An ultrasonic detection device and method for branch wear of 10kV overhead conductor insulation layer

Abstract

The present invention discloses an ultrasonic detection device and method for the wear of branches on the insulation layer of a 10kV overhead conductor. In order to solve the problem that the prior art cannot effectively detect the wear of branches on the insulation layer of overhead conductors, and there are potential safety hazards; the present invention includes a distribution network equipment real platform and an overhead conductor insulation layer wire branch wear model connected to the real platform; the model includes an overhead conductor, a branch and a simulated resistor, the overhead conductor includes an external insulation layer and an internal core wire, a wear zone is provided on the insulation layer, and the branch is arranged on the surface of the wear zone; the position of the branch close to the trunk is connected to one end of the simulated resistor through a wire, and the other end of the simulated resistor is grounded. The present invention connects the overhead conductor insulation layer branch wear model to the distribution network equipment real platform, determines the optimal partial discharge ultrasonic detection angle, improves the detection efficiency, can detect the most subtle branch wear, and reduces potential safety hazards.

Description

Technical Field

[0001] The invention relates to the field of power equipment detection, and in particular to an ultrasonic detection device and method for tree branch wear of an insulation layer of a 10kV overhead wire. Background Art

[0002] 10kV overhead insulated wire lines are widely used in urban areas and hills. Compared with bare wires, they greatly reduce tripping accidents caused by small animals, trees and floating objects, and improve the power supply reliability of users. However, since some insulated wires run in the middle of tree branches for a long time, the branches are constantly rubbed against the outer surface of the insulated wires under the action of natural wind, causing damage to the insulation layer of the insulated wires. In severe cases, the insulated wires will discharge to the branches, endangering the safe operation of the overhead insulated wire lines. When the insulated wires are worn to a certain extent by the branches, the insulated wires will have a weak discharge to the branches. Because the discharge sound is relatively light and the frequency of the discharge sound is high, the human ear may not be able to hear it directly. The sound of partial discharge can only be heard within a certain range (direction and distance) through special instruments. The staff cannot detect the discharge caused by the wear of the insulation layer branches in a timely and effective manner, which poses a safety hazard.

[0003] There are also devices for simulating wear. For example, an "overhead conductor micro-vibration simulation experimental device" disclosed in Chinese patent documents, with the announcement number "CN102661839B", includes a base, and tensioning devices are provided at both ends of the upper end surface of the base. The two ends of the conductor are connected to the tensioning device through a tension clamp and an insulator. A pressure sensor is also provided between the two ends of the conductor and the tensioning device; a suspension bracket is provided on the inner side of the tensioning device, and the suspension bracket is connected to the insulator through a suspension adjustment mechanism. The insulator is connected to the suspension clamp, and the conductor is suspended in the suspension clamp; an excitation device is provided in the middle between the suspension brackets, and the excitation device is connected to the conductor through an insulator and a suspension clamp. The device can simulate the effects of various micro-vibration conditions on wear to improve micro-vibration wear, but the device still cannot more effectively detect the discharge of the wear of the insulation layer of the overhead conductor, and there is a safety hazard. Summary of the invention

[0004] The present invention mainly solves the problem that the prior art cannot effectively detect the wear of branches on the insulation layer of overhead wires, which poses a safety hazard; it provides an ultrasonic detection device and method for the wear of branches on the insulation layer of a 10kV overhead wire, which simulates the wear of the insulation layer of the overhead wire by branches at different test orientations and distances, thereby obtaining the optimal detection angle and distance, and improving the detection efficiency.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions:

[0006] The present invention includes a distribution network equipment real platform and an overhead wire insulation layer tree branch wear model connected to the real platform; the model includes an overhead wire, a tree branch and a simulated resistor, the overhead wire includes an external insulating layer and an internal core wire, a wear area is provided on the insulating layer, and the tree branch is erected on the surface of the wear area; the position of the tree branch close to the trunk is connected to one end of the simulated resistor through a wire, and the other end of the simulated resistor is grounded.

