A device and method for locating abnormal discharge of overhead lines in a power distribution network

Abstract

The present invention belongs to the technical field of power equipment detection, and particularly relates to a device and method for locating abnormal discharge of overhead lines in a distribution network, the method comprising: installing duplex sensors and detection hosts at both ends of the overhead lines of the distribution network; two duplex sensors inject detection pulses, two detection hosts respectively measure and calculate two groups of forward propagation coefficients of the overhead lines of the distribution network, and then respectively calculate two groups of reverse propagation coefficients of the overhead lines of the distribution network, and construct two reverse propagation models of the overhead lines of the distribution network based on the two groups of reverse propagation coefficients of the overhead lines of the distribution network; detecting abnormal discharge signals occurring on the overhead lines of the distribution network, and locating the abnormal discharge position through dual-channel electromagnetic inversion based on two reverse propagation models and abnormal discharge induction signals. The present invention has high positioning efficiency and strong anti-interference ability, can accurately locate the abnormal discharge position occurring in the overhead lines of the distribution network, and evaluate the discharge intensity of the abnormal discharge occurring.

Description

Technical Field

[0001] The invention belongs to the technical field of power equipment detection, and in particular relates to a device and method for abnormal discharge live positioning of overhead lines in a distribution network. Background Art

[0002] The distribution network is the power transmission and distribution system from substations to end users in the power system. It directly serves various types of power users and is the infrastructure of power services. It plays an important role in power distribution and power supply reliability, and its importance cannot be ignored. Therefore, the stable operation of the overhead lines of the distribution network is of great significance to ensure the power supply of users.

[0003] However, abnormal discharges sometimes occur in overhead lines of distribution networks, which may be caused by insulation aging, insulator defects and / or overlapping of branches along the lines. Abnormal discharges can damage the insulation materials of equipment, reduce their insulation capacity, increase the risk of faults such as short circuits and grounding, and affect the stability and reliability of power supply. Severe abnormal discharges may also cause arcs and sparks, further causing more serious accidents and posing a serious threat to the safety of life and property.

[0004] Since abnormal discharge may cause damage to equipment along the line and unstable operation of the power system, it is necessary to repair or replace the damaged distribution network overhead lines and equipment. At present, the main method of patrolling the distribution network overhead lines is to find and locate abnormal discharges in the distribution network overhead lines. However, the method of patrolling the distribution network overhead lines requires a large number of inspection personnel, which not only consumes manpower and has low detection efficiency, but also makes it difficult to avoid detection omissions. The traveling wave method is a more efficient abnormal discharge location method commonly used in the industry. It is usually used in combination with the time difference method. The time difference between the abnormal discharge traveling wave reaching different sensors is used to calculate the position of the abnormal discharge. However, this method requires sampling equipment with a high sampling frequency and is relatively expensive. The traveling wave method combined with the single-channel electromagnetic inversion method has low requirements for sampling equipment and can judge the severity of abnormal discharges, but the single-channel electromagnetic inversion has poor anti-interference ability and low positioning accuracy. Summary of the invention

[0005] The object of the present invention is to provide a device and method for locating abnormal discharge of overhead lines in a distribution network, so as to solve the problem that the cost and positioning accuracy cannot be taken into account in the above-mentioned abnormal discharge positioning technology of overhead lines in the distribution network.

[0006] The technical solution adopted in the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for locating abnormal discharge of overhead lines in a distribution network, comprising:

[0008] Injecting a first detection pulse into a first end of an overhead line of a power distribution network, measuring the first detection pulse and its reflected pulse, and obtaining an induction signal of the first detection pulse and an induction signal of a reflected pulse of the first detection pulse;

[0009] Injecting a second detection pulse into a second end of the overhead line of the distribution network, measuring the second detection pulse and its reflected pulse, and obtaining an induced signal of the second detection pulse and an induced signal of the reflected pulse of the second detection pulse;

[0010] Calculating a first forward propagation coefficient of the overhead line of the distribution network based on the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse, calculating a first reverse propagation coefficient of the overhead line of the distribution network based on the first forward propagation coefficient of the overhead line of the distribution network, and establishing a first reverse propagation model based on the first reverse propagation coefficient of the overhead line of the distribution network;

[0011] Calculating a second forward propagation coefficient of the overhead line of the distribution network based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse, calculating a second reverse propagation coefficient of the overhead line of the distribution network based on the second forward propagation coefficient of the overhead line of the distribution network, and establishing a second reverse propagation model based on the second reverse propagation coefficient of the overhead line of the distribution network;

[0012] Using two duplex sensors to simultaneously detect abnormal discharge signals on the overhead line of the distribution network to obtain a first abnormal discharge induction signal and a second abnormal discharge induction signal;

[0013] The first abnormal discharge induction signal is brought into the first reverse propagation model to obtain the first voltage waveform at each position of the overhead line of the distribution network; the second abnormal discharge induction signal is brought into the second reverse propagation model to obtain the second voltage waveform at each position of the overhead line of the distribution network; and the abnormal discharge position is determined based on the first voltage waveform at each position of the overhead line of the distribution network and the second voltage waveform at each position of the overhead line of the distribution network.

[0014] As a further improvement of the present invention, the calculation of the first forward propagation coefficient of the overhead line of the distribution network based on the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse includes:

[0015] calculating a complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse according to the induced signal of the first detection pulse and the induced signal of the reflected pulse of the first detection pulse;

[0016] The first attenuation constant of the overhead line of the distribution network and the first phase constant of the overhead line of the distribution network are calculated based on the complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse. The calculation formula is as follows:

[0017] ;

[0018] ;

[0019] in, , and The independent variables are The function of is the frequency, is the first attenuation constant of the overhead line of the distribution network, is the first phase constant of the overhead line of the distribution network, is the length of the overhead line of the distribution network, is the complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse;

[0020] The first forward propagation coefficient of the overhead line of the distribution network is calculated by the following formula :

[0021] ;

[0022] Among them, the first forward propagation coefficient The independent variable is Function of , j represents the imaginary unit;

[0023] The calculating of the second forward propagation coefficient of the overhead line of the power distribution network based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse comprises:

[0024] calculating a complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse according to the induced signal of the second detection pulse and the induced signal of the reflected pulse of the second detection pulse;

[0025] The second attenuation constant of the overhead line of the distribution network and the second phase constant of the overhead line of the distribution network are calculated based on the complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse. The calculation formula is as follows:

[0026] ;

[0027] ;

[0028] in, , and The independent variables are The function of is the frequency, is the second attenuation constant of the overhead line of the distribution network, is the second phase constant of the overhead line of the distribution network, is the complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse;

[0029] The second forward propagation coefficient of the distribution network overhead line is calculated by the following formula :

[0030] ;

[0031] Among them, the second forward propagation coefficient for function.

