DEStech Transactions on Environment, Energy and Earth Sciences
Measurement of keff with Neutron Flux Distribution Method Based on MC Simulation
In this work, the neutron flux distribution method to determine the effective multiplication coefficient keff has been numerical analysis by MCNP program. The neutron flux distribution of four multi-sphere system models are calculated, and the characteristic parameter c of each system are fitted with keff, so as to measure the keff of multi-sphere system. And experiment based on reactor system has been carried out to prove the method. Experiment results show that the keff obtained by the neutron flux distribution method are consistent with the experimental measurement results, indicating that the method is feasible and reliable.
Research on the Treatment of Coal Washing Wastewater by Pressureless Filtration Technology in Yidong Preparation Plant
This article takes the coal washing wastewater of the Yidong Coal Preparation Plant as the research object. With the change of the raw materials to be washed, the effect of its existing treatment process is not ideal. The multi-factor response surface analysis of the four factors of PAC dosage, PAM dosage, stirring speed and stirring time was carried out, and the optimal dosage and operating parameters were obtained as PAC dosage 30.52 mg/L, PAM dosage The dose is 20.75 mg/L, the stirring speed is 407 r/min, and the stirring time is 82.5 s. Through the field industrial test, the application effect and rationality of the pressureless filtration technology are verified.
Design of Coded Neutron Source Based on a RFQ Accelerator by MCNP Simulation
In this paper, the influence of non-ideality factors of thermal neutron source for coded neutron source imaging has been studied by numerical calculation,in order to establish the design standard of coded neutron source. Then, the pinhole imaging detector (pinhole) of MCNP has been used to simulate the imaging process of the coded neutron source imaging, and the parameters such as the uniformity of the spatial distribution of the thermal neutron flux at the imaging plane and the uniformity of the angular emission of the coded neutron source are studied. The design results show that the spatial distribution of thermal neutron flux is less than 13% and the angular distribution is less than 10% with the optimized structure of moderator including a 4 cm thick polyethylene disk and a wedge of neutron absorbing layer closed to the junction surface of collimator and water tube.
Design and Analysis of Different Storage Cargo Station Project
This paper completed a program with a typical coal loading station analysis, coal systems, interior design by coal storage system loading stations will be expanded, it will be subject to the coal pit, different forms of storage bunker, coal storage shed, etc. specific technical parameters superior and its corresponding economic indicators combined standard to do a detailed comparison and determine the best technical and economic solutions Cargo station construction; focus on the application of matlab calculation program calculates the design reserves loading stations with coal shed aspect ratio, the relationship between the length of the curve values, verify the Cargo station design is reasonable to give a general rule of coal storage capacity design.
Total Independent Set Numbers on Catacondensed Polyomino Systems
A catacondensed polyomino system is a chain polyomino system in which the joining of the centers of its adjacent cells forms a tree. Total independent set number is a graph invariant that has been studied extensively in statistical mechanics and mathematical chemistry. In this paper, we introduce a new graph vector at a given edge and get some recurrence relations on the total independent set numbers of the path-like polyomino systems. Based on these relations, the reduction formulas of computing the total independent set number of any catacondensed polyomino system via transfer matrices can be obtained.
Research on Coreference Resolution Based on Conditional Random Fields
In view of the phenomenon of noun coreference in Chinese, This paper proposes a deep learning mechanism based on Conditional Random Field (CRF) to study coreference resolution based on deep semantic information representation. The text is input into the vector of Biditive Encoder Representations from Transformers model. The self-attention mechanism is used to mine the hidden features at the context semantic level. Through the reasoning ability of CRF, the complex features are used for reasoning training, and the training results are scored and classified by softmax to complete the anaphora resolution task. The experimental results show that the performance of coreference resolution can be effectively improved by making full use of text feature representation.