[0007] The distribution network equipment real platform is equivalent to an independent distribution network system. The installation method, height, equipment type, etc. of its equipment are the same as those of the running distribution network. The data obtained by simulating the actual distribution network operation is more accurate and close to reality without interfering with the normal distribution network operation. The simulated resistor is used to simulate the tree trunk, and the branches are erected on the wear area of ​​the insulation layer of the overhead wire to simulate the wear of the overhead wire by the branches in reality. It is convenient to simulate the wear of the branches on the insulation layer of the overhead wire by partial discharge ultrasonic waves in different directions and different distances, so as to obtain the optimal detection angle and distance and improve the efficiency of detection. The application of partial discharge ultrasonic technology in the live detection of 10kV distribution network equipment can effectively and timely discover the defects of the insulation layer of the overhead wire of the 10kV distribution network equipment being worn by branches. At the same time, it can also improve the efficiency of the operation, maintenance and inspection of the 10kV distribution network equipment, ensure the safe operation of the 10kV distribution network equipment, and have significant social and economic benefits.

[0008] Preferably, the simulated resistor is a water resistor, which includes an organic glass tube and water. An exhaust hole is provided at the upper end of the organic glass tube, and electrodes are provided at the upper and lower ends of the organic glass tube. Water is injected into the organic glass tube, and the water level contacts the upper electrode and is below the exhaust hole. The water overflows the upper electrode by 30 mm or more and is 15 mm or less at the exhaust hole, and contacts the upper electrode to ensure normal conduction. Since a large amount of heat will be generated when the water resistor conducts a large current, the volume of the water will expand, and the exhaust hole is designed to discharge the expanded water vapor to prevent the glass tube from bursting. Using a water resistor to simulate a tree trunk is low-cost and easy to use; it avoids the limitation of the simulation site and is more environmentally friendly.

[0009] Preferably, the water injected into the organic glass tube is a mixed liquid of pure water and ordinary water. The resistivity of pure water is relatively high, and the resistivity of ordinary water is relatively low. When used in combination, its resistance is close to the resistance of the tree trunk, and the simulation cost is low. Different trunk resistances can be simulated by using different ratios of pure water and ordinary water. Different trunk resistances can be simulated by replacing glass tubes containing different water ratios. It is easy to use, closer to reality, and the detected data is more accurate.

[0010] Preferably, the size of the wear zone is 11.5mm to 12.5mm in width, 24.5mm to 25.5mm in length, and 0.8mm to 1.2mm in depth. The wear zone is closer to the actual wear condition, so that the experimental test data is closer to reality and the obtained data is more accurate.

[0011] As a preference, the circuit in the distribution network equipment real platform includes a boost module, a current boost module, an access module and an impedance to ground RZ; the first end of the impedance to ground RZ is connected to the second end of the access module, and the second end of the impedance to ground RZ is grounded; the access module is a tree branch wear model of the insulation layer of an overhead conductor, in which the core wire of the overhead conductor is connected to the boost module and connected in series to the loop of the current boost module; the input end of the boost module is connected to the power supply UA, the first output end of the boost module is connected to the first end of the access module, and the second end of the boost module is connected to the second end of the impedance to ground RZ; the input end of the current boost module is connected to the power supply UA, the first output end of the current boost module is connected to the first end of the access module, and the second end of the current boost module is connected to the second end of the access module. The boost module increases the line voltage of the distribution network equipment real platform to 10kV~12kV, so that the overhead conductor runs at high voltage; the current boost module injects 100A of current into the loop of the distribution network equipment real platform, so that a load current of 100A flows through the overhead conductor. The boost module and current boost module provide a 10.5kV line voltage and a 100A current, which truly simulates the operating condition of a 10kV overhead insulated conductor with its insulation layer worn by tree branches.