[0032] As a further improvement of the present invention, the first reverse propagation coefficient of the overhead line of the distribution network is calculated based on the first forward propagation coefficient of the overhead line of the distribution network, and the first reverse propagation model is established based on the first reverse propagation coefficient of the overhead line of the distribution network, including:

[0033] The first attenuation constant and the first phase constant of the overhead line of the distribution network are both negative, and the first reverse propagation coefficient of the overhead line of the distribution network is obtained; based on the first reverse propagation coefficient of the overhead line of the distribution network, the first reverse propagation model is established as follows:

[0034] ;

[0035] in, A point on the overhead line of the distribution network The pulse generated, Express Time Shift , For pulse Propagate to another point on the distribution network overhead line b 1 pulse, t For time, The pulse from point Propagate to point b The actual propagation distance of 1, is the time difference between the induction signal of the reflected pulse of the first detection pulse and the induction signal of the first detection pulse, e is a natural constant, is the first back propagation coefficient of the overhead line of the distribution network;

[0036] The calculating the second reverse propagation coefficient of the overhead line of the distribution network based on the second forward propagation coefficient of the overhead line of the distribution network, and establishing the second reverse propagation model based on the second reverse propagation coefficient of the overhead line of the distribution network comprises:

[0037] The second attenuation constant of the overhead line of the distribution network and the second phase constant of the overhead line of the distribution network are negatively calculated to obtain the second reverse propagation coefficient of the overhead line of the distribution network; based on the second reverse propagation coefficient of the overhead line of the distribution network, the second reverse propagation model is established as follows:

[0038] ;

[0039] in, A point on the overhead line of the distribution network The pulse generated, Express Time Shift , For pulse Propagate to another point on the distribution network overhead line b The pulse at 2 o'clock, The pulse from point Propagate to point b The actual propagation distance of 2, is the time difference between the induction signal of the reflected pulse of the second detection pulse and the induction signal of the second detection pulse, is the second back propagation coefficient of the overhead line of the distribution network.

[0040] As a further improvement of the present invention, the method of determining the abnormal discharge position based on the first voltage waveform at each position of the overhead line of the distribution network and the second voltage waveform at each position of the overhead line of the distribution network includes:

[0041] Finding the position where the waveforms of the first voltage waveform at each position of the overhead line of the distribution network and the second voltage waveform at each position of the overhead line of the distribution network are most similar, and the position is the abnormal discharge position;

[0042] Among them, the similarity of the waveform at a certain position of the overhead line of the distribution network M The calculation formula is:

[0043] ;

[0044] in, is the voltage of the ith point of the first voltage waveform at a certain position of the overhead line of the distribution network, is the voltage of the i-th point of the second voltage waveform at a certain position of the overhead line of the distribution network, and n is the waveform length, that is, the number of points.

[0045] As a further improvement of the present invention, it also includes integrating the first voltage waveform at the abnormal discharge position with time to obtain a first discharge intensity, integrating the second voltage waveform at the abnormal discharge position with time to obtain a second discharge intensity, and averaging the first discharge intensity and the second discharge intensity to obtain the discharge intensity of the abnormal discharge.

[0046] In a second aspect, the present invention provides a device for locating abnormal discharge of overhead lines in a distribution network, comprising:

[0047] A first duplex sensor is used to inject a first detection pulse into a first end of an overhead line of a distribution network, measure the first detection pulse and its reflected pulse, obtain an induction signal of the first detection pulse and an induction signal of a reflected pulse of the first detection pulse; detect an abnormal discharge signal on the overhead line of the distribution network, and obtain a first abnormal discharge induction signal;

[0048] A first detection host is used to calculate a first forward propagation coefficient of the overhead line of the distribution network based on an induction signal of the first detection pulse and an induction signal of a reflected pulse of the first detection pulse, calculate a first reverse propagation coefficient of the overhead line of the distribution network based on the first forward propagation coefficient of the overhead line of the distribution network, and establish a first reverse propagation model based on the first reverse propagation coefficient of the overhead line of the distribution network; bring the first abnormal discharge induction signal into the first reverse propagation model to obtain a first voltage waveform at each position of the overhead line of the distribution network;

[0049] A second duplex sensor is used to inject a second detection pulse into a second end of the overhead line of the distribution network, measure the second detection pulse and its reflected pulse, obtain an induction signal of the second detection pulse and an induction signal of the reflected pulse of the second detection pulse; detect an abnormal discharge signal on the overhead line of the distribution network, and obtain a second abnormal discharge induction signal;

[0050] The second detection host is used to calculate the second forward propagation coefficient of the distribution network overhead line based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse, calculate the second reverse propagation coefficient of the distribution network overhead line based on the second forward propagation coefficient of the distribution network overhead line, and establish a second reverse propagation model based on the second reverse propagation coefficient of the distribution network overhead line; bring the second abnormal discharge induction signal into the second reverse propagation model to obtain the second voltage waveform at each position of the distribution network overhead line; determine the abnormal discharge position based on the first voltage waveform at each position of the distribution network overhead line and the second voltage waveform at each position of the distribution network overhead line.

[0051] As a further improvement of the present invention, the first duplex sensor comprises:

[0052] A first detection pulse generating device, used for generating and injecting a first detection pulse;

[0053] A first capacitive coupling sensor is used to measure the first detection pulse and its reflected pulse to obtain an induction signal of the first detection pulse and an induction signal of the reflected pulse of the first detection pulse; detect an abnormal discharge signal on the overhead line of the distribution network to obtain a first abnormal discharge induction signal;

[0054] The second duplex sensor comprises:

[0055] A second detection pulse generating device, used for generating and injecting a second detection pulse;

[0056] The second capacitive coupling sensor is used to measure the second detection pulse and its reflected pulse to obtain an induction signal of the second detection pulse and an induction signal of the reflected pulse of the second detection pulse; detect an abnormal discharge signal on the overhead line of the distribution network to obtain a second abnormal discharge induction signal.

[0057] As a further improvement of the present invention, the first capacitive coupling sensor includes a positive plate, a negative plate, an insulating plate and a detection capacitor; the positive plate and the negative plate are respectively connected to the two ends of the detection capacitor through wires, and the positive plate and the negative plate are fixedly connected through an insulating plate.

[0058] As a further improvement of the present invention, the first detection host comprises:

[0059] A first signal conditioning circuit is used to adjust the amplitude of a first electrical signal; the first electrical signal includes a first detection pulse, a reflection pulse of the first detection pulse, and an abnormal discharge signal;

[0060] a first microprocessor, used for controlling the working states of the first detection pulse generating device, the first signal conditioning circuit and the first communication device, calculating a first forward propagation coefficient of the overhead line of the distribution network based on the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse, calculating a first reverse propagation coefficient of the overhead line of the distribution network based on the first forward propagation coefficient of the overhead line of the distribution network, establishing a first reverse propagation model based on the first reverse propagation coefficient of the overhead line of the distribution network, and calculating a first voltage waveform at each position of the overhead line of the distribution network based on the first reverse propagation model and the first abnormal discharge induction signal;

[0061] A first data storage device, used to store a first attenuation constant of the overhead line of the distribution network and a first phase constant of the overhead line of the distribution network;

[0062] A first communication device is used to transmit a first voltage waveform at each position of the overhead line of the distribution network and a second voltage waveform at each position of the overhead line of the distribution network to the second communication device;

[0063] The second detection host comprises:

[0064] A second signal conditioning circuit is used to adjust the amplitude of a second electrical signal; the second electrical signal includes a second detection pulse, a reflection pulse of the second detection pulse, and an abnormal discharge signal;

[0065] a second microprocessor, used to control the working states of the second detection pulse generating device, the second signal conditioning circuit and the second communication device, calculate the second forward propagation coefficient of the overhead line of the distribution network based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse, calculate the second reverse propagation coefficient of the overhead line of the distribution network based on the second forward propagation coefficient of the overhead line of the distribution network, establish a second reverse propagation model based on the second reverse propagation coefficient of the overhead line of the distribution network, calculate the second voltage waveform at each position of the overhead line of the distribution network based on the second reverse propagation model and the second abnormal discharge induction signal; determine the abnormal discharge position and discharge intensity based on the second voltage waveform at each position of the overhead line of the distribution network and the first voltage waveform at each position of the overhead line of the distribution network sent by the first communication device;

[0066] A second data storage device, used to store a second attenuation constant of the overhead line of the distribution network, a second phase constant of the overhead line of the distribution network, and a discharge intensity;

[0067] The second communication device is used to transmit the first voltage waveform at each position of the overhead line of the distribution network and the second voltage waveform at each position of the overhead line of the distribution network to the first communication device.

