CN110927512A - Traveling wave fault location terminal, method and system for direct current transmission line - Google Patents
Traveling wave fault location terminal, method and system for direct current transmission line Download PDFInfo
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- CN110927512A CN110927512A CN201911060165.7A CN201911060165A CN110927512A CN 110927512 A CN110927512 A CN 110927512A CN 201911060165 A CN201911060165 A CN 201911060165A CN 110927512 A CN110927512 A CN 110927512A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
- G01R19/16576—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing DC or AC voltage with one threshold
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Abstract
The invention provides a traveling wave fault location terminal, a method and a system of a direct current transmission line, wherein the traveling wave fault location terminal comprises a non-contact sensor, the method comprises the steps of determining fault characteristics of the traveling wave fault location terminal, determining fault types based on the fault characteristics, and performing traveling wave fault location based on the fault types.
Description
Technical Field
The invention relates to the field of power system automation, in particular to a traveling wave fault location terminal, a method and a system for a direct current transmission line.
Background
In recent years, high-voltage direct-current transmission is rapidly developed in China, and fault location of a direct-current transmission line has important significance for rapid elimination and power restoration after line faults and safety and stability of an alternating-current and direct-current system. The existing direct current transmission line is mainly applied to a direct current transmission traveling wave fault location method based on a double-end traveling wave principle, basically meets the requirement that the average location error is about 1km, but has the following two disadvantages:
(1) the reliability is low: in the prior art, a traveling wave fault location terminal for a direct current transmission line acquires transient voltage by using a neutral point current of a coupling capacitor (or a noise filter) in a converter station, and the sampling principle of the terminal is shown in fig. 1. The coupling capacitor neutral point current corresponds to the dc transmission line voltage change rate (transient) rather than the actual voltage, leading to the following problems:
1) the influence of the length of the direct current transmission line and the position of a fault point is large. In the transmission process of the transient traveling wave, the high frequency quantity is attenuated more quickly and is in an exponential relation with the length of the direct current transmission line; when the fault point deviates to one side of the direct current transmission line, the transient state quantity of the side far away from the fault point is smaller. In a domestic artificial short circuit test, a fault point is close to two ends of a direct current transmission line, and traveling wave fault distance measurement terminals on two sides of the direct current transmission line acquire the characteristic that the amplitude difference of current of a neutral point of a coupling capacitor is large and the amplitude difference is large when the line is longer, as shown in fig. 2 and 3.
2) The direct current transmission line voltage change rate is remarkably reduced due to the fact that the direct current transmission line voltage change rate is greatly influenced by the fault transition resistance, the direct current transmission line fault instant change rate is directly related to the fault transition resistance, and when the grounding/short circuit instant transition resistance is large, the transient magnitude is low, so that the direct current transmission line voltage change rate is remarkably reduced, and the reliability of the fault distance measuring terminal is reduced.
(2) The precision is greatly influenced by the length of the line; according to the principle of the double-end traveling wave method, when the direct-current transmission line is long, the influence of the traveling wave speed is relatively enlarged. When the fault point is assumed to be close to one side of the direct current transmission line, an additional measurement error of about 0.5% of the direct current transmission line can be caused when the error between the set wave velocity and the actual wave velocity is 1%. In addition, as the length of the direct current transmission line is increased, the coverage area is increased, the length and wave velocity errors are enlarged due to factors such as sag and earth resistivity, and the distance measurement precision is low.
Disclosure of Invention
In order to overcome the defects that the reliability is low and the precision is greatly influenced by the length of a line in the prior art, the invention provides the traveling wave fault location terminal, the method and the system for the direct current transmission line.
In order to achieve the purpose of the invention, the invention adopts the following technical scheme:
on one hand, the invention provides a traveling wave fault location terminal of a direct current transmission line, which is arranged on a tower and comprises two non-contact sensors;
the non-contact sensor is connected with the traveling wave fault location terminal through a cable and is used for collecting analog voltage signals of the direct current transmission line.
