CN114325226A - High-frequency fault positioning method and system for single-end adaptive correction of power transmission line - Google Patents
High-frequency fault positioning method and system for single-end adaptive correction of power transmission line Download PDFInfo
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Abstract
The invention provides a high-frequency fault positioning method and a high-frequency fault positioning system for single-ended adaptive correction of a power transmission line, wherein traveling waves generated by a fault point are reflected to the fault point after reaching a bus, and distance measurement is carried out based on the time difference of the traveling waves reflected by the fault point and reaching the bus; recording the time corresponding to the 1 st maximum point; determining the 1 st maximum value, and recording the arrival time of the subsequent maximum values to obtain the ranging results of the arrival of a plurality of traveling waves; measuring the distance of the power transmission line by using an impedance method to obtain a fault distance; measuring a plurality of groups of fault distances, and screening the distance measurement results; when the distance measurement result shows that the near-end fault exists, the distance measurement result is directly used as the distance measurement result; the method can effectively realize single-end fault location, can carry out self-adaptive correction according to near-end faults or far-end faults, effectively improves the reliability and accuracy of fault location, and greatly improves the adaptability of fault location to field conditions by the realization of a single-end method.
Description
Technical Field
The invention belongs to the field of traveling wave fault location, and particularly relates to a high-frequency fault location method and system for single-ended adaptive correction of a power transmission line.
Background
The continuous development of an electric power system, the voltage grade and the transmission energy of a transmission line are gradually improved, the high-voltage transmission line is the life pulse of the electric power system and bears the responsibility of main electric energy transmission, a fault point is quickly found after the fault of the high-voltage transmission line occurs, the fault is removed, the normal operation power supply of the system is recovered, therefore, the manpower, material resources and financial resources consumed by fault line patrol are saved, the power failure loss is reduced, and the power supply reliability is very important to improve.
Once a transmission line has a fault, the fault position needs to be determined as soon as possible so that an operator can conveniently remove the fault, and the method plays an important role in recovering the safe operation of a power grid in the shortest time and ensuring the power supply benefit and the whole grid safety.
However, for a condition-limited area, if a traveling wave ranging device can only be installed at a single-end station, a conventional double-end traveling wave ranging method cannot be realized. At this time, an accurate fault location result cannot be obtained in a conventional manner. Therefore, how to realize high-reliability and high-precision fault location in a scene with only a single-ended traveling wave distance measuring device becomes a problem which needs to be researched urgently.
Disclosure of Invention
The invention provides a high-frequency fault positioning method for single-ended adaptive correction of a power transmission line, which can realize high-reliability and high-precision fault positioning.
The method comprises the following steps:
s101, reflecting the traveling wave generated by the fault point to the fault point after the traveling wave reaches the bus, and ranging based on the time difference of the traveling wave reflected by the fault point and reaching the bus;
s102, recording the time corresponding to the 1 st maximum point;
s103, determining the 1 st maximum value, and recording the arrival time of the subsequent maximum values to obtain the ranging results of the arrival of a plurality of traveling waves;
s104, ranging the power transmission line by using an impedance method and substituting the ranging into a formula
Obtaining a fault distance;
s105, measuring a plurality of groups of fault distances, and screening the distance measurement results;
s106, when the distance measurement result shows that the fault occurs at the near end, directly taking the fault as the distance measurement result;
and when the ranging result is a far-end fault, adjusting the ranging result by multiplying the wave velocity parameter by a coefficient of 0.96 in the ranging process.
Further, in step S101, the distance measurement is performed according to the following formula:
in the formula, XSIs the distance to failure; t iss1，Ts2Respectively the time when the initial traveling wave surge of the fault reaches the m-end bus measuring point and the time when the initial traveling wave surge of the fault is reflected back from the fault pointThe time of the measurement point; v is the traveling wave propagation velocity.
Further, in step S102, the 1 st mode maximum value is the time when the wave head arrives.
