Detector for judging live-line fault point of zero line of transformer

Abstract

The invention provides a transformer null line live-line fault point judgment detector, and relates to the field of power fault diagnosis equipment. The transformer null line live-line fault point judgment detector comprises a three-layer design architecture including a sensing layer, an analysis layer and an interaction layer, the sensing layer carries out signal capture by setting a broadband electromagnetic induction array, the sensing layer is composed of electromagnetic induction array hardware and a frequency coverage module, and high-sensitivity electromagnetic capture is realized by cooperating with a spatial arrangement technology. The hardware of the electromagnetic induction array is eight groups of nanocrystalline alloy induction coils which are annularly distributed, and each group of coils is connected in series with a 0.1 mu F high-frequency capacitor. Accurate anti-interference is realized through topology identification and feature matching, the positioning speed is improved by 300 times, the detection efficiency is greatly improved, meanwhile, the power failure loss is reduced, the economic benefit is remarkably improved, and the risk of manual contact with a live line is thoroughly eliminated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power fault diagnosis equipment, in particular to a transformer zero line live fault point judgment detector. BACKGROUND

[0002] The transformer electric quantity parameter detector is a special instrument for detecting the electric quantity parameters of the power transformer. In the complex power grid environment (such as multi-branch line and high load transformer area), the traditional equipment cannot distinguish the main line and branch line faults, often resulting in "positioning drift", which causes the investigation range to expand by 3-5 times. The manual recording of fault information is prone to omission or error, and cannot be linked with the power grid management system, making it difficult to form a closed loop of fault analysis, and the repeated fault rate is high (about 20% of the fault points will occur again within 3 months). In humid, dusty or strong electromagnetic radiation areas (such as the surrounding area of the transformer substation), the sensitivity of the traditional detection tool decreases sharply, and the detection success rate is less than 60%. Multiple detection is required, and after the fault occurs, a professional team needs to be dispatched to the scene with multiple sets of equipment, which takes an average of 1.5 hours from receiving the alarm to starting detection, seriously affecting the repair time.

[0003] Therefore, the present application provides a transformer zero line live fault point judgment detector, which effectively solves the above problems. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a transformer zero line live fault point judgment detector. The present application is a non-contact handheld detection instrument, which realizes precise anti-interference through topology identification and feature matching, improves the positioning speed by 300 times, greatly improves the detection efficiency, reduces the power loss, significantly improves the economic benefit, completely eliminates the risk of manual contact with live lines, improves the safety of workers, has safety value, and the cost is only 1 / 3 of that of imported equipment, which is suitable for popularization in basic power supply stations and has popularization value.

[0005] To achieve the above purpose, the present application realizes the following technical scheme: A transformer zero line live fault point judgment detector, the detector comprises a perception layer, an analysis layer and an interaction layer three-layer design architecture, the perception layer captures signals through a wide frequency electromagnetic induction array, the perception layer is composed of an electromagnetic induction array hardware and a frequency coverage module, and high-sensitivity electromagnetic capture is realized by cooperating with a spatial arrangement technology, the hardware of the electromagnetic induction array is 8 groups of nanocrystalline alloy induction coils arranged in a ring shape, each group of coils is connected in series with a 0.1 mu F high-frequency capacitor, and the outside is wrapped with a 0.2 mm permalloy magnetic shielding layer, the frequency coverage module realizes distortionless collection of 50Hz-10kHz full-band signals through the turn number gradient design of 200 turns of the inner circle and 100 turns of the outer circle, and the induction coils are arranged in a 360° ring shape, which ensures that the signal attenuation is less than or equal to 10% during detection at any angle. The analysis layer adopts impedance phase contrast and traveling wave distance measurement dual-mode positioning engine, the analysis layer includes anti-resistance phase ratio module, traveling wave distance measurement module and algorithm fusion module, the anti-resistance phase ratio module adopts 16-bit AD converter to digitize analog signal and then removes fundamental wave interference through 50Hz notch filter, the traveling wave distance measurement module is used for transient signal capture, and the 1kHz-10kHz traveling wave signal generated at the fault moment is captured, and the algorithm fusion module dynamically adjusts the weight based on real-time electromagnetic interference intensity; The interaction layer realizes three-dimensional channel output of screen display, alarm system and AR, including audible and visual alarm system, display module and AR real scene navigation module, the display module adopts 1.5 inch touch screen to display fault distance in real time, the audible and visual alarm system is divided into three levels of pre-warning level, fault level and emergency level, the AR real scene navigation module is wirelessly connected with the mobile phone APP through Bluetooth, the APP calls the camera to scan the surrounding environment of the line, and the fault point direction is marked with a red arrow in the real scene picture combined with GPS positioning.

