CN114089135A - Partial discharge sensor for variable distribution high-frequency current and method thereof - Google Patents
Partial discharge sensor for variable distribution high-frequency current and method thereof Download PDFInfo
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Abstract
The invention discloses a variable distribution high-frequency current partial discharge sensor and a method thereof, wherein the variable distribution high-frequency current partial discharge sensor comprises a high-frequency current Rogowski coil, the high-frequency current Rogowski coil is used for collecting partial discharge signals, the output end of the high-frequency current Rogowski coil is electrically connected with a high-frequency current detection circuit, an integral operational amplifier and a multi-stage analog amplification circuit are arranged in the high-frequency current detection circuit, and the output end of the high-frequency current detection circuit is connected with a processor; the intelligent power equipment monitoring system also comprises a temperature and humidity IC chip, wherein the output end of the temperature and humidity IC chip is connected with the processor, partial discharge signals are collected and are accessed to the power equipment Internet of things management and application platform through the APN (access point name) security encryption channel, sensing data are visually presented, and the monitoring, early warning, real-time data recording and comprehensive analysis of operation conditions can be realized, so that the safe operation of the power equipment is ensured, and the intelligent maintenance of the equipment is realized.
Description
Technical Field
The invention relates to the technical field of high-frequency current sensors, in particular to a variable distribution high-frequency current partial discharge sensor and a method thereof.
Background
In general, partial discharge is caused by an excessive concentration of an electric field in an insulator, and when the partial discharge occurs, positive and negative charges are neutralized, and a steep pulse current is generated, and a partial discharge detection method using the pulse current as a measurement target is called a pulse current method. The impulse current method is characterized in that an insulator is equivalent to a lumped parameter ground capacitance element, instantaneous impulse current and voltage change can be generated on the capacitor by partial discharge, impulse voltage can be generated in detection impedance by using the capacitive coupling effect, and partial discharge information such as apparent discharge amount, discharge phase and the like can be obtained through the impulse voltage. The high-frequency current partial discharge detection method is a common measurement method for partial discharge defects and positioning of power equipment, the detection frequency range of the high-frequency current partial discharge detection method is 3-30 MHz, and the high-frequency current partial discharge detection technology can be widely applied to partial discharge detection of power equipment such as power cables, accessories, transformers and switch cabinets. The high-frequency current sensor adopts a Rogowski coil structure and is clamped on a cable intermediate joint, a center line point connecting wire or a terminal grounding wire, and the high-frequency current sensor has the advantages of convenience in installation, good on-site anti-interference capability and the like.
The current situation is as follows: because the high-frequency partial discharge detection technology uses the high-frequency current sensor, the detection principle is similar to that of the traditional pulse current method, if the sensor and the signal processing circuit are relatively determined, the intensity of the partial discharge to be detected can be described, so that the insulation degradation degree of the partial discharge of the detected power equipment can be accurately evaluated. The design is the mounting means of opening CT, can realize the non-contact detection of partial discharge pulse current under non-embedding mode, and installation and application are convenient. The high-frequency current sensor is composed of an annular ferrite magnetic core, ferrite is matched with magnetized ceramic materials, the high-frequency current sensor has high detection sensitivity on high-frequency signals, after partial discharge occurs, discharge pulse current propagates along the axial direction of a grounding wire, a magnetic field is generated on a plane perpendicular to the current propagation direction, the high-frequency current sensor couples discharge signals from the magnetic field, and the high-frequency current sensor has the advantage of being correctable when HFCT is used for measurement.
The traditional operation mode depending on manual inspection has huge workload, long detection period and low efficiency; defects cannot be found effectively and timely; the human input cost is high, simple and repeated mechanical work such as meter reading, box opening inspection and the like occupies a large amount of time of operation and maintenance personnel, and the ultrasonic partial discharge sensor is beneficial to cost reduction and efficiency improvement; the traditional online monitoring device has a complex structure, a heavy volume and huge power consumption; the system is greatly influenced by electromagnetic environment, the networking mode is inflexible, the maintenance workload is large, and the overall practical level of the conventional online monitoring system is not high, so that the system is difficult to meet the requirements.
Disclosure of Invention
The invention provides a variable distribution high-frequency current partial discharge sensor and a method thereof, aiming at realizing reliable high-frequency current partial discharge monitoring by adopting a high-frequency current and temperature and humidity detection circuit and an MCU integrated chip; meanwhile, a low-power-consumption LoRa Internet of things wireless communication technology is utilized to monitor and early warn data, and real-time data recording is carried out to help a user eliminate hidden dangers before insulation faults occur to equipment.
