Online Temperature Monitoring System Research Articles

Simulation and on-line monitoring using optical fiber Bragg grating sensors of temperature history during laser-assisted automated fiber placement

Automated fiber placement (AFP) in situ consolidation (ISC) of thermoplastic composite possess the potential to reduce manufacturing costs and improve manufacturing efficiency. The properties of composite manufactured by the ISC are affected by several mechanisms including polymer degradation, crystallization, intimate contact, polymer healing and void dynamics. All these mechanisms are directly affected by the temperature history. Consequently, the control and accurate measurement of temperature history during ISC are particularly important for improving the properties of composite. In this study, a simplified three-dimensional transient heat transfer model was established. The effect of tool temperature and placement speed on the temperature history and peak temperature were predicted. Simultaneously, an online temperature monitoring system was built and the optical Fiber Bragg Grating sensors (FBGS) was used to measure the temperature history. The results indicated that the predicted results of the model were consistent with the measured results, the error was below 8%. In addition, the temperature history of layers was significantly affected by the tool temperature and placement speed. The temperature of the layers decreased to near the tool temperature after cooling, and a higher tool temperature increasing its peak temperature because of the reduce of the cooling rate. On the contrary, an increase in placement speed will reduce the peak temperature of the layers.

Retracted: On-Line Temperature Monitoring System of Electrical Equipment Based on Passive Wireless Sensor

Retracted: On-Line Temperature Monitoring System of Electrical Equipment Based on Passive Wireless Sensor

Prediction model of transformer top oil temperature based on data quality enhancement.

Top oil temperature (TOT) is an important parameter to evaluate the running state of a transformer. According to the variation trend of TOT, the internal thermal state of transformers can be predicted so as to arrange operation and maintenance reasonably and prevent the occurrence of accidents. However, due to the complex working environment in the field, there are often a large number of missing values in online monitoring data, which seriously affects the prediction of TOT. At the same time, it is affected by various factors such as load, ambient temperature, wind speed, and solar radiation, which cause the information of different time scales to be mixed in its monitoring data. Therefore, it is difficult to achieve the desired accuracy with a single model. In this article, a model for predicting TOT based on data quality enhancement is proposed. First, the Markov model is used to complete the online monitoring data containing missing values to obtain a complete and continuous time series. Then, using the ensemble empirical modal decomposition method, the time series of TOT is decomposed into multiple time series components to eliminate the interaction between different time scales of information, thus reducing the prediction difficulty. Finally, the sub-prediction model of the extreme learning machine is constructed, and the prediction results of all the sub-models are reconstructed to obtain the final prediction results of TOT. In order to verify the effectiveness of the model, the TOT of an operating transformer for the next two days is predicted in the article, and its mean absolute percentage error (MAPE) is 5.27% and its root mean square error (RMSE) is 2.46. Compared with the BP neural network model and the support vector machines (SVM) model, the MAPE is reduced by 69.56% and 61.92%, respectively, and the RMSE is reduced by 67.02% and 59.87%. The results of this study will provide important support for the fault diagnosis of the top oil temperature online monitoring system.

Evolution of thermal cracking, temperature distribution and deformation at mineral scale of Beishan granite during heating and cooling

Thermo-mechanical property of rock is of great importance for the long-term safety of the high-level radioactive waste (HLW) geological disposal engineering. Thermal cracking, temperature and meso-deformation on the mineral grain size scale of Beishan granite were investigated during heating (160 °C ∼ 200 °C) and cooling process using online temperature, deformation and acoustic emission monitoring system. During the heating process, the temperature difference in different mineral grain was evident that the highest temperature was observed in feldspar while lower temperature in quartz and mica, and the temperature difference reached 20%. Meanwhile the feldspar expanded as the quartz and mica being compressed during heating. During the temperature holding and cooling process, the temperature difference between different mineral grain reduced and stabilized around 5%. The thermal induced expansion was recovered gradually but irreversible deformation was left, which also demonstrated by the nuclear magnetic resonance measurement that size and volume of large pore in granite both decreased after heated. The thermal cracking emerged from 25 °C ∼ 35 °C, and the thermal cracking activity was active once temperature changed during heating and cooling stage, which was calm during temperature holding stage. In addition, the cracking process was investigated by numerical modelling. The ‘confining pressure effect’ was observed during heating process, and the mechanism of thermal strengthening effect was discussed. Overall, the mild high temperature caused by decay heat of HLW could play positive role for the long-term safety of the repository, since the tightness and strength could be both enhanced by mild high temperature.

