CN108387819B - Method and equipment for positioning overvoltage interval along AC transmission line - Google Patents

Method and equipment for positioning overvoltage interval along AC transmission line Download PDF

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Publication number
CN108387819B
CN108387819B CN201810078973.5A CN201810078973A CN108387819B CN 108387819 B CN108387819 B CN 108387819B CN 201810078973 A CN201810078973 A CN 201810078973A CN 108387819 B CN108387819 B CN 108387819B
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line
transmission line
current transmission
along
wavelength
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CN108387819A (en
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谈萌
王同勋
周胜军
刘颖英
冯丹丹
李亚琼
李毅
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State Grid Corp of China SGCC
Global Energy Interconnection Research Institute
State Grid Shanghai Electric Power Co Ltd
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State Grid Corp of China SGCC
Global Energy Interconnection Research Institute
State Grid Shanghai Electric Power Co Ltd
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/081Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/085Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16533Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
    • G01R19/16538Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies
    • G01R19/16547Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies voltage or current in AC supplies

Abstract

The invention provides a method and a device for positioning an overvoltage interval along an alternating current transmission line, wherein the method comprises the following steps: according to the fundamental wave voltage and current of the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line, the voltage transmission coefficient of the fundamental wave along the line of the half-wavelength alternating-current transmission line is obtained, according to the voltage transmission coefficient of the fundamental wave along the line, the minimum position point and the maximum position point of the overvoltage interval along the line, which is far away from the receiving end of the half-wavelength alternating-current transmission line, are obtained, and the position of the overvoltage interval along the line is determined according to the. The method for positioning the overvoltage interval along the line of the alternating current transmission line can position the overvoltage interval along the line of the half-wavelength alternating current transmission line, and solves the problem that the overvoltage interval cannot be accurately positioned along the line of the half-wavelength transmission line in the prior art.

Description

Method and equipment for positioning overvoltage interval along AC transmission line
Technical Field
The invention relates to the technical field of steady-state characteristic analysis of half-wavelength alternating-current transmission lines, in particular to a method and equipment for positioning an overvoltage interval along an alternating-current transmission line.
Background
The energy distribution in China is uneven, wind energy, solar energy and water resources are abundant in western regions, and the load center is concentrated in coastal cities in the east and south, so that the power transmission distance is long, the capacity is large, and the half-wavelength power transmission technology can be used for solving the problem of long-distance, large-scale and large-capacity power transmission between an energy base and the load center. Therefore, the research on the extra-high voltage half-wavelength alternating current transmission system has important scientific value for solving the energy structure problem faced by China at present, and has potential application prospect.
In an alternating current transmission system, along with the change of a receiving end working condition, the voltage along the line is inevitably amplified in some intervals, even more serious overvoltage is caused, the economic and safe operation of the transmission system is not facilitated, and the problem of inaccurate positioning of the overvoltage interval along the alternating current transmission line exists in the steady-state characteristic analysis of the extra-high voltage half-wavelength alternating current transmission system in the prior art. Therefore, the method has engineering application value for researching and accurately positioning the overvoltage amplification region along the half-wavelength power transmission line.
Disclosure of Invention
In view of this, the embodiment of the present invention provides a method for positioning an overvoltage interval along an ac power transmission line, so as to solve the problem in the prior art that the overvoltage interval cannot be accurately positioned along a half-wavelength power transmission line.
According to a first aspect, an embodiment of the present invention provides a method for positioning an overvoltage interval along an ac transmission line, including: obtaining a transmission coefficient of the fundamental wave voltage along the line of the half-wavelength alternating-current transmission line according to the fundamental wave voltage and current of the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line; obtaining a minimum position point and a maximum position point which are separated from a receiving end of the half-wavelength alternating current transmission line along the line overvoltage interval according to the voltage transfer coefficient of the fundamental wave along the line; and determining the position of the overvoltage interval along the line according to the minimum position point and the maximum position point.
