CN111999597A - Traveling wave fault positioning device of hybrid power transmission line - Google Patents

Abstract

The invention discloses a traveling wave fault location device for hybrid transmission lines, which belongs to the technical field of high-voltage transmission lines of power electronics; the device comprises: a current extraction module, a signal conditioning circuit, an A/D conversion module, and a GPS high-precision synchronous clock module, DSP central processor module, GPRS communication module, PC master station comprehensive analysis module; seven traveling wave extraction devices are installed in the entire hybrid transmission line, which are placed at both ends of the hybrid line, the midpoint of the overhead line, and the midpoint of the GIL. , the midpoint of the cable, the connection between the overhead line and the GIL, and the connection between the GIL and the cable. The invention utilizes GPS to synchronize the traveling wave extraction devices at each end of the transmission line to improve the accuracy of fault location; utilizes the DSP chip to process the fault signal, thereby realizing the rapid identification and location of the fault in the hybrid transmission line.

Description

A traveling wave fault location device for hybrid transmission lines

technical field

The invention belongs to the technical field of fault location of high-voltage hybrid transmission lines, in particular to a traveling wave fault location device for hybrid transmission lines.

Background technique

Overhead lines, gas insulated transmission lines (GIL) and cables can meet the laying arrangements of power transmission systems under different conditions due to their different structural characteristics, and improve the adaptability and flexibility of the entire transmission line. However, for the new overhead line-GIL-cable hybrid transmission line, the traditional single-ended and double-ended ranging cannot achieve good results.

In order to detect the transient traveling wave phenomenon in the line on the secondary side, it is necessary to accurately extract the traveling wave component in the line. At the same time, in order to ensure the fault location accuracy, there is a high requirement for the acquisition speed of the fault analog signal.

In the traditional fault location method based on traveling waves, the distance is determined by the time when the wave head of the first and second traveling waves arrives at each detection point. There will be multiple discontinuous points of wave impedance in the mixed line of the popular wave, resulting in the phenomenon of traveling wave refraction and reflection, and it will be difficult to judge that the traveling wave reaching the detection device is the wave head of the first traveling wave or the traveling wave signal obtained by subsequent reflection.

For the multi-terminal ranging method based on traveling waves, it is necessary to obtain the accurate time when the initial traveling waves arrive at each recording device on the basis of synchronous sampling of data. However, due to the time difference of each device on the transmission line, the time is not synchronized, which will eventually affect the ranging accuracy.

In conclusion, there is an urgent need for a new traveling wave fault location device for hybrid transmission lines based on GPS reference time difference.

SUMMARY OF THE INVENTION

In order to solve the distance measurement problem of overhead line-gas insulated transmission line (GIL)-cable hybrid transmission line, the present invention improves the existing traveling wave distance measurement device, and proposes a traveling wave fault location device for hybrid transmission line , using GPS to synchronize the time of the traveling wave extraction devices distributed in the transmission line, which can improve the accuracy of fault location; using DSP chip to process fault information at high speed, improving the speed of fault signal processing; using GPRS to realize fault data packets. Send, improve the automation and precision of communication.

To achieve the above object, the present invention adopts the following technical solutions:

A traveling wave fault location device for a hybrid transmission line of the present invention includes:

The current extraction module is used to extract the line fault traveling wave signal;

The signal conditioning circuit module is used to adjust the fault traveling wave signal obtained by the current extraction module to the range that conforms to the A/D conversion module, and obtain the adjusted fault traveling wave signal;

The A/D conversion module is used to process the fault traveling wave signal adjusted by the signal conditioning circuit module into a fault traveling wave digital signal;

The DSP central processor module is used to process the fault traveling wave digital signal output by the A/D conversion module, and obtain the time when the fault traveling wave signal reaches each current extraction module;

A comprehensive analysis module of the PC main station, the comprehensive analysis module of the PC main station is embedded with a fault location algorithm, which is used to complete the fault location based on the time obtained by the DSP central processing unit module.

A further improvement of the present invention is, also includes:

The GPS synchronization clock module is used to provide a unified time reference for the traveling wave fault location device.

A further improvement of the present invention is, also includes:

The GPRS communication module is used to send the fault information obtained after processing by the DSP central processing module to the comprehensive analysis module of the PC master station.