Further, step S101 further includes: using the single-ended traveling wave of the fault point reflected wave to carry out distance measurement;
the method uses the arrival time t1 and t3 of the reverse traveling wave surge;
when the fault point is positioned between the ranging point and the middle point of the line, the fault point is arranged at the installation point of the ranging device at the M side of the line, and the time when the initial fault traveling wave reaches the M end is sensed to be t1The time when the backward traveling wave surge with the reflected wave reflected by the fault point F reaches the M end is t3The time difference value of the fault traveling wave arriving at the measuring end twice is t3-t1That is, the time taken for the fault traveling wave to go back and forth once between the fault point and the measurement end, and the traveling wave propagation speed is set as v, the position of the fault point is:
further, step S101 further includes: measuring the distance by using the single-ended traveling wave of the opposite-end bus reflected wave;
the method uses the time t1 and t2 when the reverse traveling wave surge reaches the M end;
when the fault point is located in an interval outside the ranging point and the middle point, the ranging device on the line M side senses the time t1 when the initial traveling wave surge reaches the M end, the time when the traveling wave surge reflected by the opposite end bus of the fault traveling wave is refracted to the M side of the measuring end at the fault point is t2, the time t2 when the reflected wave reaches the M side of the fault traveling wave surge traveling wave is earlier than t1 because the fault point is located close to the opposite end bus, namely the opposite end bus arrives at the measuring end before the reflected wave of the fault end;
the time difference value of the two fault traveling waves reaching the M side measuring end is t2-t1, the time taken by the fault traveling waves to and fro once between the fault point and the measuring end-to-end bus is given, the line length is L, and the distance of the fault point is obtained as follows:
it should be further noted that, in step S104,
Imfh、I* mgzthe fault components of the load current and the short-circuit current of the m end are shown;
CMis the current distribution coefficient of the m-terminal,
wherein, γmThe angle is determined by the combined impedance angle on both sides of the fault point, LmFThe length of the line mF is shown, Zm and Zn are m, the system comprehensive impedance at two ends of n is shown, Zm is Rm + jXm, and Zn is Rn + jxn; i ismgxIs a conjugated complex number.
The invention also provides a high-frequency fault positioning system for the single-ended adaptive correction of the power transmission line, which comprises the following steps: the system comprises a distance measurement module, a time recording module, a fault distance measurement module, a screening module and a judgment module;
the distance measurement module is used for reflecting the traveling wave generated by the fault point to the fault point after the traveling wave reaches the bus, and measuring the distance based on the time difference of the traveling wave reflected by the fault point and reaching the bus;
the time recording module is used for recording the time corresponding to the 1 st maximum point; determining the 1 st maximum value, and recording the arrival time of the subsequent maximum values to obtain the ranging results of the arrival of a plurality of traveling waves;
the distance measurement module is also used for measuring the distance of the power transmission line by using an impedance method and substituting the distance into a formula
Obtaining a fault distance;
the screening module is used for measuring a plurality of groups of fault distances and screening the distance measurement results;
the judging module is used for directly serving as a distance measurement result when the distance measurement result shows that the near-end fault exists;
and when the ranging result is a far-end fault, adjusting the ranging result by multiplying the wave velocity parameter by a coefficient of 0.96 in the ranging process.
Further, it should be noted that the method further includes: a display module;
the display module is used for displaying the distance information measured by the distance measuring module, and also displaying the fault distance information and the result information output by the judging module;
but also for displaying operational data of the system.
It should be further noted that the storage is used for storing the distance information measured by the distance measuring module, and also storing the fault distance information and the result information output by the judging module;
and also for storing operational data of the system.
According to the technical scheme, the invention has the following advantages:
the high-frequency fault positioning method and system for the single-end adaptive correction of the power transmission line provided by the invention utilize the complementary characteristics of high precision and low reliability of a traveling wave method and low precision and high reliability of an impedance method, form a distance measurement scheme which can be realized in a single-end plant station, and have the function of adaptive correction. The invention uses the traveling wave method to carry out single-end fault location, and uses the time difference between the reflected traveling wave and the incident traveling wave of the fault point to reach the measuring end to calculate the fault distance so as to obtain a plurality of location results. And secondly, selecting a result which is closest to the result obtained by the traveling wave method according to the impedance method as a ranging result. And according to the result, the near-end fault or the far-end fault is obtained, and the result is corrected according to the result reflected wave waveform state. When the distance measurement result shows that the near-end fault occurs, the result is more reliable because the reflected wave is stronger, and the result can be directly used as the distance measurement result. When the ranging result is a far-end fault, the attenuation is serious because the traveling wave propagation distance is long, the average value of the traveling wave propagation speed is reduced by a certain range, and the wave speed parameter in the ranging process is subjected to self-adaptive adjustment, so that the purpose of self-adaptive correction of the far-end fault is realized.