[0012] Preferably, the boost module includes a voltage regulator t1 and a boost transformer T1; the two ends of the voltage regulator t1 are connected to the power supply UA, the voltage regulating output end of the voltage regulator t1 is connected to the first input end of the boost transformer T1, and the second input end of the boost transformer T1 is connected to one end of the voltage regulator t1; the first output end of the boost transformer T1 is connected to the first end of the access module, and the second output end of the boost transformer T1 is connected to the second end of the impedance to ground RZ. The power supply UA is increased to 100V by the voltage regulator t1 after passing through the boost transformer T1. The line voltage of overhead wires in the distribution network equipment real platform is 10kV~12kV, and the overhead wires are high voltage, which simulates the voltage of 10kV distribution network more realistically.

[0013] Preferably, the current-increasing module includes a voltage regulator t2 and a large current generator T2; the two ends of the voltage regulator t2 are connected to the power supply UA, the voltage-regulating output end of the voltage regulator t2 is connected to the first input end of the large current generator T2, and the second input end of the large current generator T2 is connected to one end of the voltage regulator t2; the first output end of the large current generator T2 is connected to the first end of the access module, and the second output end of the large current generator T2 is connected to the second end of the access module. According to needs, a current of 0 to 600A can be injected into the main circuit of the real platform of the 10kV distribution network equipment; the voltage regulator t2 is adjusted to inject a current of 100A, so that a load current of 100A flows through the overhead wire. The current situation of the 10kV distribution network is simulated more realistically.

[0014] An ultrasonic detection method for tree branch wear on the insulation layer of a 10kV overhead conductor comprises the following steps:

[0015] S1: Establish a tree branch wear model for the insulation layer of overhead wires;

[0016] S2: Connect the overhead conductor insulation layer tree branch wear model to the 10kV distribution network equipment real platform;

[0017] S3: The staff holds the ultrasonic testing equipment and performs partial discharge ultrasonic testing at different distances around the wear model position in the real platform to determine the direction and range of the largest amplitude of ultrasonic testing;

[0018] S4: Detect forward and backward motion in the direction of the largest ultrasonic detection amplitude, detect the maximum amplitude of the local discharge ultrasonic signal, and record its discharge waveform and decibel value of the amplitude. According to the position where the maximum decibel value of the ultrasonic wave is detected, use the Pythagorean theorem to determine the optimal detection angle.

[0019] The ultrasonic detection equipment includes an ultrasonic receiver, a detection host and headphones connected in sequence. The staff carries the ultrasonic detection instrument, hangs the ultrasonic detection host, holds the ultrasonic receiver, wears headphones, and the ultrasonic receiver faces the part where the insulation layer of the overhead wire rubs against the branches, that is, the wear area 33; around the wear area, local discharge ultrasonic detection is performed at different distances to determine the direction where the ultrasonic detection reaches a larger amplitude. After the established overhead wire insulation layer tree branch wear model is connected to the real platform, during operation, it is first tested at different distances around the wear model to obtain the direction of the signal of the larger amplitude local discharge ultrasonic detection, and then measured before and after the larger amplitude direction. After the maximum local discharge ultrasonic signal is detected, its discharge waveform and amplitude decibel value are recorded. According to the position where the maximum decibel value of the ultrasonic wave is detected, the angle between the ultrasonic receiver and the wear part of the overhead wire insulation layer (the part where the insulation layer and the branch rub against each other) is calculated using the Pythagorean theorem, that is, the optimal detection angle. Obtaining the optimal local discharge ultrasonic detection angle can effectively detect the discharge of the overhead wire insulation layer tree branch wear, improve the efficiency of detection, detect the most subtle tree branch wear, and reduce safety hazards.

[0020] Preferably, the model establishment includes using an angle grinder to grind the insulation layer of the overhead conductor to damage the insulation layer and form a wear area; then, a forked branch is cut from a growing tree, and the branch is placed on the wear area of ​​the overhead conductor, and a bare copper wire is used as a conductor, one end of the copper wire is wrapped around the branch near the trunk, and the other end of the copper wire is connected to a water resistor. Establishing a branch wear model for the insulation layer of an overhead conductor and using a water resistor to simulate a tree trunk saves cost and manpower, is convenient for testing, and has a simple structure.

