CN115902380B - Ultra-wide band current intelligent sensor - Google Patents
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Abstract
The invention discloses an ultra-wideband current intelligent sensor, which comprises a frequency domain complementary current sensing unit, a frequency division band signal conditioning unit, a synchronous time-base-variable high-speed acquisition processing unit, a frequency division band data processing compensation unit, a multi-frequency band data characteristic analysis unit, a communication module, a synchronous module and a power supply, wherein the frequency domain complementary current sensing unit is connected with the frequency division band signal conditioning unit; the frequency domain complementary type current sensing unit is coupled with current signals of different frequency bands, the frequency division band signal conditioning unit conditions and amplifies the current signals of the multiple frequency bands, the synchronous time-base-changing high-speed acquisition processing unit converts the analog signals conditioned and amplified by the multiple channels into digital signals, the frequency division band data processing compensation unit obtains broadband signals through digital signal fusion, the multi-frequency band data characteristic analysis unit extracts characteristic information of the different frequency bands for analysis, the synchronous module achieves time synchronization through mutual communication, and the communication module transmits data and analysis and diagnosis results to the background. The invention realizes synchronous acquisition and data fusion analysis of ultra-wide band current signals, and performs feature extraction and diagnosis of the running state of high-voltage equipment.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to an ultra-wideband current intelligent sensor.
Background
High voltage power equipment, such as a large power transformer, can diagnose whether insulation defects or internal faults exist in the high voltage power equipment by monitoring abnormal changes of grounding current of an iron core or a clamping piece during operation. The different frequency components of the current are closely related to the nature of the internal fault, including power frequency current, arc current, internal discharge current, etc. The current is also closely related to factors such as equipment characteristics, voltage levels, load characteristics, defect properties and the like, and the current amplitude and the frequency band range are wide, and meanwhile, the current also comprises pulse current. At present, the current detection cannot be realized by one method, and only two monitoring devices can be used for respectively monitoring the power frequency current and the high frequency current. The frequency range of the monitoring current of the power frequency iron core grounding current monitoring device is 50Hz-1kHz, the multi-point grounding fault inside the high-voltage equipment is mainly reflected, and the principle is similar to that of a common power frequency current transformer. The high-frequency current monitoring device is mainly used for monitoring the partial discharge pulse current in high-voltage equipment, and the frequency band range of the high-frequency current monitoring device is 3MHz-30MHz. The technical principle is that a rogowski coil sensor is adopted. When arc discharge or low-voltage current discharge exists in the high-voltage equipment, the generated current frequency band is between 1kHz and 5MHz. The two monitoring devices described above cannot cover such fault currents. Therefore, an ultra-wide-band current sensor capable of covering various frequency bands from power frequency 50Hz to high frequency 30MHz is needed, and the problem of monitoring fault current in high-voltage equipment is effectively solved.
The existing power frequency grounding current monitoring device consists of the current transformer and the acquisition and processing device. The current transformer is clamped on the grounding down conductor, a secondary current signal is connected to the acquisition processing device through a shielded cable, the acquisition processing device acquires, processes and stores the signal, and data is uploaded to a background server or a monitoring center according to a standard communication protocol.
The split type iron core grounding current monitoring device generally adopts a circular closed type current transformer, an original grounding down wire is required to be disconnected during installation, a current sensor is installed on a connecting wire, and the connecting wire generally adopts a copper bar or a lead which is close to the sectional area of the original grounding wire. The installation method needs to be carried out in a power-off state, and the original grounding wire needs to be disconnected during installation, so that the risk of poor contact of the grounding wire caused by loosening of connecting points exists.
With the appearance of the intelligent sensor, the split type grounding current monitoring device is gradually replaced by an integrated intelligent sensor which is more convenient to install, the intelligent sensor for grounding current is small in size and has strong power frequency leakage magnetic interference resistance, the grounding wire is not required to be disconnected in installation, but the sensor is mainly used for monitoring power frequency current at present, the frequency band range is about 50Hz-1kHz, and the multipoint grounding fault inside high-voltage equipment is mainly monitored.
