here.

[0203] The application of the embodiment of the present invention is further introduced below.

[0204] This embodiment is based on an engineering application scenario, namely: a double-circuit transmission line with a double-ended common busbar is both in an energized operating state, and proposes an energized measurement method for zero-sequence distributed parameters of a double-circuit transmission line with a double-ended common busbar, further improving the distributed parameter measurement method for a double-circuit transmission line with a double-ended common busbar, overcoming the disadvantage that a traditional method based on a concentrated parameter model causes a large measurement error when measuring long lines. Compared with the traditional measurement method that can only perform power outage measurement, the method provided in this embodiment can measure zero-sequence parameters under the condition that both lines are energized, and can measure multiple zero-sequence parameters such as zero-sequence resistance, zero-sequence inductance, and zero-sequence capacitance at one time, and the measurement accuracy is much higher than the traditional measurement method that can only measure one zero-sequence parameter each time, meeting the actual design needs of the project.

[0205] Figure 2 The present invention is a flowchart of a method for measuring zero-sequence distributed parameters of a double-circuit power transmission line with a double-terminal common busbar under power supply voltage according to an embodiment of the present invention. The method comprises the following steps:

[0206] Step 201, defining a transmission line.

[0207] In this embodiment, a first transmission line and a second transmission line are defined.

[0208] Step 202, defining a measurement method.

[0209] In this embodiment, a first measurement mode, a second measurement mode, a third measurement mode, and a fourth measurement mode are defined.

[0210] Optionally, the first measurement method is: the first measurement method is to short-term disconnect the circuit breaker of one phase at the end of the first transmission line, and then reclose the line, and the second transmission line operates normally.

[0211] Optionally, the second measurement method is: the second measurement method is to short-term disconnect the line circuit breaker of another phase at the end of the first transmission line, and then reclose the line, and the second transmission line operates normally.

[0212] Optionally, the third measurement method is: the first transmission line operates normally, and one of the phases at the end of the second transmission line is disconnected from the circuit breaker for a short time, and then the line is reclosed.

[0213] Optionally, the fourth measurement method is: the first transmission line operates normally, and the other phase at the end of the second transmission line is disconnected from the circuit breaker for a short time, and then the line is reclosed.

[0214] Step 203, calculating the zero-sequence component under different zero-sequence measurement modes.

[0215] In this embodiment, the zero-sequence components under different zero-sequence measurement modes include: the zero-sequence voltage and zero-sequence current at the head end of the first transmission line under different zero-sequence measurement modes, and the zero-sequence voltage and zero-sequence current at the end of the first transmission line under different zero-sequence measurement modes; the zero-sequence voltage and zero-sequence current at the head end of the second transmission line under different zero-sequence measurement modes, and the zero-sequence voltage and zero-sequence current at the end of the second transmission line under different zero-sequence measurement modes.

[0216] Optionally, Figure 3 The diagram is a schematic diagram of a measurement connection of a double-circuit power transmission line with a double-end common busbar according to an embodiment of the present invention.

[0217] Optionally, the zero-sequence fundamental voltage at the head end of the first transmission line under different zero-sequence measurement modes is: The zero-sequence fundamental current at the head end of the first transmission line under different zero-sequence measurement methods is: The zero-sequence fundamental voltage at the head end of the second transmission line under different zero-sequence measurement methods is: The zero-sequence fundamental current at the head end of the second transmission line under different zero-sequence measurement methods is: The zero-sequence fundamental voltage at the end of the first transmission line under different zero-sequence measurement methods is: The zero-sequence fundamental current at the end of the first transmission line under different zero-sequence measurement methods is: The zero-sequence fundamental voltage at the end of the second transmission line under different zero-sequence measurement methods is: The zero-sequence fundamental current at the end of the second transmission line under different zero-sequence measurement methods is:

[0218] Step 204, calculating an intermediate parameter matrix according to the zero-sequence component.

[0219] In this embodiment, the intermediate variables A1, A2, A3, A4, r1, r2 are calculated according to the measured line head end voltage value, end end voltage value, head end current value and end end current value; the intermediate parameter matrix P is calculated according to the intermediate variables A1, A2, A3, A4, r1, r2.