[0021] Preferably, the model is connected to the real platform, including connecting the overhead wires in the established model to one phase of the overhead wires in the 10kV equipment real platform, and then performing zero-start voltage and zero-start current boosting on the model through the boost module and current boost module of the 10kV distribution network real platform to simulate the operating conditions of the 10kV distribution network. The boost module is used to provide a line voltage of 10.5kV for the real platform, and the current boost module is used to provide a current of 100A for the real platform, which is closer to the real value, making the detected data more accurate and more reliable.

[0022] The beneficial effects of the present invention are:

[0023] 1. The tree branch wear model of the 10kV overhead conductor insulation layer is connected to the 10kV distribution network equipment real-type platform to determine the optimal partial discharge ultrasonic detection angle, improve the efficiency of detection, detect the most subtle tree branch wear, and eliminate safety hazards.

[0024] 2. Use water resistors to simulate tree trunks, which is environmentally friendly, saves economic and labor costs, and can simulate tree trunks with different resistance values, avoiding environmental restrictions.

[0025] 3. Use the boost module to provide 10.5kV line voltage, and use the current boost module to provide 100A current, which can more realistically simulate the 10kV distribution network real platform, making the detected data more accurate, closer to reality, and more instructive. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a true platform ultrasonic detection diagram of the present invention.

[0027] Figure 2 This is a model diagram of overhead wire tree branch wear of the present invention.

[0028] Figure 3 It is a true platform circuit diagram of the present invention.

[0029] Figure 4 It is a flow chart of a detection method of the present invention.

[0030] In the figure, 1. tree branch, 2. electric pole, 3. overhead wire, 31. insulation layer, 32. core wire, 33. wear area, 4. water resistance, 5. ultrasonic detection device, 51. ultrasonic receiver, 52. detection host, 53. earphone, 6. access module, 7. boost module, 8. current boost module. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0032] Example:

[0033] An ultrasonic detection device for the wear of branches on the insulation layer of a 10kV overhead conductor, such as Figure 1 As shown, it includes the overhead wire insulation layer tree branch wear model and the 10kV distribution network equipment real platform.

[0034] The overhead conductor insulation layer tree branch wear model includes overhead conductor 3, tree branch 1 and simulated resistor 4; the 10kV distribution network equipment real platform includes electric pole 2 and overhead conductor 3. The real platform is equivalent to an independent distribution network system, and the installation method, height, equipment type, etc. of its equipment are the same as those of the running distribution network.

[0035] By simulating the actual distribution network operation, the data obtained is more accurate and closer to reality without interfering with the normal distribution network operation.

[0036] Overhead wire 3 is installed on the top of pole 2. Overhead wire 3 in the model is connected to the overhead wire of the real platform. Branch 1 is installed on overhead wire 3. Branch 1 is connected to wire near the trunk. The wire is connected to one end of water resistor 4. The other end of water resistor 4 is grounded through wire. The insulation layer thickness of overhead wire 3 is 3.4mm. Pole 2 is 12m high and buried 1.8m deep.

[0037] Water resistors are used to simulate tree trunks, and branches are placed on the wear area of ​​the overhead wire insulation layer to simulate the wear of the overhead wire by branches in reality. This facilitates the simulation of the wear of branches on the insulation layer by partial discharge ultrasonic detection in different directions and at different distances, thereby obtaining the optimal detection angle and distance and improving the efficiency of detection. The application of partial discharge ultrasonic technology in the live detection of 10kV distribution network equipment can effectively and timely discover the defects of the insulation layer of the overhead insulated wire of the 10kV distribution network equipment being worn by branches. At the same time, it can also improve the efficiency of the operation, maintenance and repair of the 10kV distribution network equipment, ensure the safe operation of the 10kV distribution network equipment, and have significant social and economic benefits.