Through the steps, the transmission coefficient of the fundamental wave voltage along the line of the half-wavelength alternating-current transmission line formed by the fundamental wave voltage at the sending end of the line and the fundamental wave voltage at the receiving end of the line is established through the fundamental wave voltage and the current at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line, and the maximum position point and the minimum position point of the transmission coefficient are determined because the transmission coefficient is related to the maximum position point and the minimum position point of the overvoltage interval from the receiving end of the half-wavelength alternating-current transmission line, so that the position of the overvoltage interval along the line can. Through the process, the overvoltage interval along the line of the half-wavelength alternating-current power transmission line can be positioned, and the problem that the overvoltage interval cannot be accurately positioned along the line of the half-wavelength alternating-current power transmission line in the prior art is solved.
With reference to the first aspect, in the first implementation manner of the first aspect of the embodiment of the present invention, the step of obtaining the along-line fundamental wave voltage transfer coefficient of the half-wavelength alternating-current transmission line according to the fundamental wave voltage and the current of the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line includes: obtaining the fundamental wave voltage and current along the line of the half-wavelength alternating-current transmission line according to the fundamental wave voltage and current at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line; and obtaining the voltage transfer coefficient of the fundamental wave along the line of the half-wavelength alternating-current transmission line according to the voltage and the current of the fundamental wave along the line of the half-wavelength alternating-current transmission line. Through the steps, the fundamental wave voltage and the current along the half-wavelength alternating-current transmission line are obtained firstly, and the fundamental wave voltage transfer coefficients related to the maximum position point and the minimum position point of the overvoltage interval from the receiving end of the half-wavelength alternating-current transmission line can be obtained more accurately.
With reference to the first implementation manner of the first aspect, in the second implementation manner of the first aspect of the embodiment of the present invention, the voltage and the current along the line of the half-wavelength ac transmission line are calculated by the following formulas:
wherein the content of the first and second substances,base for respectively representing half-wavelength AC transmission line sending endWave voltage and current;respectively representing fundamental wave voltage and current along the line of the half-wavelength alternating-current transmission line; beta is ahRepresenting a fundamental wave phase constant, x representing the distance from a receiving end of a half-wavelength alternating current transmission line, l representing the preset length of the half-wavelength alternating current transmission line, and ZBDenotes a lossless wave impedance, and h is 1.
With reference to the second implementation manner of the first aspect, in the third implementation manner of the first aspect of the embodiment of the present invention, the along-line fundamental wave voltage transfer coefficient of the half-wavelength alternating-current transmission line is calculated by the following formula:
wherein, IphRepresenting the real part of the current vector at the delivery end of a half-wavelength AC transmission line, IqhRepresenting the imaginary part, U, of the current vector at the transmitting end of a half-wavelength AC transmission lineShAnd the voltage scalar value of the sending end of the half-wavelength alternating-current transmission line is represented.
With reference to the third implementation manner of the first aspect, in a fourth implementation manner of the first aspect of the embodiment of the present invention, the minimum position point and the maximum position point of the line overvoltage interval from the receiving end of the half-wavelength ac power transmission line are calculated according to the following formulas:
wherein:
wherein the content of the first and second substances,Iphrepresenting the current at the sending end of a half-wavelength AC transmission lineReal part of vector, IqhRepresenting the imaginary part of the current vector at the transmitting end of a half-wavelength AC transmission line, IShScalar value, Z, representing the current at the sending end of a half-wavelength AC transmission lineBDenotes a lossless wave impedance, h is 1, and k denotes a linear fundamental wave voltage transfer coefficient.