For detecting the internal partial discharge defect of high-voltage equipment, the high-frequency current partial discharge detection technology enters a practical stage from the 90 th year of the 20 th century, particularly the maturity of a digital processor and a high-speed sampling technology is entered in the 21 st century, a foundation is laid for developing a novel high-frequency partial discharge detection device, and the high-frequency partial discharge detection method is widely popularized and applied in the state detection field of power equipment such as transformers, reactors, rotating electrical machines, high-voltage power cables and accessories thereof. The optimization and perfection of the high-frequency current partial discharge detection method are all the focus of students at home and abroad and industrial field application, and are particularly embodied in aspects of sensor performance improvement, signal processing, equipment discharge point positioning methods and the like, and the high-frequency current partial discharge detection method is mainly used for researching a high-frequency pulse current monitoring technology, and the frequency band is between 3MHz and 30MHz.
Sensor performance improvement aspects. In recent years, there have been intensive studies and researches on rogowski coil sensors in China, such as Qinghua university, western-style transportation university, shanghai university, north China electric power university, etc., and a great deal of results have been achieved. Liang Tao et al at the university of western traffic propose a method for complex permeability broadband measurement using a single turn-around full-pack structure, and point out that the method is applicable to complex permeability measurement at frequencies below 400 MHz. The low-temperature sintered NiZnCu ferrite ceramic material with fine grains, high magnetic permeability and high resistivity is developed by the university of Qinghua Bai Hailin, wang Xiaohui, etc., the initial magnetic permeability is more than or equal to 1000, and the resistivity is improved by two orders of magnitude compared with that of a solid phase method. Zhang Chongyuan et al of North China university of electric power adopts a high magnetic permeability material as a framework of a coil, increases the number of turns of coil windings as much as possible within the allowable range of the coil size, proposes a method for establishing a high-frequency transfer function model of the transformer by approaching the actual measurement frequency response characteristic of the transformer by adopting a vector matching method, and provides a method for reducing the order of the high-frequency transfer function model of the transformer. The magnetic core taking NiZn ferrite as a main formula is developed by the global energy Internet research institute in 2016, the maximum sensitivity of the magnetic core in the frequency band of 0.3 MHz-300 MHz is 3 times that of domestic similar products, and the frequency spectrum characteristics in the frequency bands of 30-60MHz and 80MHz-100MHz are superior to those of products of Techimp company. The comprehensive performance of the high-frequency sensor developed by some domestic professional companies reaches the advanced level abroad, and the research focus of the technology is on the frequency band above 30MHz.
Signal processing method aspects. The signal sensed by the high-frequency pulse current sensor may be a partial discharge signal in the high-voltage equipment or an external interference signal, and the signal needs to be analyzed and identified, namely, processed. The method has more work at home and abroad, and representative methods comprise controllable bandwidth filtering, time-frequency separation, frequency domain filtering, three-phase comparison, wavelet transformation, waveform identification, fuzzy clustering and the like. The Shanghai university of transportation Guo Canxin et al designs a partial discharge signal sensor based on a high-frequency and ultrahigh-frequency detection principle, portable detection equipment and the like, and distinguishes detected pulse signals by means of extracting pulse signal waveforms, multi-sensor signal joint comparison analysis and the like, so that external interference is eliminated, and real partial discharge signals from the inside of the equipment can be distinguished. Du Lin of Chongqing university uses db3 wavelet to denoise the partial discharge signal in the study, finds that the sqtwolog threshold is the best way to remove periodic narrowband interference, and the minimum threshold is the best way to remove white noise, and good results are obtained. The Techimp company adopts the equivalent time length and equivalent bandwidth technology proposed by Italy G.C. Montanari professor to extract and analyze the signals of the high-frequency current sensor, and the effect is good.
The above studies have focused on high frequency partial discharge pulse current technology, while relatively few studies have been conducted on how to detect and analyze faults for the frequency bands 1kHz-5MHz covered by amperometric discharge and arc current.
Disclosure of Invention
The invention aims to provide an ultra-wideband current intelligent sensor so as to solve the problems.