[0038] like Figure 2 As shown, the overhead conductor 3 includes an outer insulating layer 31 and an inner core wire 32. The insulating layer 31 is provided with a wear area 33. The branch 1 is mounted on the surface of the wear area 33. The branch 1 is connected to one end of the water resistor 4 through a wire near the trunk, and the other end of the water resistor 4 is grounded. The water resistor simulates the resistance of the trunk, which is 50kΩ in this embodiment. The wire is a bare copper wire, which is wound 50cm away from the bifurcation of the branch and tightly wound to ensure good contact with the branch.

[0039] The size of the wear zone is 11.5 mm to 12.5 mm in width, 24.5 mm to 25.5 mm in length, and 0.8 mm to 1.2 mm in depth. In this embodiment, the wear zone has a width of 12 mm, a length of 25 mm, and a depth of 1.2 mm.

[0040] The water resistor 4 includes an organic glass tube and water. The upper end of the organic glass tube is provided with an exhaust hole. The upper and lower ends of the organic glass tube are provided with electrodes. The electrodes are connected with wires. The interior of the organic glass tube is filled with water. The water level surface contacts the upper electrode and is below the exhaust hole. The water injected into the organic glass tube is a mixed liquid of pure water and ordinary water. In this embodiment, the injected water overflows the upper electrode by 30 mm or more and is 15 mm or less from the exhaust hole.

[0041] Water flows over the upper electrode to ensure normal conduction. Since a large amount of heat will be generated by the water resistor when a large current is conducted, the volume of the water will expand. The exhaust hole is designed to discharge the expanded water vapor to prevent the glass tube from bursting.

[0042] Pure water has a relatively high resistivity, while ordinary water has a relatively low resistivity. Mixing them together makes their resistance close to that of the tree trunk, and the simulation cost is low. Different tree trunk resistance values ​​can be simulated by using different ratios of pure water and ordinary water. Replacing glass tubes containing different water ratios can simulate different tree trunk resistance values. It is easy to use, closer to reality, and the detected data is more accurate. Using water resistors to simulate tree trunks is low-cost and easy to use; it avoids the limitation of the simulation site and is more environmentally friendly.

[0043] like Figure 3 As shown in the figure, the circuit structure of the 10kV distribution network equipment real platform includes a boost module 7, a current boost module 8, an access module 6 and an impedance to ground RZ. SZ is the contact point between the tree branch and the overhead conductor 3, RS is the equivalent resistance of the tree, and since the insulation layer 31 of the overhead conductor 3 is worn to a certain depth by the tree branch, when the 10kV overhead conductor is charged with a high voltage, an ultrasonic signal of partial discharge will be generated; RZ is the equivalent impedance of the 10kV distribution network real platform to the ground.

[0044] The first end of the impedance to ground RZ is connected to the second end of the access module, and the second end of the impedance to ground RZ is grounded; the access module 6 is a tree branch wear model of the overhead conductor insulation layer, in which the core wire in the overhead conductor is connected to the boost module and connected in series to the loop of the boost module. The input end of the boost module 7 is connected to the power supply UA, the first output end of the boost module 7 is connected to the first end of the access module 6, and the second end of the boost module 7, i.e., the output end, is connected to the second end of the impedance to ground RZ. The input end of the boost module 8 is connected to the power supply UA, the first output end of the boost module 8 is connected to the first end of the access module 6, and the second end of the boost module 8, i.e., the output end, is connected to the second end of the access module 6. The first end of the access module 6 and the second end of the access module 6 are both the two ends of the contact point SZ between the tree branch and the overhead conductor 3.

[0045] The boost module 7 includes a voltage regulator t1 and a boost transformer T1. The two ends of the voltage regulator t1 are connected to the power supply UA, the voltage regulating output end of the voltage regulator t1 is connected to the first input end of the boost transformer T1, and the second input end of the boost transformer T1 is connected to one end of the voltage regulator t1; the first output end of the boost transformer T1 is connected to the first end of the access module 6, and the second output end of the boost transformer T1 is connected to the second end of the ground impedance RZ.