The non-contact sensor comprises an induction electrode, a shielding electrode, a measuring capacitor and a protective cover;
the protection casing is located shielding electrode upper portion, the response electrode is located inside the shielding electrode, shielding electrode ground connection, measure electric capacity one end and connect the response electrode, the shielding electrode is connected to the other end, just it is parallelly connected with traveling wave fault ranging device to measure electric capacity.
The area of the induction electrode is more than or equal to 0.25m2And the distance between the induction electrode and the shielding electrode is more than 10 cm.
The traveling wave fault location terminal further includes:
the AD conversion module is used for converting the analog voltage signal acquired by the non-contact sensor into a digital voltage signal;
and the wireless communication module is used for sending the digital voltage signal.
And the non-contact sensor and the direct current transmission line keep a preset safety distance.
On the other hand, the invention provides a traveling wave fault location method for a direct current transmission line, which comprises the following steps:
determining the fault characteristics of the traveling wave fault location terminal based on the voltage signal acquired by the traveling wave fault location terminal;
determining the fault of which the fault voltage amplitude values of the two traveling wave fault location terminals with the maximum amplitude values are larger than a preset transient voltage threshold value as a conventional fault; otherwise, determining the fault as a high-resistance fault;
and (4) performing traveling wave fault location based on the conventional fault/high-resistance fault.
Determining a fault signature of a traveling wave fault location device, comprising:
extracting a detail coefficient of wavelet transformation by adopting a wavelet transformation method based on the transient voltage acquired by the traveling wave fault location terminal;
calculating a sequence of modulo maxima based on the detail coefficients;
and determining the initial moment of the fault based on the modulus maximum value sequence, and setting the transient voltage amplitude corresponding to the initial moment of the fault as the fault voltage amplitude.
Conventional faults include: the transition resistance of the fault is no greater than 300 ohms;
the high resistance fault includes: the transition resistance of the fault is greater than 300 ohms.
Traveling wave fault location is carried out based on conventional trouble/high resistance fault, includes:
setting the traveling wave fault location terminal with the earliest fault initial time as the 1 st traveling wave fault location terminal;
and performing traveling wave fault location based on the distance between the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminal and the correction wave speed of the traveling wave.
Based on distance between 1 st travelling wave fault location terminal and nth travelling wave fault location terminal and the correction wave speed of travelling wave carry out travelling wave fault location, include:
determining the distance between the fault point and the 1 st traveling wave fault location terminal according to the following formula:
l1＝d1-(tn-t1)×v/2
in the formula I1Distance between fault point and first traveling wave fault location terminal, d1Is the distance between the 1 st traveling wave fault distance measurement terminal and the n th traveling wave fault distance measurement terminal, tnThe fault initial time t of the nth traveling wave fault location terminal1And v is the corrected traveling wave speed at the initial fault time of the 1 st traveling wave fault location terminal.
Traveling wave fault location is carried out based on conventional trouble/high resistance fault, includes:
and calculating the distance between the fault point and the traveling wave fault distance measurement terminal according to the following formula:
ln≈Δl+d1/2
in the formula InThe distance between the fault point and the nth traveling wave fault location terminal is obtained; and delta l is the distance difference between the fault point to the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminal, and is determined based on the attenuation coefficient of the transient voltage amplitude.
On the other hand, the invention also provides a traveling wave fault location system for the direct current transmission line, which comprises the following components:
the data receiving module is used for receiving a voltage signal of the traveling wave fault location terminal;
the first determining module is used for determining the fault characteristics of the traveling wave fault location terminal based on the voltage signal;
the second determining module is used for determining the fault of which the fault voltage amplitude values of the two traveling wave fault location terminals with the maximum amplitude values are larger than a preset transient voltage threshold value as a conventional fault; otherwise, determining the fault as a high-resistance fault;
the distance measurement module is used for carrying out traveling wave fault distance measurement based on the conventional fault/high resistance fault;
the fault signature includes a fault initiation time and a fault voltage magnitude.
