To overcome the disadvantages of conventional DGA (dissolved gas-in-oil)analysis using gas chromatography and other electrochemical sensors, initial researches werecompleted to realize on-line monitoring of dissolved ...To overcome the disadvantages of conventional DGA (dissolved gas-in-oil)analysis using gas chromatography and other electrochemical sensors, initial researches werecompleted to realize on-line monitoring of dissolved gas-in-oil of power transformers using FTIR(Fourier Transform InfraRed) spectroscopy. Gas cell method is used to determine the characteristicabsorption peaks of each diagnostic gas; simple and novel devices and procedures were designed inorder to get measurable samples and spectra of mixed diagnostic gases with known concentration aretaken using long optical path gas cell. The range of wavelength is estimated to be 3.0-13.9 mum fromexperimental spectra data. Hence the corresponding sampling frequency range should be in 536-4288Hz and usable optical materials are suggested. It is concluded that a resolution of 10 cm^(-1) maywell satisfy the monitoring of all diagnostic gases and water content except hydrogen, and thelowest detection limit may be as low as 2Xl0^(-8) to acetylene with a 2.4-meter-long optical length.展开更多
On-line measurement for dielectric loss angle can effectively monitor the insulation condition of capacitive equipment in power systems. Synthetic relative measuring methods not only markedly overcome the shortcomings...On-line measurement for dielectric loss angle can effectively monitor the insulation condition of capacitive equipment in power systems. Synthetic relative measuring methods not only markedly overcome the shortcomings of traditional absolute measuring methods but also greatly improve the accuracy of dielectric loss angle measurement. However, synthetic relative measuring methods based on two or three pieces of capacitive equipment do not have the characteristic of generality. In this paper, a principle of synthetic relative measuring method is presented. The example of application for synthetic relative methods based on three and four pieces of capacitive equipment running in the same phase is taken to present the failure judgment matrices for N pieces of equipment. According to these matrices, the fault condition of N pieces of capacitive equipment can be watched, which is more general. Then some problems needing to be concerned along with two diagnostic methods used in diagnostic system are introduced. Finally, two programmable flow charts for the two methods are given and corresponding examples demonstrate their feasibility in practice.展开更多
At present the detecting of ultra high voltage direct current (UHVDC) earth electrode frequently uses manual inspection. This method can't get the real-time operational data of the earth electrodes, and meanwhile,...At present the detecting of ultra high voltage direct current (UHVDC) earth electrode frequently uses manual inspection. This method can't get the real-time operational data of the earth electrodes, and meanwhile, the labor cost is very high. In order to satisfy the security needs of UHVDC, this paper designs an on-line monitoring system for UHVDC earth electrode. By 3G wireless communication-technologies, the system can monitor remotely many kinds of data such as the value of the grounding current, water level of the observation well, soil temperature and humidity near the earth electrode, the micro-climate around the earth electrode site, video data, etc. Through analyzing the datum, the system has broad prospect on fault detection and life evaluation of the UHVDC earth electrode.展开更多
Because the melting point of the alkalis is very high and the metal activity is strong, the common pressure sensor can't be used to measure pressure of liquid metal. In this paper, a differential transformer differen...Because the melting point of the alkalis is very high and the metal activity is strong, the common pressure sensor can't be used to measure pressure of liquid metal. In this paper, a differential transformer differential pressure sensor for measuring liquid alkalis pressure is designed, the working principle and specific design plan of the sensor are introduced, the standard current signal ( 4 -20 mA) or digital communication RS485 can be output according to the needs, and the functions of remote monitoring and data optimization can be realized through the LAN interface.展开更多
The characteristics and distribution law of electromagnetic environment around substations with different levels of voltage were studied,and the main influencing factors were discussed. Meanwhile,a scheme for locating...The characteristics and distribution law of electromagnetic environment around substations with different levels of voltage were studied,and the main influencing factors were discussed. Meanwhile,a scheme for locating monitoring points suitable for an on-line monitoring system of electromagnetic environment was proposed.展开更多
Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are suscept...Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are susceptible to external interferences and, thus, cannot meet the increasingly strict monitoring needs of a complex air-conducting pipeline system of an aircraft. In view of this point, this paper studies an alternative sensor system based on a dense array fiber grating. To obtain a compact and light-weight airborne signal processing system, a field programmable gate array is used as the main control core that controls the output of the light source. The functions of pulse modulation, analog-to-digital conversion,data buffering and transmission are integrated into a single system, while the linear sensing monitoring is obtained by detecting the time-division and wavelength-division wavelength drift signals of the fiber Bragg grating array. Our experiments show that the spatial resolution of the linear sensing system approaches 5 cm, the temperature measurement accuracy reaches 2 ℃, the temperature measurement range is between 0–250 ℃, and the response time is within 4 s. Compared with the existing electrical monitoring systems, various monitoring indicators have been greatly improved and have broad application prospects.展开更多
Discusses on-line monitoring of electric parameters, such as dielectric loss, divulging current, equivalent capacitance and running voltage, and presents an on-line monitoring system of insulation quality, based on mo...Discusses on-line monitoring of electric parameters, such as dielectric loss, divulging current, equivalent capacitance and running voltage, and presents an on-line monitoring system of insulation quality, based on monitoring divulging current and dielectric loss of high voltage equipment, and its advantages, such as helping people to discover the hidden problems in a timely manner, to reduce power cut and overhaul and to improve security of power supply.展开更多
An on-line monitoring system for partial discharge from high voltage transformer is presented with structure of hardware and principle of software discussed and a new effective method combining DFT with DWT is propose...An on-line monitoring system for partial discharge from high voltage transformer is presented with structure of hardware and principle of software discussed and a new effective method combining DFT with DWT is proposed to get rid of both sinusoidal continuous noise and other external discharges.展开更多
Based on the collection of relevant literature and cases,the research and application status of on-line monitoring technology for electromagnetic environment of power transmission and transformation projects at home a...Based on the collection of relevant literature and cases,the research and application status of on-line monitoring technology for electromagnetic environment of power transmission and transformation projects at home and abroad were introduced.Moreover,the problems existing in the on-line monitoring of electromagnetic environment were expounded,and the development prospect was forecasted.展开更多
This study presented an insulation state monitoring method for large generator based on radio frequency (RF) technique. As an on-line condition monitor and the precondition of condition-based maintenance (CBM), the RF...This study presented an insulation state monitoring method for large generator based on radio frequency (RF) technique. As an on-line condition monitor and the precondition of condition-based maintenance (CBM), the RF monitor used the high frequency current mutual inductor to detect the partial discharge signal from neutral wire of stator windings. According to the magnitude of indicative value of RF monitor, a five phase model was also proposed to manage the generator’s running better. The practices show that the proposed method is effective.展开更多
At present, the on-line monitoring is widely applied to the power line monitoring. In this paper, a new mechanical calculation model is established according to the on-line monitoring. And this model is based on the p...At present, the on-line monitoring is widely applied to the power line monitoring. In this paper, a new mechanical calculation model is established according to the on-line monitoring. And this model is based on the parameters that tension sensors and angle sensors on suspended points detect, and combines with the parameters of the wire itself, and also considers the deflection angel of wires due to wind. In this model, mechanics parameters of wires are turned into the new coordinate plane after deflection angel of wires due to wind, or windage yaw plane. A statics tension balance equation is built in the vertical direction of the new windage yaw plane. According to the theoretical analysis and algorithm, we verify the accuracy of this newly developed mechanical calculation model.展开更多