The high-frequency fault positioning method and system for single-ended adaptive correction of the power transmission line can effectively realize single-ended fault location, can carry out adaptive correction according to near-end faults or far-end faults, effectively improve the reliability and accuracy of fault location, and greatly improve the adaptability of fault location to field conditions by realizing a single-ended method.
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In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a flow chart of a high-frequency fault location method for single-ended adaptive correction of a power transmission line;
FIG. 2 is an exploded view of a line fault condition;
FIG. 3 is a schematic diagram of internal faults of a double-end power supply single-phase line;
FIG. 4 is a diagram of a simulated power system architecture;
FIG. 5 is a traveling wave diagram of the phase voltage at the M terminal A;
FIG. 6 is a traveling wave diagram of the M-terminal B-phase voltage;
FIG. 7 is a traveling wave diagram of the M-terminal C-phase voltage;
FIG. 8 is a waveform of the M-terminal 0 modulus;
FIG. 9 is a diagram of M-terminal 1 modulus waveform;
fig. 10 is a graph of M-terminal 2 modulus waveform.
Detailed Description
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 only a part of the embodiments of the present invention, and not all of the embodiments. 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 units and algorithm steps of each example described in the embodiments disclosed in the method and system for locating a single-ended adaptive correction high-frequency fault of a power transmission line provided by the present invention can be implemented by electronic hardware, computer software, or a combination of the two. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The block diagram shown in the attached drawing of the power transmission line single-ended adaptive correction high-frequency fault positioning method and system provided by the invention is only a functional entity, and does not necessarily correspond to a physically independent entity. I.e. these functional entities may be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and/or processor means and/or microcontroller means.
The high-frequency fault positioning method for the single-ended adaptive correction of the power transmission line is suitable for a scene with only a single-ended traveling wave distance measuring device, does not need to distinguish whether an initial reflected wave is a fault point reflected wave or an opposite-end bus reflected wave, and directly utilizes the wave head to combine the line length to obtain a plurality of possible distance measuring results. And then, screening according to the ranging result of the impedance method, and selecting the similar traveling wave ranging result as a final result. As shown in fig. 1, the specific steps are as follows:
and S101, measuring the distance by methods such as reflecting the traveling wave generated by the fault point to the fault point after reaching the bus, reflecting the traveling wave to the bus by the fault point, and the like. The invention proceeds with ranging according to the following formula:
in the formula, XSIs the distance to failure; t iss1,Ts2Respectively determining the time when the initial fault traveling wave surge reaches the m-end bus measuring point and reflects the initial fault traveling wave surge from the fault point to the measuring point; v is the traveling wave propagation velocity.
S102, recording the time corresponding to the 1 st maximum value, wherein the time corresponding to the 1 st maximum value is the arrival time of the initial traveling wave of the fault point, and the reflected waves of the fault point corresponding to the 2 nd, the 3 rd and the 4 th wave heads appearing later, the reflected waves of the opposite-end bus and the refracted waves of the adjacent lines.
S103, determining the 1 st maximum value, recording the arrival time of the following maximum values without distinguishing the corresponding sequence, and obtaining the ranging results of the arrival of a plurality of traveling waves.
S104, in the travelling wave method distance measurement, in order to obtain a more accurate distance measurement value, a distributed parameter model is adopted; in the impedance method distance measurement, a lumped parameter model is adopted to simplify the calculation in consideration of the fact that the impedance method only plays a role in distinguishing the intervals.
The impedance method is used for ranging the transmission line, the same line parameters as those of the traveling wave method are adopted, and the number is substituted into a formula
And obtaining the fault distance obtained by the impedance method.
And S105, accurately screening the distance measurement results of the multiple groups of data measured by the traveling wave method by using the data obtained by the impedance method.
S106, when the distance measurement result shows that the near-end fault exists, the obtained result is more reliable because the reflected wave is stronger, and the result can be directly used as the distance measurement result. When the ranging result is a far-end fault, the attenuation is serious because the traveling wave propagation distance is long, the average value of the traveling wave propagation speed is reduced by a certain extent, and the wave speed parameter is multiplied by a 0.96 coefficient to carry out self-adaptive adjustment in the ranging process.