[0220] Step 205, calculating the intermediate variables according to the intermediate parameter matrix.

[0221] In this embodiment, intermediate variables B1, B2, B3, B4 are calculated.

[0222] Step 206: Calculate line impedance parameters and line admittance parameters according to the intermediate variables.

[0223] According to the expressions of intermediate variables B1, B2, B3, B4, r1, r2 and the intermediate parameter matrix P, the zero-sequence impedance Z of the double-circuit transmission line with two terminals and a common busbar is obtained. 11 ,Z 22 ,Z 12 .

[0224] According to the intermediate parameter matrix P and the zero-sequence impedance Z of the double-circuit transmission line with two-terminal common busbar 11 ,Z 22 ,Z 12 , we can get the zero-sequence admittance Y of the double-circuit transmission line with two terminals and a common busbar: 11 ,Y 22 ,Y 12 .

[0225] Step S207, calculating the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the double-circuit transmission line with a double-terminal common busbar according to the line impedance parameters and the line admittance parameters.

[0226] In this embodiment, the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the double-circuit power transmission line with a double-terminal common bus are calculated according to the line impedance parameters and the line admittance parameters.

[0227] Optionally, the calculation of the zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance of the double-circuit power transmission line with a double-terminal common busbar may refer to the introduction of the aforementioned step S103, which will not be repeated here.

[0228] In this embodiment, a simulation model is established in PSCAD (power system simulation software). Table 1 is an example table of theoretical values ​​of unit length of a transmission line, which reflects the theoretical values ​​of unit length of a transmission line.

[0229] Table 1 Example of theoretical values ​​of unit length of transmission line

[0230]

[0231] Optionally, the length of the transmission line is changed from 200 km to 800 km by simulation, and the measurement results obtained by using the method of the present invention are shown in Table 2, Table 3, and Table 4. Table 2 is an example table of zero-sequence resistance measurement results, Table 3 is an example table of zero-sequence inductance measurement results, and Table 4 is an example table of zero-sequence capacitance measurement results.

[0232] Table 2 Example of zero-sequence resistance measurement results

[0233]

[0234] Table 3 Example table of zero-sequence inductance measurement results

[0235]

[0236]

[0237] Table 4 Example of zero-sequence capacitance measurement results

[0238]

[0239] The measurement accuracy of the method in the embodiment of the present invention is not affected by the distance of the transmission line, because the embodiment of the present invention is based on the parameter derivation under the distribution model, taking into account the distribution effect of the line, and is therefore applicable to the same-tower / non-same-tower double-circuit transmission lines with two-terminal common busbars of any length. The zero-sequence resistance parameter error of the same-tower / non-same-tower double-circuit transmission lines with two-terminal common busbars within 800km measured by the embodiment of the present invention is no more than 0.9%, the zero-sequence inductance error is no more than 0.15%, and the zero-sequence capacitance error is no more than 0.2%. The measurement accuracy of the method in the embodiment of the present invention is not affected by the degree of deviation of the theoretical value of the line parameters, because the embodiment of the present invention does not impose any restrictions on the theoretical value of the zero-sequence parameter during theoretical derivation, so the embodiment of the present invention is applicable to the same-tower / non-same-tower double-circuit transmission lines with two-terminal common busbars of any voltage level.

[0240] In this embodiment, by measuring the head-end zero-sequence voltage and zero-sequence current of each transmission line in the double-circuit transmission line on the same tower / not on the same tower with a double-end common bus, a line impedance parameter matrix and an admittance parameter matrix are constructed according to the head-end zero-sequence voltage and zero-sequence current of each transmission line, and then the line impedance parameter matrix and the admittance parameter matrix are mathematically derived and solved to obtain the zero-sequence parameters of the double-circuit transmission line on the same tower / not on the same tower with a double-end common bus, so as to achieve the technical effect of effectively solving the zero-sequence parameters of the double-circuit transmission line on the same tower / not on the same tower with a double-end common bus, thereby solving the technical problem that the line parameters of the double-circuit transmission line on the same tower / not on the same tower with a double-end common bus cannot be measured under power.