With reference to the first aspect, in a fifth implementation manner of the first aspect of the embodiments of the present invention, the determining the position of the overvoltage interval along the line according to the minimum position point and the maximum position point includes: judging whether the actual length of the half-wavelength alternating current transmission line is consistent with the preset length or not; and when the actual length of the half-wavelength alternating-current transmission line is consistent with the preset length, judging that the maximum position and the minimum position are positions of overvoltage intervals along the line. In practical application, the actual length of the half-wavelength alternating-current transmission line may be inconsistent with the preset length, and only when the actual length of the half-wavelength alternating-current transmission line is consistent with the preset length, the overvoltage interval along the line is an interval formed by the maximum position point and the minimum position point obtained in the above specific embodiment.
With reference to the fifth implementation manner of the first aspect, in the sixth implementation manner of the first aspect of the embodiments of the present invention, when the actual length of the half-wavelength ac power transmission line is not consistent with the preset length of the half-wavelength ac power transmission line, it is determined that the maximum position point and the minimum position point are the planned positions of the line overvoltage intervals, and the planned positions are corrected to obtain the actual positions of the line overvoltage intervals. Specifically, when the actual half-wavelength ac transmission line is not consistent with the preset length, the maximum position point and the minimum position point obtained according to the preset length in the above specific embodiment are the planned position of the overvoltage interval, and the actual position of the overvoltage interval needs to be corrected to obtain the actual position of the overvoltage interval.
With reference to the sixth implementation manner of the first aspect, in a seventh implementation manner of the first aspect of the present invention, the proposed position is corrected to obtain the actual position of the overvoltage interval along the line by the following steps: calculating a first difference value between the preset length of the half-wavelength alternating-current transmission line and the actual length of the half-wavelength alternating-current transmission line; obtaining the lower limit of the line overvoltage interval according to the minimum position point of the line overvoltage interval from the receiving end of the half-wavelength alternating current transmission line and the first difference value; when the maximum position point of the line overvoltage region at a distance from the receiving end of the half-wavelength alternating current transmission line is smaller than or equal to the preset length of the half-wavelength alternating current transmission line, the maximum position point is the upper limit of the line overvoltage region; when the maximum position point is larger than the preset length of the half-wavelength alternating current transmission line, a second difference value between the maximum position point and the first difference value is an upper limit of the line overvoltage interval; and determining the actual position of the overvoltage interval along the line according to the upper limit of the overvoltage interval along the line and the lower limit of the overvoltage interval along the line.
According to a second aspect, an embodiment of the present invention provides a computer device, including: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to cause the at least one processor to execute the method for positioning along an ac power transmission line overvoltage interval as described in the first aspect or any one of the embodiments of the first aspect.
According to a third aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to perform the method for positioning overvoltage intervals along an ac power transmission line according to the first aspect or any one of the embodiments of the first aspect.
The technical scheme of the embodiment of the invention has the following advantages:
the embodiment of the invention provides a method for positioning an overvoltage interval along an alternating current transmission line, which comprises the following steps: according to the fundamental wave voltage and current of the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line, the voltage transmission coefficient of the fundamental wave along the line of the half-wavelength alternating-current transmission line is obtained, according to the voltage transmission coefficient of the fundamental wave along the line, the minimum position point and the maximum position point of the overvoltage interval along the line, which is far away from the receiving end of the half-wavelength alternating-current transmission line, are obtained, and the position of the overvoltage interval along the line is determined according to the. Through the steps, the transmission coefficient of the fundamental wave voltage along the line of the half-wavelength alternating-current transmission line formed by the fundamental wave voltage at the sending end of the line and the fundamental wave voltage at the receiving end of the line is established through the fundamental wave voltage and the current at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line, and the maximum position point and the minimum position point can be determined due to the fact that the transmission coefficient is related to the maximum position point and the minimum position point of the overvoltage interval from the receiving end of the half-wavelength alternating-current transmission line, and therefore the overvoltage interval along the line can. The method for positioning the overvoltage interval along the line of the alternating-current transmission line, provided by the embodiment of the invention, can be used for positioning the overvoltage interval along the line of the half-wavelength alternating-current transmission line, and solves the problem that the overvoltage interval cannot be accurately positioned along the line of the half-wavelength transmission line in the prior art.