The method provided by the invention utilizes the complementary characteristics of high precision and low reliability of a traveling wave method and low precision and high reliability of an impedance method, forms a distance measurement scheme which can be realized in a single-ended plant station, and has a self-adaptive correction function.
The method firstly uses a traveling wave method to carry out single-end fault location, and calculates the fault distance by using the time difference between the reflected traveling wave and the incident traveling wave of the fault point to reach the measuring end to obtain a plurality of location results. And secondly, selecting a result which is closest to the result obtained by the traveling wave method according to the impedance method as a ranging result. On the basis, the result is further corrected according to the near-end fault or the far-end fault and the result reflected wave waveform state. When the distance measurement result shows that the near-end fault occurs, the result is more reliable because the reflected wave is stronger, and the result can be directly used as the distance measurement result. When the ranging result is a far-end fault, the attenuation is serious because the traveling wave propagation distance is long, the average value of the traveling wave propagation speed is reduced by a certain range, and the wave speed parameter in the ranging process is subjected to self-adaptive adjustment, so that the purpose of self-adaptive correction of the far-end fault is realized.
In the traveling wave fault location according to the present invention, when a single-phase ground fault occurs in a transmission line, as shown in fig. 2, the state of the network configuration diagram is a fault state (fig. a), and the fault state can be divided into a non-fault state (fig. c) and a fault-added state (fig. d) by using the superposition principle.
As can be seen from graph (a), the voltage and current at various points in the overall post-fault network is the sum of the pre-fault load component and the fault component. Namely, it is
u＝up+ug
i＝ip+ig
The non-fault state refers to the normal operation state before the line fault, and the fault additional state refers to the additional equivalent power supply after the fault occurs, wherein the equivalent voltage source U in the non-fault statepEquivalent power supply U with fault additional stategThe values are equal and the directions are opposite, and the fault adding state is independent of the non-fault state and is influenced by the operation mode of the system. Equivalent voltage source U in fault attachment stategThe transmission line will generate a forward wave propagating from the fault point to both ends of the line, and due to the distributed parameter characteristics of the transmission line, the forward wave has high frequency properties and a propagation speed close to the speed of light, thereby generating a fault traveling wave.
For the single-end traveling wave distance measurement related by the invention, voltage traveling waves are taken as analysis objects, the distance measurement device is arranged at the M-end bus side, and if the direction from the bus M to the line MN is taken as the positive direction, the initial voltage traveling wave surge reaching the bus from a fault point is taken as a reverse traveling wave surge; the forward traveling wave surge is reflected by the bus M; the reverse traveling wave surge returns to the M end through the fault point; the initial fault traveling wave surge reaching the N-side bus is reflected by the N-side bus and transmitted through the fault point F to reach the M-side bus as a reverse traveling wave surge. And the distance measurement of the fault point is realized by detecting the time difference between the moment when the fault initial traveling wave surge reaches the measuring end and the moment when the fault point reflected wave or the opposite end bus reflected wave reaches the measuring end. Single-ended traveling wave ranging can be classified into the following forms according to the reflected wave used:
(1) single-ended traveling wave ranging using fault point reflected waves;
the method of the invention uses the arrival time t of the reverse traveling wave surge1And t3. When the fault point is between the distance measuring point and the middle point of the line, the fault point is arranged at the installation point of the distance measuring device at the M side of the line, and the time when the initial fault traveling wave reaches the M end is sensed to be t1The time when the backward traveling wave surge with the reflected wave reflected by the fault point F reaches the M end is t3The time difference value of the fault traveling wave arriving at the measuring end twice is t3-t1That is, the time taken for the fault traveling wave to go back and forth once between the fault point and the measurement end, and the traveling wave propagation speed is set as v, the position of the fault point is:
this mode requires that the timing at which the reflected wave of the fault-initiating traveling wave reflected again at the F point reaches the M side must be accurately determined.