Application of Passive Wireless Temperature Online Monitoring System Based on Internet of Things Technology in Substation

With the improvement of the automation level of the power system, the number of operation and maintenance personnel continues to decrease, but the use of switchgear is quite large. Since the switchgear is a metal armoured device with a closed shell, the hot spots inside the switchgear cannot be detected in time during operation. Effective temperature measurement and the safety of equipment cannot be effectively guaranteed. In order to avoid the aging caused by the excessive current load of the switch cabinet, poor contact of cable joints and contacts, or long-term operation, which will cause heat in the place, forming a vicious circle and eventually leading to insulation breakdown or fire accidents, Establish a wireless temperature measurement system for switch cabinets to monitor the temperature of the parts where the equipment is prone to overheat, and issue an alarm message when the temperature rises abnormally. At present, the manual inspection of switch cabinets in the power supply system cannot effectively and timely detect fire hazards, so the problem of online monitoring of switch cabinet temperature is particularly prominent. Using the Internet of Things sensing technology and communication technology, build an Internet of Things-based electrical connection point temperature online monitoring system, the all-weather real-time monitoring of the connection parts of high-voltage electrical equipment can effectively reduce the equipment failure rate, promote the condition maintenance of power equipment, and ensure the safe and economical operation of the power system.

On-Line Temperature Monitoring System of Electrical Equipment Based on Passive Wireless Sensor

In order to solve the temperature measurement problem of fully enclosed equipment for power equipment operation inspection, the authors propose an online temperature monitoring system for electrical equipment based on passive wireless sensors. Aiming at the disadvantages of traditional temperature monitoring methods, the system adopts radio frequency technology. The scheme mainly expounds the key technologies and switchgear implementation in the monitoring system research and discusses the feasibility of the system scheme through experiments. Monitor all important components at different times, and establish a temperature monitoring network to complete monitoring and management. According to the test results, in the case of overheating, the temperature can rise to more than 75°C, and the temperature difference measured wirelessly is 0.5°C, which is sufficient to indicate the health of the change. Electrical equipment, the accuracy, and real-time performance of temperature monitoring are guaranteed.

Morphological and heat transfer characteristics of biomass briquette during steam gasification process

The morphological evolution and heat transfer characteristics of biomass briquette greatly affect the directional regulation of target products during steam gasification process. In this work, a visual gasifier with an on-line temperature monitoring system was developed to investigate the coupling relationship between the morphological change and temperature distribution of biomass briquette. The gasification behaviors of biomass briquette at different temperatures and steam concentrations were comprehensively examined and compared. The shrinkage rate and heating rate of biomass briquette both reached the maximum at 1–2 min. The morphological evolution of biomass briquette in the heating process was shrinking particle mode, then changed to the shrinking core mode when the biomass temperature kept relatively stable. The high-quality syngas with a high H2/CO ratio of 3.07 at 50 vol% steam concentration and 700 °C was obtained, which were idealized to synthesize other fuels/chemicals.