The invention solves the technical problems by adopting the following technical scheme:
an ultra-wideband current intelligent sensor, comprising: the device comprises a frequency domain complementary type current sensing unit, a frequency division band signal conditioning unit, a synchronous time-base-changing high-speed acquisition processing unit, a frequency division band data processing compensation unit, a multi-frequency band data characteristic analysis unit, a communication module, a synchronous module and a power supply;
the frequency domain complementary type current sensing unit is coupled with more than two different frequency band current signals, the frequency division band signal conditioning unit respectively conditions and amplifies the multiple frequency band current signals, the synchronous time-base-changing high-speed acquisition processing unit converts the analog signals conditioned and amplified by the multiple channels into digital signals, the frequency division band data processing compensation unit compensates, fuses and synthesizes the converted digital signals to obtain broadband signals, the multi-frequency band data characteristic analysis unit respectively extracts different frequency band characteristic information for analysis, the synchronous module achieves time synchronization through mutual communication, the communication module transmits data and analysis diagnosis results to the background, and the power supply provides working power for the frequency division band signal conditioning unit, the synchronous time-base-changing high-speed acquisition processing unit, the frequency division band data processing compensation unit, the multi-frequency band data characteristic analysis unit, the synchronous module and the communication module.
Further, the device also comprises a shell, wherein the frequency domain complementary type current sensing unit, the frequency division band signal conditioning unit, the synchronous time-base-changing high-speed acquisition processing unit, the frequency division band data processing compensation unit, the multi-frequency band data characteristic analysis unit, the communication module, the synchronous module and the power supply are all arranged in the shell.
Further, the frequency domain complementary current sensing unit is composed of 2-3 current sensing coils made of different magnetic characteristic materials and meeting the requirements of specific frequency bands, and the frequency bands of the current sensing coils cover the measured frequency bands; the sensing coils are isolated by magnetic shielding materials, the shielding materials are selected according to frequency bands, and the whole combined frequency domain complementary current sensing unit is sealed and fixed together by metal shielding materials.
Further, compensation and data fusion are carried out through a sampling and data processing fusion technology based on frequency division signal conditioning and time base changing, and an ultra-wideband current signal is obtained; the method comprises the steps of converting an analog signal into a digital signal through synchronous time-base-changing sampling, carrying out digital amplitude normalization processing, separating data into frequency domain data by utilizing a window function, synthesizing the separated data in a frequency domain range, constructing a wideband time domain signal by utilizing frequency domain inverse transformation, and extracting characteristic signals of different frequency bands from the wideband time domain signal.
Further, the method for separating the data into frequency domain data comprises the following steps:
(1) Determining a filter functionH d (e jW )；
(2) From the following componentsH d (e jW ) Determining an amplitude functionAd(Ω)：
Wherein,,Ωin order to be of an angular frequency,Ωcis the cut-off frequency;
(3) Determining a filter amplitude-frequency characteristic function according to the formula (1):
(4) Windowing yields the impulse response of the actual filter:
Wherein the window functionW N [k]Is formula (4):
(5) Band-pass filtering the sampled signal xk using equation (5) to obtain processed data yk:
yk=xk h k formula (5)
(6) And (3) performing frequency domain separation calculation on y [ k ] by using a formula (6):
Y m is the discrete Fourier transform of the signal, and m is the frequency domain argument.
Further, the method for performing frequency domain synthesis using the formula (7) is:
yout (n) =y1 (n) ×s1 (n) +y2 (n) ×s2 (n) +y3 (n) ×s3 (n) formula (7)
In formula (7):
yout (n) is the intelligent sensor frequency domain output;
y1,2 and 3 (n) are the outputs of the 1 st, 2 nd and 3 rd frequency band sensor units respectively;
s1,2 and 3 (n) are respectively 1 st, 2 nd and 3 rd frequency band sensor correction value coefficients.
Further, the implementation method for constructing the broadband time domain signal comprises the following steps:
transforming the frequency domain synthesized data by using a formula (8), ensuring the sensitivity and the dynamic range of each detection frequency band by the transformed data, and carrying out continuous time domain and frequency domain characteristic analysis on the full current signal obtained by frequency domain fusion:
y 1 [k]Is a time domain signal after inverse discrete fourier transform.
Further, the method for extracting the characteristic signals of different frequency bands comprises the following steps:
reconstructing time domain signals in the 40 Hz-60 MHz signal frequency bands by the ultra-wideband current sensor through data fusion, wherein the accuracy and waveform of the reconstructed signals in each frequency band have integrity; the detection performance of each frequency band is ensured by extracting pulse signals in a specific period and multi-frequency band energy spectrum characteristic signals.
Advantageous effects
1) The frequency range of the power frequency current signal and the high frequency pulse signal is covered by the detection frequency band of the ultra-wide band current sensing technology, and the performance and the sensitivity of each frequency band are ensured through a frequency domain fusion data processing algorithm.