In order to achieve the technical purpose and achieve the technical effect, the invention is realized by the following technical scheme: a variable distribution high-frequency current partial discharge sensor comprises a high-frequency current Rogowski coil, wherein the high-frequency current Rogowski coil is used for collecting partial discharge signals, the output end of the high-frequency current Rogowski coil is electrically connected with a high-frequency current detection circuit, an integral operational amplifier and a multi-stage analog amplification circuit are arranged in the high-frequency current detection circuit, and the output end of the high-frequency current detection circuit is connected with a processor; the intelligent power transmission and transformation system is characterized by further comprising a temperature and humidity IC chip, wherein the output end of the temperature and humidity IC chip is connected with the processor, the communication end of the processor is connected with the power transmission and transformation node equipment terminal through signals, and the processor supplies power through the power management circuit.
Preferably, in the variable distribution high-frequency current partial discharge sensor, the high-frequency current rogowski coil adopts high-frequency current with the frequency of 3-30 MHz, the model of the temperature and humidity IC chip is SHT31, the temperature of the power equipment is monitored to be-40-80 ℃, and the humidity is 0-99% RH; the type of the integral operational amplifier is AD8032, and the multistage analog amplification circuit adopts an amplifier with the type of OPA 379; the processor adopts the model ARM Cortex-M4, detects according to the set sampling period, and uploads data including high-frequency current HFCT signals and the temperature and humidity of the operating environment.
Preferably, in the variable distribution high-frequency current partial discharge sensor, the variable distribution high-frequency current partial discharge sensor and the power transmission and transformation node device are transmitted by using a 470MHz LoRa wireless communication technology, and data is transmitted to the terminal of the power transmission and transformation node device through a wireless transceiver SX1268 chip.
Preferably, in the above power distribution transformation high-frequency current partial discharge sensor, the power management circuit is powered by an industrial-grade lithium secondary battery and is provided with a battery power detection AD sampling processing circuit.
Preferably, the transformer distribution high-frequency current partial discharge sensor adopts an integrally formed packaging cast aluminum shell, and the bottom of the shell is provided with a magnetic suction block.
Preferably, in the above power transformation and distribution high-frequency current partial discharge sensor, the transmission of the LoRa wireless communication technology is connected with the power transmission and transformation node device through an internet of things wireless networking protocol of the power transmission and transformation device; and the LoRa wireless communication technology adopts an edge calculation frame and carries partial discharge diagnosis APP.
A use method of a variable distribution high-frequency current partial discharge sensor specifically comprises the following steps:
step one, assembling and distributing a network of distributed high-frequency current partial discharge sensors, positioning and installing each high-frequency current sensor on a partial discharge source through a magnetic block at the bottom of the high-frequency current sensor, and simultaneously accessing each high-frequency current sensor to a power transmission and transformation node equipment terminal through LoRa wireless communication and a power transmission and transformation equipment Internet of things wireless networking protocol for debugging;
secondly, operating a high-frequency current partial discharge sensor, collecting partial discharge signals by a high-frequency current Rogowski coil, adjusting and amplifying the signals collected by the sensor by an integral operational amplifier and a multi-stage analog amplification circuit, collecting the temperature and humidity of a partial discharge source by a temperature and humidity IC chip, detecting by a processor according to a set sampling period, uploading data, and transmitting the data to transmission and transformation node equipment through a wireless receiving and transmitting SX1268 chip;
and thirdly, transmitting the transmission and transformation node equipment, wherein the transmission and transformation node equipment is accessed into the terminal equipment through the Internet of things wireless networking protocol based on the acquired data, and the terminal equipment can visually present the acquired sensing data.
Preferably, in the method for using the variable distribution high-frequency current partial discharge sensor, in the positioning of the partial discharge source in the first step, the high-frequency current partial discharge sensor is used for detecting partial discharge signals at a cable terminal and each joint respectively, and the initial positioning of the discharge source is performed by comparing and analyzing time domain and frequency domain characteristics of discharge signals at different sensor positions; then, the position of a discharge source is preliminarily judged by utilizing the principle that a discharge pulse signal is transmitted and attenuated in a cable, the amplitude of the discharge signal is reduced along with the propagation of the discharge signal, the rise time is reduced, the pulse broadband is widened, the high-frequency component of the signal is seriously attenuated, and the like; and finally, synchronously measuring at continuous joints by utilizing distributed partial discharge synchronous detection, and accurately positioning the position of a discharge source according to the difference of the amplitude, the polarity and the arrival time of the same pulse signal coupled to the measurement position.