[0241] Example 3

[0242] According to an embodiment of the present invention, a live measuring device for zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar is also provided. It should be noted that the live measuring device for zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar can be used to execute the live measuring method for zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar in Example 1.

[0243] Figure 4 Schematic diagram of a live zero-sequence distribution parameter measurement device for a double-circuit line with a double-ended common busbar according to an embodiment of the present invention. Figure 4As shown, the live zero-sequence distributed parameter measurement device 700 for a double-circuit line with a double-terminal common busbar may include: a measuring unit 701 , a constructing unit 702 and a determining unit 703 .

[0244] The measuring unit 701 is used to measure the power parameters of the double-circuit power transmission line with a double-terminal common bus, wherein the power parameters are used to at least indicate the operating state of the double-circuit power transmission line with a double-terminal common bus.

[0245] The construction unit 702 is used to construct a line impedance parameter matrix and an admittance parameter matrix of the double-circuit transmission line with a double-end common bus based on the power parameters of the double-circuit transmission line with a double-end common bus, wherein the line impedance parameter matrix is ​​used to indicate the impedance characteristics of the double-circuit transmission line with a double-end common bus, and the admittance parameter matrix is ​​used to indicate the admittance characteristics of the double-circuit transmission line with a double-end common bus.

[0246] The determination unit 703 is used to determine the zero-sequence parameters of the double-circuit transmission line with a double-terminal common bus based on the line impedance parameter matrix and the admittance parameter matrix, wherein the zero-sequence parameters include at least one of the following: zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance.

[0247] Optionally, the measuring unit 701 may include: a first determination module, used to determine multiple measurement methods for each transmission line in a double-circuit transmission line with a common bus at both ends; a first acquisition module, used to acquire the power parameters of each transmission line in the double-circuit transmission line with a common bus at both ends under multiple measurement methods when the double-circuit transmission line with a common bus at both ends is in a power outage state.

[0248] Optionally, the first determination module may include: a first submodule, which is used for short-term disconnection of a circuit breaker of one phase at the end of the first transmission line, and then reclosing the line, and the second transmission line operates normally; a second submodule, which is used for short-term disconnection of a circuit breaker of another phase at the end of the first transmission line, and then reclosing the line, and the second transmission line operates normally. A third submodule, which is used for normal operation of the first transmission line, and short-term disconnection of a circuit breaker of one phase at the end of the second transmission line, and then reclosing the line. A fourth submodule, which is used for normal operation of the first transmission line, and short-term disconnection of a circuit breaker of another phase at the end of the second transmission line, and then reclosing the line.

[0249] Optionally, the construction unit 702 may include: a first calculation module, which is used to calculate the unit length distributed zero-sequence self-impedance and the unit length distributed zero-sequence mutual impedance of each transmission line based on the power parameters of each transmission line in the double-circuit transmission line with a double-ended common bus; and a first generation module, which generates a line impedance parameter matrix of the double-circuit transmission line with a double-ended common bus based on the unit length distributed zero-sequence self-impedance and the unit length distributed zero-sequence mutual impedance of each transmission line in the double-circuit transmission line with a double-ended common bus.

[0250] Optionally, the construction unit 702 may also include: a second calculation module, which is used to calculate the unit length distributed zero-sequence self-admittance and the unit length distributed zero-sequence mutual-admittance of each transmission line based on the power parameters of each transmission line in the double-circuit transmission line with a common bus at both ends; and a second generation module, which is used to generate the admittance parameter matrix of the double-circuit transmission line with a common bus at both ends based on the unit length zero-sequence self-admittance and the unit length distributed zero-sequence mutual-admittance of each transmission line in the double-circuit transmission line with a common bus at both ends.

[0251] Optionally, the determination unit 703 may include: a comparison module, used to compare the various parameters in the line impedance parameter matrix to obtain a first comparison result of the various parameters, and to compare the various parameters in the admittance parameter matrix to obtain a second comparison result of the various parameters; a substitution module, used to replace the parameters with equal values ​​in the line impedance parameter matrix with one of the parameters based on the first comparison result to obtain a simplified line impedance parameter matrix, and to replace the parameters with equal values ​​in the admittance parameter matrix with one of the parameters based on the second comparison result to obtain a simplified admittance parameter matrix; a second determination module, used to determine the zero-sequence parameters of the double-circuit transmission line with a double-end common bus based on the simplified line impedance parameter matrix and the simplified admittance parameter matrix.