[0068] As a further improvement of the present invention, the first signal conditioning circuit includes a lower capacitor, the lower capacitor is connected to the first end of the capacitor group, and the second end of the capacitor group is connected to the first microprocessor through a single-pole triple-throw switch; the capacitor group includes three upper capacitors with different capacitance values.

[0069] Compared with the prior art, the present invention has the following beneficial technical effects:

[0070] The abnormal discharge locating method for overhead lines in a distribution network provided by the present invention compensates for the propagation attenuation between the abnormal discharge signal generation point and the detection point through dual-channel signal electromagnetic inversion, eliminates the uncertainty error caused by the abnormal discharge signal transmission loss, and improves the accuracy and reliability of the on-site abnormal discharge locating method for overhead lines in the distribution network.

[0071] Furthermore, the discharge intensity is calculated based on the positioning method to achieve normalized measurement of the discharge intensity at different locations, thereby improving the accuracy and scientificity of the on-site abnormal discharge defect hazard level assessment.

[0072] The distribution network overhead line abnormal discharge live positioning device provided by the present invention adopts a duplex sensor, and simultaneously realizes the detection of abnormal discharge and the sending of detection pulses. One sensor replaces the traditional abnormal discharge current type or voltage type sensor and the detection pulse sending device, and has the advantages of high integration and small size. At the same time, due to the use of a capacitive coupling solution, the structure is simpler than traditional sensors, and has the advantages of non-invasiveness, light weight and low cost, and is more suitable for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 A schematic diagram of the structure of a device for locating abnormal discharge of overhead lines in a power distribution network provided by the present invention;

[0074] Figure 2 A schematic diagram of the connection between the first capacitive coupling sensor and the first detection host provided by the present invention;

[0075] Figure 3 A schematic diagram of a first signal conditioning circuit provided by the present invention;

[0076] Figure 4 A flow chart of a method for locating abnormal discharge of overhead lines in a distribution network provided by the present invention;

[0077] Figure 5 A schematic diagram of the installation and detection of a device for locating abnormal discharge of overhead lines in a power distribution network provided by the present invention;

[0078] Figure 6 A flow chart of establishing a first forward propagation model provided by the present invention;

[0079] Figure 7 The present invention provides a flow chart of a method for locating abnormal discharge of overhead lines in a distribution network and calculating discharge intensity.

[0080] Among them, 1. a first duplex sensor; 2. a first detection host; 3. a second duplex sensor; 4. a second detection host; 5. an overhead line of a distribution network; 6. a first detection pulse generating device; 7. a first capacitive coupling sensor; 8. a first signal conditioning circuit; 9. a first data acquisition device; 10. a first microprocessor; 11. a first data storage device; 12. a first touch display screen; 13. a first communication device; 14. a first power supply; 15. a second detection pulse generating device; 16. a second capacitive coupling sensor; 17. a second signal conditioning circuit; 18. a second data acquisition device; 19. a second microprocessor; 20. a second data storage device; 21. a second touch display screen; 22. a second communication device; 23. a second power supply; 24. a positive plate; 25. a negative plate; 26. an insulating plate; 27. a detection capacitor; 28. an upper capacitor; 29. ​​a lower capacitor; 30. a single-pole three-throw switch. DETAILED DESCRIPTION

[0081] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0082] Reference Figure 1, a device for locating abnormal discharge of overhead lines in a power distribution network, comprising a first locating component and a second locating component; the first locating component comprises an electrically connected first duplex sensor 1 and a first detection host 2; the second locating component comprises an electrically connected second duplex sensor 3 and a second detection host 4. When working, the first locating component and the second locating component are respectively arranged at both ends of the overhead line 5 of the power distribution network, and the first detection host 2 and the second detection host 4 communicate wirelessly through a first communication device 13 and a second communication device 22, respectively forming a first channel and a second channel, and the first channel and the second channel form a dual channel for dual-channel electromagnetic inversion detection.

[0083] The first duplex sensor 1 includes a first detection pulse generating device 6 and a first capacitive coupling sensor 7; the first detection host 2 includes a first signal conditioning circuit 8, a first data acquisition device 9, a first microprocessor 10, a first data storage device 11, a first touch display screen 12, a first communication device 13 and a first power supply 14.

[0084] The first duplex sensor 1 is used to inject a first detection pulse into the overhead line 5 of the distribution network, measure the first detection pulse and its reflected pulse, and obtain an induction signal of the first detection pulse and an induction signal of the reflected pulse of the first detection pulse; detect an abnormal discharge signal on the overhead line 5 of the distribution network, and obtain a first abnormal discharge induction signal.

[0085] The first detection pulse generating device 6 is used to generate and inject a first detection pulse with high amplitude and wide frequency. The high amplitude means that the pulse amplitude is above 50V, and the wide frequency means that the pulse frequency bandwidth is above 1GHz.

[0086] The first capacitive coupling sensor 7 is used to measure the first detection pulse and its reflected pulse to obtain the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse; detect the abnormal discharge signal on the overhead line 5 of the distribution network to obtain the first abnormal discharge induction signal.

[0087] Reference Figure 2 The first capacitive coupling sensor 7 includes a positive plate 24, a negative plate 25, an insulating plate 26 and a detection capacitor 27; the positive plate 24 and the negative plate 25 are connected to the two ends of the detection capacitor 27 through a wire, and the positive plate 24 and the negative plate 25 are fixed by an insulating plate. The detection capacitor 27 is used to divide the voltage to sense the first electrical signal in the overhead line 5 of the distribution network. The capacitance value of the detection capacitor 27 is determined according to the capacitance of the overhead line 5 of the distribution network to the ground. The first electrical signal includes a first detection pulse, a reflected pulse of the first detection pulse and an abnormal discharge signal.

[0088] Specifically, in the first detection host 2:

[0089] The input end of the first signal conditioning circuit 8 is connected to the first capacitive coupling sensor 7, and the output end is connected to the input end of the first microprocessor 10 and the input end of the first data acquisition device 9; the first data acquisition device 9, the first touch display screen 12, the first communication device 13 and the first data storage device 11 are all electrically connected to the first microprocessor 10.