2) Through the joint analysis of the current signals in different frequency bands and the high-frequency pulse current signals, the fault position and the fault type can be estimated and diagnosed.
3) The defect that the current high-frequency current sensor cannot detect arc current and low-frequency discharge current is overcome.
4) The system can realize synchronous acquisition of multiple sensors by flexible networking, and thoroughly changes the comprehensive monitoring architecture of the current centralized high-voltage equipment.
5) The installation is simple and convenient, the power supply and the high-speed communication can be realized through the network cable, the networking is rapid, and the maintenance cost is reduced.
6) The synchronous device has an accurate synchronous function, the synchronous time difference is less than 1us, synchronous acquisition can be realized with other state quantity sensors, and the internal defects of the high-voltage equipment are diagnosed and analyzed.
Drawings
FIG. 1 is a block diagram of the structure of the present invention;
FIG. 2 is a cross-sectional view of the present invention;
FIG. 3 is an external construction diagram of the present invention;
FIG. 4 is a signal processing diagram of an ultra-wideband current intelligent sensor of the present invention;
FIG. 5 is a flow chart of a data fusion process according to the present invention;
fig. 6 is a schematic diagram of the frequency domain synthesis of the present invention.
Wherein, in the figure:
1-a frequency domain complementary current sensing unit; a 2-split signal conditioning unit; 3-a synchronous time-base-changing high-speed acquisition processing unit; a 4-sub-band data processing compensation unit; 5-a multi-band data characteristic analysis sheet; 6-a synchronization module; 7-a communication module; 8-power supply.
Description of the embodiments
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The ultra-wide band current intelligent sensor replaces all current monitoring devices with one sensor, realizes synchronous acquisition, data fusion analysis, feature extraction and diagnosis of the running state of high-voltage equipment.
Referring to fig. 1, the invention discloses an ultra-wideband current intelligent sensor, which comprises: the device comprises a frequency domain complementary type current sensing unit, a frequency division band signal conditioning unit, a synchronous time-base-changing high-speed acquisition processing unit, a frequency division band data processing compensation unit, a multi-frequency band data characteristic analysis unit, a communication module, a synchronous module and a power supply;
the frequency domain complementary type current sensing unit is coupled with more than two different frequency band current signals, the frequency division band signal conditioning unit respectively conditions and amplifies the multiple frequency band current signals, the synchronous time-base-changing high-speed acquisition processing unit converts the analog signals conditioned and amplified by the multiple channels into digital signals, the frequency division band data processing compensation unit compensates, fuses and synthesizes the converted digital signals to obtain broadband signals, the multi-frequency band data characteristic analysis unit respectively extracts different frequency band characteristic information for analysis, the synchronous module achieves time synchronization through mutual communication, the communication module transmits data and analysis diagnosis results to the background, and the power supply provides working power for the frequency division band signal conditioning unit, the synchronous time-base-changing high-speed acquisition processing unit, the frequency division band data processing compensation unit, the multi-frequency band data characteristic analysis unit, the synchronous module and the communication module.
In general, for the current sensor to achieve the best performance in the operating frequency band, iron core materials with different magnetic characteristics need to be selected. The ultra-wideband current sensor is characterized in that magnetic materials with different characteristics are utilized, a sensing unit with specific performance is designed according to frequency division, the sensor acquires original data, and then ultra-wideband current signals are acquired through compensation and data fusion, the sensor can independently acquire signals in a certain frequency band according to specific requirements, meanwhile, acquisition and processing of pulse signals and continuous signals can be synchronously completed, and synchronous signals of the sensor adopt alternating current POE power supply synchronization or network synchronization. The sensor has a specially designed opening structure, can be installed in the running state of equipment, and has an error lower than 2mA in the 40Gs electromagnetic interference environment.
The ultra-wide band current intelligent sensor diagnoses equipment faults and evaluates fault positions and fault types by comprehensively analyzing and identifying broadband current signals. The ultra-wide band current intelligent sensor can realize high-speed communication and power supply through a network cable, can realize quick networking, can also realize independent work through battery power supply, and the sensor can realize accurate synchronization by utilizing a synchronization source or a network and can work in cooperation with other sensors.