[0252] Optionally, the second determination module may include: an analysis submodule, used to analyze the simplified line impedance parameter matrix and the simplified admittance parameter matrix according to Kirchhoff's principle to determine the zero-sequence distribution parameters of the double-circuit transmission line with a double-terminal common bus.

[0253] In this embodiment, the power parameters of the double-circuit transmission line with a double-ended common bus are measured; based on the power parameters of the double-circuit transmission line with a double-ended common bus, the line impedance parameter matrix and the admittance parameter matrix of the double-circuit transmission line with a double-ended common bus are constructed; based on the line impedance parameter matrix and the admittance parameter matrix, the zero-sequence distribution parameters of the double-circuit transmission line with a double-ended common bus are determined. In other words, the present invention can construct the line impedance parameter matrix and the admittance parameter matrix of the double-circuit transmission line with a double-ended common bus through the power parameters of the double-circuit transmission line with a double-ended common bus, solve the line impedance parameter matrix and the admittance parameter matrix by mathematical derivation, and determine the zero-sequence distribution parameters of the double-circuit transmission line with a double-ended common bus, thereby achieving the technical effect of effectively solving the zero-sequence parameters of the double-circuit transmission line with a double-ended common bus, and then solving the technical problem that the zero-sequence distribution parameters of the double-circuit transmission line cannot be measured under power.

[0254] Example 4

[0255] According to an embodiment of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer program is executed by a processor, the method for measuring zero-sequence distributed parameters of a double-circuit line with a double-terminal common busbar under the condition of live measurement in Example 1 can be executed.

[0256] Example 5

[0257] According to an embodiment of the present invention, there is also provided an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for energized measurement of zero-sequence distributed parameters of a double-circuit line with a double-ended common busbar in Example 1 can be executed.

[0258] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0259] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for measuring zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar, characterized in that: include: Measuring power parameters of a double-circuit power transmission line with a double-ended common bus, wherein the power parameters are used to at least indicate the operating state of the double-circuit power transmission line with a double-ended common bus; Based on the power parameters of the double-circuit power transmission line with two ends and a common bus, a line impedance parameter matrix and an admittance parameter matrix of the double-circuit power transmission line with two ends and a common bus are constructed, wherein the line impedance parameter matrix is ​​used to indicate the impedance characteristics of the double-circuit power transmission line with two ends and a common bus, and the admittance parameter matrix is ​​used to indicate the admittance characteristics of the double-circuit power transmission line with two ends and a common bus; Based on the line impedance parameter matrix and the admittance parameter matrix, the zero-sequence parameter of the double-circuit transmission line with two ends and a common bus is determined, wherein the zero-sequence parameter includes at least one of a zero-sequence resistance, a zero-sequence inductance and a zero-sequence capacitance.

2. The method for measuring zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar as claimed in claim 1, characterized in that: Measure the power parameters of double-circuit transmission lines with double-ended common busbars, including: Determine multiple measurement methods for each transmission line in the double-circuit transmission line with a double-terminal common busbar; When the double-circuit power transmission line with a common bus at both ends is in an energized operation state, the power parameters of each power transmission line in the double-circuit power transmission line with a common bus at both ends are obtained under the multiple measurement modes.

3. The method for measuring zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar as claimed in claim 2 is characterized in that: The power parameters of each transmission line include at least the zero-sequence voltage and the zero-sequence current at the head end of each transmission line, and the zero-sequence voltage and the zero-sequence current at the end of each transmission line.

4. The method for measuring zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar as claimed in claim 2, characterized in that: The double-circuit transmission line with a double-terminal common busbar comprises a first transmission line and a second transmission line. The multiple measurement methods of each transmission line in the double-circuit transmission line with a double-terminal common busbar at least include: One of the phases at the end of the first transmission line is disconnected for a short time, and then the line is reclosed, and the second transmission line operates normally; The other phase at the end of the first transmission line is disconnected for a short time by a circuit breaker, and then the line is reclosed, and the second transmission line operates normally; The first transmission line operates normally, and one of the phases at the end of the second transmission line is disconnected for a short time by a circuit breaker, and then the line is reclosed; The first transmission line operates normally, and the other phase at the end of the second transmission line disconnects the circuit breaker for a short time and then recloses the line.