[0090] The first signal conditioning circuit 8 is used to adjust the amplitude of the first electrical signal;

[0091] The first data acquisition device 9 is used to convert the first electrical signal collected by the first duplex sensor 1 into a digital signal and send it to the first microprocessor 10;

[0092] The first microprocessor 10 is used to control the working states of the first detection pulse generating device 6, the first signal conditioning circuit 8 and the first communication device 13, and calculate the first forward propagation coefficient of the distribution network overhead line 5 based on the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse, establish a first forward propagation model and a first reverse propagation model based on the first forward propagation coefficient of the distribution network overhead line 5, and calculate the first voltage waveform at each position of the distribution network overhead line 5 based on the first reverse propagation model and the first abnormal discharge induction signal;

[0093] The first data storage device 11 is used to store the first attenuation constant of the distribution network overhead line 5, the first phase constant of the distribution network overhead line 5 and the discharge intensity;

[0094] The first touch display screen 12 is used to display the first attenuation constant of the overhead line 5 of the distribution network, the first phase constant and the discharge intensity of the overhead line 5 of the distribution network, and is used to control the first detection host 2;

[0095] The first communication device 13 is used to transmit the first voltage waveform at each position of the overhead line 5 of the distribution network, the second voltage waveform at each position of the overhead line 5 of the distribution network, and the discharge intensity with the second communication device 22;

[0096] The first power supply 14 is used to supply power to the first detection host 2 and the first duplex sensor 1 .

[0097] Reference Figure 3 , the first signal conditioning circuit 8 comprises:

[0098] three upper capacitors 28, one lower capacitor 29 and a single-pole triple-throw switch 30;

[0099] The lower capacitor 29 is connected in series with three upper capacitors 28 with different capacitance values ​​through a single-pole triple-throw switch 30, the lower capacitor 29 is connected to the first data acquisition device 9, and the single-pole triple-throw switch 30 is connected to the first microprocessor 10;

[0100] The single-pole three-throw switch 30 is controlled by the first microprocessor 10 and is used to switch the upper capacitor 28 with different capacitance values ​​to adjust the voltage division ratio, thereby adjusting the amplitude of the first detection pulse signal and the first abnormal discharge induction signal output from the first capacitive coupling sensor 7, so that the voltage of the first electrical signal received by the first data acquisition device 9 is suitable for its sampling range. The single-pole three-throw switch 30 is connected to the upper capacitor 28 with the largest capacitance value in the initial state. If the voltage of the first detection pulse voltage or the first abnormal discharge induction signal collected by the first data acquisition device 9 exceeds the sampling range, the single-pole three-throw switch 30 is controlled to switch to the upper capacitor 28 with a smaller capacitance value until the voltage of the first electrical signal received by the first data acquisition device 9 is suitable for its sampling range.

[0101] The second duplex sensor 3 includes a second detection pulse generating device 15 and a second capacitive coupling sensor 16; the second detection host 4 includes a second signal conditioning circuit 17, a second data acquisition device 18, a second microprocessor 19, a second data storage device 20, a second touch display screen 21, a second communication device 22 and a second power supply 23.

[0102] The second duplex sensor 3 is used to inject a second detection pulse into the distribution network overhead line 5, measure the second detection pulse and its reflected pulse, and obtain an induction signal of the second detection pulse and an induction signal of the reflected pulse of the second detection pulse; detect an abnormal discharge signal on the distribution network overhead line 5, and obtain a second abnormal discharge induction signal.

[0103] The second detection pulse generating device 15 is used to generate and inject a second detection pulse with high amplitude and wide frequency.

[0104] The second capacitive coupling sensor 16 is used to measure the second detection pulse and its reflected pulse to obtain an induction signal of the second detection pulse and an induction signal of the reflected pulse of the second detection pulse; detect an abnormal discharge signal on the overhead line 5 of the distribution network to obtain a second abnormal discharge induction signal.

[0105] The second capacitive coupling sensor 16 includes a positive plate 24, a negative plate 25, an insulating plate 26 and a detection capacitor 27; the positive plate 24 and the negative plate 25 are connected to the two ends of the detection capacitor 27 through a wire, and the positive plate 24 and the negative plate 25 are fixed by an insulating plate. The detection capacitor 27 is used to divide the voltage to sense the second electrical signal in the overhead line 5 of the distribution network. The capacitance value of the detection capacitor 27 is determined according to the capacitance of the overhead line 5 of the distribution network to the ground. The second electrical signal includes a second detection pulse, a reflected pulse of the second detection pulse and an abnormal discharge signal.

[0106] Specifically, in the second detection host 4:

[0107] The input end of the second signal conditioning circuit 17 is connected to the second capacitive coupling sensor 16, and the output end is connected to the input end of the second microprocessor 19 and the input end of the second data acquisition device 18; the second data acquisition device 18, the second touch display screen 21, the second communication device 22 and the second data storage device 20 are all electrically connected to the second microprocessor 19.

[0108] The second signal conditioning circuit 17 is used to adjust the amplitude of the second electrical signal;

[0109] The second data acquisition device 18 is used to convert the second electrical signal collected by the second duplex sensor 3 into a digital signal and send it to the second microprocessor 19;

[0110] The second microprocessor 19 is used to control the working states of the second detection pulse generating device 15, the second signal conditioning circuit 17 and the second communication device 22, and calculate the second forward propagation coefficient of the distribution network overhead line 5 based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse, establish a second forward propagation model and a second reverse propagation model based on the second forward propagation coefficient of the distribution network overhead line 5, calculate the second voltage waveform at each position of the distribution network overhead line 5 based on the second reverse propagation model and the second abnormal discharge induction signal; determine the abnormal discharge position and discharge intensity based on the first voltage waveform at each position of the distribution network overhead line 5 and the second voltage waveform at each position of the distribution network overhead line 5;

[0111] The second data storage device 20 is used to store the second attenuation constant of the distribution network overhead line 5, the second phase constant of the distribution network overhead line 5 and the discharge intensity;

[0112] The second touch display screen 21 is used to display the second attenuation constant of the overhead line 5 of the distribution network, the second phase constant and the discharge intensity of the overhead line 5 of the distribution network, and is used to control the second detection host 4;

[0113] The second communication device 22 is used to transmit the first voltage waveform at each position of the overhead line 5 of the distribution network, the second voltage waveform at each position of the overhead line 5 of the distribution network, and the discharge intensity with the first communication device 13;

[0114] The second power supply 23 is used to supply power to the second detection host 4 and the second duplex sensor 3 .

[0115] The second signal conditioning circuit 17 comprises:

[0116] three upper capacitors 28, one lower capacitor 29 and a single-pole triple-throw switch 30;

[0117] The lower capacitor 29 is connected in series with three upper capacitors 28 with different capacitance values ​​through a single-pole triple-throw switch 30, the lower capacitor 29 is connected to the second data acquisition device 18, and the single-pole triple-throw switch 30 is connected to the second microprocessor 19;

[0118] The single-pole three-throw switch 30 is controlled by the second microprocessor 19 and is used to switch the upper capacitor 28 with different capacitance values ​​to adjust the voltage division ratio, thereby adjusting the amplitude of the second detection pulse signal and the second abnormal discharge induction signal output from the second capacitive coupling sensor 16, so that the voltage of the second electrical signal received by the second data acquisition device 18 is suitable for its sampling range. The single-pole three-throw switch 30 is connected to the upper capacitor 28 with the largest capacitance value in the initial state. If the second detection pulse voltage or the voltage of the second abnormal discharge induction signal collected by the second data acquisition device 18 exceeds the sampling range, the single-pole three-throw switch 30 is controlled to switch to the upper capacitor 28 with a smaller capacitance value until the voltage of the second electrical signal received by the second data acquisition device 18 is suitable for its sampling range.