Drawings
The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:
fig. 1 is a flow chart of a method for locating an overvoltage interval along an ac transmission line according to an embodiment of the invention;
FIG. 2 is a diagram (I) of simulation results of voltage transfer coefficients of fundamental waves along an AC transmission line according to an embodiment of the invention;
FIG. 3 is a diagram (II) of simulation results of voltage transfer coefficients of fundamental waves along the line of the AC transmission line according to the embodiment of the invention;
fig. 4 is a schematic diagram (three) of simulation results of voltage transfer coefficients of fundamental waves along the ac transmission line according to the embodiment of the present invention;
fig. 5 is a schematic diagram of a hardware structure of a computer device of a method for positioning an overvoltage interval along an ac power transmission line according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a method for positioning an overvoltage interval along an alternating-current transmission line, which comprises the following steps of:
step S101: and obtaining the transmission coefficient of the fundamental wave voltage along the line of the half-wavelength alternating-current transmission line according to the fundamental wave voltage and current at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line. Specifically, in the alternating-current transmission system, along with the change of the working conditions along the line, some intervals are usually existed in the fundamental wave voltage and the current at the line sending end in the transmission process along the line and are amplified, so that the transmission coefficient of the fundamental wave voltage along the line of the half-wavelength alternating-current transmission line needs to be obtained.
Step S102: and obtaining a minimum position point and a maximum position point of the receiving end of the line overvoltage interval from the half-wavelength alternating current transmission line according to the voltage transfer coefficient of the fundamental wave along the line. Since the along-line fundamental wave voltage transfer coefficient is an expression relating to the minimum position point and the maximum position point of the overvoltage interval from the receiving end along the line, the minimum position point and the maximum position point of the overvoltage interval from the receiving end of the line can be obtained from the along-line fundamental wave voltage transfer coefficient.
Step S103: and determining the position of the overvoltage interval along the line according to the minimum position point and the maximum position point. And determining the overvoltage interval along the line according to the minimum position point and the maximum position point and the length of the actual half-wavelength power transmission line.
Through the steps, the transmission coefficient of the fundamental wave voltage along the line of the half-wavelength alternating-current transmission line formed by the fundamental wave voltage at the sending end of the line and the fundamental wave voltage at the receiving end of the line is established through the fundamental wave voltage and the current at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line, and the maximum position point and the minimum position point can be determined due to the fact that the transmission coefficient is related to the maximum position point and the minimum position point of the overvoltage interval from the receiving end of the half-wavelength alternating-current transmission line, and therefore the overvoltage interval along the line can. Through the process, the overvoltage interval along the line of the half-wavelength alternating-current power transmission line can be positioned, and the problem that the overvoltage interval cannot be accurately positioned along the line of the half-wavelength alternating-current power transmission line in the prior art is solved.
Step S101 relates to a step of obtaining a transmission coefficient of a fundamental wave voltage along a line of a half-wavelength ac transmission line according to a fundamental wave voltage and a current at a transmission end of the half-wavelength ac transmission line and a preset length of the half-wavelength ac transmission line, and in a specific embodiment, the step includes: according to the voltage and the current of the fundamental wave at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line, the voltage and the current of the fundamental wave along the line of the half-wavelength alternating-current transmission line are obtained, and according to the voltage and the current of the fundamental wave along the line of the half-wavelength alternating-current transmission line, the voltage transmission coefficient of the fundamental wave along the line of the half-wavelength alternating-. Specifically, the along-line fundamental wave voltage transfer coefficient is calculated by the following formula:
the voltage and current of the sending end of the half-wavelength power transmission line are set as follows:
in the formula (1), IphRepresenting the real part of the current vector at the delivery end of a half-wavelength AC transmission line, IqhRepresenting the imaginary part, U, of the current vector at the transmitting end of a half-wavelength AC transmission lineShAnd the voltage scalar value of the sending end of the half-wavelength alternating-current transmission line is represented.