Preferably, in the above method for using the variable distribution high-frequency current partial discharge sensor, electromagnetic interference noise is mixed in the discharge signal coupled by the high-frequency current sensor in the second step, and the method for processing the digital signal by the high-frequency current and resisting interference includes a cluster analysis method and a wavelet analysis method according to the time domain waveform characteristics.
Preferably, in the above method for using the variable power distribution high-frequency current partial discharge sensor, the wavelet analysis method is based on an analysis means of a non-stationary signal, has good localization properties in both time domain and frequency domain, and is suitable for processing irregular and transient signals for interference suppression measures of high-frequency current partial discharge detection; the clustering analysis method classifies the discharge signals according to respective equivalent frequency, equivalent duration and waveform-related characteristic parameters to form a time-frequency domain mapping spectrogram.
Compared with the prior art, the invention has the beneficial effects that: according to the method, a partial discharge signal is collected, the partial discharge signal passes through the APN (access point name) security encryption channel, is accessed to the power equipment Internet of things management and application platform, and is visually presented to perception data, so that monitoring and early warning of partial discharge, real-time data recording and comprehensive analysis of operation conditions can be realized, thereby ensuring the safe operation of the power equipment and realizing intelligent maintenance of the equipment; therefore, comprehensive online acquisition of power production site, operation and control data is realized, reliable and flexible network transmission is realized, various intelligent applications are met, the states of equipment in all links of a power grid can be measured, visualized and controlled, the equipment on the side of the power grid is operated and inspected, the equipment is overhauled afterwards, pre-diagnosis and active early warning are realized, the technology of the Internet of things is utilized, automatic switching of a power supply network is finally realized, and the purpose of self-healing is achieved.
Drawings
FIG. 1 is a block diagram of the present invention, showing a high frequency current partial discharge sensor and method;
fig. 2 is a diagram of an application scenario of a variable distribution high-frequency current partial discharge sensor and a method thereof according to the present invention;
fig. 3 is a flow chart of a method for a variable distribution high-frequency current partial discharge sensor according to the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, the present invention provides a technical solution: a variable distribution high-frequency current partial discharge sensor comprises a high-frequency current Rogowski coil, wherein the high-frequency current Rogowski coil is used for collecting partial discharge signals, the output end of the high-frequency current Rogowski coil is electrically connected with a high-frequency current detection circuit, an integral operational amplifier and a multi-stage analog amplification circuit are arranged in the high-frequency current detection circuit, and the output end of the high-frequency current detection circuit is connected with a processor; the power transmission and transformation node equipment terminal further comprises a temperature and humidity IC chip, the output end of the temperature and humidity IC chip is connected with the processor, the communication end of the processor is in signal connection with the power transmission and transformation node equipment terminal, and the processor supplies power through the power management circuit.
Specifically, the high-frequency current Rogowski coil adopts high-frequency current with the frequency of 3-30 MHz, the model of a temperature and humidity IC chip is set as SHT31, the temperature of the power equipment is monitored to be-40-80 ℃, and the humidity is 0-99% RH; the model of the integrating operational amplifier is AD8032, and the multistage analog amplification circuit adopts an amplifier with the model of OPA 379; the processor adopts the model ARM Cortex-M4, detects according to the set sampling period, and uploads data including high-frequency current HFCT signals and the temperature and the humidity of the operating environment.
Furthermore, a 470MHz LoRa wireless communication technology is adopted for transmission between the power transformation and distribution high-frequency current partial discharge sensor and the power transmission and transformation node equipment, and data are transmitted to the power transmission and transformation node equipment terminal through a wireless receiving and transmitting SX1268 chip. Meanwhile, the power management circuit is powered by an industrial-grade lithium-ion battery and is provided with a battery power detection AD sampling processing circuit. And a sleep mode and an awakening mode are adopted, so that the power supply is effectively managed, and the continuous working time of the battery is ensured.