[0119] Reference Figure 4 Based on the above-mentioned distribution network overhead line abnormal discharge live locating device, the present invention also provides a distribution network overhead line abnormal discharge live locating method, comprising the following steps:

[0120] S1. Reference Figure 5 , respectively installing a first positioning assembly and a second positioning assembly at both ends of the overhead line 5 of the distribution network;

[0121] S2, the first duplex sensor 1 injects a first detection pulse into the overhead line 5 of the distribution network, and measures the first detection pulse and its reflected pulse, the second duplex sensor 3 injects a second detection pulse into the overhead line 5 of the distribution network, and measures the second detection pulse and its reflected pulse, to obtain the induction signals of the two groups of detection pulses and the induction signals of the reflected pulses, and calculate the first forward propagation coefficient of the overhead line 5 of the distribution network and the second forward propagation coefficient of the overhead line 5 of the distribution network based on the induction signals of the two groups of detection pulses and the induction signals of the reflected pulses; establish a first forward propagation model based on the first forward propagation coefficient of the overhead line 5 of the distribution network, and establish a second forward propagation model based on the second forward propagation coefficient of the overhead line 5 of the distribution network; update the first forward propagation coefficient of the overhead line 5 of the distribution network based on the first forward propagation model, and update the second forward propagation coefficient of the overhead line 5 of the distribution network based on the second forward propagation model;

[0122] S3, the first duplex sensor 1 and the second duplex sensor 3 detect the abnormal discharge signal of the overhead line 5 of the distribution network in real time. After the abnormal discharge occurs in the overhead line 5 of the distribution network, the first duplex sensor 1 measures the first abnormal discharge induction signal and transmits the first abnormal discharge induction signal to the first detection host 2, and the first detection host 2 records the first abnormal discharge induction signal; the second duplex sensor 3 measures the second abnormal discharge induction signal and transmits the second abnormal discharge induction signal to the second detection host 4, and the second detection host 4 records the second abnormal discharge induction signal;

[0123] S4. Establish a first reverse propagation model based on the updated first forward propagation coefficient of the distribution network overhead line 5, establish a second reverse propagation model based on the updated second forward propagation coefficient of the distribution network overhead line 5, locate the abnormal discharge position through dual-channel electromagnetic inversion based on the first reverse propagation model, the second reverse propagation model, the first abnormal discharge induction signal and the second abnormal discharge induction signal, and calculate the discharge intensity of the abnormal discharge.

[0124] More specifically, step S1 includes:

[0125] A first duplex sensor 1 is installed below a first end of an overhead line 5 of a power distribution network, the first duplex sensor 1 is connected to a first detection host 2, and the first detection host 2 is turned on;

[0126] A second duplex sensor 3 is installed below the second end of the overhead line 5 of the power distribution network, the second duplex sensor 3 is connected to a second detection host 4, and the second detection host 4 is turned on;

[0127] The first detection host 2 and the second detection host 4 perform wireless communication via the first communication device 13 and the second communication device 22 to form a first channel and a second channel respectively, and the first channel and the second channel constitute a dual channel.

[0128] More specifically, step S2 includes:

[0129] S2.1. Reference Figure 6 The first detection pulse generating device 6 injects a first detection pulse into the first end of the overhead line 5 of the distribution network. The first detection pulse has a length of The first detection pulse is transmitted through the overhead line 5 of the distribution network, and is reflected to form a reflected pulse of the first detection pulse after being transmitted to the second end of the overhead line 5 of the distribution network, and is transmitted back to the first duplex sensor 1. The first duplex sensor 1 measures the first detection pulse and the reflected pulse generated on the overhead line 5 of the distribution network, and obtains the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse. The first detection host 2 controls the single-pole three-throw switch 30 to adjust to a suitable voltage division ratio. The first data acquisition device 9 converts the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse into digital signals, and transmits the digital signals to the first microprocessor 10.

[0130] S2.2, the first microprocessor 10 calculates the first attenuation constant of the distribution network overhead line 5 and the first phase constant of the distribution network overhead line 5 according to the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse, and then obtains the first forward propagation coefficient of the distribution network overhead line 5, and establishes a first forward propagation model according to the first forward propagation coefficient of the distribution network overhead line 5, specifically including the following steps:

[0131] S2.2.1. The first microprocessor 10 calculates the complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse by the following formula: :

[0132] ;

[0133] in, is the frequency domain form of the induction signal of the first detection pulse, is the frequency domain form of the induction signal of the reflected pulse of the first detection pulse, and both are respectively composed of the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse Fourier transform is performed to obtain: t represents time; the complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse , the frequency domain form of the induction signal of the first detection pulse The frequency domain form of the induced signal of the reflected pulse of the first detection pulse The independent variables are The function of is the frequency, and the overhead line 5 of the distribution network is regarded as a linear system. Then, the complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse is The first microprocessor 10 calculates the first attenuation constant of the overhead line 5 of the distribution network by the following two formulas: and the first phase constant of the distribution network overhead line 5 :

[0134] ;

[0135] ;

[0136] Among them, the first attenuation constant of the overhead line 5 of the distribution network is and the first phase constant of the distribution network overhead line 5 The independent variables are The function of is the length of the overhead line 5 of the distribution network. Since the measurement is performed at one end of the overhead line 5 of the distribution network, the total propagation distance of the first detection pulse is twice the length of the overhead line 5 of the distribution network, that is, 2 ;

[0137] S2.2.2. The first microprocessor 10 obtains the first forward propagation coefficient of the distribution network overhead line 5 according to the first attenuation constant of the distribution network overhead line 5 and the first phase constant of the distribution network overhead line 5. :

[0138] ;

[0139] Among them, the first forward propagation coefficient The independent variable is Function of , j represents the imaginary unit;

[0140] S2.2.3, the first microprocessor 10 is based on the first forward propagation coefficient of the overhead line 5 of the power distribution network Construct the first forward propagation model. The expression of the first forward propagation model is:

[0141] ;

[0142] in, A point on the overhead line 5 of the distribution network The pulse generated, For pulse Propagate to another point on the distribution network overhead line 5 b 1 pulse, t For time, The pulse from point Propagate to point b The actual propagation distance of 1, is the time difference between the induction signal of the reflected pulse of the first detection pulse and the induction signal of the first detection pulse, Express Time Shift , e is a natural constant;

[0143] S2.3, the second forward propagation coefficient of the overhead line 5 of the distribution network is obtained by the following method ;

[0144] S2.3.1, the second detection pulse generating device 15 injects a second detection pulse into the second end of the distribution network overhead line 5, and the second detection pulse has a length of The second detection pulse is transmitted through the overhead line 5 of the distribution network, and is reflected after being transmitted to the first end of the overhead line 5 of the distribution network to form a reflected pulse of the second detection pulse and is transmitted back to the second duplex sensor 3. The second duplex sensor 3 measures the second detection pulse and the reflected pulse generated on the overhead line 5 of the distribution network to obtain an induction signal of the second detection pulse and an induction signal of the reflected pulse of the second detection pulse. The second detection host 4 controls the single-pole three-throw switch 30 to adjust to a suitable voltage division ratio. The second data acquisition device 18 converts the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse into digital signals, and transmits the digital signals to the second microprocessor 19.