5. The method for measuring zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar as claimed in claim 1, characterized in that: Based on the power parameters of the double-circuit power transmission line with two ends and a common busbar, a line impedance parameter matrix of the double-circuit power transmission line with two ends and a common busbar is constructed, including: Based on the power parameters of each transmission line in the double-circuit transmission line with a double-ended common busbar, calculate the distributed zero-sequence self-impedance per unit length of each transmission line and the distributed zero-sequence mutual impedance per unit length between the double-circuit transmission lines; Based on the distributed zero-sequence self-impedance per unit length and the distributed zero-sequence mutual impedance per unit length of the double-circuit power transmission line with a common bus at both ends, the line impedance parameter matrix of the double-circuit power transmission line with a common bus at both ends is generated.

6. The method for measuring zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar as claimed in claim 1, characterized in that: Based on the power parameters of the double-circuit power transmission line with two ends and a common busbar, an admittance parameter matrix of the double-circuit power transmission line with two ends and a common busbar is constructed, comprising: Based on the power parameters of each transmission line in the double-circuit transmission line with a double-terminal common busbar, calculate the distributed zero-sequence self-admittance per unit length of each transmission line and the distributed zero-sequence mutual admittance per unit length between the double-circuit transmission lines; The admittance parameter matrix of the double-circuit transmission line with a common bus at both ends is generated based on the zero-sequence self-admittance per unit length and the distributed zero-sequence mutual-admittance per unit length of the double-circuit transmission line with a common bus at both ends.

7. The method for measuring zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar as claimed in claim 1, characterized in that: Determining the zero-sequence parameter of the double-circuit power transmission line with two ends and a common busbar based on the line impedance parameter matrix and the admittance parameter matrix includes: Comparing the parameters in the line impedance parameter matrix to obtain a first comparison result of the parameters in the line impedance parameter matrix, and comparing the parameters in the admittance parameter matrix to obtain a second comparison result of the parameters in the admittance parameter matrix; Based on the first comparison result, the parameters with equal values ​​in the line impedance parameter matrix are replaced by one of the parameters to obtain a simplified line impedance parameter matrix; and based on the second comparison result, the parameters with equal values ​​in the admittance parameter matrix are replaced by one of the parameters to obtain a simplified admittance parameter matrix; Based on the simplified line impedance parameter matrix and the simplified admittance parameter matrix, the zero-sequence parameters of the double-circuit power transmission line with two ends and a common bus are determined.

8. A live measuring device for zero-sequence distribution parameters of a double-circuit line with a double-ended common busbar, characterized in that: include: A measuring unit, used for measuring power parameters of a double-circuit power transmission line with a double-terminal common bus, wherein the power parameters are used for at least indicating the operating state of the double-circuit power transmission line with a double-terminal common bus; A construction unit, configured to construct a line impedance parameter matrix and an admittance parameter matrix of the double-circuit power transmission line with a double-end common bus based on the power parameters of the double-circuit power transmission line with a double-end common bus, wherein the line impedance parameter matrix is ​​used to indicate the impedance characteristics of the double-circuit power transmission line with a double-end common bus, and the admittance parameter matrix is ​​used to indicate the admittance characteristics of the double-circuit power transmission line with a double-end common bus; A determination unit is used to determine the zero-sequence parameters of the double-circuit transmission line with a double-terminal common bus based on the line impedance parameter matrix and the admittance parameter matrix, wherein the zero-sequence parameters include at least one of zero-sequence resistance, zero-sequence inductance and zero-sequence capacitance.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the live measurement method for zero-sequence distributed parameters of a double-circuit line with a double-ended common busbar according to any one of claims 1 to 7 is implemented.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the live measurement method for zero-sequence distributed parameters of a double-circuit line with a double-terminal common busbar according to any one of claims 1 to 7 is implemented.

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