A further improvement of the present invention is that the current extraction modules are respectively arranged at both ends of the hybrid line, the midpoint of the overhead line, the midpoint of the GIL, the midpoint of the cable, the connection between the overhead line and the GIL, and the connection between the GIL and the cable;

The current extraction module includes: a current transformer, which is used to convert the current signal on the primary side of the transmission line into a current signal that is convenient for collection and measurement through the secondary side current transformer; wherein, the collected current signal is a circuit fault. Three-phase current signal.

A further improvement of the present invention is that the conditioning circuit module includes: a Π-type filter circuit and an analog amplifier circuit.

The further improvement of the present invention lies in that, in the DSP central processing unit, firstly, phase-mode transformation is performed on the collected fault current traveling wave signal to obtain the α line mode component; wavelet transformation is performed on the extracted α line mode component, and the maximum modulus is analyzed. value to obtain the time for the fault traveling wave signal to reach each current extraction module.

A further improvement of the present invention is that, in the DSP central processing unit,

The expression for the continuous wavelet transform of the α component is:

为所选择的母小波的复共轭。In the formula, χ(t) is the current signal, a is the scale factor, b is the transfer factor,

is the complex conjugate of the chosen mother wavelet.

A further improvement of the present invention is that the fault location algorithm embedded in the comprehensive analysis module of the PC master station is: based on the time when the fault traveling wave signal reaches each current extraction module, according to the minimum time method and the time difference comparison method of the adjacent measuring points Determine the section where the fault occurs; calculate the wave speed and fault starting time based on the obtained section where the fault occurs; determine the fault location and complete the fault location based on the calculated wave speed and fault starting time.

A further improvement of the present invention is that, in the fault location algorithm embedded in the comprehensive analysis module of the PC master station:

When the time t _m is the smallest, the fault occurs in the first half of the overhead line;

When the time _{ta is the smallest, if t b >} t _m , the fault occurs in the first half of the overhead line; otherwise, the fault occurs in the second half of the overhead line;

When the time t _b is the smallest, if t _d -t _c =t _c -t _b , the fault occurs in the second half of the overhead line; otherwise, the fault occurs in the first half of the gas-insulated transmission line;

When the time t _c is the smallest, if t _b < t _d , the fault occurs in the first half of the gas-insulated transmission line; otherwise, the fault occurs in the second half of the gas-insulated transmission line;

When the time t _d is the smallest, if t _e -t _d =t _n -t _e , the fault occurs in the second half of the gas-insulated transmission line; otherwise, the fault occurs in the first half of the cable;

When the time t _e is the smallest, if t _n >t _d , the fault occurs in the first half of the cable; otherwise, the fault occurs in the second half of the cable;

When the time t _n is the smallest, the fault occurs in the second half of the cable;

Among them, t _m is the arrival time of the first wave head of the traveling wave probe at the terminal m, t _a is the arrival time of the first wave head of the traveling wave probe at the midpoint of the overhead line, and t _b is the connection between the overhead line and the gas-insulated transmission line The arrival time of the first wave head of the traveling wave probe at , t _c is the arrival time of the first wave head of the traveling wave probe at the midpoint of the gas-insulated transmission line, and t _d is the traveling wave probe at the connection between the gas-insulated transmission line and the cable line The arrival time of the first wave head at , t _e is the arrival time of the first wave head of the traveling wave probe at the midpoint of the cable line, and t _n is the arrival time of the first wave head of the traveling wave probe at the terminal n.

A further improvement of the present invention is that,

(1) The fault occurs in the first half of the overhead line. The expressions for calculating the wave speed and the fault starting time t ₀ are:

The expression for determining the fault location is: d=(t _m -t ₀ )v ₁ ;

(2) The fault occurs in the second half of the overhead line, and the expressions for calculating the wave speed and the fault start time t ₀ are:

The expression for determining the fault location is: d=l ₁ +(t _a -t ₀ )v ₁ ;

(3) The fault occurs in the first half of the gas-insulated transmission line, and the expressions for calculating the wave speed and the fault start time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +(t _b -t ₀ )v ₂ ;

(4) The fault occurs in the second half of the gas-insulated transmission line. The expressions for calculating the wave speed and the fault start time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +l ₂ +(t _c -t ₀ );

(5) The fault occurs in the first half of the cable, and the expressions for calculating the wave speed and the fault starting time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +2l ₂ +(t _d -t ₀ )v ₃ ;

(6) The fault occurs in the second half of the cable, and the expressions for calculating the wave speed and the fault starting time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +2l ₂ +l ₃ +(t _e -t ₀ )v ₃ ;

In the formula, l ₁ is half the length of the overhead line, l ₂ is half the length of the gas-insulated transmission line, l ₃ is half the length of the cable, v ₁ is the propagation speed of the traveling wave in the overhead line, and v ₂ is the traveling wave The propagation velocity in the gas-insulated transmission line, _v3 is the propagation velocity of the traveling wave in the cable, and d is the distance between the fault location and the terminal m.