Compared with the closest prior art, the technical scheme provided by the invention has the following beneficial effects:
the direct current transmission line traveling wave fault location terminal provided by the invention is arranged on a tower and comprises two non-contact sensors; the non-contact sensor is connected with the traveling wave fault location terminal through a cable and used for collecting analog voltage signals of the direct current transmission line, and the non-contact sensor is located beyond the safe distance of the direct current transmission line and can be installed in a charged mode;
in the method for measuring the fault of the traveling wave fault of the direct-current transmission line, the fault characteristics of a traveling wave fault measuring terminal are determined based on a voltage signal acquired by the traveling wave fault measuring terminal; determining the fault of which the fault voltage amplitude values of the two traveling wave fault location terminals with the maximum amplitude values are larger than a preset transient voltage threshold value as a conventional fault; otherwise, determining the fault as a high-resistance fault; the traveling wave fault location is carried out based on the conventional fault/high resistance fault, so that the reliability of location is greatly improved, the influence of the line length on the precision is small, and the location precision is improved;
according to the invention, based on the transient voltages collected by the traveling wave fault location terminals which are distributed, the direct current transmission line between the adjacent traveling wave fault location terminals is relatively short, so that the influence of the transient voltage on the starting reliability of the traveling wave fault location terminal due to long-distance transmission attenuation is reduced;
according to the method, the correction of the traveling wave speed is realized at the initial moment of the fault collected by the plurality of distributed traveling wave fault location terminals, and the length of the direct-current transmission line between the adjacent traveling wave fault location terminals is shorter, so that the influence of wave speed errors is reduced, and the fault location precision of the direct-current transmission line is improved;
the invention can normally finish the traveling wave fault location under the condition that a certain traveling wave fault location terminal is abnormal, and has higher reliability;
according to the invention, the direct current transmission line is segmented by the distributed traveling wave fault location terminals, the length of the direct current transmission line is indirectly shortened, and the influence of the wave velocity is reduced by correcting the traveling wave velocity;
the invention identifies the fault type, selects the corresponding traveling wave fault location based on different fault types, has high precision and realizes the location of the high resistance fault.
Drawings
FIG. 1 is a schematic diagram of a sampling principle of a traveling wave fault location terminal of a direct current transmission line in the prior art;
FIG. 2 is a prior art current waveform diagram closer to a fault point;
FIG. 3 is a prior art current waveform at a far side from a fault point;
FIG. 4 is a flow chart of a method for ranging a traveling wave fault of a DC transmission line according to an embodiment of the present invention;
FIG. 5 is a schematic side view of a non-contact sensor in accordance with an embodiment of the present invention;
FIG. 6 is a schematic top view of a non-contact sensor in accordance with an embodiment of the present invention;
fig. 7 is a schematic diagram of traveling wave fault location of multiple traveling wave fault location terminals in an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Example 1
The embodiment 1 of the invention provides a traveling wave fault location terminal of a direct current transmission line, which is arranged on a tower and comprises two non-contact sensors;
the non-contact sensor is connected with the traveling wave fault location terminal through a cable and is used for collecting analog voltage signals of the direct current transmission line.
The traveling wave fault location terminal further includes:
the AD conversion module is used for converting the analog voltage signal acquired by the non-contact sensor into a digital voltage signal;
and the wireless communication module is used for sending the digital voltage signal.
The non-contact sensor keeps a preset safe distance with the direct current transmission line.
As shown in fig. 5 and 6, the non-contact sensor includes an induction electrode, a shield electrode, a measurement capacitance, and a shield;
the protective cover is positioned on the upper part of the shielding electrode, the sensing electrode is positioned inside the shielding electrode, the shielding electrode is grounded, one end of the measuring capacitor is connected with the sensing electrode, the other end of the measuring capacitor is connected with the shielding electrode, and the measuring capacitor is connected with the traveling wave fault distance measuring device in parallel.