Referring to fig. 2-3, the invention further comprises a housing, wherein the frequency domain complementary type current sensing unit 1, the frequency division band signal conditioning unit 2, the synchronous time-varying base high-speed acquisition processing unit 3, the frequency division band data processing compensation unit 4, the multi-frequency band data characteristic analysis unit 5, the communication module 7, the synchronous module 6 and the power supply 8 are all arranged in the housing.
In this embodiment, the frequency domain complementary current sensing unit is composed of 2-3 current sensing coils made of materials with different magnetic characteristics and meeting the requirement of a specific frequency band, and the frequency band covers the measured frequency band; the sensing coils are isolated by magnetic shielding materials, the shielding materials are selected according to frequency bands, and the whole combined frequency domain complementary current sensing unit is sealed and fixed together by metal shielding materials. The frequency domain complementary type current sensing unit can be of an opening structure or a closed structure, the end part of the opening structure can adopt a staggered interface or a plane interface, and the whole sensing assembly is shielded by adopting a plurality of layers of electromagnetic shielding materials.
The signal processing flow of the ultra-wideband current intelligent sensor is shown in fig. 4. The sensor acquires current signals of different frequency bands through coils with more than two frequency band characteristics, after acquiring multi-channel signal original data, the synchronous time-base-variable high-speed acquisition processing unit completes synchronous high-speed acquisition processing of pulse signals and continuous signals, the frequency-division-data processing compensation unit performs compensation and data fusion through frequency-division-band signal conditioning and time-base-variable sampling and data processing fusion technologies based on FPGA and DSP technologies to acquire ultra-wide-band current signals, and meanwhile, the multi-frequency-band data characteristic analysis unit can independently acquire signals of a certain frequency band according to specific requirements, performs multi-frequency-band waveform data characteristic analysis through edge calculation to determine defects of high-voltage equipment, and the communication module transmits data and analysis diagnosis results to the background.
The ultra-wideband current signal is obtained by compensating and data fusion based on the technology of frequency division signal conditioning and time base changing sampling and data processing fusion; the method comprises the steps of converting an analog signal into a digital signal through synchronous time-base-changing sampling, carrying out digital amplitude normalization processing, separating data into frequency domain data by utilizing a window function, synthesizing the separated data in a frequency domain range, constructing a wide-band time domain signal by utilizing frequency domain inverse transformation, extracting characteristic signals of different frequency bands from the wide-band time domain signal, and carrying out fault diagnosis by utilizing different characteristic information.
The method for separating the data into frequency domain data comprises the following steps:
(1) Determining a filter functionH d (e jW )；
(2) From the following componentsH d (e jW ) Determining an amplitude functionAd(Ω)：
Wherein,,Ωin order to be of an angular frequency,Ωcis the cut-off frequency;
(3) Determining a filter amplitude-frequency characteristic function according to the formula (1):
(4) Windowing yields the impulse response of the actual filter:
Wherein the window functionW N [k]Is formula (4):
(5) Band-pass filtering the sampled signal xk using equation (5) to obtain processed data yk:
yk=xk h k formula (5)
(6) And (3) performing frequency domain separation calculation on y [ k ] by using a formula (6):
Y m is the discrete Fourier transform of the signal, and m is the frequency domain argument.
In this embodiment, as shown in fig. 6, frequency domain data synthesis implementation is shown in fig. 6, where F1S, F1E are the low-end cutoff frequency and the high-end cutoff frequency of the frequency band 1, F2S, F2E are the low-end cutoff frequency and the high-end cutoff frequency of the frequency band 2, and F3S, F3E are the low-end cutoff frequency and the high-end cutoff frequency of the frequency band 3.
The method for frequency domain synthesis using equation (7) is:
yout (n) =y1 (n) ×s1 (n) +y2 (n) ×s2 (n) +y3 (n) ×s3 (n) formula (7)
In formula (7):
yout (n) is the intelligent sensor frequency domain output;
y1,2 and 3 (n) are the outputs of the 1 st, 2 nd and 3 rd frequency band sensor units respectively;
s1,2 and 3 (n) are respectively 1 st, 2 nd and 3 rd frequency band sensor correction value coefficients.
In this embodiment, the implementation method for constructing the wideband time domain signal includes:
transforming the frequency domain synthesized data by using a formula (8), ensuring the sensitivity and the dynamic range of each detection frequency band by the transformed data, and carrying out continuous time domain and frequency domain characteristic analysis on the full current signal obtained by frequency domain fusion:
y 1 [k]Is a time domain signal after inverse discrete fourier transform.