Compared with the prior art, the present invention has the following beneficial effects:

The traveling wave fault locating device of the hybrid transmission line based on the GPS reference time difference of the present invention uses GPS to perform time synchronization on the traveling wave extracting devices distributed in the transmission line, which can improve the accuracy of fault locating; High-speed processing, improve the speed of fault signal processing; use GPRS to realize the transmission of fault data packets, improve the automation and accuracy of communication. The invention can meet the fault location of overhead line-gas-insulated transmission line (GIL)-cable hybrid transmission line, and is also suitable for fault location and distance measurement of traditional single transmission line and overhead line-cable hybrid transmission line. . To achieve fault location, it is only necessary to analyze the arrival time of the first wave head, compare the time values of different measurement points to determine the fault occurrence time, reduce the problem of refraction and reflection of traveling waves, and ensure the accuracy of fault location. At the same time, the device uses the GPS reference time difference to perform time synchronization and calibration on each traveling wave extraction device in the transmission line, thereby improving the reliability of the device ranging.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings used in the description of the embodiments or the prior art; obviously, the accompanying drawings in the following description are For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative efforts.

1 is a schematic structural diagram of a traveling wave fault location device for a hybrid transmission line based on GPS reference time difference according to an embodiment of the present invention;

2 is a schematic diagram of a traveling wave acquisition and processing system in an embodiment of the present invention;

3 is a schematic diagram of the principle of a signal conditioning circuit in an embodiment of the present invention;

4 is a schematic diagram of the principle of a GPS high-precision synchronization clock module in an embodiment of the present invention;

FIG. 5 is a schematic work flow diagram of a traveling wave fault location device for a hybrid transmission line based on a GPS reference time difference according to an embodiment of the present invention.

Detailed ways

In order to make the purposes, technical effects and technical solutions 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 accompanying drawings in the embodiments of the present invention; are some embodiments of the present invention. Based on the embodiments disclosed in the present invention, other embodiments obtained by persons of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Referring to FIG. 1 , a traveling wave fault location device for a hybrid transmission line based on GPS reference time difference according to an embodiment of the present invention is used for fault location of a GPS-based overhead line-gas-insulated transmission line (GIL)-cable hybrid line. The traveling wave fault location device includes: a current extraction module, a signal conditioning circuit module, an A/D conversion module, a GPS high-precision synchronous clock module, a DSP central processor module, a GPRS communication module and a PC master station comprehensive analysis module; wherein, Seven traveling wave extraction devices are installed in the entire hybrid transmission line, which are placed at both ends of the hybrid line, the midpoint of the overhead line, the midpoint of the GIL, the midpoint of the cable line, the connection between the overhead line and the GIL, and the connection between the GIL and the cable.

In the embodiment of the present invention, real-time current extraction is performed on the transmission line by using a current transformer, and the current transformer converts the large current signal from the primary side of the transmission line into a small current signal that is convenient for collection and measurement

When the line fails, the DSP will detect the current signal with sudden change, and then control the A/D conversion chip and the GPS interface unit to sample the fault current traveling wave signal within a predetermined time;

The signal conditioning circuit module adjusts the small current signal on the secondary side of the current transformer to the range of the A/D conversion chip without distortion; at the same time, the signal conditioning circuit is used to realize the electrical connection between the digital quantity and the analog quantity. Isolation, to avoid strong currents in series with low-voltage components.

The GPS high-precision synchronous clock module is used to provide a unified and precise time reference for the entire fault location device. Specifically, the GPS high-precision synchronous clock module is suitable for synchronizing the clocks of each receiving module in the power grid, ensuring the high-precision synchronous operation of the clocks everywhere in the device, and outputting a high-precision second clock signal and sending it to the DSP in the module.