[0145] S2.3.2, the second microprocessor 19 calculates the complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse by the following formula: :

[0146] ;

[0147] in, , and The independent variables are The function of is the frequency, is the frequency domain form of the induction signal of the second detection pulse, is the frequency domain form of the induction signal of the reflected pulse of the second detection pulse, and both are respectively composed of the induction signal of the second detection pulse V in2 The induction signal of the reflected pulse of the second detection pulse V out2 Fourier transform is performed to obtain: t represents time; the complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse , the frequency domain form of the induction signal of the second detection pulse The frequency domain form of the induced signal of the reflected pulse of the second detection pulse The independent variables are function, considering the overhead line 5 of the distribution network as a linear system, the complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse is The second microprocessor 19 calculates the second attenuation constant of the overhead line 5 of the distribution network by the following two formulas: and the second phase constant of the distribution network overhead line 5 :

[0148] ;

[0149] ;

[0150] Among them, the second attenuation constant of the overhead line 5 of the distribution network is and the second phase constant of the distribution network overhead line 5 The independent variables are Function of

[0151] S2.3.3, the second microprocessor 19 obtains the second forward propagation coefficient of the distribution network overhead line 5 according to the second attenuation constant of the distribution network overhead line 5 and the second phase constant of the distribution network overhead line 5 :

[0152] ;

[0153] Among them, the second forward propagation coefficient The independent variable is Function of

[0154] S2.3.4, the second microprocessor 19 is based on the second forward propagation coefficient of the overhead line 5 of the distribution network Construct the second forward propagation model. The expression of the second forward propagation model is:

[0155] ;

[0156] in, A point on the overhead line 5 of the distribution network The pulse generated, For pulse Propagate to another point on the distribution network overhead line 5 b The pulse at 2 o'clock, The pulse from point Propagate to point b The actual propagation distance of 2, is the time difference between the induction signal of the reflected pulse of the second detection pulse and the induction signal of the second detection pulse, Express Time Shift .

[0157] Preferably, it also includes:

[0158] S2.4. Correct and iteratively optimize the first attenuation constant of the overhead line 5 of the distribution network, the first phase constant of the overhead line 5 of the distribution network, the second attenuation constant of the overhead line 5 of the distribution network, and the second phase constant of the overhead line 5 of the distribution network: calculate the reflected pulse of the first detection pulse obtained by propagating the first detection pulse on the overhead line 5 of the distribution network according to the first forward propagation model, and compare the calculated reflected pulse of the first detection pulse with the induced signal of the reflected pulse of the first detection pulse, and correct and iteratively optimize the first attenuation constant of the overhead line 5 of the distribution network and the first phase constant of the overhead line 5 of the distribution network; calculate the reflected pulse of the second detection pulse obtained by propagating the second detection pulse on the overhead line 5 of the distribution network according to the second forward propagation model, and compare the calculated reflected pulse of the second detection pulse with the induced signal of the reflected pulse of the second detection pulse, and correct and iteratively optimize the second attenuation constant of the overhead line 5 of the distribution network and the second phase constant of the overhead line 5 of the distribution network; the following is an example of correcting and iteratively optimizing the first attenuation constant of the overhead line 5 of the distribution network and the first phase constant of the overhead line 5 of the distribution network;

[0159] Correcting and iteratively optimizing the first attenuation constant and the first phase constant of the overhead line 5 of the distribution network comprises the following steps:

[0160] S2.4.1. Based on the first forward propagation model, the reflected pulse of the first detection pulse obtained by propagating the first detection pulse on the overhead line 5 of the distribution network is calculated. At this time, the actual propagation distance of the first detection pulse is , the calculation formula of the reflected pulse of the first detection pulse is:

[0161] ;

[0162] in, is the reflected pulse of the first detection pulse calculated based on the first forward propagation model, is the induction signal of the first detection pulse, Represents the induction signal of the first detection pulse Time Shift ;

[0163] S2.4.2. Perform Fourier transform on the induced signal of the reflected pulse of the first detection pulse and the calculated reflected pulse of the first detection pulse to obtain the amplitude and phase of the two;

[0164] If the calculated reflected pulse of the first detection pulse is larger than the induced signal amplitude of the reflected pulse of the first detection pulse, then the first attenuation constant of the overhead line 5 of the distribution network is increased, otherwise, the first attenuation constant of the overhead line 5 of the distribution network is decreased; if the calculated reflected pulse of the first detection pulse is larger than the phase of the induced signal of the reflected pulse of the first detection pulse, then the first phase constant of the overhead line 5 of the distribution network is increased, otherwise, the first phase constant of the overhead line 5 of the distribution network is decreased;

[0165] Perform iterative optimization: substitute the adjusted first attenuation constant of the distribution network overhead line 5 and the first phase constant of the distribution network overhead line 5 into the first forward propagation model to obtain a revised first forward propagation model; recalculate the reflected pulse of the first detection pulse based on the revised first forward propagation model; compare the reflected pulse of the first detection pulse calculated again with the induced signal of the reflected pulse of the first detection pulse; and revise the first forward propagation model again, until the difference between the first attenuation constants of the distribution network overhead line 5 calculated twice is less than 3% of the average value of the two calculation results, and the difference between the first phase constant results is less than 3% of the average value of the two calculation results.

[0166] Reference Figure 7 , step S4 comprises the following steps:

[0167] S4.1. Negate the first attenuation constant of the overhead line 5 of the distribution network and the first phase constant of the overhead line 5 of the distribution network to obtain the first reverse propagation coefficient of the overhead line 5 of the distribution network , the second attenuation constant of the distribution network overhead line 5 and the second phase constant of the distribution network overhead line 5 are negatively calculated to obtain the second reverse propagation coefficient of the distribution network overhead line 5 ; The first reverse propagation coefficient of the distribution network overhead line 5 and the second back propagation coefficient of the distribution network overhead line 5 The expression is as follows:

[0168] ;

[0169] S4.2. A first reverse propagation model is established based on the first reverse propagation coefficient of the overhead line 5 of the distribution network:

[0170] ;

[0171] in, Express Time Shift ;

[0172] The second back propagation model is established based on the second back propagation coefficient of the distribution network overhead line 5:

[0173] ;

[0174] in, Express Time Shift ;

[0175] S4.3, substituting the first abnormal discharge induction signal received by the first channel into the first reverse propagation model, and obtaining the first voltage waveform at each position of the overhead line 5 of the distribution network, that is, the electromagnetic inversion result of the first channel; substituting the second abnormal discharge induction signal received by the second channel into the second reverse propagation model, and obtaining the second voltage waveform at each position of the overhead line 5 of the distribution network, that is, the electromagnetic inversion result of the second channel;

[0176] Substituting the first abnormal discharge induction signal into the first back propagation model, we have:

[0177] ;

[0178] in, is the distance between the first duplex sensor and the overhead line 5 of the distribution network The first voltage waveform at is a first abnormal discharge induction signal measured by a first duplex sensor, Express Time Shift ;

[0179] Substituting the second abnormal discharge induction signal into the second back propagation model, we have:

