Step voltage testing device

Abstract

The invention discloses a step voltage testing device. The step voltage testing device comprises a handheld rod and a measuring main body, the probe is connected to one end of the handheld rod; the connecting wire is electrically connected with the handheld rod, the measuring main body and the probe respectively; the acquisition and core calculation module is arranged in the measurement main body and is used for receiving and processing a signal acquired by the probe; the lock-in amplifier is integrated on the acquisition and core calculation module and is used for synchronously transmitting signals and comparing the signals with input signals so as to extract target frequency signals and suppress noise interference; the accommodating groove is formed in the handheld rod, is far away from one end of the probe and is used for accommodating the probe; and the sealing cover is detachably connected to the open end of the accommodating groove and is used for fixing the probe. The method can accurately and quickly locate the position of a fault point in a complex environment, improves the detection accuracy, and has the characteristics of simplicity and convenience in operation, good stability and strong anti-interference capability.

Description

Technical Field

[0001] The invention relates to the technical field of electric power equipment, and in particular to a step voltage testing device. Background Art

[0002] In the precise detection of cable sheath faults, the handheld step voltage tester is a commonly used device. The device mainly consists of a measuring instrument and a handheld probe rod. During operation, the probe needle is assembled with one end of the handheld rod, the wire of the measuring instrument is connected to the socket at the other end of the handheld rod, and then the probe needle is inserted into the soil for measurement.

[0003] However, the existing handheld step voltage tester has some design deficiencies. First, although the cone-shaped design of the probe needle is convenient for inserting into the soil, it needs to be removed from the hand-held rod after the measurement, which makes it impossible to store the probe needle, the measuring instrument and the hand-held rod in an integrated manner. The cone end of the probe needle is prone to wear on the surface of the measuring instrument and the hand-held rod during carrying, affecting the service life and portability of the equipment. Secondly, the existing handheld step voltage meter is easily interfered by environmental stray voltage during the measurement process. The superposition of stray voltage and the signal of the fault point not only prolongs the judgment time of the fault signal, but also may cause signal misjudgment, affecting the accurate positioning of the fault point. In addition, large stray voltage signals may also damage the tester, further reducing the service life of the equipment. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a step voltage testing device to improve the portability, measurement accuracy and service life of the device.

[0005] In order to solve the above technical problems, the present invention provides a step voltage testing device, comprising:

[0006] Hand-held rod and measuring body;

[0007] a detection needle connected to one end of the hand-held rod;

[0008] Connecting wires electrically connected to the hand-held rod, the measuring body and the detection needle respectively;

[0009] An acquisition and core computing module disposed inside the measuring body, for receiving and processing the signal acquired by the detection needle;

[0010] A phase-locked amplifier integrated in the acquisition and core computing module is used to synchronize the transmitted signal and compare it with the input signal to extract the target frequency signal and suppress noise interference;

[0011] A receiving groove is provided inside the hand-held rod and away from one end of the detection needle, and is used to receive the detection needle;

[0012] A sealing cover detachably connected to the open end of the receiving groove is used to fix the detection needle.

[0013] Preferably, the acquisition and core computing module specifically includes:

[0014] A voltage attenuation circuit for adjusting the amplitude of an input signal;

[0015] AD acquisition module, used to convert analog signals into digital signals;

[0016] STM32 control acquisition module is used to control signal acquisition and processing.

[0017] Preferably, the lock-in amplifier specifically includes a signal channel, a phase-sensitive detector and a low-pass filter.

[0018] Preferably, a spring connected to the hand-held rod is provided at one end of the storage groove away from the sealing cover, and a push plate slidably connected to the inner wall of the storage groove is connected to one end of the spring away from the hand-held rod.

[0019] Preferably, the detection needle is stored in the receiving groove in the following manner: the detection needle is disassembled by rotation and inserted into the receiving groove, and the detection needle is automatically pushed out and fixed by the cooperation of the spring and the push plate.

[0020] Preferably, one end of the surface of the hand-held rod away from the detection needle is fixedly sleeved with a rubber sleeve for increasing the friction of the hand-held rod and isolating the voltage.

[0021] Preferably, the step voltage testing device also includes an outer shell connected to the top of the measuring body, and a display module and a human-computer interaction module are respectively clamped inside the outer shell, and the display module and the human-computer interaction module are respectively electrically connected to the acquisition and core computing module.