The traveling wave acquisition and processing system needs to record the complete waveform of the current initial traveling wave signal when it reaches the bus measurement place, and the frequency is relatively high. Large-capacity data memory SDRAM is supported.

The waveform and data of the time signal and the traveling wave signal of the faulty circuit with the precision of us level are recorded through the data bus and the address bus.

The DSP central processing unit firstly performs phase-mode transformation on the collected fault current traveling wave signal to obtain the α line mode component. Wavelet transform is performed on the extracted α line mode component, and its mode maximum is analyzed, so as to obtain the time when the fault traveling wave signal reaches each current extraction module. Optionally, the discretized fault signal is processed, which specifically includes applying wavelet transform to analyze the modulo maximum value of the signal, identifying the first extreme value information, using GPS to synchronize the clock, and extracting the accuracy of the first traveling wave head. Arrival time; requires that the SDRAM space in the DSP chip is large enough to avoid data coverage caused by external faults and internal faults during the conversion process, and improve the reliability of the system.

The GPRS communication module converts the serial data into IP data, and transmits the data to the PC processor through the wireless communication network. Specifically, the GPRS communication module is suitable for communication between the traveling wave acquisition and processing system and the comprehensive analysis module of the PC main station, and sends the fault information obtained after being processed by the DSP central processing module to the comprehensive analysis module of the PC main station.

The PC master station analysis module receives the fault information sent by GPRS communication, and the data analysis and processing and fault location calculation are realized by MATLAB programming. The PC master station comprehensive analysis module is suitable for receiving and storing fault reports, receiving data processed by the DSP central processor module, starting the host computer program, and realizing the automation of traveling wave fault location.

In the embodiment of the present invention, in the DSP central processing unit, the expression for performing continuous wavelet transform on the α component is:

为所选择的母小波的复共轭。In the formula, χ(t) is the current signal, a is the scale factor, b is the transfer factor,

is the complex conjugate of the chosen mother wavelet.

In the embodiment of the present invention, the fault location algorithm embedded in the comprehensive analysis module of the PC master station is: based on the time when the fault traveling wave signal arrives at each current extraction module, according to the minimum time method and the comparison method of the time difference between adjacent measuring points. The section where the fault occurred; based on the obtained section where the fault occurred, calculate the wave speed and the fault start time; based on the calculated wave speed and the fault start time, determine the fault location and complete the fault location.

A further improvement of the present invention is that, in the fault location algorithm embedded in the comprehensive analysis module of the PC master station:

When the time t _m is the smallest, the fault occurs in the first half of the overhead line;

When the time _{ta is the smallest, if t b >} t _m , the fault occurs in the first half of the overhead line; otherwise, the fault occurs in the second half of the overhead line;

When the time t _b is the smallest, if t _d -t _c =t _c -t _b , the fault occurs in the second half of the overhead line; otherwise, the fault occurs in the first half of the gas-insulated transmission line;

When the time t _c is the smallest, if t _b < t _d , the fault occurs in the first half of the gas-insulated transmission line; otherwise, the fault occurs in the second half of the gas-insulated transmission line;

When the time t _d is the smallest, if t _e -t _d =t _n -t _e , the fault occurs in the second half of the gas-insulated transmission line; otherwise, the fault occurs in the first half of the cable;

When the time t _e is the smallest, if t _n >t _d , the fault occurs in the first half of the cable; otherwise, the fault occurs in the second half of the cable;

When the time t _n is the smallest, the fault occurs in the second half of the cable;

Among them, t _m is the arrival time of the first wave head of the traveling wave probe at the terminal m, t _a is the arrival time of the first wave head of the traveling wave probe at the midpoint of the overhead line, and t _b is the connection between the overhead line and the gas-insulated transmission line The arrival time of the first wave head of the traveling wave probe at , t _c is the arrival time of the first wave head of the traveling wave probe at the midpoint of the gas-insulated transmission line, and t _d is the traveling wave probe at the connection between the gas-insulated transmission line and the cable line The arrival time of the first wave head at , t _e is the arrival time of the first wave head of the traveling wave probe at the midpoint of the cable line, and t _n is the arrival time of the first wave head of the traveling wave probe at the terminal n.