Research on Operation Management Technology of Cable Joints of Ring Network Cabinet Based on Temperature Sensors

In this paper, aiming at the operation and maintenance of the internal cable joints of the ring main unit, the research on the operation and management technology of the ring main unit cable joints based on temperature sensors is carried out. Starting from the principle of temperature sensing technology for cable joints, an online temperature monitoring system for the cable joints of the ring network cabinet is developed during the operating cycle. Comprehensive consideration of factors such as seasons, ambient temperature and humidity, line load current, etc., to evaluate the operating status of the cable joint temperature data as the main basis. A simple and adjustable bracket suitable for the fixed installation of the non-contact temperature sensor of the ring main unit has been developed. A method of managing the cable joints of the ring main unit during the operating cycle is proposed to realize the effective evaluation of the cable joint status. It can greatly improve the accuracy of condition monitoring, and improve the efficiency and level of operation and maintenance.

Online monitoring and analysis of TBM cutter temperature: A case study in China

Excessive cutter temperature during TBM tunnelling may cause severe cutter wear, mud cake formation, or even blockage of the cutterhead. It will increase construction costs and safety risks. Therefore, in this study, based on the PT100 temperature sensor and wireless transmission technology, a set of cutter temperature online monitoring system has been developed and applied to an TBM construction in-site. Statistical analysis of the in-site temperature data shows that: (1) During excavation, the cutter temperature range was about 13–25 ℃. (2) When penetration is less than 32.4 mm/r, the relative temperature change (ΔT) will increase as the installation radius increases. On the contrary, as the installation radius increases, the ΔT decreases first, then increases. (3) The ΔT is affected by the flow velocity of sludge (PTR). When PTR decreases, if the heat lost by the sludge is higher than the heat generated by the penetration, the ΔT will decrease.

Three-level modified sine wave inverter equipped with online temperature monitoring system

Research and development on power converters are getting more interesting in recent years. It is also buttressed by rapid development in related fields, such as power semiconductor, digital advanced control, magnetic material and use of power converters in many sectors. In addition to the power quality matter, simplicity of inverter circuits is another notable aspect that should be considered toward economical feature. Adding the quantity of power switches will increase complexity of overall inverter circuits. This paper discusses a circuit configuration of three-level modified sine wave neutral point shorted power inverter which work converting dc power into ac power with less number of power switches. To improve the performance and feature of inverter circuits, the inverter was equipped with online temperature monitoring, and overheat protection based on internet of things. Adding online temperature monitoring system makes easier in monitoring of circuits to prevent the excessive faults of inverter. Some computer based test data are shown and discussed. Furthermore, experiment results of the inverter prototype, and its online monitoring system are presented. Test outputs demonstrated that the proposed system worked properly generating a three-level modified sine wave voltage, with online temperature monitoring system.

Hydrodynamic Snaring Array for Trapping and Perfusion Culture of Single Cell

A hydrodynamic snare and well array were developed to accomplish single-cell trapping and stem-cell perfusion culture. Directed streamline distribution is induced using unique V-shaped weir to load single bone marrow stem cell into U-shaped dwelling weir. The voids decrease flow speed in the dwelling area and enable a stable perfusion culture. The hydrodynamic snaring array was integrated with an on-line temperature control and monitoring system, and the ultraviolet illumination effect on a microscope is eliminated that is suitable for the long-term growth of single bone marrow stem cell with minimal external interventions.

Three Dimensional Study of Eddy Current Field and Temperature Field of 126kV three-phase enclosure-type GIS Bus

Heat is one of the most obvious characteristics of gas insulated switchgear (GIS) bus. This paper established three-dimensional eddy current field mathematical model for 126kV three-phase enclosure-type GIS bus. Magnetic field finite element method (FEM) was employed to calculate power loss in the conductors and the tank, and the result was the input data for the solution of temperature field. According to the theory of computational fluid dynamics (CFD),SF6 gas movement differential equations was given as well as solved region and boundary conditions of three dimensional fluid field. Nussle number was utilized to figure out nature convection coefficients of different segments of the bus. Solving the differential equations, fluid and temperature field distribution of the bus was calculated, which theoretically supported temperature on-line monitoring system of GIS bus.