[0022] Preferably, the display module is used for real-time waveform display, bar graph display and fault point position indication arrow display, and the direction of the arrow is determined based on the maximum voltage value within 10 seconds or within a preset time period.

[0023] Preferably, the overall height of the handheld rod and the detection needle does not exceed 1500mm, the overall circumference does not exceed 200mm, and the overall mass does not exceed 7kg; the overall mass of the measuring body does not exceed 1.5kg, and the overall circumference does not exceed 400mm.

[0024] Preferably, the anti-bending bearing capacity of the hand-held rod, the detection needle and the measuring body is not less than 10 kg.

[0025] The implementation of the present invention has the following beneficial effects: the present invention significantly improves the portability, anti-interference ability and detection accuracy of the device by optimizing the structure and function of the handheld step voltage tester. First, by arranging a storage groove and a sealing cover inside the handheld rod, the safe storage of the detection needle is achieved, and the wear of the equipment and personal injury caused by the exposure of the detection needle is avoided. At the same time, the problem of mixed use of the detection needle and the handheld rod is solved, and the practicality and portability of the equipment are improved. Secondly, by adopting the phase-locked amplifier technology, the fault signal is automatically identified and accurately located by synchronously transmitting the signal and comparing it with the input signal, which effectively suppresses the interference of environmental stray voltage and can quickly and accurately detect tiny signals in complex environments. In addition, by automatically judging the fault signal, manual intervention is reduced, the judgment error caused by the operator's lack of skills is reduced, and the accuracy and efficiency of the detection are significantly improved. The present invention has the advantages of simple operation, good stability, strong anti-interference ability, etc., and is suitable for accurate location detection of cable outer sheath faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the overall structure of a step voltage testing device according to an embodiment of the present invention.

[0028] Figure 2 It is a schematic cross-sectional structural diagram of a hand-held rod in an embodiment of the present invention.

[0029] Figure 3 It is a schematic diagram of the explosion structure of the measuring body in the embodiment of the present invention.

[0030] Figure 4 It is a principle module diagram of an embodiment of the present invention.

[0031] Figure 5 1 is a schematic diagram of a lock-in amplifier according to an embodiment of the present invention.

[0032] Figure 6 It is a schematic diagram of the step voltage grounding fault location principle in an embodiment of the present invention.

[0033] Figure 7 It is a schematic diagram of a fault point test principle of an embodiment of the present invention.

[0034] The accompanying drawings are marked as follows: 1. hand-held rod; 2. measuring body; 3. detection needle; 4. connecting line; 5. storage slot; 6. spring; 7. push plate; 8. sealing cover; 9. outer shell; 10. display module; 11. human-computer interaction module; 12. acquisition and core computing module; 13. lithium battery; 14. rubber sleeve. DETAILED DESCRIPTION

[0035] The following descriptions of the embodiments are with reference to the accompanying drawings to illustrate specific embodiments in which the present invention can be implemented. In the description of the present invention, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0036] Please also refer to Figure 1-3 As shown, an embodiment of the present invention provides a step voltage testing device, comprising:

[0037] Hand-held rod 1 and measuring body 2;

[0038] A detection needle 3 connected to one end of the handheld rod 1;

[0039] A connection line 4 electrically connected to the hand-held rod 1, the measuring body 2 and the detection needle 3 respectively;

[0040] An acquisition and core computing module 12 disposed inside the measuring body 2, for receiving and processing the signal acquired by the detection needle 3;

[0041] A phase-locked amplifier integrated in the acquisition and core computing module 12 is used to synchronize the transmitted signal and compare it with the input signal to extract the target frequency signal and suppress noise interference;

[0042] A receiving groove 5 is provided inside the hand-held rod 1 and away from one end of the detection needle 3, and is used to receive the detection needle 3;

[0043] The sealing cover 8 detachably connected to the open end of the receiving groove 5 is used to fix the detection needle 3 .

[0044] From the above settings, it can be seen that the embodiment of the present invention solves the problem of stray voltage interference and improves the signal detection accuracy through the phase-locked amplifier technology; through the design of the storage slot and the sealing cover, the problem of the inconvenience of carrying and easy wear of the detection needle is solved, and the portability and safety of the equipment are improved.