The transformer and distribution high-frequency current partial discharge sensor to be described adopts an integrally formed packaging cast aluminum shell, and the bottom of the shell is provided with a magnetic suction block. Adopt miniaturized integrated encapsulation cast aluminium shell, magnetism is inhaled formula mounting means or is utilized the ribbon to fix main control unit, and magnetism is inhaled the formula and will be had the base of magnetic force and adsorb on the power equipment surface, presss from both sides high frequency current sensor on cable intermediate head, central line point wiring or terminal department earth connection.
In this embodiment, it should be noted that the LoRa wireless communication technology is connected to the power transmission and transformation node device through the internet of things wireless networking protocol of the power transmission and transformation device; each sensor corresponds to a unique ID number, and the corresponding sensor needs to be added into node equipment and a background before use. And (5) access initialization, and configuring sensor white list and blacklist attributes. And according to the scheduling result of the access node, broadcasting the access of the low-power consumption sensor at the appointed frame number, wherein the low-power consumption sensor can be scheduled in advance (random access is not needed, uplink communication can be carried out at the appointed frame number and time slot position) or can be accessed randomly (the processes of random competition and registration are completed).
Preferably, the LoRa wireless communication technology adopts an edge computing framework and partial discharge diagnosis APP carrying. Through electric power APN safety encryption channel, access power equipment thing networking management and application platform, through the visual presentation of high-frequency current partial discharge sensor perception data, realize power cable and annex, transformer core and folder, arrester, cubical switchboard and other power equipment's partial discharge monitoring, early warning, real-time data record, the integrated analysis of behavior to guarantee power equipment safe operation, realize the intelligent maintenance of equipment.
Based on the above, the power transformation and distribution high-frequency current partial discharge sensor adopts a miniaturized integrated packaging cast aluminum shell, is installed in a magnetic type manner or is fixed by a binding belt, is accessed to a power equipment internet of things management and application platform through a power APN safety encryption channel, and senses data to be visually presented through the high-frequency current partial discharge sensor.
Referring to fig. 2, the partial discharge monitoring and early warning, real-time data recording, and comprehensive analysis of the operation condition of the power equipment such as the power cable and the accessories, the transformer core and the clamping piece, the lightning arrester, and the switch cabinet are simultaneously realized, so that the safe operation of the power equipment is ensured, and the intelligent maintenance of the equipment is realized.
Referring to fig. 3, with reference to fig. 1, a method for using a variable distribution high-frequency current partial discharge sensor specifically includes the following steps:
step one, assembling and distributing a network of distributed high-frequency current partial discharge sensors, positioning and installing each high-frequency current sensor on a partial discharge source through a magnetic block at the bottom of the high-frequency current sensor, and simultaneously accessing each high-frequency current sensor to a power transmission and transformation node equipment terminal through LoRa wireless communication and a power transmission and transformation equipment Internet of things wireless networking protocol for debugging;
specifically, in the positioning of the partial discharge source, firstly, the high-frequency current partial discharge sensor is used to detect partial discharge signals at the cable terminal and each joint, and the time domain and frequency domain characteristics of the discharge signals at different sensor positions are analyzed by comparison to perform initial positioning of the discharge source; then, the position of a discharge source is preliminarily judged by utilizing the principle that a discharge pulse signal is transmitted and attenuated in a cable, the amplitude of the discharge signal is reduced along with the propagation of the discharge signal, the rise time is reduced, the pulse broadband is widened, the high-frequency component of the signal is seriously attenuated, and the like; and finally, synchronously measuring at continuous joints by utilizing distributed partial discharge synchronous detection, and accurately positioning the position of a discharge source according to the difference of the amplitude, the polarity and the arrival time of the same pulse signal coupled to the measurement position. Based on the above, the double-end partial discharge positioning adopts a pulse reflection principle, the high-frequency current sensors are respectively installed at the two ends of the cable, and when the far end detects a discharge pulse signal, the large-amplitude pulse generator is triggered to send out a pulse with a large amplitude, so that the cable defect can be accurately positioned according to the time difference between the original pulse and the large pulse signal.
In order to solve the problem that external background noise mainly comprises periodic interference signals, pulse interference signals and white noise interference signals, electromagnetic interference noise is mixed in discharge signals coupled by a high-frequency current sensor, and according to the characteristics of time domain waveforms, the anti-interference method for processing digital signals by high-frequency current comprises a cluster analysis method and a wavelet analysis method.