In the process of transmitting voltage by the half-wavelength alternating-current transmission line, if the loss of the line is not counted, obtaining fundamental wave voltage and current along the half-wavelength alternating-current transmission line:
in the formula (2), the first and second groups,respectively representing fundamental wave voltage and current of a transmitting end of a half-wavelength alternating-current transmission line;respectively representing fundamental wave voltage and current along the line of the half-wavelength alternating-current transmission line; beta is ahRepresenting a fundamental wave phase constant, x representing the distance from a receiving end of a half-wavelength alternating current transmission line, l representing the preset length of the half-wavelength alternating current transmission line, and ZBDenotes a lossless wave impedance, and h is 1.
And (3) combining the formula (1) and the formula (2) to obtain the voltage transfer coefficient of the fundamental wave along the line:
in the formula (3), βhRepresenting a fundamental wave phase constant, x representing the distance from a receiving end of a half-wavelength alternating current transmission line, l representing the preset length of the half-wavelength alternating current transmission line, and ZBDenotes the lossless wave impedance, h is 1, IphRepresenting the real part of the current vector at the delivery end of a half-wavelength AC transmission line, IqhRepresenting the imaginary part, U, of the current vector at the transmitting end of a half-wavelength AC transmission lineShAnd the voltage scalar value of the sending end of the half-wavelength alternating-current transmission line is represented.
Order toX, Y are eachThe real and imaginary parts of (a) are:
X2+Y2=k2 (4)
in equation (4):
in a specific embodiment, a formula (4) and a formula (5) are combined to obtain a minimum position point and a maximum position point of a receiving end of a half-wavelength alternating-current transmission line away from a line overvoltage interval when a line fundamental wave voltage transfer coefficient k is greater than 1:
in equation (6):
in the formula (7), the first and second groups,Iphrepresenting the real part of the current vector at the delivery end of a half-wavelength AC transmission line, IqhRepresenting the imaginary part of the current vector at the transmitting end of a half-wavelength AC transmission line, IShScalar value, Z, representing the current at the sending end of a half-wavelength AC transmission lineBDenotes a lossless wave impedance, h is 1, and k denotes a linear fundamental wave voltage transfer coefficient.
Step S103 involves determining the position of the overvoltage interval along the line according to the minimum position point and the maximum position point, and in a specific embodiment, the step includes: and judging whether the actual length of the half-wavelength alternating-current transmission line is consistent with the preset length or not, and judging that the maximum position point and the minimum position point are positions of the overvoltage interval along the line when the actual length of the half-wavelength alternating-current transmission line is consistent with the preset length. And when the actual length of the half-wavelength alternating-current transmission line is inconsistent with the preset length of the half-wavelength alternating-current transmission line, judging that the maximum position point and the minimum position point are the planned positions of the overvoltage intervals along the line, and correcting the planned positions to obtain the actual positions of the overvoltage intervals along the line. In practical application, the actual length of the half-wavelength alternating-current transmission line may be inconsistent with the preset length, and only when the actual length of the half-wavelength alternating-current transmission line is consistent with the preset length, the overvoltage interval along the line is an interval formed by the maximum position point and the minimum position point obtained in the above specific embodiment. Specifically, when the actual half-wavelength ac transmission line is not consistent with the preset length, the maximum position point and the minimum position point obtained according to the preset length in the above specific embodiment are the planned position of the overvoltage interval, and the actual position of the overvoltage interval needs to be corrected to obtain the actual position of the overvoltage interval.