[0045] Specifically, the top of the measuring body 2 is connected to an outer shell 9, and the inner part of the outer shell 9 is respectively connected to a display module 10 and a human-computer interaction module 11. The inner part of the measuring body 2 is connected to a collection and core computing module 12 which is electrically connected to the display module 10 and the human-computer interaction module 11. Figure 4 As shown, the acquisition and core calculation module 12 includes a voltage attenuation circuit, an AD acquisition module, and an STM32 control acquisition module; Figure 5 As shown, the phase-locked amplifier includes a signal channel, a phase-sensitive detector, a low-pass filter, etc.

[0046] The measuring body 2 is internally connected with a lithium battery 13 which is electrically connected to the display module 10 and the acquisition and core computing module 12. The lithium battery 13 has functions such as power monitoring protection, overcharge protection, discharge protection, charging circuit short circuit, and open circuit protection.

[0047] A storage groove 5 is provided at one end of the hand-held rod 1 away from the detection needle 3, and a sealing cover 8 is provided at the end of the hand-held rod 1 away from the detection needle 3 and is threadedly connected to the storage groove 5. A spring 6 connected to the hand-held rod 1 is provided at one end of the storage groove 5 away from the sealing cover 8, and a push plate 7 slidably connected to the inner wall of the storage groove 5 is connected at one end of the spring 6 away from the hand-held rod 1. By providing the storage groove 5 inside the hand-held rod 1, the detection needle 3 can be stored inside the storage groove 5 and fixed by the sealing cover 8, so that the detection needle 3 can be reasonably stored to avoid the detection needle 3 being placed outside and causing injuries to the equipment or staff. At the same time, the detection needles 3 of the corresponding models of the hand-held rod 1 are stored together, which can also avoid confusion between different detection needles 3 and the hand-held rod 1, thereby improving practicality.

[0048] A rubber sleeve 14 is fixedly sleeved on one end of the surface of the hand-held rod 1 away from the detection needle 3, which is used to increase the friction force on the surface of the hand-held rod 1 to facilitate holding, and at the same time isolate the voltage to avoid harm to personnel.

[0049] The overall height of the hand-held rod 1 and the detection needle 3 does not exceed 1500mm, the overall circumference does not exceed 200mm, and the overall mass does not exceed 7kg. The overall mass of the measuring body 2 does not exceed 1.5kg, and the overall circumference does not exceed 400mm. As a result, the embodiment of the present invention has a compact and light internal structure, a simple and compact appearance, and fully considers ergonomic design, so it is easy to use.

[0050] The bending resistance of the hand-held rod 1, the detection needle 3 and the measuring body 2 is not less than 10kg, and the waterproof grade is required to be IPV6, so as to ensure the structural strength in the working state and protect against impact and collision.

[0051] The housing of the measuring body 2 and the outer shell 9 are both made of light metal, plastic or rubber. The use of light metal, plastic or rubber can reduce the overall weight, making it easier to carry.

[0052] The disassembly and assembly process of the embodiment of the present invention is as follows: the detection needle 3 is disassembled by rotating it from one end of the hand-held rod 1, and the sealing cover 8 is rotated open from the inside of the storage groove 5, so that the detection needle 3 can be slidably inserted into the inside of the storage groove 5 for storage. Then the sealing cover 8 is rotated again to cover the inside of the storage groove 5 to fix the detection needle 3, so that the tip of the detection needle 3 pushes the push plate 7 to slide, so that the spring 6 is contracted together. When the detection needle 3 needs to be reused, after the sealing cover 8 is rotated open, the push plate 7 can use the rebound force of the spring 6 to drive the detection needle 3 to slide, thereby pushing the detection needle 3 out of the storage groove 5.

[0053] The embodiment of the present invention adopts the working principle of a phase-locked amplifier, the transmission signal of a synchronous transmitter, compares the input signal with the signal of the synchronous transmitter, automatically identifies the fault signal, and then gives a judgment result. It is equivalent to passing through a narrowband filter with an extremely high Q value, which is not affected by noise signals other than the frequency to be measured, and has good electromagnetic shielding performance to reduce the interference of external electromagnetic radiation on signal acquisition, so that extremely small signals can be measured, and the fault point can still be accurately and quickly located in a complex environment. Modern signal processing methods such as digital filtering technology and wavelet transform are used to improve the signal-to-noise ratio of the signal.