Furthermore, the wavelet transformation is based on the analysis means of non-stationary signals, has good localization property in time domain and frequency domain, and is suitable for the interference suppression measure of irregular and transient signal processing for high-frequency current partial discharge detection. And comparing the discharge signal with different defect discharge characteristic databases to identify the discharge signal pattern, including discharge signal measurement, discharge signal characteristic extraction and classification and characteristic fingerprint database comparison, and judging whether the measured signal is a real discharge signal and what kind of discharge.
Specifically, the wavelet analysis method is based on the analysis means of non-stationary signals, has good localization properties in a time domain and a frequency domain, and is suitable for processing irregular and transient signals and used in interference suppression measures of high-frequency current partial discharge detection; and classifying the discharge signals according to respective equivalent frequency, equivalent duration and waveform-related characteristic parameters by a clustering analysis method to form a time-frequency domain mapping spectrogram. The wavelet analysis method utilizes the shape characteristics of a phase statistical spectrogram and confirms and identifies the defect type by calculating characteristic parameters such as skewness, steepness, mutual correlation factors and the like of the statistical spectrogram; the time-frequency spectrogram in the cluster analysis method is characterized in that a plurality of discharge sources and partial discharge pulses of different discharge types can be mapped to different convergence points, so that real discharge and noise interference can be conveniently distinguished on a partial discharge phase spectrogram, and the calculation of amplitude, phase or frequency of coupled signals can be classified by utilizing three-phase synchronous partial discharge detection.
Secondly, operating a high-frequency current partial discharge sensor, collecting partial discharge signals by a high-frequency current Rogowski coil, adjusting and amplifying the signals collected by the sensor by an integral operational amplifier and a multi-stage analog amplification circuit, collecting the temperature and humidity of a partial discharge source by a temperature and humidity IC chip, detecting by a processor according to a set sampling period, uploading data, and transmitting the data to transmission and transformation node equipment through a wireless receiving and transmitting SX1268 chip;
specifically, the external integrating rogowski coil is called a narrow-band current sensor, and in order to obtain a current waveform, the output of the coil needs to pass through a passive external integrating circuit and an active external integrating circuit formed by an operational amplifier. The self-integrating rogowski coil is called a wide-band type current sensor, and has a relatively wide detection frequency band. Due to the fact that the integral resistor is directly adopted, the frequency response is fast, and the method is used for measuring the pulse current signal with short rising time. The detection frequency range of the Rogowski coil is 3-30 MHz, the measured partial discharge signal is a tiny high-frequency current signal, and the sensor needs to have higher sensitivity in a wider frequency band, so the HFCT selects a magnetic core with high magnetic conductivity as a coil framework and adopts a self-integrating coil structure. In practice, HFCT is required to have as high sensitivity as possible and a smooth amplitude-frequency response curve over a wide frequency band. And the HFCT is required to have stronger power frequency magnetic saturation resistance, because power frequency current inevitably flows during actual detection, the detection result is not influenced by magnetic core saturation. The grounding wire HFCT adopts a split type coil to be opened and closed, and is convenient to install and disassemble during testing. The lower limit cut-off frequency of the HFCT sensor is more than 1MHz, and the upper limit cut-off frequency is 30 MHz. The sensor output signal needs to be filtered and amplified. In actual measurement, various noises and interference signals exist, and a hardware filter and a digital filter are matched for filtering. The filtered signal amplitude is attenuated to a certain degree and needs to be amplified by a bandwidth amplifier, so that the purpose of improving the signal-to-noise ratio of the partial discharge signal is achieved, the partial discharge pulse signal amplified by filtering is subjected to detection processing, and the requirement on subsequent signal processing is reduced. The performance of the signal processing unit is mainly measured by upper and lower limit cut-off frequencies and amplification factors. The signal acquisition unit converts acquired analog signals into digital signals, and the main performance parameters are sampling rate, sampling resolution, bandwidth and storage depth. The sampling rate of the high-frequency current partial discharge sensor is several M/s to 100M/s, and the higher the sampling rate, the higher the high-frequency component of the partial discharge signal can be restored. The partial discharge data processing and analysis diagnosis comprises single-pulse time domain waveform, single-period (20 ms) time domain waveform, multi-period partial discharge spectrogram, PRPD spectrogram and partial discharge pulse frequency spectrum analysis, and realizes the functions of digital filtering, partial discharge type pattern recognition and partial discharge positioning.