[0006] Further, the anti-resistance phase contrast module of the analysis layer calculates the phase based on fast Fourier transform to extract the 50Hz fundamental wave phase, calculate the phase difference between the zero line and the ground line, the calculation method is that the zero line voltage signal is , the ground line voltage signal is , both are continuous alternating signals changing with time, the continuous signal is sampled at a sampling frequency to obtain a discrete time sequence: ; Wherein is the sampling period, is the total number of sampling points, and then the time domain signal is converted into a frequency domain complex sequence by FFT transform:

[0007] Wherein, is the frequency index, is the imaginary unit, is the frequency domain complex, and finally the 50Hz fundamental wave frequency positioning is performed, the frequency resolution of FFT is , the actual frequency corresponding to the first frequency point is:

[0008] Find the frequency point index closest to 50Hz:

[0009] Wherein, in engineering, usually , , then , , corresponding frequency , when the phase difference deviates from the threshold value for 3 consecutive periods, it is marked as a suspicious area with an error ≤1 meter.

[0010] Further, the traveling wave distance measurement module of the analysis layer utilizes the propagation characteristics of the transient traveling wave generated by the fault point in the process of transient signal capture, and the propagation speed of the traveling wave in the conductor is , the time when the incident wave front reaches the detector is , the time when the reflected wave front reaches the detector is , and the time difference is: ; Since the total distance from the traveling wave from the detector to the fault point and back to the detector is , the fault distance L is: ; Distance error is determined by the time difference measurement error and the wave speed error , which needs to be quantified and controlled by the formula: ; The error is ≤0.3 meters by calculating the fault distance from the traveling wave front arrival time difference (Δt).

[0011] Further, the algorithm fusion module of the analysis layer dynamically adjusts the weight of impedance phase contrast and traveling wave distance measurement based on real-time electromagnetic interference intensity, detects the real-time interference intensity with a noise sensor, and uses to represent: ; Where is the minimum interference threshold, is the maximum interference threshold, , 0 represents no interference, 1 represents extremely strong interference, the weight of impedance phase contrast is , the weight of traveling wave distance measurement is , and it needs to satisfy: :

[0012] After obtaining and by the above weight formula, the final fault distance is the weighted sum of the two positioning results: ; wherein fault distance for impedance phase contrast calculation, fault distance for traveling wave distance calculation.

[0013] Further, the interaction layer realizes human-computer interaction design, the AR real scene navigation module is scanned automatically after self-checking, the display module supports visible brightness adjustment under sunlight, real-time display fault distance is accurate to 0.1 meters, and screen response time is < 100 ms.

[0014] Further, the sound and light alarm module of the interaction layer, the limit range of the early warning level is > 15V, the warning performance of the early warning level is yellow light constant light, which prompts approaching the fault area, the limit range of the fault level is > 36V, the warning performance of the fault level is red light flashing and buzzer ringing, which prompts that the fault point is reached, the limit range of the emergency level is > 50V, the warning performance of the emergency level is red light constant light, buzzer continuous ringing, and alarm information is sent to the background at the same time.

[0015] The application provides a transformer zero line live fault point judgment detector. 1. The application provides a transformer zero line live fault point judgment detector, compared with the traditional fault point judgment detector, the application is a non-contact handheld detector, which realizes precise anti-interference through topology identification and feature matching, improves positioning speed by 300 times, greatly improves detection efficiency, reduces power loss, significantly improves economic benefit, completely eliminates the risk of manual contact with live lines, improves the safety of workers, has safety value, and the cost is only 1 / 3 of imported equipment, is suitable for popularization in basic power supply stations, and has popularization value and is suitable for popularization.