In the embodiment of the present invention,

(1) The fault occurs in the first half of the overhead line. The expressions for calculating the wave speed and the fault starting time t ₀ are:

The expression for determining the fault location is: d=(t _m -t ₀ )v ₁ ;

(2) The fault occurs in the second half of the overhead line, and the expressions for calculating the wave speed and the fault start time t ₀ are:

The expression for determining the fault location is: d=l ₁ +(t _a -t ₀ )v ₁ ;

(3) The fault occurs in the first half of the gas-insulated transmission line, and the expressions for calculating the wave speed and the fault start time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +(t _b -t ₀ )v ₂ ;

(4) The fault occurs in the second half of the gas-insulated transmission line. The expressions for calculating the wave speed and the fault start time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +l ₂ +(t _c -t ₀ );

(5) The fault occurs in the first half of the cable, and the expressions for calculating the wave speed and the fault starting time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +2l ₂ +(t _d -t ₀ )v ₃ ;

(6) The fault occurs in the second half of the cable, and the expressions for calculating the wave speed and the fault starting time t ₀ are:

The expression for determining the fault location is: d=2l ₁ +2l ₂ +l ₃ +(t _e -t ₀ )v ₃ ;

In the formula, l ₁ is half the length of the overhead line, l ₂ is half the length of the gas-insulated transmission line, l ₃ is half the length of the cable, v ₁ is the propagation speed of the traveling wave in the overhead line, and v ₂ is the traveling wave The propagation velocity in the gas-insulated transmission line, _v3 is the propagation velocity of the traveling wave in the cable, and d is the distance between the fault location and the terminal m.

The advantages of the device according to the embodiment of the present invention include: it can meet the fault location of a new type of overhead line-gas insulated transmission line (GIL)-cable hybrid transmission line, and is also applicable to traditional single transmission line and overhead line-cable hybrid transmission line. Fault location and distance measurement of transmission lines. To achieve fault location, it is only necessary to analyze the arrival time of the first wave head, and compare the time values of different measurement points to determine the fault occurrence time, which reduces the problem of refraction and reflection of traveling waves and ensures the accuracy of fault location. At the same time, the device uses the GPS reference time difference to perform time synchronization and calibration on each traveling wave extraction device in the transmission line, thereby improving the reliability of the device ranging.

Referring to FIG. 1 , a schematic structural diagram of an overhead line-gas-insulated transmission line (GIL)-cable hybrid transmission line fault location device based on GPS reference time difference according to an embodiment of the present invention is shown in FIG. 1 , and the fault location device includes: distributed Traveling wave acquisition and processing device, GPRS communication module, and PC master station comprehensive analysis module; wherein, the distributed traveling wave acquisition device modules are placed at both ends of the hybrid line, the midpoint of the overhead line, the midpoint of the GIL, the midpoint of the cable line, and the overhead line. Line and GIL connection, GIL and cable connection.

Please refer to Figure 2 and Figure 3, the structure of the analysis traveling wave acquisition and processing system is shown in Figure 2. The real-time current extraction of the transmission line is carried out by using the current transformer connected to the secondary circuit, and the large current signal from the primary side of the transmission line is converted into a small current signal which is convenient for acquisition and measurement. Then filter and amplify the high-frequency small current signal, input it to the A/D conversion module, and digitize the analog data. Among them, the current acquisition and processing circuit is shown in Figure 3. In order to prevent the aliasing phenomenon of the signal, the current signal needs to be filtered by _a low _- pass filter to filter out the high-frequency components in the signal before sampling. Standard signal required for D-converter.

Input the discretized fault signal into the DSP central processing unit for analysis. After sampling, the DSP central processing unit firstly performs phase-mode transformation on the collected fault current traveling wave signal to obtain the α line mode component, which includes applying wavelet transform to analyze the maximum value of the signal and identify the first extreme value information. , use GPS to synchronize the clock, and extract the accurate arrival time of the first traveling wave head. The DSP records the waveform and data of the time signal and the traveling wave signal of the fault circuit with the precision reaching the us level through the data bus and the address bus. It is required that the SDRAM space in the DSP chip is large enough to avoid the data coverage caused by the conversion process of external faults and internal faults, and improve the reliability of the system.

The GPS synchronization clock module in the system is used to provide a unified and accurate time reference for the fault location system of the distributed traveling wave method for high-voltage transmission lines. The time basis of the current traveling wave signal.