(2) The invention uses single-ended traveling wave distance measurement of opposite-end bus reflected waves;
the method of the invention uses the time t when the backward traveling wave surge reaches the M end1And t2. When the fault point is located in the interval beyond the ranging point and the middle point, the time t when the initial traveling wave surge reaches the M end is sensed by the ranging device at the M side of the line1When the traveling wave surge of the fault traveling wave reflected by the opposite end bus is refracted to the side of the measuring end M at the fault pointIs m between t2Then, since the fault point is located at the side close to the bus at the opposite end, the time t when the reflected wave reaches the M side2Is to precede t1Namely, the opposite end bus reflected wave reaches the measuring end before the fault end reflected wave. The time difference value of the two fault traveling waves reaching the M side measuring end is t2-t1If the length of the line is L, the distance between the fault points is:
it is clear that when the fault point is at the midpoint of the line, both ends can be used to measure the distance of its M side to the fault for either end of the line. From the above, it is important to reliably and accurately identify which end of the second reflected wave is reflected.
For the impedance method ranging related to the present invention, as shown in fig. 3, under the assumed conditions, the established two-terminal power single-line fault ranging model is explained by taking a single-phase system as an example because the transmission line is a three-phase symmetric line. The circuit equation is obtained as follows:
Um＝ImZLmg+IfRg
Imgz＝Im-Imfh＝GMIF
therefore, it is not only easy to use
Wherein, I* mgx、I* mgzFault components of load current and short-circuit current at m terminal, IFIs the fault point current. CMIs the current distribution coefficient of the m-terminal,
wherein, γmThe angle is determined by the combined impedance angle on both sides of the fault point, LmfFor the length of the line mF, Zm、ZnIs the system integrated impedance of m, n two terminals, Zm＝Rm+jXm,Zn＝Rn+jxn。ImgxIs a conjugated complex number. The above formula shows that the ranging result is not affected by the transition resistance Rg. In the above formula, Z is known, the measured voltage and current at the m end can be measured in real time, the fault component of the current at the m end can be solved in real time, and only C is usedMUnknown, and the gammam angle varies with the position of the fault point and is difficult to determine. Considering that γ m is small, generally smaller than 10, an approximation calculation is performed, and γ m is taken to be 0. The distance measurement formula under various short circuit conditions can be obtained by decomposing the sequence network diagram by a symmetric component method.
Based on the method, the invention also provides a high-frequency fault positioning system for the single-ended adaptive correction of the power transmission line, which comprises the following steps: the system comprises a distance measurement module, a time recording module, a fault distance measurement module, a screening module and a judgment module;
the distance measurement module is used for reflecting the traveling wave generated by the fault point to the fault point after the traveling wave reaches the bus, and measuring the distance based on the time difference of the traveling wave reflected by the fault point and reaching the bus;
the time recording module is used for recording the time corresponding to the 1 st maximum point; determining the 1 st maximum value, and recording the arrival time of the subsequent maximum values to obtain the ranging results of the arrival of a plurality of traveling waves;
the distance measurement module is also used for measuring the distance of the power transmission line by using an impedance method and substituting the distance into a formula
Obtaining a fault distance;
the screening module is used for measuring a plurality of groups of fault distances and screening the distance measurement results;
the judging module is used for directly serving as a distance measurement result when the distance measurement result shows that the near-end fault exists;
and when the ranging result is a far-end fault, adjusting the ranging result by multiplying the wave velocity parameter by a coefficient of 0.96 in the ranging process.
Further, the system further comprises: a display module and a memory;
the display module is used for displaying the distance information measured by the distance measuring module, and also displaying the fault distance information and the result information output by the judging module; but also for displaying operational data of the system.
The storage device is used for storing the distance information measured by the distance measuring module, and also storing the fault distance information and the result information output by the judging module; and also for storing operational data of the system.
The method and the system for high-frequency fault positioning of single-ended adaptive correction of the power transmission line are subjected to simulation analysis, a PSB module in Matlab simulation software is used for simulation, and a Matlab program is used for carrying out wavelet analysis on simulation data. The structure diagram of the running simulation power system is as follows:
as shown in fig. 4: the simulation adopts a transmission line with 500kV double power supplies of a certain line, a 50Hz three-phase distribution line model is used, and the line parameters are as follows:
R1＝0.0208Ω/km,R0＝0.1148Ω/km；
L1＝0.8984e-3H/km,L0＝2.2886e-3H/km；
C1＝0.0129e-6F/km,C0＝0.00523e-6F/km；
the total length L of the line is 150.00km, the line fault is an A-phase fault, the distance from a fault point to an M end is 10km, and the distance from the fault point to an N end is XSThe source resistance is 1.05 Ω, the source reactance is 0.1375 Ω/km, the ground resistance is 1 Ω, and the sampling frequency is 1 MHz.