[0046] The current boost module 8 includes a voltage regulator t2 and a large current generator T2. The two ends of the voltage regulator t2 are connected to the power supply UA, the voltage regulation output end of the voltage regulator t2 is connected to the first input end of the large current generator T2, and the second input end of the large current generator T2 is connected to one end of the voltage regulator t2; the first output end of the large current generator T2 is connected to the first end of the access module 6, and the second output end of the large current generator T2 is connected to the second end of the access module 6.

[0047] Through the voltage regulator t1, the power supply UA is increased to According to the needs, in this embodiment, the line voltage is increased to 10.5kV to be consistent with the 10kV grid voltage, so that the overhead insulated wires in the distribution network equipment real platform are high voltage, which more realistically simulates the operating voltage of the 10kV distribution network.

[0048] According to the needs, the current from 0 to 600A can be injected into the main circuit of the 10kV distribution network equipment real platform; adjust the voltage regulator t2, inject 100A current, so that the overhead wire flows through the 100A load current. More realistically simulate the operating current of the 10kV distribution network.

[0049] An ultrasonic detection method for branch wear of 10kV overhead conductor insulation layer, such as Figure 4 As shown, the method comprises the following steps: S1: establishing a tree branch wear model for the insulation layer of an overhead wire.

[0050] Use an angle grinder to grind down the insulation of overhead conductors to damage the insulation and create wear areas.

[0051] Then, branches with forks are cut from the growing trees and placed on the worn area of ​​the insulated wire. A bare copper wire is used as the wire, one end of which is wound around the branch near the trunk, and the other end of the copper wire is connected to the water resistor. In this embodiment, the copper wire is wound around the branch 50 cm away from the fork.

[0052] A tree branch wear model for the insulation layer of overhead wires was established, and water resistors were used to simulate tree trunks, which saved costs and manpower, facilitated testing, and had a simple structure.

[0053] S2: Connect the overhead conductor insulation layer tree branch wear model to the 10kV distribution network equipment real platform.

[0054] The overhead conductor in the established model is connected to one phase of the overhead conductor of the real platform of the 10kV equipment. In this embodiment, the tree branch wear model of the overhead conductor insulation layer is connected to the A phase of the overhead conductor of the real platform of the 10kV equipment.

[0055] Then, the model is subjected to zero-start voltage and zero-start current boosting through the boost module and current boost module of the 10kV distribution network real platform. In this embodiment, the boost module is used to provide a line voltage of 10.5kV for the real platform, and the current boost module is used to provide a current of 100A for the real platform, so as to be closer to the real value, so that the detected data is more accurate and more reliable.

[0056] S3: The staff holds the ultrasonic testing device 5 and performs partial discharge ultrasonic testing at different distances around the wear model position in the real platform to determine the direction and range of the ultrasonic testing with a larger amplitude.

[0057] The ultrasonic detection device 5 includes an ultrasonic receiver 51, a detection host 52 and earphones 53 connected in sequence. The staff carries the ultrasonic detection instrument 5, hangs the ultrasonic detection host 52 on the body, holds the ultrasonic receiver 51, wears the earphones 53, and the ultrasonic receiver 51 faces the part where the insulating layer 31 on the overhead wire 3 and the branch 1 rub against each other, that is, the wear area 33. Around the wear area 33, partial discharge ultrasonic detection is performed at different distances to determine the direction where the ultrasonic detection has a larger amplitude.

[0058] S4: Detect forward and backward motion in the direction of the largest ultrasonic detection amplitude, detect the maximum amplitude of the local discharge ultrasonic signal, and record its discharge waveform and decibel value of the amplitude. According to the position where the maximum decibel value of the ultrasonic wave is detected, use the Pythagorean theorem to determine the optimal detection angle.

[0059] After connecting the established overhead conductor insulation layer tree branch wear model to the real-type platform, during operation, first test at different distances around the wear model to obtain the azimuth of the signal of the larger amplitude local discharge ultrasonic detection; then measure before and after the larger amplitude azimuth, and after detecting the maximum local discharge ultrasonic signal, record its discharge waveform and amplitude decibel value, and according to the position where the maximum decibel value of the ultrasonic wave is detected, use the Pythagorean theorem to calculate the angle between the ultrasonic receiver 51 and the overhead conductor insulation layer wear area 33 (the part where the insulation layer and the tree branch rub against each other), that is, the optimal detection angle.