The area of the induction electrode is more than or equal to 0.25m2And the distance between the induction electrode and the shielding electrode is more than 10 cm.
Stray capacitance exists between the induction electrode and the direct current transmission line, and when the distance between the non-contact sensor and the direct current transmission line is larger than a safe distance, the capacitance value of the stray capacitance is mainly related to the size of the induction electrode due to an isolated conductor effect. When the induction electrode is circular and its diameter is 0.5m, the capacitance value of the stray capacitance is 2pF at a safety distance of 10 m. The induction electrode is not limited to round and square, and has an area of 0.25m or more2That is, the shield electrode is mainly used to shield the influence of the adjacent pole lines, and the distance between the induction electrode and the shield electrodeGreater than 10 cm. The protective cover is mainly used for preventing water and dust and ensuring normal work of the sensor. And the measuring capacitor is used for extracting transient voltage, and when the voltage division ratio is 1: the capacitance of the measurement capacitor is 2uF at 1000.
Each traveling wave fault location terminal is connected with two non-contact sensors, and the two non-contact sensors correspond to the positive and negative circuits respectively. The non-contact sensor is equivalent to a capacitive voltage divider in principle, so that direct current isolation is realized, and through transient quantity, under a normal condition, a sampling value of the non-contact sensor approaches to zero, and fault instantaneous voltage rises. In addition, the installation position of the non-contact sensor is beyond the safe distance of a line, and the electrified installation of equipment can be realized.
Example 2
Embodiment 2 of the present invention provides a method for ranging a traveling wave fault of a direct current transmission line, where a specific flowchart is shown in fig. 4, and the specific process is as follows:
s101: determining the fault characteristics of the traveling wave fault location terminal based on the voltage signal acquired by the traveling wave fault location terminal;
s102: determining the fault of which the fault voltage amplitude values of the two traveling wave fault location terminals with the maximum amplitude values are larger than a preset transient voltage threshold value as a conventional fault; otherwise, determining the fault as a high-resistance fault;
s103: and (4) performing traveling wave fault location based on the conventional fault/high-resistance fault.
Determining the fault characteristics of the traveling wave fault location terminal, comprising:
extracting a detail coefficient of wavelet transformation by adopting a wavelet transformation method based on the transient voltage acquired by the traveling wave fault location terminal;
calculating a sequence of modulo maxima based on the detail coefficients;
and determining the initial moment of the fault based on the modulus maximum value sequence, and setting the transient voltage amplitude corresponding to the initial moment of the fault as the fault voltage amplitude.
Conventional faults include: the transition resistance of the fault is no greater than 300 ohms;
the high resistance fault includes: the transition resistance of the fault is greater than 300 ohms.
When a fault occursWhen the fault is a normal fault, two traveling wave fault location terminals with the earliest initial time are selected (for example, when t is1、tnAt the earliest, the 1 st traveling wave fault location terminal 1 and the nth traveling wave fault location terminal) are selected to perform traveling wave fault location at the fault initial time, the transmission wave speed of the transient traveling wave on the direct current transmission line is related to line inductance/capacitance parameters, and the parameters are related to the environment, so that the line transmission wave speed can change in a small range and is not a fixed value. For a direct current transmission line with an ultra-long distance, a small amount of wave speed deviation can also cause a large fault distance measurement error. Thus, when the fault is a normal fault, the traveling wave fault location is specifically based on the corrected wave speed of the traveling wave.
Specifically, the traveling wave fault location based on the conventional fault comprises the following steps:
setting the traveling wave fault location terminal with the earliest fault initial time as the 1 st traveling wave fault location terminal;
and performing traveling wave fault location based on the distance between the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminal and the correction wave speed of the traveling wave.