[0016] 2. The application provides a transformer zero line live fault point judgment detector, which is the first to realize a zero line fault detection mode of non-contact scanning and AR visualization, solves the misjudgment problem in complex environments through a double-mode positioning algorithm, and designs an automatic detection process with zero learning cost according to the characteristics of large differences in the operation ability of basic electricians, realizes a foolproof operation design, reduces the use threshold, breaks through the industry bottleneck that the cost and precision of traditional equipment cannot be compatible, and can still be positioned in the area without GPS signal through image recognition technology matching the GIS database. DETAILED DESCRIPTION

[0017] Fig. 1 It is a functional module diagram of the detector of the application; Fig. 2 It is a system architecture diagram of the detector of the application. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] Example 1: like Figs. 1-2 As shown, an embodiment of the present invention provides a transformer neutral line live fault point judgment detector, which includes a three-layer design architecture of a perception layer, an analysis layer, and an interaction layer. The perception layer captures signals by setting a wide-band electromagnetic induction array. The perception layer is composed of electromagnetic induction array hardware and a frequency coverage module, and cooperates with spatial arrangement technology to achieve high-sensitivity electromagnetic capture. The hardware of the electromagnetic induction array is 8 groups of nanocrystalline alloy induction coils distributed in a ring. Each group of coils is connected in series with a 0.1μF high-frequency capacitor and wrapped with a 0.2mm permalloy magnetic shielding layer. The frequency coverage module realizes distortion-free acquisition of full-band signals of 50Hz-10kHz through a coil turn gradient design with 200 turns in the inner circle and 100 turns in the outer circle. The induction coils are arranged in a 360° ring, ensuring that the signal attenuation is ≤10% when detecting at any angle. The analysis layer uses a dual-mode positioning engine based on impedance phase comparison and traveling wave ranging. The analysis layer includes an impedance phase ratio module, a traveling wave ranging module, and an algorithm fusion module. The impedance phase ratio module uses a 16-bit AD converter to digitize the analog signal and then eliminates fundamental wave interference through a 50Hz notch filter. The traveling wave ranging module is used to capture transient signals, capturing the 1kHz-10kHz traveling wave signal generated at the moment of the fault. The algorithm fusion module dynamically adjusts the weight based on the real-time electromagnetic interference intensity. The interactive layer realizes the three-dimensional channel output of screen display, alarm system and AR, including the sound and light alarm system, display module and AR real-scene navigation module. The display module uses a 1.5-inch touch screen to display the fault distance in real time. The sound and light alarm system is divided into three levels: warning level, fault level and emergency level. The AR real-scene navigation module is wirelessly connected to the mobile phone APP via Bluetooth. The APP calls the camera to scan the surrounding environment of the line, and combines GPS positioning to mark the direction of the fault point with a red arrow in the real-scene picture.

[0020] Example 2: like Figs. 1-2 As shown, the embodiment of the present invention provides a transformer neutral line live fault point judgment detector, the analysis layer's anti-group phase comparison module calculates the phase, extracts the 50Hz fundamental phase based on the fast Fourier transform, and calculates the phase difference between the neutral line and the ground line. The calculation method is to set the neutral line voltage signal to be , the ground voltage signal is , are all continuous AC signals that vary with time. For continuous signals, the sampling frequency is Sampling is performed to obtain a discrete time series: ; in is the sampling period, is the total number of sampling points, and then the time domain signal is converted into a frequency domain complex sequence through FFT transformation:

[0021] in, is the frequency index, is the imaginary unit, is a complex number in the frequency domain, and finally the 50Hz fundamental wave frequency is located. The frequency resolution of FFT is , No. The actual frequency corresponding to each frequency point is:

[0022] Find the frequency index closest to 50Hz :