[0060] Obtaining the optimal partial discharge ultrasonic detection angle can effectively detect the discharge of branch wear on the insulation layer of overhead wires, improve the efficiency of detection, discover the most subtle branch wear, and reduce safety hazards.

[0061] The data obtained in this implementation are:

[0062] The maximum sound wave signal detected by the ultrasonic receiver is 6dB when the horizontal distance from the model is 2.5m and the vertical distance from the model is 7.6m; the maximum sound wave signal detected by the ultrasonic receiver is 7dB when the horizontal distance from the model is 3.5m and the vertical distance from the model is 7.6m; the maximum sound wave signal detected by the ultrasonic receiver is 6dB when the horizontal distance from the model is 4.5m and the vertical distance from the model is 7.6m; the maximum sound wave signal detected by the ultrasonic receiver is 5dB when the horizontal distance from the model is 5.5m and the vertical distance from the model is 7.6m; the maximum sound wave signal detected by the ultrasonic receiver is 3dB when the horizontal distance from the model is 6.5m and the vertical distance from the model is 7.6m; the maximum sound wave signal detected by the ultrasonic receiver is 2dB when the horizontal distance from the model is 7.5m and the vertical distance from the model is 7.6m.

[0063] From the above experimental data, we can know that because the vertical distance of the model is 7.6m, the optimal horizontal distance is 3.5m. According to the Pythagorean theorem, the optimal detection angle can be obtained. The optimal partial discharge ultrasonic detection angle can effectively detect the discharge of the branch wear of the overhead wire insulation layer, improve the efficiency of detection, find the most subtle branch wear, and reduce safety hazards.

[0064] The present invention connects the tree branch wear model of the overhead conductor insulation layer to the distribution network equipment real platform, determines the optimal partial discharge ultrasonic detection angle, improves the detection efficiency, can detect the most subtle branch wear, and eliminates safety hazards. Using water resistors to simulate tree trunks is environmentally friendly, saves economic and labor costs, can simulate tree trunks with different resistance values, and avoids environmental restrictions. Using a boost module to provide a 10.5kV line voltage and a current boost module to provide a 100A current can more realistically simulate a 10kV distribution network real platform, making the detected data more accurate, closer to reality, and more instructive.

Claims

1. An ultrasonic detection device for the wear of branches on the insulation layer of a 10kV overhead conductor, characterized in that: It includes a distribution network equipment real platform and an overhead wire insulation layer tree branch wear model connected to the real platform; the model includes overhead wires, tree branches and simulated resistors, the overhead wires include an external insulation layer and an internal core wire, a wear zone is provided on the insulation layer, and tree branches are erected on the surface of the wear zone; the position of the branch close to the trunk is connected to one end of the simulated resistor through a wire, and the other end of the simulated resistor is grounded; the simulated resistor is a water resistor, and the circuit in the distribution network equipment real platform includes a boost module, a current boost module, an access module and a ground impedance RZ; It also includes ultrasonic detection equipment, which includes an ultrasonic receiver, a detection host and headphones connected in sequence. The ultrasonic receiver faces the wear area on the overhead wire and performs local discharge ultrasonic detection at different distances around the wear area. The optimal detection angle is determined based on the detection data.

2. The ultrasonic detection device for 10kV overhead wire insulation layer tree branch wear according to claim 1 is characterized in that: The water resistor includes an organic glass tube and water. An exhaust hole is arranged at the upper end of the organic glass tube. Electrodes are arranged at the upper and lower ends of the organic glass tube. Water is filled inside the organic glass tube. The water level surface contacts the upper electrode and is below the exhaust hole.

3. The ultrasonic detection device for 10kV overhead wire insulation layer tree branch wear according to claim 2, characterized in that: The water injected into the organic glass tube is a mixed liquid of pure water and ordinary water.