This paper uses CT to gain the energy directly from the high-voltage transmission line, to address the problem of power supply for monitoring system in high voltage side of transmission line. The draw-out power coil c...This paper uses CT to gain the energy directly from the high-voltage transmission line, to address the problem of power supply for monitoring system in high voltage side of transmission line. The draw-out power coil can induce voltage from the transmission line, using single-chip microcomputer to analog and output PMW wave to control the charging module, provides a stable 3.4 V DC voltage to the load, and solve the problem of easy saturating of core. The power supply based on this kind of draw-out power coil has undergone the overall testing, and it is verified-showing that it can properly work in a non-saturated status within the current range of 50 - 1000 A, and provide a stable output. The equipment also design protection circuit to improve the reliability to avid the impacts of the impulse current or short-circuit current. It effectively solves the problem of power supply for On-line Monitoring System of Transmission.展开更多
Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China,and its components,which include ultrafine particles(UFPs),volatile organic compounds(VOCs),and other reactive gases,su...Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China,and its components,which include ultrafine particles(UFPs),volatile organic compounds(VOCs),and other reactive gases,such as NH3and NOx,are the most harmful to human health.China has released various regulations and standards to address pollution from mobile and stationary sources.Thus,it is urgent to develop online monitoring technology for atmospheric pollution source emissions.This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years.These instruments have been applied to monitor emissions from motor vehicles,ships,airports,the chemical industry,and electric power generation.Not only has the level of atmospheric environment monitoring technology and equipment been improving,but relevant regulations and standards have also been constantly updated.Meanwhile,the developed instruments can provide scientific assistance for the successful implementation of regulations.According to the potential problem areas in atmospheric pollution in China,some research hotspots and future trends of atmospheric online monitoring technology are summarized.Furthermore,more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.展开更多
Real-time and on-line monitoring volatile organic compounds(VOCs) are valuable for real-time evalua- ting air quality and monitoring the key source of pollution. A self-developed proton transfer reaction-mass spectr...Real-time and on-line monitoring volatile organic compounds(VOCs) are valuable for real-time evalua- ting air quality and monitoring the key source of pollution. A self-developed proton transfer reaction-mass spectro- meter(PTR-MS) was constructed and applied to on-line monitoring trace VOCs in ambient air in Hefei, China. With the help of a self-developed catalytic converter, the background signal of the instrument was detected and the stability of the instrument was evaluated. The relative standard deviation of signal at m/z 21 was only 0.74% and the detection limit of PTR-MS was 97 part per trillion(97x 10-12, volume ratio). As a case of the air monitoring in Hefei, the am- bient air at Dongpu reservoir spot was on-line monitored for 13 d with our self-developed PTR-MS. Meanwhile, a solid-phase micro-extraction(SPME) technique coupled to gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) was also used for the off-line detection of the air. The results show that our self-developed PTR-MS can be used for the on-line and long-term monitoring of VOCs in air at part per trillion level, and the change trend of VOCs concentration monitored with PTR-MS was consistent with that detected with the conventional SPME-GC-MS. This self-developed PTR-MS can fully satisfy the requirements of air quality monitoring and real-time monitoring of the key pollution sources.展开更多
The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has b...The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has been considered for this purpose,its monitoring accuracy is relatively low.Moreover,the influence of background noise on the dynamic monitoring accuracy of GNSS-PPP remains unclear.Hence,it is imperative to further validate the feasibility of GNSS-PPP for deformation monitoring of offshore platforms.To address these concerns,vibration table tests with different amplitudes and frequencies are conducted.The results demonstrate that GNSS-PPP can effectively monitor horizontal vibration displacement as low as±30 mm,which is consistent with GNSS-RTK.Furthermore,the spectral characteristic of background noise in GNSS-PPP is similar