[0180] ;

[0181] in, The distance between the overhead line 5 of the distribution network and the second duplex sensor The second voltage waveform at is a second abnormal discharge induction signal measured by the second duplex sensor, Express Time Shift ;

[0182] S4.4, perform dual-channel information fusion: compare the electromagnetic inversion results of the first channel with the electromagnetic inversion results of the second channel, and find out the similarity between the first voltage waveform and the second voltage waveform at each position of the overhead line 5 of the distribution network M The maximum position is the abnormal discharge position;

[0183] The similarity of waveforms at a certain position of overhead line 5 of the distribution network M The calculation formula is:

[0184] ;

[0185] in, is the voltage of the i-th point of the first voltage waveform at a certain position of the overhead line 5 of the distribution network, is the voltage of the ith point of the second voltage waveform at a certain position of the overhead line 5 of the distribution network, n is the waveform length, i.e., the number of points;

[0186] The first voltage waveform and the second voltage waveform of the dual-channel electromagnetic inversion result at the abnormal discharge position are respectively integrated with respect to time to obtain the discharge intensity of the dual channels, and the discharge intensity of the dual channels is averaged to obtain the discharge intensity of the abnormal discharge.

Claims

1. A method for locating abnormal discharge of overhead lines in a distribution network, characterized in that: include: Injecting a first detection pulse into a first end of an overhead line (5) of a power distribution network, measuring the first detection pulse and its reflected pulse, and obtaining an induction signal of the first detection pulse and an induction signal of the reflected pulse of the first detection pulse; Injecting a second detection pulse into a second end of the overhead line (5) of the distribution network, measuring the second detection pulse and its reflected pulse, and obtaining an induced signal of the second detection pulse and an induced signal of the reflected pulse of the second detection pulse; Calculating a first forward propagation coefficient of the overhead line (5) of the distribution network based on an induction signal of the first detection pulse and an induction signal of a reflected pulse of the first detection pulse, calculating a first reverse propagation coefficient of the overhead line (5) of the distribution network based on the first forward propagation coefficient of the overhead line (5) of the distribution network, and establishing a first reverse propagation model based on the first reverse propagation coefficient of the overhead line (5) of the distribution network; Calculating a second forward propagation coefficient of the distribution network overhead line (5) based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse, calculating a second reverse propagation coefficient of the distribution network overhead line (5) based on the second forward propagation coefficient of the distribution network overhead line (5), and establishing a second reverse propagation model based on the second reverse propagation coefficient of the distribution network overhead line (5); Using two duplex sensors to simultaneously detect abnormal discharge signals on the overhead line (5) of the distribution network to obtain a first abnormal discharge induction signal and a second abnormal discharge induction signal; Substituting the first abnormal discharge induction signal into the first reverse propagation model to obtain a first voltage waveform at each position of the overhead line (5) of the distribution network, substituting the second abnormal discharge induction signal into the second reverse propagation model to obtain a second voltage waveform at each position of the overhead line (5) of the distribution network, and determining the abnormal discharge position based on the first voltage waveform at each position of the overhead line (5) of the distribution network and the second voltage waveform at each position of the overhead line (5) of the distribution network; The method of calculating the first forward propagation coefficient of the overhead line (5) of the power distribution network based on the induction signal of the first detection pulse and the induction signal of the reflected pulse of the first detection pulse comprises: calculating a complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse according to the induced signal of the first detection pulse and the induced signal of the reflected pulse of the first detection pulse; A first attenuation constant of the overhead line (5) of the distribution network and a first phase constant of the overhead line (5) of the distribution network are calculated based on the complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse, and the calculation formula is as follows: ； ； in, , and The independent variables are The function of is the frequency, is the first attenuation constant of the overhead line (5) of the distribution network, is the first phase constant of the overhead line (5) of the distribution network, is the length of the distribution network overhead line (5), is the complex voltage ratio between the reflected pulse of the first detection pulse and the first detection pulse; The first forward propagation coefficient of the overhead line of the distribution network (5) is calculated by the following formula: : ； Among them, the first forward propagation coefficient The independent variable is Function of , j represents the imaginary unit; The method of calculating the second forward propagation coefficient of the overhead line (5) of the power distribution network based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse comprises: calculating a complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse according to the induced signal of the second detection pulse and the induced signal of the reflected pulse of the second detection pulse; A second attenuation constant of the distribution network overhead line (5) and a second phase constant of the distribution network overhead line (5) are calculated based on the complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse, and the calculation formula is as follows: ； ； in, , and The independent variables are The function of is the frequency, is the second attenuation constant of the overhead line (5) of the distribution network, is the second phase constant of the overhead line (5) of the distribution network, is the complex voltage ratio between the reflected pulse of the second detection pulse and the second detection pulse; The second forward propagation coefficient of the distribution network overhead line (5) is calculated by the following formula: : ； Among them, the second forward propagation coefficient for Function of The step of calculating a first reverse propagation coefficient of the distribution network overhead line (5) based on a first forward propagation coefficient of the distribution network overhead line (5), and establishing a first reverse propagation model based on the first reverse propagation coefficient of the distribution network overhead line (5) comprises: The first attenuation constant of the distribution network overhead line (5) and the first phase constant of the distribution network overhead line (5) are both negative, so as to obtain a first reverse propagation coefficient of the distribution network overhead line (5); and a first reverse propagation model is established based on the first reverse propagation coefficient of the distribution network overhead line (5): ； in, A point on the overhead line (5) of the distribution network The pulse generated, Express Time Shift , For pulse Propagate to another point on the distribution network overhead line (5) b 1 pulse, t For time, The pulse from point Propagate to point b The actual propagation distance of 1, is the time difference between the induction signal of the reflected pulse of the first detection pulse and the induction signal of the first detection pulse, e is a natural constant, is the first back propagation coefficient of the overhead line (5) of the distribution network; The step of calculating the second reverse propagation coefficient of the distribution network overhead line (5) based on the second forward propagation coefficient of the distribution network overhead line (5), and establishing the second reverse propagation model based on the second reverse propagation coefficient of the distribution network overhead line (5) comprises: The second attenuation constant of the distribution network overhead line (5) and the second phase constant of the distribution network overhead line (5) are negatively calculated to obtain a second reverse propagation coefficient of the distribution network overhead line (5); based on the second reverse propagation coefficient of the distribution network overhead line (5), a second reverse propagation model is established as follows: ； in, A point on the overhead line (5) of the distribution network The pulse generated, Express Time Shift , For pulse Propagate to another point on the distribution network overhead line (5) b The pulse at 2 o'clock, The pulse from point Propagate to point b The actual propagation distance of 2, is the time difference between the induction signal of the reflected pulse of the second detection pulse and the induction signal of the second detection pulse, is the second back propagation coefficient of the distribution network overhead line (5); The method of determining the abnormal discharge position based on the first voltage waveform at each position of the overhead line (5) of the distribution network and the second voltage waveform at each position of the overhead line (5) of the distribution network comprises: Finding the position where the waveforms of the first voltage waveform at each position of the overhead line (5) of the distribution network and the second voltage waveform at each position of the overhead line (5) of the distribution network are most similar, and the position is the abnormal discharge position; Among them, the waveform similarity at a certain position of the distribution network overhead line (5) is M The calculation formula is: ； in, is the voltage of the ith point of the first voltage waveform at a certain position of the overhead line (5) of the distribution network, is the voltage of the ith point of the second voltage waveform at a certain position of the overhead line (5) of the distribution network, and n is the waveform length, that is, the number of points.