Specifically, the voltage transfer coefficient k of the fundamental wave along the line is the amplification level of overvoltage along the line which is set randomly, and only the overvoltage interval along the line needs to be analyzedThe situation of time. When the transmitting end voltage is the fundamental wave voltage, the interval (x)min,xmax) Namely, the overvoltage interval along the line, and meanwhile, the position of the maximum value of the voltage transfer coefficient of the fundamental wave along the line is as follows:
the embodiment of the invention also provides a specific implementation mode of the positioning method of the overvoltage interval along the AC transmission line, and the known reactance and susceptance of the half-wavelength transmission line in unit length are 0.2615 omega/km and 4.328 multiplied by 10 respectively-6S/km, the accurate half wavelength is 2953km, and the natural power SIL of the line transmission is approximately equal to 4485 MVA. Because the transmission power and the power factor of a half-wave line can cause important influence on the line overvoltage, when the transmission power of the line is 1.5SIL and the power factor theta is 1 and +/-0.8 respectively, the interval of the line overvoltage is analyzed. If the overvoltage level along the line is k<1.4, the section k is greater than or equal to 1.4 is an overvoltage section, and it is assumed that the fundamental voltage U of the transmission end of the line isS1And when the angle is 1 & lt 0 & gt pu, calculating to obtain the positions (unit: km) of the overvoltage interval (unit: km) along the line and the maximum value of the transmission coefficient along the line according to the formula (6) and the formula (8) respectively as follows:
the simulation results of the voltage transfer coefficient along the line at different power factors are shown in fig. 2.
In one embodiment, the actual position along the overvoltage interval is obtained by correcting the proposed position by: calculating a first difference value between the preset length of the half-wavelength alternating-current transmission line and the actual length of the half-wavelength alternating-current transmission line, and obtaining a lower limit of a line overvoltage interval according to a minimum position point between the line overvoltage interval and a receiving end of the half-wavelength alternating-current transmission line and the first difference value; when the maximum position point of the line overvoltage interval from the receiving end of the half-wavelength alternating current transmission line is smaller than or equal to the preset length of the half-wavelength alternating current transmission line, the maximum position point is the upper limit of the line overvoltage interval; and when the maximum position point is greater than the preset length of the half-wavelength alternating current transmission line, a second difference value between the maximum position point and the first difference value is an upper limit of the line overvoltage interval, and the actual position of the line overvoltage interval is determined according to the upper limit of the line overvoltage interval and the lower limit of the line overvoltage interval.
Specifically, when a half-wavelength power transmission line is actually designed, the length of the line is not necessarily implemented by installing an accurate preset length, and when the length of the line is not equal to the preset length, because the fundamental wave cannot keep an integer of half-wave characteristics, under the same working condition, the overvoltage interval along the line will change compared with the preset length of the half-wavelength alternating current power transmission line, and the proposed interval needs to be corrected, wherein the correction process is as follows:
let Δ l be (l-l'), the lower limit of the overvoltage interval is:
upper limit of overvoltage intervalComprises the following steps:
in the formula (10), h is 1, l represents the preset length of the half-wavelength alternating-current transmission line, and is affected by factors such as a lead arrangement mode, the number of splits, a skin effect, a ground resistivity, a cyclic transposition of a circuit and the like; l' represents the actual length of the half-wavelength ac transmission line.
And similarly, the position of the maximum value of the fundamental wave voltage transmission coefficient along the line under the actual length of the half-wavelength alternating-current transmission line can be obtained by taking the average value of the upper limit and the lower limit of the overvoltage interval. Still taking the fundamental wave voltage as an example, when the system operation condition is unchanged, and the actual line length is 2800km and 3200km, respectively, if the along-line fundamental wave voltage transfer coefficient is 1.4, the simulation results of the along-line fundamental wave voltage transfer coefficient are shown in fig. 3 and 4, respectively, the overvoltage interval calculated by correcting equations (9) and (10) is shown in table 1, and the position of the maximum value of the corresponding along-line fundamental wave voltage transfer coefficient is shown in table 2.