During simulation of the impedance method, the sampling frequency is 2000HZ, the simulation starting time is 0.06S, the simulation ending time is 0.14S, and 40 points are sampled per cycle.
If the fault occurrence time is set to be 0.02s by the traveling wave method, the transient voltage traveling wave waveform obtained by the measuring end M is shown in fig. 5 to 7.
The traveling wave signals are decoupled by wavelet transformation, after the phase quantity is converted into the modulus, the moduli are independent from each other and have no coupling relation, and three modulus waveforms obtained after M-terminal voltage traveling wave decoupling are shown in fig. 8 to 10.
Wavelet analysis is used for carrying out wavelet transformation on the 1 moduli of the M end and the N end to obtain the arrival time of the travelling wave head. The following chart shows the results of the M-end 1 modulus wavelet transform and the wavelet transform modulus maximum detection:
from the wavelet transform results, t is measured1＝20029us，t2＝20097us，t3＝20166us，t420982us, the measured time parameter is substituted into the formula (4-1) to obtain the distance measurement result.
The fault distances are respectively measured to be 10km, 50km, 100km and 140km by the same method. And the simulation results of the fault distance measured by the down wave method when the transition resistance is 1 omega, 10 omega and 50 omega are shown in table 1:
TABLE 1 line different fault distances and ranging results of common fault points of transition resistance
For the convenience of comparison and analysis, the parameters of the traveling wave ranging are used for ranging by an impedance method, the ranging results are obtained in each case as shown in the following table 2, and the final ranging results are obtained by screening the ranging results by the impedance method as shown in the following table 3.
TABLE 2 ranging results by impedance method
From the comparison of the results, the most similar one is taken as the final ranging result for the near-end fault comparison traveling wave ranging and impedance method result. For the faults of 100km and 140km far ends, according to the method provided by the invention, the traveling wave propagation distance is long, the attenuation is serious, the propagation average speed is reduced, and the result needs to be corrected in a self-adaptive manner. According to the method, the final result and error obtained after correcting the far-end fault result are shown in the following graph.
TABLE 3 Final ranging results
In conclusion, the method provided by the invention can effectively realize single-end fault location, can carry out self-adaptive correction according to the near-end fault or the far-end fault, effectively improves the reliability and the accuracy of fault location, and greatly improves the adaptability of fault location to field conditions by realizing the single-end method.
The high-frequency fault location method and system for single-ended adaptive correction of power transmission lines provided by the invention are the units and algorithm steps of each example described in combination with the embodiments disclosed herein, and can be realized by electronic hardware, computer software or a combination of the two. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. A high-frequency fault positioning method for single-ended adaptive correction of a power transmission line is characterized by comprising the following steps:
s101, reflecting the traveling wave generated by the fault point to the fault point after the traveling wave reaches the bus, and ranging based on the time difference of the traveling wave reflected by the fault point and reaching the bus;
s102, recording the time corresponding to the 1 st maximum point;
s103, determining the 1 st maximum value, and recording the arrival time of the subsequent maximum values to obtain the ranging results of the arrival of a plurality of traveling waves;
s104, ranging the power transmission line by using an impedance method and substituting the ranging into a formula
Obtaining a fault distance;
s105, measuring a plurality of groups of fault distances, and screening the distance measurement results;
s106, when the distance measurement result shows that the fault occurs at the near end, directly taking the fault as the distance measurement result;
and when the ranging result is a far-end fault, adjusting the ranging result by multiplying the wave velocity parameter by a coefficient of 0.96 in the ranging process.
2. The transmission line single-ended adaptive correction high-frequency fault location method according to claim 1,
in step S101, ranging is performed according to the following formula:
in the formula, XSIs the distance to failure; t iss1，Ts2Respectively the time when the initial fault traveling wave surge reaches the m-end bus measuring point and the time when the initial fault traveling wave surge is reflected back to the measuring point from the fault point; v is the traveling wave propagation velocity.
3. The transmission line single-ended adaptive correction high-frequency fault location method according to claim 1,
in step S102, the 1 st mode maximum value is the time when the wave head arrives.