2. A method for locating abnormal discharge of overhead lines in a distribution network according to claim 1, characterized in that: It also includes integrating the first voltage waveform at the abnormal discharge position over time to obtain a first discharge intensity, integrating the second voltage waveform at the abnormal discharge position over time to obtain a second discharge intensity, and averaging the first discharge intensity and the second discharge intensity to obtain the discharge intensity of the abnormal discharge.

3. A device for locating abnormal discharge of overhead lines in a distribution network, characterized in that: The method for implementing any one of claims 1 to 2 comprises: A first duplex sensor (1) is used to inject a first detection pulse into a first end of an overhead line (5) of a distribution network, measure the first detection pulse and its reflected pulse, and obtain an induction signal of the first detection pulse and an induction signal of the reflected pulse of the first detection pulse; and detect an abnormal discharge signal on the overhead line (5) of the distribution network to obtain a first abnormal discharge induction signal; A first detection host (2) is used to calculate a first forward propagation coefficient of the overhead line (5) of the distribution network based on an induction signal of a first detection pulse and an induction signal of a reflected pulse of the first detection pulse, calculate a first reverse propagation coefficient of the overhead line (5) of the distribution network based on the first forward propagation coefficient of the overhead line (5) of the distribution network, and establish a first reverse propagation model based on the first reverse propagation coefficient of the overhead line (5) of the distribution network; and bring the first abnormal discharge induction signal into the first reverse propagation model to obtain a first voltage waveform at each position of the overhead line (5) of the distribution network; The second duplex sensor (3) is used to inject a second detection pulse into a second end of the overhead line (5) of the distribution network, measure the second detection pulse and its reflected pulse, and obtain an induction signal of the second detection pulse and an induction signal of the reflected pulse of the second detection pulse; detect an abnormal discharge signal on the overhead line (5) of the distribution network, and obtain a second abnormal discharge induction signal; The second detection host (4) is used to calculate the second forward propagation coefficient of the distribution network overhead line (5) based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse, calculate the second reverse propagation coefficient of the distribution network overhead line (5) based on the second forward propagation coefficient of the distribution network overhead line (5), and establish a second reverse propagation model based on the second reverse propagation coefficient of the distribution network overhead line (5); bring the second abnormal discharge induction signal into the second reverse propagation model to obtain the second voltage waveform at each position of the distribution network overhead line (5); and determine the abnormal discharge position based on the first voltage waveform at each position of the distribution network overhead line (5) and the second voltage waveform at each position of the distribution network overhead line (5).

4. A device for locating abnormal discharge of overhead lines in a power distribution network according to claim 3, characterized in that: The first duplex sensor (1) comprises: A first detection pulse generating device (6), used for generating and injecting a first detection pulse; A first capacitive coupling sensor (7) is used to measure the first detection pulse and its reflected pulse to obtain an induction signal of the first detection pulse and an induction signal of the reflected pulse of the first detection pulse; detect an abnormal discharge signal on the overhead line (5) of the distribution network to obtain a first abnormal discharge induction signal; The second duplex sensor (3) comprises: A second detection pulse generating device (15), used for generating and injecting a second detection pulse; The second capacitive coupling sensor (16) is used to measure the second detection pulse and its reflected pulse to obtain an induction signal of the second detection pulse and an induction signal of the reflected pulse of the second detection pulse; and detect an abnormal discharge signal on the overhead line (5) of the distribution network to obtain a second abnormal discharge induction signal.

5. A device for locating abnormal discharge of overhead lines in a power distribution network according to claim 4, characterized in that: The first capacitive coupling sensor (7) comprises a positive plate (24), a negative plate (25), an insulating plate (26) and a detection capacitor (27); the positive plate (24) and the negative plate (25) are respectively connected to two ends of the detection capacitor (27) via wires, and the positive plate (24) and the negative plate (25) are fixedly connected via an insulating plate (26).

6. The device for locating abnormal discharge of overhead lines in a power distribution network according to claim 3, characterized in that: The first detection host (2) comprises: A first signal conditioning circuit (8) is used to adjust the amplitude of a first electrical signal; the first electrical signal comprises a first detection pulse, a reflected pulse of the first detection pulse and an abnormal discharge signal; A first microprocessor (10) is used to control the working states of a first detection pulse generating device (6), a first signal conditioning circuit (8) and a first communication device (13), calculate a first forward propagation coefficient of the distribution network overhead line (5) based on an induction signal of the first detection pulse and an induction signal of a reflected pulse of the first detection pulse, calculate a first reverse propagation coefficient of the distribution network overhead line (5) based on the first forward propagation coefficient of the distribution network overhead line (5), establish a first reverse propagation model based on the first reverse propagation coefficient of the distribution network overhead line (5), and calculate a first voltage waveform at each position of the distribution network overhead line (5) based on the first reverse propagation model and the first abnormal discharge induction signal; A first data storage device (11) is used to store a first attenuation constant of the overhead line (5) of the distribution network and a first phase constant of the overhead line (5) of the distribution network; A first communication device (13) is used to transmit a first voltage waveform at each position of the overhead line (5) of the distribution network and a second voltage waveform at each position of the overhead line (5) of the distribution network to a second communication device (22); The second detection host (4) comprises: A second signal conditioning circuit (17) is used to adjust the amplitude of a second electrical signal; the second electrical signal comprises a second detection pulse, a reflected pulse of the second detection pulse, and an abnormal discharge signal; The second microprocessor (19) is used to control the working states of the second detection pulse generating device (15), the second signal conditioning circuit (17) and the second communication device (22); calculate the second forward propagation coefficient of the distribution network overhead line (5) based on the induction signal of the second detection pulse and the induction signal of the reflected pulse of the second detection pulse; calculate the second reverse propagation coefficient of the distribution network overhead line (5) based on the second forward propagation coefficient of the distribution network overhead line (5); establish a second reverse propagation model based on the second reverse propagation coefficient of the distribution network overhead line (5); calculate the second voltage waveform at each position of the distribution network overhead line (5) based on the second reverse propagation model and the second abnormal discharge induction signal; and determine the abnormal discharge position and discharge intensity based on the second voltage waveform at each position of the distribution network overhead line (5) and the first voltage waveform at each position of the distribution network overhead line (5) sent by the first communication device (13); A second data storage device (20) is used to store a second attenuation constant of the distribution network overhead line (5), a second phase constant of the distribution network overhead line (5), and a discharge intensity; The second communication device (22) is used to transmit the first voltage waveform at each position of the overhead line (5) of the distribution network and the second voltage waveform at each position of the overhead line (5) of the distribution network to the first communication device (13).

7. A device for locating abnormal discharge of overhead lines in a power distribution network according to claim 6, characterized in that: The first signal conditioning circuit (8) comprises a lower capacitor (29), the lower capacitor (29) is connected to a first end of a capacitor group, and a second end of the capacitor group is connected to a first microprocessor (10) via a single-pole triple-throw switch (30); the capacitor group comprises three upper capacitors (28) with different capacitance values.

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