to that of GNSS-RTK(Real Time Kinematic).Building on this observation,an improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)has been proposed to de-noise the data and enhance the dynamic monitoring accuracy of GNSS-PPP.Field monitoring application research is also undertaken,successfully extracting and analyzing the dynamic deformation of an offshore platform structure under environmental excitation using GNSS-PPP monitoring in conjunction with improved CEEMDAN de-noising.By comparing the de-noised dynamic deformation trajectories of the offshore platform during different periods,it is observed that the platform exhibits reversible alternating vibration responses under environmental excitation,with more pronounced displacement deformation in the direction of load action.The research results confirm the feasibility and potential of GNSS-PPP for dynamic deformation monitoring of offshore platforms.展开更多
文摘To overcome the disadvantages of conventional DGA (dissolved gas-in-oil)analysis using gas chromatography and other electrochemical sensors, initial researches werecompleted to realize on-line monitoring of dissolved gas-in-oil of power transformers using FTIR(Fourier Transform InfraRed) spectroscopy. Gas cell method is used to determine the characteristicabsorption peaks of each diagnostic gas; simple and novel devices and procedures were designed inorder to get measurable samples and spectra of mixed diagnostic gases with known concentration aretaken using long optical path gas cell. The range of wavelength is estimated to be 3.0-13.9 mum fromexperimental spectra data. Hence the corresponding sampling frequency range should be in 536-4288Hz and usable optical materials are suggested. It is concluded that a resolution of 10 cm^(-1) maywell satisfy the monitoring of all diagnostic gases and water content except hydrogen, and thelowest detection limit may be as low as 2Xl0^(-8) to acetylene with a 2.4-meter-long optical length.
文摘On-line measurement for dielectric loss angle can effectively monitor the insulation condition of capacitive equipment in power systems. Synthetic relative measuring methods not only markedly overcome the shortcomings of traditional absolute measuring methods but also greatly improve the accuracy of dielectric loss angle measurement. However, synthetic relative measuring methods based on two or three pieces of capacitive equipment do not have the characteristic of generality. In this paper, a principle of synthetic relative measuring method is presented. The example of application for synthetic relative methods based on three and four pieces of capacitive equipment running in the same phase is taken to present the failure judgment matrices for N pieces of equipment. According to these matrices, the fault condition of N pieces of capacitive equipment can be watched, which is more general. Then some problems needing to be concerned along with two diagnostic methods used in diagnostic system are introduced. Finally, two programmable flow charts for the two methods are given and corresponding examples demonstrate their feasibility in practice.
文摘At present the detecting of ultra high voltage direct current (UHVDC) earth electrode frequently uses manual inspection. This method can't get the real-time operational data of the earth electrodes, and meanwhile, the labor cost is very high. In order to satisfy the security needs of UHVDC, this paper designs an on-line monitoring system for UHVDC earth electrode. By 3G wireless communication-technologies, the system can monitor remotely many kinds of data such as the value of the grounding current, water level of the observation well, soil temperature and humidity near the earth electrode, the micro-climate around the earth electrode site, video data, etc. Through analyzing the datum, the system has broad prospect on fault detection and life evaluation of the UHVDC earth electrode.
文摘Because the melting point of the alkalis is very high and the metal activity is strong, the common pressure sensor can't be used to measure pressure of liquid metal. In this paper, a differential transformer differential pressure sensor for measuring liquid alkalis pressure is designed, the working principle and specific design plan of the sensor are introduced, the standard current signal ( 4 -20 mA) or digital communication RS485 can be output according to the needs, and the functions of remote monitoring and data optimization can be realized through the LAN interface.
基金Supported by the Open Project of Jiangsu Key Laboratory of Environmental Engineering(ZX2017005)
文摘The characteristics and distribution law of electromagnetic environment around substations with different levels of voltage were studied,and the main influencing factors were discussed. Meanwhile,a scheme for locating monitoring points suitable for an on-line monitoring system of electromagnetic environment was proposed.