Please refer to Figure 4. The GPS receiver in the GPS synchronous clock module outputs a 1PPS second pulse signal, which is stabilized by the phase-locked loop and then output to the CPLD control module. Accuracy compensation is performed on the second pulse signal obtained by the GPS receiver, and the corrected 1PPS second pulse signal is obtained by CPLD processing, which provides a unified clock signal for the system. The workflow is shown in Figure 4.

Please refer to Figure 5, the data packets processed by the DSP central processing module are sent to the PC master station comprehensive analysis module through the GPRS network and the public network, and the PC master station comprehensive analysis module is composed of a PC master controller. After the occurrence, the module enters the fault processing program, and realizes data exchange between the traveling wave acquisition module and the comprehensive analysis module of the PC main station through the communication network. The comprehensive analysis module of the PC main station is embedded with a fault location algorithm, which can Automatically display ranging results and actively report fault information. The workflow is shown in Figure 5.

To sum up, the embodiment of the present invention discloses a fault location device for an overhead line-gas-insulated transmission line (GIL)-cable hybrid transmission line based on GPS reference time difference, which belongs to the technical field of high-voltage transmission lines of power electronics; including current extraction module, signal conditioning circuit, A/D conversion module, GPS high-precision synchronous clock module, DSP central processing unit module, GPRS communication module, PC master station comprehensive analysis module; seven traveling wave extraction devices are installed in the entire hybrid transmission line, They are placed at both ends of the hybrid line, the midpoint of the overhead line, the midpoint of the GIL, the midpoint of the cable, the connection between the overhead line and the GIL, and the connection between the GIL and the cable. The invention is characterized in that: using GPS to synchronize the traveling wave extraction devices at each end of the transmission line, the accuracy of fault location is improved; using DSP chip to process the fault signal, so as to realize the rapid detection of faults in the hybrid transmission line Identify and locate.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still modify or equivalently replace the specific embodiments of the present invention. , any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are all within the protection scope of the claims of the present invention for which the application is pending.

Claims (10)

1. The utility model provides a traveling wave fault locating device of hybrid transmission line which characterized in that includes:

the current extraction module is used for extracting a line fault traveling wave signal;

the signal conditioning circuit module is used for adjusting the fault traveling wave signal obtained by the current extraction module to a range conforming to the A/D conversion module to obtain an adjusted fault traveling wave signal;

the A/D conversion module is used for processing the fault traveling wave signal adjusted by the signal conditioning circuit module into a fault traveling wave digital signal;

the DSP central processing unit module is used for processing the fault traveling wave digital signals output by the A/D conversion module to obtain the time for the fault traveling wave signals to reach each current extraction module;

and the PC master station comprehensive analysis module is embedded with a fault distance measurement algorithm and is used for completing fault positioning based on the time obtained by the DSP central processor module.

2. The traveling wave fault locating device of a hybrid transmission line according to claim 1, further comprising:

and the GPS synchronous clock module is used for providing a uniform time reference for the traveling wave fault positioning device.

3. The traveling wave fault locating device of a hybrid transmission line according to claim 1, further comprising:

and the GPRS communication module is used for transmitting the fault information obtained after the processing of the DSP central processing module to the PC master station comprehensive analysis module.

4. The traveling wave fault location device of a hybrid transmission line according to claim 1,

the current extraction modules are respectively arranged at two ends of the hybrid line, the middle point of the overhead line, the middle point of the GIL, the middle point of the cable, the connecting position of the overhead line and the GIL and the connecting position of the GIL and the cable;

the current extraction module includes:

the current transformer is used for converting a current signal at the primary side of the power transmission line into a current signal convenient to collect and measure through the secondary side current transformer; the collected current signals are three-phase current signals of circuit faults.

5. The traveling wave fault location device of a hybrid transmission line according to claim 1,

the conditioning circuit module includes: a pi-type filter circuit and an analog amplifying circuit.

6. The traveling wave fault location device of a hybrid power transmission line according to claim 1, wherein the DSP central processing unit first performs phase-mode conversion on the collected fault current traveling wave signal to obtain an α -line-mode component; and performing wavelet transformation on the extracted alpha line mode component, and analyzing the mode maximum value of the alpha line mode component to obtain the time of the fault traveling wave signal reaching each current extraction module.