A new hybrid FBG with a π-shift for temperature sensing in overhead high voltage transmission lines

Temperature monitoring in overhead high voltage transmission lines (OHV TLs) on continuous basis have become a subject of much interest and research in recent years. Since the transmission lines are subjected to various harsh meteorological and geographical conditions such as high temperature, this can cause disastrous effects on the lines such as flashovers, line breakings, and even tower collapsing. For this aim, a distributed on-line temperature monitoring system based on a new hybrid fiber Bragg grating (FBG) technology is proposed in this paper, since the development of the FBG sensing technology became prominent for the monitoring of temperature on the power lines for having several unique advantages compared to the traditional electronic sensors. The new proposed hybrid FBG consists of two apodized fiber Bragg gratings: one Nuttall and one Cos8 separated by a pi-phase shift. This showed an optimum remarkable performance in terms of the evaluation parameters including the peak reflectivity, full width at half maximum, side lobes analysis and ripple factor as well. Moreover, it has shown a stable operation over the increased temperature when subjected to temperature variation, under the variation of the controlling parameters such as the grating length and the refractive index modulation amplitude. The proposed hybrid is compared to the traditional uniform FBGs in terms of the evaluation parameters showing its superiority as a best temperature sensor in OHV TLs.

Online air velocity control, temperature and humidity monitoring system for clean room using Raspberry Pi

The requirement of a clean room in the pharmaceutical industry is to maintain the airflow between 0.36-0.54 m/sec and record the temperature and humidity parameters. The laminar airflow machine is used to maintain the air velocity. The air velocity settings in laminar airflow machine are usually done manually by adjusting the speed control knop. In this study, we have designed a prototype of automatic air velocity control, temperature, and humidity monitoring system using Arduino nano and Raspberry Pi. The airflow control is done by the PID method. From the test results, the prototype has worked as expected. The accuracy of the measurement is ± 5% for air velocity, ± 2 °C for temperature and ± 5% for moisture. The system can control the air velocity between 0.36 m/s to 0.54 m/s. The measured parameters then send to the server and utilized for online monitoring the air velocity, temperature, and humidity in the clean room.

A Geometry Effect of Carbon Nanomaterials on Flame Retardancy and Mechanical Properties of Ethylene-Vinyl Acetate/Magnesium Hydroxide Composites.

This study was aimed at investigating the effects of carbon nanomaterials with different geometries on improving the flame retardancy of magnesium hydroxide–filled ethylene-vinyl acetate (EM). The thermal stability and flame retardancy were studied by thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL-94 test, and cone calorimeter test (CCT). The in situ temperature monitoring system and interrupted combustion offered direct evidence to link flame retardancy and composite structure. Results demonstrated that carbon nanomaterials enhanced the thermal stability and fire safety of EM. The geometry of carbon nanomaterials played a key role in synergistic flame retardancy of EM, with the flame-retardant order of carbon nanotube > nanoscale carbon black > graphene. Based on an online temperature monitoring system and interrupted combustion test, one-dimensional carbon nanotube was more inclined to form the network structure synergistically with magnesium hydroxide in ethylene-vinyl acetate, which facilitated the generation of more continuous char structure during combustion. In parallel, the mechanical property was characterized by a tensile test and dynamic mechanical analysis (DMA). The incorporation of carbon nanomaterials presented a limited effect on the mechanical properties of the EM system.

Design of Ultra-Low Temperature Online Monitoring System Based on Data Fusion Technology

Large amounts of data in the ultra-low temperature online monitoring system is needed to monitor and transmit in real time, at the same time. The data collected is usually erroneous because of the characteristics of sensors itself. In order to solve this problem, the data fusion technology is applied to the ultra-low temperature online monitoring system, and erroneous data will be removed through correlation function careless error elimination method based on the fuzzy theory. The reliability and effectiveness of the whole monitoring system is improved. According to the theory above, an ultra-low temperature online monitoring system is designed in this paper. In this paper, the overall structure of the ultra low temperature on-line monitoring system is introduced in detail, the hardware and software design of the system was analyzed, and the whole system was tested. The test results show that the system is stable and reliable with very important market application value.