TABLE 1 overvoltage interval for half-wavelength AC transmission lines
TABLE 2 location of maxima of fundamental voltage transfer coefficients along the line
According to the method for positioning the overvoltage interval along the alternating-current transmission line, the corresponding overvoltage interval is calculated by using the derived overvoltage interval formula and the correction formula thereof under different working conditions on the basis of the set overvoltage amplification level, and the position of the overvoltage maximum point along the line is further calculated. The method is simple in principle, can position the overvoltage interval along the half-wavelength power transmission line only by setting the overvoltage amplification level and the system operation parameters, and has high application value.
Fig. 5 is a schematic diagram of a hardware structure of a computer device of a method for positioning an overvoltage interval along an ac power transmission line according to an embodiment of the present invention, as shown in fig. 5, the computer device includes one or more processors 51 and a memory 52, and one processor 51 is taken as an example in fig. 5.
The computer device may further include: an input device 53 and an output device 54.
The processor 51, the memory 52, the input device 53 and the output device 54 may be connected by a bus or other means, and fig. 5 illustrates the bus connection.
The processor 51 may be a Central Processing Unit (CPU). The Processor 51 may also be other general purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components, or combinations thereof. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 52 is a non-transitory computer readable storage medium, and can be used to store non-transitory software programs, non-transitory computer executable programs, and modules, such as program instructions/modules corresponding to the method for positioning overvoltage intervals along an ac power transmission line in the embodiment of the present invention. The processor 51 executes various functional applications and data processing of the server by running the non-transitory software program, instructions and modules stored in the memory 52, that is, the method for positioning the overvoltage interval along the ac power transmission line according to the above embodiment of the method is implemented.
The memory 52 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created from use of devices positioned along the overvoltage interval along the ac transmission line, and the like. Further, the memory 52 may include high speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory 52 optionally includes memory remotely located from the processor 51, and these remote memories may be connected to the devices located along the ac power line over-voltage intervals via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The input device 53 may receive a user-entered query request (or other numeric or alphanumeric information) and generate key signal inputs relating to user settings and function controls of the positioning device along the overvoltage interval along the ac power transmission line. The output device 54 may include a display device such as a display screen for outputting the calculation result.
The one or more modules are stored in the memory 52 and, when executed by the one or more processors 51, perform the method shown in fig. 1.
The product can execute the method provided by the embodiment of the invention, and has corresponding functional modules and beneficial effects of the execution method. For details of the embodiments of the present invention, reference may be made to the description of the embodiments shown in fig. 1 to 4.
The embodiment of the invention also provides a non-transient computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions can execute the method for positioning the overvoltage interval along the alternating current transmission line in any method embodiment. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Hard Disk (Hard Disk Drive, abbreviated as HDD), a Solid State Drive (SSD), or the like; the storage medium may also comprise a combination of memories of the kind described above.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (7)

1. A method for positioning an overvoltage interval along an alternating current transmission line is characterized by comprising the following steps:
obtaining a transmission coefficient of the fundamental wave voltage along the line of the half-wavelength alternating-current transmission line according to the fundamental wave voltage and current of the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line;
obtaining a minimum position point and a maximum position point which are separated from a receiving end of the half-wavelength alternating current transmission line along the line overvoltage interval according to the voltage transfer coefficient of the fundamental wave along the line;
determining the position of the overvoltage interval along the line according to the minimum position point and the maximum position point, wherein the determining comprises the following steps: judging whether the actual length of the half-wavelength alternating current transmission line is consistent with the preset length or not;
when the actual length of the half-wavelength alternating-current transmission line is consistent with the preset length, the maximum position point and the minimum position point are judged to be positions of overvoltage intervals along the line;
calculating the voltage transfer coefficient of the fundamental wave along the line of the half-wavelength alternating-current transmission line by the following formula:
wherein the content of the first and second substances,representing the fundamental wave voltage along the line of the half-wavelength alternating current transmission line;the method comprises the steps of representing fundamental wave voltage of a transmitting end of a half-wavelength alternating-current transmission line; beta is ahRepresenting a fundamental wave phase constant, x representing the distance from a receiving end of a half-wavelength alternating current transmission line, l representing the preset length of the half-wavelength alternating current transmission line, and IphRepresenting the real part of the current vector at the delivery end of a half-wavelength AC transmission line, IqhRepresenting the imaginary part, U, of the current vector at the transmitting end of a half-wavelength AC transmission lineShThe voltage scalar value of the sending end of the half-wavelength alternating current transmission line is represented; zBDenotes a lossless wave impedance, h is 1;
calculating the minimum position point and the maximum position point of the line overvoltage interval from the receiving end of the half-wavelength alternating current transmission line according to the following formula:
wherein:
wherein the content of the first and second substances,IShand the scalar value of the current of the sending end of the half-wavelength alternating current transmission line is represented.