As shown in FIG. 7, assuming that fault location is realized by n traveling wave fault location terminals, T1-T4 are 4 traveling wave fault location terminals, F is a fault point, T is a fault point1-t4The 1 st traveling wave fault location terminal to the 4 th traveling wave fault location terminal,
determining the distance between the fault point and the 1 st traveling wave fault location terminal according to the following formula:
l1＝d1-(tn-t1)×v/2
in the formula I1Distance between fault point and first traveling wave fault location terminal, d1Is the distance between the 1 st traveling wave fault distance measurement terminal and the n th traveling wave fault distance measurement terminal, tnThe fault initial time t of the nth traveling wave fault location terminal1V is the corrected traveling wave speed at the initial fault time of the 1 st traveling wave fault location terminal, and v is determined according to the following formula:
v＝dn/(tn-tn-1)
in the formula, tn-1The fault initial time, d, of the n-1 traveling wave fault location terminalnAnd the distance between the nth traveling wave fault distance measurement terminal and the (n-1) th traveling wave fault distance measurement terminal is obtained.
When the fault is a high-impedance fault, selecting the traveling wave fault location terminal with the maximum amplitude (for example, when U is detected)f1、UfnAnd when the fault voltage is maximum, selecting the fault initial time and the fault voltage amplitude of the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminal) to perform traveling wave fault location.
Traveling wave fault location is carried out based on high resistance fault, include:
and calculating the distance between the fault point and the traveling wave fault distance measurement terminal according to the following formula:
ln≈Δl+d1/2
in the formula InThe distance between the fault point and the nth traveling wave fault location terminal is obtained; Δ l is a distance difference between the fault point to the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminal, and is determined based on an attenuation coefficient of the transient voltage amplitude, specifically determined according to the following formula:
Δl＝ln-l1＝-ln(Ufn/Uf1)/γ
in the formula I1Distance, U, between fault point and 1 st traveling wave fault location terminalfnFault voltage amplitude, U, for nth traveling wave fault ranging terminalfn-1The fault voltage amplitude of the n-1 traveling wave fault location terminal is obtained, gamma is an attenuation coefficient, and gamma is determined according to the following formula:
γ＝-ln(Ufn/Ufn-1)/dn
in the formula of UfnAnd the fault voltage amplitude of the n-1 traveling wave fault location terminal is obtained.
Example 3
Based on the same inventive concept, embodiment 3 of the present invention further provides a traveling wave fault location system for a dc transmission line, and the following describes the functions of each component in detail:
the data receiving module is used for receiving a voltage signal of the traveling wave fault distance measuring terminal in embodiment 1 of the invention;
the first determining module is used for determining the fault characteristics of the traveling wave fault location terminal based on the voltage signal;
the second determining module is used for determining the fault of which the fault voltage amplitude values of the two traveling wave fault location terminals with the maximum amplitude values are larger than a preset transient voltage threshold value as a conventional fault; otherwise, determining the fault as a high-resistance fault;
the distance measurement module is used for carrying out traveling wave fault distance measurement based on the conventional fault/high resistance fault;
the fault signature includes a fault initiation time and a fault voltage magnitude.
The first determining module is specifically configured to:
extracting a detail coefficient of wavelet transformation by adopting a wavelet transformation method based on the transient voltage acquired by the traveling wave fault location terminal;
calculating a sequence of modulo maxima based on the detail coefficients;
and determining the initial moment of the fault based on the modulus maximum value sequence, and setting the transient voltage amplitude corresponding to the initial moment of the fault as the fault voltage amplitude.
Conventional faults include: the transition resistance of the fault is no greater than 300 ohms;
the high resistance fault includes: the transition resistance of the fault is greater than 300 ohms.