And thirdly, transmitting the transmission and transformation node equipment, wherein the transmission and transformation node equipment is accessed into the terminal equipment through the Internet of things wireless networking protocol based on the acquired data, and the terminal equipment can visually present the acquired sensing data.
Specifically, the detected power equipment and the power equipment are connected with the internet of things of the power equipment, and the overall architecture of the internet of things of the power equipment is as follows: the system comprises an access layer sensor system, a node system, an edge computing system and a platform layer background access system. The sensing layer consists of sensors and node (including edge proxy) equipment, is a core level of an Internet of things architecture and is a key for realizing equipment state acquisition. The system covers various aspects of wireless communication, data transmission, sensors and the like, and is the basis for realizing interconnection of the Internet of things system. The node equipment transfers the data to the edge agent, the edge frame or the side APP converts the sensor data format into JSON format data meeting the requirement of the pipe platform, and then the MQTT protocol or the UDP protocol is adopted to realize the data interaction between the edge Internet of things agent and the background access system.
The state perception of the power transformation main equipment is realized in the embodiment. Uploading equipment operation information such as current and voltage and equipment abnormal alarm signals in the station, and monitoring sensors such as a high-frequency current partial discharge sensor, an ultrasonic partial discharge sensor, an SF6 micro-water sensor, a lightning arrester leakage current sensor, an SF6 micro-water sensor and a temperature sensor on line to realize the omnibearing real-time sensing of the state of the power transformation equipment. And sensing the state of the operating environment of the transformer substation. The temperature and humidity of the transformer substation, microclimate, noise, smoke, water level water logging of a cable trench, SF6 gas and other sensor data are collected and analyzed, the state sensing of the operation environment of the transformer substation is achieved, and the early warning of the safety operation risk in the transformer substation is timely pushed.
In particular, High Frequency Current (HFCT) measurement techniques are used to detect faults in partial discharges in electrical devices. The sensor magnetism is inhaled formula mounting means or is utilized the ribbon to fix main control unit, and magnetism is inhaled the formula and will be had the base of magnetic force and adsorb on the power equipment surface, presss from both sides high frequency current sensor on cable intermediate head, central line point wiring or terminal department earth connection, does not have any harm to high voltage power equipment, and all detections do not produce any influence to high voltage equipment's operation. Can carry out signal multicycle observation to measuring, carry out frequency identification to discharging to carry out the analysis through multiple mode, can clearly judge whether the cubical switchboard breaks down.
According to the invention, the power equipment Internet of things management and application platform is accessed through the APN security encryption channel, the high-frequency current partial discharge sensor senses visual data presentation, and the partial discharge monitoring, early warning, real-time data recording and comprehensive analysis of the operation condition are carried out, so that the safe operation of the power equipment is ensured, and the intelligent maintenance of the equipment is realized. The comprehensive online acquisition of power production site, operation and control data is realized, various intelligent applications are met through reliable and flexible network transmission, various power equipment forms a huge interconnected power wide area network, a panoramic holographic power internet of things which covers all links of power transmission, power transformation and power distribution and has unified information models, unified communication protocols, unified data services and unified application services is finally formed, the states of all links of a power grid can be measured, visualized and controllable, the operation and the maintenance of equipment on the power grid side to the prior diagnosis and the active early warning are realized, the technology of the internet of things is utilized, and the automatic switching of the power supply network is finally realized, so that the self-healing purpose is achieved.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. The utility model provides a become distribution high frequency current partial discharge sensor which characterized in that: the high-frequency current Rogowski coil is used for collecting partial discharge signals, the output end of the high-frequency current Rogowski coil is electrically connected with a high-frequency current detection circuit, an integral operational amplifier and a multi-stage analog amplification circuit are arranged in the high-frequency current detection circuit, and the output end of the high-frequency current detection circuit is connected with a processor; the intelligent power transmission and transformation system is characterized by further comprising a temperature and humidity IC chip, wherein the output end of the temperature and humidity IC chip is connected with the processor, the communication end of the processor is connected with the power transmission and transformation node equipment terminal through signals, and the processor supplies power through the power management circuit.