文摘Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are susceptible to external interferences and, thus, cannot meet the increasingly strict monitoring needs of a complex air-conducting pipeline system of an aircraft. In view of this point, this paper studies an alternative sensor system based on a dense array fiber grating. To obtain a compact and light-weight airborne signal processing system, a field programmable gate array is used as the main control core that controls the output of the light source. The functions of pulse modulation, analog-to-digital conversion,data buffering and transmission are integrated into a single system, while the linear sensing monitoring is obtained by detecting the time-division and wavelength-division wavelength drift signals of the fiber Bragg grating array. Our experiments show that the spatial resolution of the linear sensing system approaches 5 cm, the temperature measurement accuracy reaches 2 ℃, the temperature measurement range is between 0–250 ℃, and the response time is within 4 s. Compared with the existing electrical monitoring systems, various monitoring indicators have been greatly improved and have broad application prospects.
文摘Discusses on-line monitoring of electric parameters, such as dielectric loss, divulging current, equivalent capacitance and running voltage, and presents an on-line monitoring system of insulation quality, based on monitoring divulging current and dielectric loss of high voltage equipment, and its advantages, such as helping people to discover the hidden problems in a timely manner, to reduce power cut and overhaul and to improve security of power supply.
文摘An on-line monitoring system for partial discharge from high voltage transformer is presented with structure of hardware and principle of software discussed and a new effective method combining DFT with DWT is proposed to get rid of both sinusoidal continuous noise and other external discharges.
基金Supported by the Open Project of Jiangsu Key Laboratory of Environmental Engineering(ZX2017005)
文摘Based on the collection of relevant literature and cases,the research and application status of on-line monitoring technology for electromagnetic environment of power transmission and transformation projects at home and abroad were introduced.Moreover,the problems existing in the on-line monitoring of electromagnetic environment were expounded,and the development prospect was forecasted.
文摘This study presented an insulation state monitoring method for large generator based on radio frequency (RF) technique. As an on-line condition monitor and the precondition of condition-based maintenance (CBM), the RF monitor used the high frequency current mutual inductor to detect the partial discharge signal from neutral wire of stator windings. According to the magnitude of indicative value of RF monitor, a five phase model was also proposed to manage the generator’s running better. The practices show that the proposed method is effective.
文摘At present, the on-line monitoring is widely applied to the power line monitoring. In this paper, a new mechanical calculation model is established according to the on-line monitoring. And this model is based on the parameters that tension sensors and angle sensors on suspended points detect, and combines with the parameters of the wire itself, and also considers the deflection angel of wires due to wind. In this model, mechanics parameters of wires are turned into the new coordinate plane after deflection angel of wires due to wind, or windage yaw plane. A statics tension balance equation is built in the vertical direction of the new windage yaw plane. According to the theoretical analysis and algorithm, we verify the accuracy of this newly developed mechanical calculation model.
文摘This paper uses CT to gain the energy directly from the high-voltage transmission line, to address the problem of power supply for monitoring system in high voltage side of transmission line. The draw-out power coil can induce voltage from the transmission line, using single-chip microcomputer to analog and output PMW wave to control the charging module, provides a stable 3.4 V DC voltage to the load, and solve the problem of easy saturating of core. The power supply based on this kind of draw-out power coil has undergone the overall testing, and it is verified-showing that it can properly work in a non-saturated status within the current range of 50 - 1000 A, and provide a stable output. The equipment also design protection circuit to improve the reliability to avid the impacts of the impulse current or short-circuit current. It effectively solves the problem of power supply for On-line Monitoring System of Transmission.
基金the framework of the China-Greece joint research andtechnology programmes 2000-2002(Project title:‘Investigation on the characteristics of forest fires in the early stage andits control technique National Natural Science Foundation of China under Grants 50346038 , 50320120156,the China NK-BRSF project(No.2001CB409600)the Anhui Ex-cellent Youth Scientist Fundation(2001-2002),and the National Key Technologies R&D Programme(2001BA510B09-03).