The ranging module is specifically configured to:
setting the traveling wave fault location terminal with the earliest fault initial time as the 1 st traveling wave fault location terminal;
carry out travelling wave fault location based on the distance between 1 st travelling wave fault location terminal and the nth travelling wave fault location terminal and the correction wave speed of travelling wave, specifically include:
determining the distance between the fault point and the 1 st traveling wave fault location terminal according to the following formula:
l1＝d1-(tn-t1)×v/2
in the formula I1Distance between fault point and first traveling wave fault location terminal, d1Is the distance between the 1 st traveling wave fault distance measurement terminal and the n th traveling wave fault distance measurement terminal, tnThe fault initial time t of the nth traveling wave fault location terminal1V is the corrected traveling wave speed at the initial fault time of the 1 st traveling wave fault location terminal, and v is determined according to the following formula:
v＝dn/(tn-tn-1)
in the formula, tn-1The fault initial time, d, of the n-1 traveling wave fault location terminalnAnd the distance between the nth traveling wave fault distance measurement terminal and the (n-1) th traveling wave fault distance measurement terminal is obtained.
The distance measurement module calculates the distance between the fault point and the traveling wave fault distance measurement terminal according to the following formula:
ln≈Δl+d1/2
in the formula InThe distance between the fault point and the nth traveling wave fault location terminal is obtained; Δ l is a distance difference between the fault point to the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminal, and is determined based on an attenuation coefficient of the transient voltage amplitude, specifically determined according to the following formula:
Δl＝ln-l1＝-ln(Ufn/Uf1)/γ
in the formula, l1 is the distance between the fault point and the 1 st traveling wave fault location terminal, UfnFault voltage amplitude, U, for nth traveling wave fault ranging terminalfn-1The fault voltage amplitude of the n-1 traveling wave fault location terminal is obtained, gamma is an attenuation coefficient, and gamma is determined according to the following formula:
γ＝-ln(Ufn/Ufn-1)/dn
in the formula of UfnAnd the fault voltage amplitude of the n-1 traveling wave fault location terminal is obtained.
For convenience of description, each part of the above-described terminal is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware when implementing the present application.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and a person of ordinary skill in the art can make modifications or equivalents to the specific embodiments of the present invention with reference to the above embodiments, and such modifications or equivalents without departing from the spirit and scope of the present invention are within the scope of the claims of the present invention as set forth in the claims.
Claims (12)
1. The utility model provides a direct current transmission line travelling wave fault location terminal, its characterized in that, travelling wave fault location terminal installs on the shaft tower, includes: two non-contact sensors;
the non-contact sensor is connected with the traveling wave fault location terminal through a cable and is used for collecting analog voltage signals of the direct current transmission line.
2. The direct current transmission line traveling wave fault location terminal of claim 1, wherein the non-contact sensor includes an inductive electrode, a shield electrode, a measurement capacitor, and a shield;
the protection casing is located shielding electrode upper portion, the response electrode is located inside the shielding electrode, shielding electrode ground connection, measure electric capacity one end and connect the response electrode, the shielding electrode is connected to the other end, just it is parallelly connected with the terminal to measure electric capacity.
3. The traveling wave fault location terminal for DC transmission line according to claim 2, wherein the area of the induction electrode is 0.25m or more2And the distance between the induction electrode and the shielding electrode is more than 10 cm.
4. The direct current transmission line traveling wave fault location terminal of claim 1, wherein the traveling wave fault location terminal further comprises:
the AD conversion module is used for converting the analog voltage signal acquired by the non-contact sensor into a digital voltage signal;
and the wireless communication module is used for sending the digital voltage signal.
5. The direct current transmission line traveling wave fault location terminal of claim 1, wherein the non-contact sensor is kept at a preset safety distance from the direct current transmission line.
6. A traveling wave fault location method for a direct current transmission line is characterized by comprising the following steps:
determining fault characteristics of the traveling wave fault location terminal based on the voltage signals collected by the traveling wave fault location terminal of claims 1-5;
determining the fault of which the fault voltage amplitude values of the two traveling wave fault location terminals with the maximum amplitude values are larger than a preset transient voltage threshold value as a conventional fault; otherwise, determining the fault as a high-resistance fault;
traveling wave fault location is carried out based on the conventional fault/high resistance fault;
the fault signature includes a fault initiation time and a fault voltage magnitude.