2. The variable distribution high-frequency current partial discharge sensor according to claim 1, wherein: the high-frequency current Rogowski coil adopts high-frequency current with the frequency of 3-30 MHz, the model of the temperature and humidity IC chip is SHT31, the temperature of the power equipment is monitored to be-40-80 ℃, and the humidity is 0-99% RH; the type of the integral operational amplifier is AD8032, and the multistage analog amplification circuit adopts an amplifier with the type of OPA 379; the processor adopts the model ARM Cortex-M4, detects according to the set sampling period, and uploads data including high-frequency current HFCT signals and the temperature and humidity of the operating environment.
3. The variable distribution high-frequency current partial discharge sensor according to claim 1, wherein: the variable distribution high-frequency current partial discharge sensor and the power transmission and transformation node equipment are transmitted by adopting a 470MHz LoRa wireless communication technology, and data are transmitted to the power transmission and transformation node equipment terminal through a wireless receiving and transmitting SX1268 chip.
4. The variable distribution high-frequency current partial discharge sensor according to claim 1, characterized in that: the power management circuit is powered by an industrial-grade lithium sub-battery and is provided with a battery power detection AD sampling processing circuit.
5. The variable distribution high-frequency current partial discharge sensor according to claim 1, wherein: the transformer and distribution high-frequency current partial discharge sensor adopts an integrally formed packaging cast aluminum shell, and the bottom of the shell is provided with a magnetic suction block.
6. A variable distribution high frequency current partial discharge sensor according to claim 3, wherein: the LoRa wireless communication technology is connected with the power transmission and transformation node equipment through a power transmission and transformation equipment Internet of things wireless networking protocol; and the LoRa wireless communication technology adopts an edge computing frame and carries partial discharge diagnosis APP.
7. A method for a variable distribution high frequency current partial discharge sensor according to any one of claims 1 to 6, characterized in that: the method specifically comprises the following steps:
step one, assembling and distributing a network of distributed high-frequency current partial discharge sensors, positioning and installing each high-frequency current sensor on a partial discharge source through a magnetic block at the bottom of the high-frequency current sensor, and simultaneously accessing each high-frequency current sensor to a power transmission and transformation node equipment terminal through LoRa wireless communication and a power transmission and transformation equipment Internet of things wireless networking protocol for debugging;
secondly, operating a high-frequency current partial discharge sensor, collecting partial discharge signals by a high-frequency current Rogowski coil, adjusting and amplifying the signals collected by the sensor by an integral operational amplifier and a multi-stage analog amplification circuit, collecting the temperature and humidity of a partial discharge source by a temperature and humidity IC chip, detecting by a processor according to a set sampling period, uploading data, and transmitting the data to transmission and transformation node equipment through a wireless receiving and transmitting SX1268 chip;
and thirdly, transmitting the transmission and transformation node equipment, wherein the transmission and transformation node equipment is accessed into the terminal equipment through the Internet of things wireless networking protocol based on the acquired data, and the terminal equipment can visually present the acquired sensing data.
8. The method of claim 7, wherein the method comprises the following steps: the method comprises the following steps that firstly, partial discharge signals are detected at a cable terminal and each joint by using a high-frequency current partial discharge sensor, and the discharge source is initially positioned by comparing and analyzing time domain and frequency domain characteristics of the discharge signals at different sensor positions; then, the position of a discharge source is preliminarily judged by utilizing the principle that a discharge pulse signal is transmitted and attenuated in a cable, the amplitude of the discharge signal is reduced along with the propagation of the discharge signal, the rise time is reduced, the pulse broadband is widened, the high-frequency component of the signal is seriously attenuated, and the like; and finally, synchronously measuring at continuous joints by utilizing distributed partial discharge synchronous detection, and accurately positioning the position of a discharge source according to the difference of the amplitude, the polarity and the arrival time of the same pulse signal coupled to the measurement position.
9. The method for the variable distribution high-frequency current partial discharge sensor according to claim 7, wherein: and in the second step, the discharge signal coupled with the high-frequency current sensor is mixed with electromagnetic interference noise, and the anti-interference method for processing the digital signal by the high-frequency current comprises a cluster analysis method and a wavelet analysis method according to the time domain waveform characteristics.
10. The method of claim 9, wherein the method comprises the following steps: the wavelet analysis method is based on the analysis means of non-stationary signals, has good localization property in time domain and frequency domain, and is suitable for the interference suppression measures of irregular and transient signal processing and high-frequency current partial discharge detection; the clustering analysis method classifies the discharge signals according to respective equivalent frequency, equivalent duration and waveform-related characteristic parameters to form a time-frequency domain mapping spectrogram.
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