4. The method for positioning the high-frequency fault of the single-ended adaptive correction of the power transmission line according to claim 1, wherein the step S101 further comprises: using the single-ended traveling wave of the fault point reflected wave to carry out distance measurement;
the method uses the arrival time t1 and t3 of the reverse traveling wave surge;
when the fault point is positioned between the ranging point and the middle point of the line, the fault point is arranged at the installation point of the ranging device at the M side of the line, and the time when the initial fault traveling wave reaches the M end is sensed to be t1The time when the backward traveling wave surge with the reflected wave reflected by the fault point F reaches the M end is t3The time difference value of the fault traveling wave arriving at the measuring end twice is t3-t1That is, the time taken for the fault traveling wave to go back and forth once between the fault point and the measurement end, and the traveling wave propagation speed is set as v, the position of the fault point is:
5. the method for positioning the high-frequency fault of the single-ended adaptive correction of the power transmission line according to claim 1, wherein the step S101 further comprises: measuring the distance by using the single-ended traveling wave of the opposite-end bus reflected wave;
the method uses the time t1 and t2 when the reverse traveling wave surge reaches the M end;
when the fault point is located in an interval outside the ranging point and the middle point, the ranging device on the line M side senses the time t1 when the initial traveling wave surge reaches the M end, the time when the traveling wave surge reflected by the opposite end bus of the fault traveling wave is refracted to the M side of the measuring end at the fault point is t2, the time t2 when the reflected wave reaches the M side of the fault traveling wave surge traveling wave is earlier than t1 because the fault point is located close to the opposite end bus, namely the opposite end bus arrives at the measuring end before the reflected wave of the fault end;
the time difference value of the two fault traveling waves reaching the M side measuring end is t2-t1, the time taken by the fault traveling waves to and fro once between the fault point and the measuring end-to-end bus is given, the line length is L, and the distance of the fault point is obtained as follows:
6. the transmission line single-ended adaptive correction high-frequency fault location method according to claim 1,
in the step S104, the process proceeds,
Imfh、I* mgzthe fault components of the load current and the short-circuit current of the m end are shown;
CMis the current distribution coefficient of the m-terminal,
wherein, γmThe angle is determined by the combined impedance angle on both sides of the fault point, LmFThe length of the line mF is shown, Zm and Zn are m, the system comprehensive impedance at two ends of n is shown, Zm is Rm + jXm, and Zn is Rn + jxn; i ismgxIs a conjugated complex number.
7. A high-frequency fault positioning system for single-ended adaptive correction of a power transmission line is characterized in that a high-frequency fault positioning method for single-ended adaptive correction of the power transmission line according to any one of claims 1 to 6 is adopted; the system comprises: the system comprises a distance measurement module, a time recording module, a fault distance measurement module, a screening module and a judgment module;
the distance measurement module is used for reflecting the traveling wave generated by the fault point to the fault point after the traveling wave reaches the bus, and measuring the distance based on the time difference of the traveling wave reflected by the fault point and reaching the bus;
the time recording module is used for recording the time corresponding to the 1 st maximum point; determining the 1 st maximum value, and recording the arrival time of the subsequent maximum values to obtain the ranging results of the arrival of a plurality of traveling waves;
the distance measurement module is also used for measuring the distance of the power transmission line by using an impedance method,and substitute into the formula
Obtaining a fault distance;
the screening module is used for measuring a plurality of groups of fault distances and screening the distance measurement results;
the judging module is used for directly serving as a distance measurement result when the distance measurement result shows that the near-end fault exists;
and when the ranging result is a far-end fault, adjusting the ranging result by multiplying the wave velocity parameter by a coefficient of 0.96 in the ranging process.
8. The power transmission line single-ended adaptive correction high-frequency fault location system according to claim 7, further comprising: a display module;
the display module is used for displaying the distance information measured by the distance measuring module, and also displaying the fault distance information and the result information output by the judging module;
but also for displaying operational data of the system.
9. The power transmission line single-ended adaptive correction high-frequency fault location system according to claim 7, further comprising: a reservoir;
the storage device is used for storing the distance information measured by the distance measuring module, and also storing the fault distance information and the result information output by the judging module;
and also for storing operational data of the system.
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