A Wireless On-line Temperature Monitoring System for Rotating Electrical Machine

Wireless communication can be a useful method to monitor the electrical machine as it provides the main characteristics of online signal processing. Our contribution in this current paper consists in studying a new system to monitor the rotating electrical machines based on wireless communication. The main objective of this system is to detect the temperature value of the squirrel cage induction machine’s rotor, using the IEEE 802.11 protocol. However, the application of wireless communication inside the rotating electrical machines is not self-evident due to the fact that the electromagnetic compatibility problems between devices isn’t obviously guaranteed. So, in order to obtain a good reliability for wireless communication, the study of the electromagnetic field inside rotating electrical machine is essential. As a first step in this paper, we are going to focus mainly on the flux effect of the rotating electrical machine through the finite element method which offers so much information on the phenomena characterizing the electrical machine operation. This method proves that the high frequency domain transmitter won’t be disturbed by the low frequency existing flux inside the machine. As a second step in this study, the proposed network system design is presented. Then, the communication protocol, the hardware design based on the transmitting chip Roving Networks (RN-171) as well as the software design are illustrated. Finally, the experimental results of the proposed system are investigated to validate its feasibility.

A Wireless and Passive Online Temperature Monitoring System for GIS Based on Surface-Acoustic-Wave Sensor

A novel temperature monitoring system for gas-insulated switchgears (GISs) based on surface-acoustic-wave (SAW) sensing is proposed in this paper. Compared with the existing systems, this system has several unique advantages, such as being wireless, passive, and at a proper cost with continuous monitoring. First, an accurate SAW temperature sensor is designed for the GIS conductor, where epoxy encapsulating and loop antennas are adopted in the SAW sensor to prohibit the potential partial discharge of the sensor itself. After that, a multifunctional reader antenna is developed, which can measure the conductor temperature and partial discharge by the time-division multiplexing technique. Experiments are carried out to examine the accuracy and response speed of the SAW sensors, and the results indicate that the uncertainty of the contact temperature measurement is smaller than 10 $^{\circ}$ C. Moreover, the insulation level and anti-interference ability are demonstrated based on experiments carried out on a 126-kV GIS. At last, temperature monitoring performance of the developed system is investigated by changing the current in the 126-kV GIS conductor. The experiment results prove that the developed system can meet the requirement of temperature monitoring in GIS.

On-line Temperature Monitoring of the GIS Contacts Based on Infrared Sensing Technology

Gas insulated switchgear (GIS) is widely used in the power systems, however, the contacts overheating of the inside circuit breaker or disconnector may be a potential cause of developing accidents. As the temperature of the contacts cannot be directly acquired due to existence of the metallic shield, an infrared sensor is adopted to directly measure the temperature of the shield and then the contacts temperature can be indirectly obtained by data fitting, based on which the on-line temperature monitoring technology specifically for GIS contacts based on infrared sensing is proposed in this paper. A real GIS test platform is constructed and experimental studies are carried out to account for the influential factors that affect the accuracy of the infrared temperature measurement. A heat transfer model of the GIS module is also developed, together with experimental studies, the nonlinear temperature relationship among the contacts, the metallic shield and the environment based on a neural network algorithm is established. Finally, an integrated on-line temperature monitoring system for the GIS contacts is developed for on-site applications.

Research on Flue Gas Temperature Monitoring in Acoustic Pyrometry of 200 MW Boiler Furnace

An online temperature monitoring system for flue gas based on acoustic pyrometry was developed and installed in a boiler of 200 MW. Hot-state experimental research of acoustic source signals included linear sweeping frequency signal and pseudo random binary sequence were tested, and the temperature was measured by K ceramic thermocouples which were specially made for verification. Research indicates that those signals can be used as sound source signals due to the treatment. The error of temperature in the measurement used acoustic pyrometry which is stable and reliable can be less than 1%, and it provides important consultation for this technology popularizing application.