[0054] It can be understood that the basic principle of phase-sensitive detection technology is to perform correlation operations on the signal to be measured and a reference signal with the same frequency and fixed phase relationship, thereby extracting the signal component related to the reference signal and filtering out the noise component outside the reference frequency.

[0055] According to the orthogonality principle of sine functions, when a sine function with a frequency of ω is multiplied by another sine function with a frequency of ω, and then the product is integrated (the integration time is much longer than the period of the two functions), the result is zero. However, if the frequencies of the two functions are equal and the phases are the same, the average value is equal to half of the product of the amplitudes.

[0056] The input signal is multiplied by the reference signal. Assume the input signal is Among them, A s is the signal amplitude, ω is the signal angular frequency, is the signal phase; the reference signal is Among them, A r is the reference signal amplitude, is the reference signal phase. After multiplication, we get:

[0057]

[0058] The low-pass filter module performs low-pass filtering on the output result of the multiplication module. Since noise usually has a wide spectrum distribution, and the target signal is a periodic signal with a specific frequency ω, after low-pass filtering, the high-frequency component can be filtered out. Only the DC component related to the signal amplitude and phase is retained By adjusting the frequency and phase of the reference signal to match the frequency and phase of the signal to be measured, the target signal can be extracted to the greatest extent while suppressing the noise.

[0059] Please refer to Figure 6 , Figure 7 As shown, the working principle and process of the embodiment of the present invention are as follows:

[0060] First, use the human-computer interaction module 11 to open the measurement body 2. By adjusting the up and down buttons of the human-computer interaction module 11 to switch the sensitivity, you can pause the waveform observation data or save the current measurement data. Click the real-time waveform columnar area on this page to switch to the columnar display mode. Max is the maximum value within the set maximum value calculation time period. The direction of the arrow represents the direction of the larger voltage. This direction is the direction judgment made by the maximum value within 10s or when the maximum value time is set to less than 10s. The sensitivity can be set in manual or automatic mode, or the sensitivity level can be pre-set. The filtering algorithm is divided into two levels, and the data is filtered after the first level and then filtered at the second level.

[0061] 1# algorithm-----60ms sliding window filtering;

[0062] 2# algorithm----Kalman filter;

[0063] 3# Algorithm----10th order FIR filter algorithm

[0064] 4# algorithm----Low-pass filter algorithm, the frequency needs to be set, the default is 1Hz, and the maximum is 200Hz.

[0065] When the filtering algorithm is working, the top bar displays the currently set algorithm. For example, F-4-1 means that the first-level 4# and second-level 1# filtering algorithms are working at the same time, and F-3-0 means that only the first-level algorithm 3 is working.

[0066] The 4# algorithm can only be set in the first-level algorithm.

[0067] Near the fault point of the direct buried cable, the current flows into the earth in all directions from the damaged point of the sheath. There is a potential difference between any two points on the ground, which is the step voltage. By detecting the intensity and direction of the step voltage, the location of the fault point can be determined. This fault location method is the step voltage grounding fault location method.

[0068] Then, the two detection needles 3 are inserted into the soil along the cable path respectively; during the positioning process, the directions of the two detection needles 3 must be maintained, with detection needle one facing the signal source end and detection needle two facing the far end; the two detection needles 3 are spaced a certain distance apart, and the distance is appropriately increased when the signal is weak, and the distance is shortened when the signal is strong. When very close to the fault point, the distance can be very small to facilitate accurate positioning.

[0069] Press the power switch of the human-computer interaction module 11 for more than 1 second, turn on the power of the measuring body 2, insert the detection needle 3 into the soil near the top of the faulty cable (do not hold the probe with your hand), and observe the signal waveform displayed on the display module 10. If the waveform amplitude is very small, the gain should be adjusted higher. Observe the signal waveform displayed on the display module 10 again until the gain is adjusted appropriately. Wait for about 15 seconds and observe the arrow indicating the direction of the fault point. Then move forward about 10 meters in the direction indicated by the arrow and continue measuring. When the displayed signal is strong and the direction of the arrow indicating the direction of the fault point is reversed, it means that the fault point has been crossed. Shorten the moving distance, look back carefully for the point where the arrow direction changes and the signal is strong, which is the fault point.