2. The method for positioning the overvoltage interval along the line of the alternating-current transmission line according to claim 1, wherein the step of obtaining the voltage transmission coefficient of the fundamental wave along the line of the half-wavelength alternating-current transmission line according to the voltage and the current of the fundamental wave at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line comprises the following steps:
obtaining the fundamental wave voltage and current along the line of the half-wavelength alternating-current transmission line according to the fundamental wave voltage and current at the sending end of the half-wavelength alternating-current transmission line and the preset length of the half-wavelength alternating-current transmission line;
and obtaining the voltage transfer coefficient of the fundamental wave along the line of the half-wavelength alternating-current transmission line according to the voltage and the current of the fundamental wave along the line of the half-wavelength alternating-current transmission line.
3. The method for positioning the overvoltage interval along the line of the alternating-current transmission line according to claim 2, wherein the voltage and the current of the fundamental wave along the line of the half-wavelength alternating-current transmission line are calculated by the following formulas:
wherein the content of the first and second substances,respectively representing fundamental wave voltage and current of a transmitting end of a half-wavelength alternating-current transmission line;respectively representing fundamental wave voltage and current along the line of the half-wavelength alternating-current transmission line; beta is ahRepresenting a fundamental wave phase constant, x representing the distance from a receiving end of a half-wavelength alternating current transmission line, l representing the preset length of the half-wavelength alternating current transmission line, and ZBDenotes a lossless wave impedance, and h is 1.
4. The method according to claim 1, wherein when the actual length of the half-wavelength alternating current transmission line is inconsistent with the preset length of the half-wavelength alternating current transmission line, the maximum position point and the minimum position point are determined to be the planned positions of the overvoltage intervals along the line, and the planned positions are corrected to obtain the actual positions of the overvoltage intervals along the line.
5. The method according to claim 4, wherein the proposed position is corrected to obtain the actual position of the overvoltage interval along the line by:
calculating a first difference value between the preset length of the half-wavelength alternating-current transmission line and the actual length of the half-wavelength alternating-current transmission line;
obtaining the lower limit of the line overvoltage interval according to the minimum position point of the line overvoltage interval from the receiving end of the half-wavelength alternating current transmission line and the first difference value;
when the maximum position point of the line overvoltage region at a distance from the receiving end of the half-wavelength alternating current transmission line is smaller than or equal to the preset length of the half-wavelength alternating current transmission line, the maximum position point is the upper limit of the line overvoltage region;
when the maximum position point is larger than the preset length of the half-wavelength alternating current transmission line, a second difference value between the maximum position point and the first difference value is an upper limit of the line overvoltage interval;
and determining the actual position of the overvoltage interval along the line according to the upper limit of the overvoltage interval along the line and the lower limit of the overvoltage interval along the line.
6. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out a method for locating overvoltage intervals along an ac transmission line according to any one of claims 1 to 5.
7. A computer device, comprising:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executable by the at least one processor to cause the at least one processor to perform the method of locating along an ac power transmission line overvoltage interval as claimed in any one of claims 1 to 5.
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