In this embodiment, the method for extracting the characteristic signals of different frequency bands includes:
reconstructing time domain signals in the 40 Hz-60 MHz signal frequency bands by the ultra-wideband current sensor through data fusion, wherein the accuracy and waveform of the reconstructed signals in each frequency band have integrity; by extracting pulse signals in a specific period and multi-band energy spectrum characteristic signals, the detection performance of each band is guaranteed, the pulse signals can be truly restored by high-speed sampling, the power frequency and harmonic current can be obtained by low-speed multi-period sampling, and the method is more effective for fault type diagnosis.
The detection frequency band of the ultra-wide band current sensing technology covers the frequency range of the power frequency current signal and the high-frequency pulse signal, and the performance and the sensitivity of each frequency band are ensured through a frequency domain fusion data processing algorithm. Through the joint analysis of the current signals in different frequency bands and the high-frequency pulse current signals, the fault position and the fault type can be estimated and diagnosed. The defect that the current high-frequency current sensor cannot detect arc current and low-frequency discharge current is overcome. The system can realize synchronous acquisition of multiple sensors by flexible networking, and thoroughly changes the comprehensive monitoring architecture of the current centralized high-voltage equipment. The installation is simple and convenient, the power supply and the high-speed communication can be realized through the network cable, the networking is rapid, and the maintenance cost is reduced. The synchronous device has an accurate synchronous function, the synchronous time difference is less than 1us, synchronous acquisition can be realized with other state quantity sensors, and the internal defects of the high-voltage equipment are diagnosed and analyzed.
The grounding current generated by the internal faults of the high-voltage equipment covers a wide frequency band, and the frequency bands of the grounding fault current have great differences among different internal defects. Such as transformer core, clamp ground current, cable fault ground current. At present, a plurality of independent sensors and monitoring devices are generally adopted for monitoring power frequency and high frequency respectively, arc current and current type discharge current are not covered, and practice proves that the monitoring is incomplete for fault diagnosis. Generally, the power frequency current is required to monitor 50-200 Hz, and the high-frequency pulse current is 3-30 MHz, which can not meet the frequency band requirement of fault diagnosis. Such as: the frequency band of the current type discharge generated by poor grounding of the iron core in the transformer is only tens of kHz, the grounding current harmonic wave generated by the iron core fault is not in the frequency band, and meanwhile, a plurality of independent monitoring devices are complex to install, high in cost and difficult in data joint analysis. The ultra-wideband current intelligent sensor provided by the invention covers 40 Hz-60 MHz detection frequency band, so that the problems can be well solved, and meanwhile, the traditional architecture of the current centralized monitoring device can be thoroughly changed, and the intelligent sensor is simple to install and convenient to operate.
The invention provides a through type current sensor for detecting broadband current signals of power equipment, which uses more than two magnetic materials with different characteristics as iron cores to manufacture a sensing unit with multi-frequency band complementary characteristics, acquires data of each frequency band by time-varying sampling, and acquires full-frequency band signals through data fusion, frequency domain data separation and frequency domain signal synthesis. The method is mainly used for state monitoring and fault diagnosis of various power equipment, in particular to high-voltage power equipment such as a power transformer, a cable and the like.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (2)
1. An ultra-wideband current intelligent sensor, comprising: the device comprises a frequency domain complementary type current sensing unit, a frequency division band signal conditioning unit, a synchronous time-base-changing high-speed acquisition processing unit, a frequency division band data processing compensation unit, a multi-frequency band data characteristic analysis unit, a communication module, a synchronous module and a power supply;
the frequency domain complementary type current sensing unit is coupled with more than two different frequency band current signals, the frequency division band signal conditioning unit respectively conditions and amplifies the multiple frequency band current signals, the synchronous time-base-changing high-speed acquisition processing unit converts the analog signals conditioned and amplified by the multiple channels into digital signals, the frequency division band data processing compensation unit compensates, fuses and synthesizes the converted digital signals to obtain broadband signals, the multi-frequency band data characteristic analysis unit respectively extracts different frequency band characteristic information for analysis, the synchronous module achieves time synchronization through mutual communication, the communication module transmits data and analysis diagnosis results to the background, and the power supply provides working power for the frequency division band signal conditioning unit, the synchronous time-base-changing high-speed acquisition processing unit, the frequency division band data processing compensation unit, the multi-frequency band data characteristic analysis unit, the synchronous module and the communication module;