7. The traveling wave fault location method for the direct current transmission line according to claim 6, wherein the determining the fault characteristics of the traveling wave fault location terminal includes:
extracting a detail coefficient of wavelet transformation by adopting a wavelet transformation method based on the transient voltage acquired by the traveling wave fault location terminal;
calculating a sequence of modulo maxima based on the detail coefficients;
and determining the initial moment of the fault based on the modulus maximum value sequence, and setting the transient voltage amplitude corresponding to the initial moment of the fault as the fault voltage amplitude.
8. The direct current transmission line traveling wave fault location method of claim 6, wherein the normal fault comprises: the transition resistance of the fault is no greater than 300 ohms;
the high resistance fault includes: the transition resistance of the fault is greater than 300 ohms.
9. The traveling wave fault location method for the direct current transmission line according to claim 6, wherein the traveling wave fault location based on the normal fault/high impedance fault includes:
setting the traveling wave fault location terminal with the earliest fault initial time as the 1 st traveling wave fault location terminal;
and performing traveling wave fault location based on the distance between the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminal and the correction wave speed of the traveling wave.
10. The traveling wave fault location method for the direct current transmission line according to claim 9, wherein the traveling wave fault location based on the distance between the 1 st traveling wave fault location terminal and the n-th traveling wave fault location terminal and the corrected wave speed of the traveling wave comprises:
determining the distance between the fault point and the 1 st traveling wave fault location terminal according to the following formula:
l1＝d1-(tn-t1)×v/2
in the formula I1Distance between fault point and first traveling wave fault location terminal, d1Is the distance between the 1 st traveling wave fault distance measurement terminal and the n th traveling wave fault distance measurement terminal, tnThe fault initial time t of the nth traveling wave fault location terminal1And v is the corrected traveling wave speed at the initial fault time of the 1 st traveling wave fault location terminal.
11. The method according to claim 10, wherein the travelling wave fault location based on the conventional fault/high impedance fault comprises:
and calculating the distance between the fault point and the traveling wave fault distance measurement terminal according to the following formula:
ln≈Δl+d1/2
in the formula InThe distance between the fault point and the nth traveling wave fault location terminal is obtained; delta l is the distance difference between the fault point to the 1 st traveling wave fault location terminal and the nth traveling wave fault location terminalWhich is determined based on the attenuation coefficient of the transient voltage amplitude.
12. A direct current transmission line traveling wave fault location system is characterized by comprising:
a data receiving module, configured to receive a voltage signal of the traveling wave fault location terminal according to any one of claims 1 to 5;
the first determining module is used for determining the fault characteristics of the traveling wave fault location terminal based on the voltage signal;
the second determining module is used for determining the fault of which the fault voltage amplitude values of the two traveling wave fault location terminals with the maximum amplitude values are larger than a preset transient voltage threshold value as a conventional fault; otherwise, determining the fault as a high-resistance fault;
the distance measurement module is used for carrying out traveling wave fault distance measurement based on the conventional fault/high resistance fault;
the fault signature includes a fault initiation time and a fault voltage magnitude.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111289843A (en) * | 2020-03-30 | 2020-06-16 | 云南电网有限责任公司电力科学研究院 | MMC-MTDC system direct-current line interelectrode fault distance measurement method |
| CN113030648A (en) * | 2021-03-19 | 2021-06-25 | 国网河北省电力有限公司邢台供电分公司 | Method and device for determining position of fault point of power cable and terminal equipment |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111289843A (en) * | 2020-03-30 | 2020-06-16 | 云南电网有限责任公司电力科学研究院 | MMC-MTDC system direct-current line interelectrode fault distance measurement method |
| CN111289843B (en) * | 2020-03-30 | 2022-04-12 | 云南电网有限责任公司电力科学研究院 | MMC-MTDC system direct-current line interelectrode fault distance measurement method |
| CN113030648A (en) * | 2021-03-19 | 2021-06-25 | 国网河北省电力有限公司邢台供电分公司 | Method and device for determining position of fault point of power cable and terminal equipment |
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