[0023] Among them, the engineering usually takes 、 ,but , , corresponding to the frequency ), when the phase difference deviates from the threshold by more than 3 for three consecutive cycles, it is marked as a suspicious area with a positioning error of ≤1 meter; The traveling wave ranging module of the analysis layer uses the propagation characteristics of the transient traveling wave generated by the fault point in the line during the transient signal capture process. The propagation speed of the traveling wave in the conductor is , the time it takes for the incident wave head to reach the detector is , the time it takes for the reflected wave head to reach the detector is , then the time difference is: ; Since the total distance of the traveling wave from the detector to the fault point and back to the detector is , so the fault distance L is: ; Distance error Measuring error by time difference and wave velocity error Jointly determined, to be quantified and controlled by formula: ; The fault distance is calculated by the time difference (Δt) of the wave head of the traveling wave, so that the error is less than or equal to 0.3 meters; The algorithm fusion module of the analysis layer dynamically adjusts the weight of the impedance phase contrast and the traveling wave distance measurement based on the real-time electromagnetic interference intensity, detects the real-time interference intensity by a noise sensor, and adjusts the weight of the impedance phase contrast and the traveling wave distance measurement based on the real-time interference intensity. Wherein is a minimum interference threshold, is a maximum interference threshold, 0 represents no interference, 1 represents extremely strong interference, the weight of the impedance phase contrast is , and the weight of the traveling wave distance measurement is , and needs to meet:

[0024] After the above weight formula is obtained and , the final fault distance is a weighted sum of the two positioning results: Wherein is the fault distance calculated by the impedance phase contrast, is the fault distance calculated by the traveling wave distance measurement; The interactive layer realizes human-computer interaction design, the AR real scene navigation module automatically scans along the line after self-checking after starting, the display module supports sunlight visible brightness adjustment, and the fault distance is accurately displayed to 0.1 meters in real time, the screen response time is less than 100 ms, the sound and light alarm module of the interactive layer, the limited range of the early warning level is greater than 15V, the warning performance of the early warning level is that the yellow light is always on to prompt the approach to the fault area, the limited range of the fault level is greater than 36V, the warning performance of the fault level is that the red light flashes and the buzzer buzzes, prompting that the fault point is near, and the limited range of the emergency level is greater than 50V, the warning performance of the emergency level is that the red light is always on, the buzzer continuously buzzes, and alarm information is sent to the background.

[0025] Working principle: the transformer zero line live fault point judgment detector of the present application is a non-contact handheld detector, and the fault point is quickly positioned through three steps: Step 1: electromagnetic signal capture: sensing the abnormal current of the zero line within 0.3-0.5m distance; Step 2: intelligent positioning: analyzing the fault position in combination with the line impedance characteristics and signal propagation characteristics; Step 3: visual alarm: displaying the fault distance on the screen, and marking the positioning point by AR technology.​​​​

[0026] In this document, the following points need to be noted: 1. The drawings of the embodiments of the present disclosure only relate to the structures involved in the embodiments of the present disclosure, and other structures can refer to the general design.

[0027] 2. In the case of no conflict, the embodiments of the present disclosure and the features in the embodiments can be combined to obtain new embodiments.

[0028] Although the embodiments of the present application have been shown and described, it should be understood by those ordinary skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents. Based on the embodiments in the present application, all other embodiments obtained by those ordinary skilled in the art without creative labor are within the scope of protection of the present application.

Claims

1. A transformer neutral line live fault point determination detector, characterized by: The detector includes a three-layer design architecture: a perception layer, an analysis layer, and an interaction layer. The perception layer captures signals by setting up a broadband electromagnetic induction array. The perception layer is composed of electromagnetic induction array hardware and a frequency coverage module, and uses spatial arrangement technology to achieve high-sensitivity electromagnetic capture. The hardware of the electromagnetic induction array consists of 8 groups of nanocrystalline alloy induction coils distributed in a ring. Each group of coils is connected in series with a 0.1μF high-frequency capacitor and wrapped with a 0.2mm permalloy magnetic shielding layer. The frequency coverage module achieves distortion-free acquisition of signals in the full frequency band of 50Hz-10kHz through a gradient design of coil turns of 200 turns in the inner circle and 100 turns in the outer circle. The induction coils are arranged in a 360-degree ring, ensuring signal attenuation of ≤10% when detecting at any angle. The analysis layer uses a dual-mode positioning engine of impedance phase comparison and traveling wave ranging. The analysis layer includes an impedance phase ratio module, a traveling wave ranging module, and an algorithm fusion module. The impedance phase ratio module uses a 16-bit AD converter to digitize the analog signal and then eliminates fundamental wave interference through a 50Hz notch filter. The traveling wave ranging module is used to capture transient signals, capturing the 1kHz-10kHz traveling wave signal generated at the moment of the fault. The algorithm fusion module dynamically adjusts the weight based on the real-time electromagnetic interference intensity. The interactive layer realizes the three-dimensional channel output of screen display, alarm system and AR, including the sound and light alarm system, display module and AR real-scene navigation module. The display module uses a 1.5-inch touch screen to display the fault distance in real time. The sound and light alarm system is divided into three levels: warning level, fault level, and emergency level. The AR real-scene navigation module is wirelessly connected to the mobile phone APP via Bluetooth. The APP calls the camera to scan the surrounding environment of the line, and combines GPS positioning to mark the direction of the fault point with a red arrow in the real-scene picture.