compensating and data fusion are carried out by a frequency division signal conditioning and time base changing sampling and data processing fusion technology, and an ultra-wideband current signal is obtained; converting an analog signal into a digital signal through synchronous time-base-changing sampling, carrying out digital amplitude normalization processing, separating data into frequency domain data by utilizing a window function, synthesizing the separated data in a frequency domain range, constructing a wideband time domain signal by utilizing frequency domain inverse transformation, and extracting characteristic signals of different frequency bands from the wideband time domain signal;
the method for separating the data into frequency domain data comprises the following steps:
(1) Determining a filter function H d (e jW )；
(2) From H d (e jW ) Determining an amplitude function Ad (Ω):
wherein Ω is an angular frequency, and Ω is a cut-off frequency;
(3) Determining a filter amplitude-frequency characteristic function according to the formula (1):
(4) Windowing yields the impulse response of the actual filter:
h[k]＝h d [k]·w N [k]formula (3)
Wherein the window function W N [k]Is formula (4):
R N (k) Is a rectangular window function, where N is the window length;
(5) Band-pass filtering the sampled signal xk using equation (5) to obtain processed data yk:
yk=xk h k formula (5)
(6) And (3) performing frequency domain separation calculation on y [ k ] by using a formula (6):
y < m > is signal discrete Fourier transform, m is frequency domain independent variable;
the method for frequency domain synthesis using equation (7) is:
yout (n) =y1 (n) ×s1 (n) +y2 (n) ×s2 (n) +y3 (n) ×s3 (n) formula (7)
In formula (7):
yout (n) is the intelligent sensor frequency domain output;
y1,2 and 3 (n) are the outputs of the 1 st, 2 nd and 3 rd frequency band sensor units respectively;
s1,2 and 3 (n) are respectively 1 st, 2 nd and 3 rd frequency band sensor correction value coefficients;
the implementation method for constructing the broadband time domain signal comprises the following steps:
transforming the frequency domain synthesized data by using a formula (8), ensuring the sensitivity and the dynamic range of each detection frequency band by the transformed data, and carrying out continuous time domain and frequency domain characteristic analysis on the full current signal obtained by frequency domain fusion:
y 1 [k]is a time domain signal after inverse discrete Fourier transform;
the method for extracting the characteristic signals of different frequency bands comprises the following steps:
reconstructing time domain signals in the signal frequency bands of 40 Hz-60 MHz by the ultra-wideband current sensor through data fusion, wherein the accuracy and waveform of the reconstructed signals in each frequency band have integrity; the detection performance of each frequency band is ensured by extracting pulse signals in a specific period and multi-frequency band energy spectrum characteristic signals;
the frequency domain complementary current sensing unit consists of 2-3 current sensing coils which are made of materials with different magnetic characteristics and meet the requirements of specific frequency bands, and the frequency bands of the current sensing coils cover the measured frequency bands; the sensing coils are isolated by magnetic shielding materials, the shielding materials are selected according to frequency bands, and the whole combined frequency domain complementary current sensing unit is sealed and fixed together by metal shielding materials;
the sensor acquires current signals of different frequency bands through coils with more than two frequency band characteristics, after acquiring multi-channel signal original data, the synchronous time-base-variable high-speed acquisition processing unit completes synchronous high-speed acquisition processing of pulse signals and continuous signals, the frequency division data processing compensation unit performs compensation and data fusion through frequency division signal conditioning and time-base-variable sampling and data processing fusion technologies based on FPGA and DSP technologies, ultra-wide band current signals are obtained, meanwhile, the multi-frequency band data characteristic analysis unit independently acquires signals of a certain frequency band according to specific requirements, performs multi-frequency band waveform data characteristic analysis through edge calculation, determines high-voltage equipment defects, and transmits data and analysis diagnosis results to the background through the communication module.
2. The ultra-wideband current intelligent sensor according to claim 1, further comprising a housing, wherein the frequency domain complementary current sensing unit, the frequency division band signal conditioning unit, the synchronous time-base-variable high-speed acquisition processing unit, the frequency division band data processing compensation unit, the multi-frequency band data characteristic analysis unit, the communication module, the synchronous module and the power supply are all installed inside the housing.
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