4. The ultrasonic detection device for 10kV overhead wire insulation layer tree branch wear according to claim 1, characterized in that: The size of the wear zone is 11.5mm to 12.5mm in width, 24.5mm to 25.5mm in length, and 0.8mm to 1.2mm in depth.

5. An ultrasonic detection device for 10kV overhead wire insulation layer tree branch wear according to claim 1, 2 or 3, characterized in that: The first end of the impedance to ground RZ is connected to the second end of the access module, and the second end of the impedance to ground RZ is grounded; the access module is a tree branch wear model of the insulation layer of an overhead conductor, and the core wire in the overhead conductor in the model is connected to the boost module and is connected in series to the loop of the current boost module; the input end of the boost module is connected to the power supply UA, the first output end of the boost module is connected to the first end of the access module, and the second end of the boost module is connected to the second end of the impedance to ground RZ; the input end of the current boost module is connected to the power supply UA, the first output end of the current boost module is connected to the first end of the access module, and the second end of the current boost module is connected to the second end of the access module.

6. The ultrasonic detection device for tree branch wear of the insulation layer of a 10kV overhead wire according to claim 5, characterized in that: The boost module includes a voltage regulator t1 and a boost transformer T1; two ends of the voltage regulator t1 are connected to a power supply UA, a voltage regulating output end of the voltage regulator t1 is connected to a first input end of the boost transformer T1, and a second input end of the boost transformer T1 is connected to one end of the voltage regulator t1; a first output end of the boost transformer T1 is connected to a first end of the access module, and a second output end of the boost transformer T1 is connected to a second end of the ground impedance RZ.

7. The ultrasonic detection device for 10kV overhead wire insulation layer tree branch wear according to claim 5, characterized in that: The current boost module includes a voltage regulator t2 and a large current generator T2; the two ends of the voltage regulator t2 are connected to the power supply UA, the voltage regulation output end of the voltage regulator t2 is connected to the first input end of the large current generator T2, and the second input end of the large current generator T2 is connected to one end of the voltage regulator t2; the first output end of the large current generator T2 is connected to the first end of the access module, and the second output end of the large current generator T2 is connected to the second end of the access module.

8. An ultrasonic detection method for the wear of branches on the insulation layer of a 10 kV overhead conductor, using an ultrasonic detection device for the wear of branches on the insulation layer of a 10 kV overhead conductor according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Establish a tree branch wear model for the insulation layer of overhead wires; S2: Connect the overhead conductor insulation layer tree branch wear model to the 10kV distribution network equipment real platform; S3: The staff holds the ultrasonic testing equipment and performs partial discharge ultrasonic testing at different distances around the wear model position in the real platform to determine the direction and range of the largest amplitude of ultrasonic testing; S4: Detect forward and backward motion in the direction of the largest ultrasonic detection amplitude, detect the maximum amplitude of the local discharge ultrasonic signal, and record its discharge waveform and decibel value of the amplitude. According to the position where the maximum decibel value of the ultrasonic wave is detected, use the Pythagorean theorem to determine the optimal detection angle.

9. The ultrasonic detection method for tree branch wear of the insulation layer of a 10kV overhead wire according to claim 8, characterized in that: The model establishment includes using an angle grinder to grind the insulation layer of the overhead wire to damage the insulation layer and form a wear area; then cutting off a forked branch from a growing tree, placing the branch on the wear area of ​​the overhead wire, using a bare copper wire as a conductor, one end of the copper wire is wrapped around the branch near the trunk, and the other end of the copper wire is connected to a water resistor.

10. The ultrasonic detection method for tree branch wear of the insulation layer of a 10kV overhead wire according to claim 8, characterized in that: The connecting the model to the real platform includes connecting the overhead wires in the established model to one phase of the overhead wires of the 10kV equipment real platform, and then performing zero-starting voltage and zero-starting current boosting on the model through the boost module and current boost module of the 10kV distribution network real platform to simulate the operating conditions of the 10kV distribution network.

Images