基金supported by the National Key Research and Development Program of China(Nos.2016YFC0201000 and 2016YFC0201100)the Plan for Anhui Major Provincial Science&Technology Project(Nos.202203a07020004 and 202003a07020005)+1 种基金the National Natural Science Foundation of China(Nos.U2133212 and 42005108)the Science and Technological Fund of Anhui Province for Outstanding Youth(No.1808085J19)。
文摘Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China,and its components,which include ultrafine particles(UFPs),volatile organic compounds(VOCs),and other reactive gases,such as NH3and NOx,are the most harmful to human health.China has released various regulations and standards to address pollution from mobile and stationary sources.Thus,it is urgent to develop online monitoring technology for atmospheric pollution source emissions.This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years.These instruments have been applied to monitor emissions from motor vehicles,ships,airports,the chemical industry,and electric power generation.Not only has the level of atmospheric environment monitoring technology and equipment been improving,but relevant regulations and standards have also been constantly updated.Meanwhile,the developed instruments can provide scientific assistance for the successful implementation of regulations.According to the potential problem areas in atmospheric pollution in China,some research hotspots and future trends of atmospheric online monitoring technology are summarized.Furthermore,more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.
基金Supported by the National Natural Science Foundation of China(Nos.21477132, 21577145), the National Key Technology Research and Development Program of China(No.2015BAI01B04), the National Key Research Program of China (No.2016YFC0200200), the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology of China(No.2014FXCX007) and the Functional Development Program of Instrument and Equipment in Chinese Academy of Sciences.
文摘Real-time and on-line monitoring volatile organic compounds(VOCs) are valuable for real-time evalua- ting air quality and monitoring the key source of pollution. A self-developed proton transfer reaction-mass spectro- meter(PTR-MS) was constructed and applied to on-line monitoring trace VOCs in ambient air in Hefei, China. With the help of a self-developed catalytic converter, the background signal of the instrument was detected and the stability of the instrument was evaluated. The relative standard deviation of signal at m/z 21 was only 0.74% and the detection limit of PTR-MS was 97 part per trillion(97x 10-12, volume ratio). As a case of the air monitoring in Hefei, the am- bient air at Dongpu reservoir spot was on-line monitored for 13 d with our self-developed PTR-MS. Meanwhile, a solid-phase micro-extraction(SPME) technique coupled to gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) was also used for the off-line detection of the air. The results show that our self-developed PTR-MS can be used for the on-line and long-term monitoring of VOCs in air at part per trillion level, and the change trend of VOCs concentration monitored with PTR-MS was consistent with that detected with the conventional SPME-GC-MS. This self-developed PTR-MS can fully satisfy the requirements of air quality monitoring and real-time monitoring of the key pollution sources.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFB4200705)the National Natural Science Foundation of China(Grant No.52109146)。
文摘The real-time dynamic deformation monitoring of offshore platforms under environmental excitation is crucial to their safe operation.Although Global Navigation Satellite System-Precise Point Positioning(GNSS-PPP)has been considered for this purpose,its monitoring accuracy is relatively low.Moreover,the influence of background noise on the dynamic monitoring accuracy of GNSS-PPP remains unclear.Hence,it is imperative to further validate the feasibility of GNSS-PPP for deformation monitoring of offshore platforms.To address these concerns,vibration table tests with different amplitudes and frequencies are conducted.The results demonstrate that GNSS-PPP can effectively monitor horizontal vibration displacement as low as±30 mm,which is consistent with GNSS-RTK.Furthermore,the spectral characteristic of background noise in GNSS-PPP is similar to that of GNSS-RTK(Real Time Kinematic).Building on this observation,an improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)has been proposed to de-noise the data and enhance the dynamic monitoring accuracy of GNSS-PPP.Field monitoring application research is also undertaken,successfully extracting and analyzing the dynamic deformation of an offshore platform structure under environmental excitation using GNSS-PPP monitoring in conjunction with improved CEEMDAN de-noising.By comparing the de-noised dynamic deformation trajectories of the offshore platform during different periods,it is observed that the platform exhibits reversible alternating vibration responses under environmental excitation,with more pronounced displacement deformation in the direction of load action.The research results confirm the feasibility and potential of GNSS-PPP for dynamic deformation monitoring of offshore platforms.