2. The transformer neutral line live fault point determination detector according to claim 1, characterized in that: The anti-group phase contrast module of the analysis layer calculates the phase difference between the neutral line and the ground line by extracting the 50Hz fundamental phase based on the fast Fourier transform. The calculation method is to set the neutral line voltage signal as , the ground voltage signal is , are all continuous AC signals that vary with time. For continuous signals, the sampling frequency is Sampling is performed to obtain a discrete time series: ； in is the sampling period, is the total number of sampling points, and then the time domain signal is converted into a frequency domain complex sequence through FFT transformation: in, is the frequency index, is the imaginary unit, is a complex number in the frequency domain, and finally the 50Hz fundamental wave frequency is located. The frequency resolution of FFT is , No. The actual frequency corresponding to each frequency point is: Find the frequency index closest to 50Hz : Among them, the engineering usually takes 、 ,but , , corresponding to the frequency ), when the phase difference deviates from the threshold by more than 3 for three consecutive cycles, it is marked as a suspicious area with a positioning error of ≤1 meter.

3. The transformer neutral line live fault point determination detector according to claim 1, characterized in that: The traveling wave ranging module of the analysis layer uses the propagation characteristics of the transient traveling wave generated by the fault point in the line during the transient signal capture process. The propagation speed of the traveling wave in the conductor is , the time it takes for the incident wave head to reach the detector is , the time it takes for the reflected wave head to reach the detector is , then the time difference is: ； Since the total distance of the traveling wave from the detector to the fault point and back to the detector is , so the fault distance L is: ； Distance error Measuring error by time difference and wave velocity error Jointly determined, to be quantified and controlled by formula: ； The fault distance is calculated by the arrival time difference (Δt) of the traveling wave head so that the error is ≤ 0.3 meters.

4. The transformer neutral line live fault point determination detector according to claim 1, characterized in that: The algorithm fusion module of the analysis layer dynamically adjusts the weights of impedance phase contrast and traveling wave ranging based on the real-time electromagnetic interference intensity, detects the real-time interference intensity through the noise sensor, and uses express: ； in is the minimum interference threshold, is the maximum interference threshold, , 0 means no interference, 1 means extremely strong interference, and the weight of impedance phase contrast is , the weight of traveling wave ranging is , must meet the following requirements: ： The above weight formula is obtained and After that, the final fault distance is the weighted sum of the two positioning results: ； in The fault distance calculated for impedance phase contrast, Fault distance calculated for traveling wave ranging.

5. The transformer neutral line live fault point determination detector according to claim 1, characterized in that: The interactive layer implements human-computer interaction design. The AR real-scene navigation module automatically scans along the route after power-on self-test. The display module supports visible brightness adjustment under sunlight, displays the fault distance in real time with an accuracy of 0.1 meter, and the screen response time is less than 100ms.

6. The transformer neutral line live fault point determination detector according to claim 1, characterized in that: The sound and light alarm module of the interactive layer has a warning level limit range of >15V, and the warning level warning is manifested by a yellow light that is always on to indicate that the fault area is approaching. The fault level limit range is >36V, and the fault level warning is manifested by a red light flashing and a buzzer beeping, indicating that the fault point has been reached. The emergency level limit range is >50V, and the emergency level warning is manifested by a red light that is always on and a buzzer beeping continuously, while sending an alarm message to the background.

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