7. The traveling wave fault location device of a hybrid power transmission line according to claim 6, wherein, in the DSP central processing unit,

the expression for the continuous wavelet transform on the alpha component is:

wherein χ (t) is a current signal, a is a scaling factor, b is a transfer factor,

is the complex conjugate of the selected mother wavelet.

8. The traveling wave fault location device of a hybrid power transmission line of claim 1, wherein the fault location algorithm embedded in the PC master station comprehensive analysis module is: judging a fault occurring section according to a minimum time method and an adjacent measuring point time difference comparison method based on the time of the fault traveling wave signal reaching each current extraction module; calculating a wave speed and a fault starting time based on the obtained section where the fault occurs; and determining the fault position based on the wave speed and the fault starting time obtained by calculation, and completing fault positioning.

9. The traveling wave fault location device of a hybrid power transmission line of claim 4, wherein in the fault location algorithm embedded in the PC master station comprehensive analysis module:

when time t is_mWhen the fault is minimum, the fault occurs in the first half section of the overhead line;

when time t is_aAt minimum, if t_b>t_mThe fault occurs in the first half section of the overhead line; otherwise, the fault occurs in the second half section of the overhead line;

when time t is_bAt minimum, if t_d-t_c＝t_c-t_bThe fault occurs in the second half section of the overhead line; otherwise, the fault occurs in the first half section of the gas insulated transmission line;

when time t is_cAt minimum, if t_b<t_dThe fault occurs in the first half section of the gas insulated transmission line; otherwise, the fault occurs in the second half section of the gas insulated transmission line;

when time t is_dAt minimum, if t_e-t_d＝t_n-t_eThe fault occurs in the second half section of the gas insulated transmission line; otherwise, the fault occurs in the front half section of the cable;

when time t is_eAt minimum, if t_n>t_dThe fault occurs in the front half section of the cable; otherwise, the fault occurs in the rear half section of the cable;

when time t is_nWhen the fault is minimum, the fault occurs in the rear half section of the cable;

wherein, t_mThe first wave head arrival time t of the traveling wave probe at the position m of the terminal_aThe first wave head arrival time, t, of the travelling wave probe in the neutral point of the overhead line_bPower transmission for overhead lines and gas insulationTime of arrival, t, of the first wave head of a travelling-wave probe at a line connection_cThe first wave head arrival time t of the traveling wave probe at the midpoint of the gas insulated transmission line_dThe first wave head arrival time t of the traveling wave probe at the joint of the gas insulated transmission line and the cable_eThe arrival time of the first wave head of the cable midpoint traveling wave probe is t_nThe time of arrival of the first wave head of the traveling wave probe at the terminal n.

10. The traveling wave fault location device of a hybrid transmission line according to claim 9,

(1) the fault occurs in the first half section of the overhead line, and the wave speed and the fault starting time t are calculated₀The expression of (a) is:

the expression for determining the fault location is: d ═ t_m-t₀)v₁；

(2) The fault occurs in the second half section of the overhead line, and the wave speed and the fault starting time t are calculated₀The expression of (a) is:

the expression for determining the fault location is: d ═ l₁+(t_a-t₀)v₁；

(3) The fault occurs in the first half section of the gas insulated transmission line, and the wave speed and the fault starting time t are calculated₀The expression of (a) is:

the expression for determining the fault location is: d 2l₁+(t_b-t₀)v₂；

(4) The fault occurs in the second half section of the gas insulated transmission line, and the wave speed and the fault starting time t are calculated₀The expression of (a) is:

the expression for determining the fault location is: d 2l₁+l₂+(t_c-t₀)；

(5) The fault occurs in the first half section of the cable, the wave speed and the fault starting time t are calculated₀The expression of (a) is:

the expression for determining the fault location is: d 2l₁+2l₂+(t_d-t₀)v₃；

(6) The fault occurs in the second half section of the cable, and the wave speed and the fault starting time t are calculated₀The expression of (a) is:

the expression for determining the fault location is: d 2l₁+2l₂+l₃+(t_e-t₀)v₃；

In the formula I₁Is half the length of the overhead line,/₂Is half of the length of the gas insulated transmission line₃Is half the length of the cable, v₁Is the propagation velocity, v, of a travelling wave in an overhead line₂For the propagation velocity, v, of a travelling wave in a gas-insulated power transmission line₃D is the distance from the fault location to the terminal m, which is the propagation speed of the traveling wave in the cable.

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