[0070] At the same time, during the process of positioning, if the displayed signal amplitude is very small, the direction indicated by the arrow will change left and right, indicating that the measurement point is still far away from the fault point, and you can continue to move forward for measurement. Or increase the signal gain and measure for a longer period of time, and the direction indicated by the arrow will stabilize.

[0071] Compared with the prior art, the beneficial effect brought by the embodiment of the present invention is that the present invention significantly improves the portability, anti-interference ability and detection accuracy of the device by optimizing the structure and function of the handheld step voltage tester. First, by arranging a storage groove and a sealing cover inside the handheld rod, the safe storage of the detection needle is achieved, and the wear of the equipment and the injury to personnel caused by the exposure of the detection needle are avoided. At the same time, the problem of mixed use of the detection needle and the handheld rod is solved, and the practicality and portability of the equipment are improved. Secondly, by adopting the phase-locked amplifier technology, the fault signal is automatically identified and accurately located by synchronously transmitting the signal and comparing it with the input signal, and the interference of the environmental stray voltage is effectively suppressed, and the tiny signal can be detected quickly and accurately in a complex environment. In addition, by automatically judging the fault signal, manual intervention is reduced, the judgment error caused by the operator's lack of skills is reduced, and the accuracy and efficiency of the detection are significantly improved. The present invention has the advantages of simple operation, good stability, strong anti-interference ability, etc., and is suitable for accurate positioning detection of cable outer sheath faults.

[0072] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A step voltage test device, characterized in that: include: Hand-held rod and measuring body; a detection needle connected to one end of the hand-held rod; Connecting wires electrically connected to the hand-held rod, the measuring body and the detection needle respectively; An acquisition and core computing module disposed inside the measuring body, for receiving and processing the signal acquired by the detection needle; A phase-locked amplifier integrated in the acquisition and core computing module is used to synchronize the transmitted signal and compare it with the input signal to extract the target frequency signal and suppress noise interference; A receiving groove is provided inside the hand-held rod and away from one end of the detection needle, and is used to receive the detection needle; A sealing cover detachably connected to the open end of the receiving groove is used to fix the detection needle.

2. The step voltage test device according to claim 1, characterized in that: The acquisition and core computing module specifically includes: A voltage attenuation circuit for adjusting the amplitude of an input signal; AD acquisition module, used to convert analog signals into digital signals; STM32 control acquisition module is used to control signal acquisition and processing.

3. The step voltage test device according to claim 2, characterized in that: The phase-locked amplifier specifically includes a signal channel, a phase-sensitive detector and a low-pass filter.

4. The step voltage test device according to claim 1, characterized in that: A spring connected to the hand-held rod is arranged at one end of the storage groove away from the sealing cover, and a push plate slidably connected to the inner wall of the storage groove is connected to one end of the spring away from the hand-held rod.

5. The step voltage test device according to claim 4, characterized in that: The storage method of the detection needle in the storage groove is: the detection needle is disassembled by rotation and inserted into the storage groove, and the detection needle is automatically pushed out and fixed by the cooperation of the spring and the push plate.

6. The step voltage test device according to claim 1, characterized in that: One end of the surface of the hand-held rod away from the detection needle is fixedly sleeved with a rubber sleeve, which is used to increase the friction force of the hand-held rod and isolate the voltage.

7. The step voltage test device according to claim 1, characterized in that: It also includes an outer shell connected to the top of the measuring body, wherein a display module and a human-computer interaction module are respectively clamped inside the outer shell, and the display module and the human-computer interaction module are respectively electrically connected to the acquisition and core computing module.

8. The step voltage test device according to claim 7, characterized in that: The display module is used for real-time waveform display, bar graph display and fault point direction indication arrow display, and the direction of the arrow is determined based on the maximum voltage value within 10 seconds or a preset time period.

9. The step voltage test device according to claim 1, characterized in that: The overall height of the hand-held rod and the detection needle does not exceed 1500mm, the overall circumference does not exceed 200mm, and the overall mass does not exceed 7kg; the overall mass of the measuring body does not exceed 1.5kg, and the overall circumference does not exceed 400mm.

10. The step voltage test device according to claim 1, characterized in that: The anti-bending bearing capacity of the hand-held rod, the detection needle and the measuring body is not less than 10kg.

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