Tagging Tone for Mandarin Pinyin Based on Sequence Labelling
Generally, fundamental frequency (F0) is applied as the clue for tone recognition in normal speech. Tone recognition in whisper speech without F0 could be based on the temporal and spectral cues. However, the Mandarin Electro-Laryngeal (EL) speech with fixed F0 has no tone information. Therefore, the tone recognition of Mandarin EL speech is so difficult. And the researches about tone recognition for Mandarin EL speech is insufficient. In this paper, a new method labelling the tone for pinyin is proposed based on the context information to identify the tone of Mandarin speech without tone information. The experiment result shows that the precision, recall and the F value are all above 97% based on the test dataset. The amount of semantic information influences the performance of proposed method. If the amount of semantic information is little, the accuracy of tone labelling would be poor. The result shows that the proposed method has a good precision and robustness. The method can label the tone for pinyin without any tone information only based on the context information. The proposed method can label tones for tonal language, such as the Mandarin speech.
Information Security Risks in Civil Aviation Network: Classification, Identification and Preventive Strategies
Information security of civil aviation network is an important issue in national cyberspace security governance. Based on the ISO27001 information security management system, the main contribution of this paper is build a classification and identification framework to identify key sources and specific factors of information security risks in civil aviation network through generalization and summary approaches. The detected risk sources mainly include management subject, management process, technology, laws and regulations, and infrastructure. In accordance with the attributes of different risk sources, systematic preventive strategies are proposed in this paper to serve as references for preventing and resolving information security risks in civil aviation network.
Quality Control of Marine Big Data for Marine Physical Property Monitoring System
To make good use of the ocean, we must know enough about it. Supported by the Ministry of science and technology of China, the marine physical parameters monitor is developed to obtain real-time marine physical parameters such as temperature, humidity, pressure, rainfall, wind speed, wind direction, solar radiation, water depth, salinity, conductivity and other data. The integrated intelligent service software platform for marine physical property monitoring data is used for real-time collection, storage, historical data analysis, integrated display and other work of these data. As a part of the integrated intelligent service software platform, an improved big data quality control method which comprehensively uses the meteorological industry standards test, least square polynomial fitting, multiple regression and other technologies is proposed in this paper to improve the correct and efficient use of these real-time or historical data in terms of data inspection, correction, reconstruction and quality evaluation, etc. The existing historical data prove the effectiveness of this method.
Study on Temperature Control Strategy of Boiler Main Steam for Frequent Action of AGC Command in Power Grid
Traditional PID is widely used in the main steam temperature control system of thermal power unit Cascade control. Although this control scheme is easy to be debugged on site, it is impossible to solve the problem of large fluctuation and over temperature of steam temperature only by adjusting PID parameters due to the characteristics of variable parameters, large inertia and large time delay of main steam temperature control system. Especially when the AGC command of power grid fluctuates frequently, the conventional control strategy is difficult to deal with, resulting in the change of main steam temperature regulation quality Poor, affecting unit economy and safety. In this paper, the sub PID set value adaptive control logic and desuperheating water injection logic to prevent the main steam temperature overshoot are used to solve the problem of the quality deterioration of the main steam temperature regulation under the frequent fluctuation of AGC instructions.
Research on Operating Conditions of Electric Propulsion Ships under Transformer Interturn Short Circuit
Most ships currently use electric propulsion systems. In this system, the transformer plays a key role in power distribution. The probability of interturn short circuit occurs in the transformer is high, it will cause faults such as three-phase voltage imbalance and endanger the safe operation of the ship. The simulation model of ship electric propulsion system established in this paper includes propellers and transformers, and the influence of the interturn short circuit of a transformer on the sailing conditions is studied. The research results show that the transformer interturn short circuit will generate a huge inrush current and have a huge impact on the torque and speed of the propeller.
Research on the Verification Method of Flyback High-Frequency Transformer (FHFT) Based on Field-Circuit Coupling Model
In view of the current status of research on verification of the correctness and effectiveness of FHFT design, a field-circuit coupling based FHFT design verification method is proposed in this paper. This paper proposes a FHFT design verification method based on field-circuit coupling. The steps of FHFT verification using field-circuit coupling method are elaborated in detail. A three-dimensional physical model of FHFT based on AP method is established. The calculation of FHFT flux density and the verifying of transformer output waveform are completed by using the fieldcircuit coupling method of alternating iteration of non-linear magnetic field solution and circuit. On the basis of completing the flux density calculation, the field circuit coupling method is used to verify the output waveform of the transformer. It is found that the output waveform of FHFT is not an ideal square wave, but has some distortion, which is caused by neglecting the leakage inductance of transformer in the design process. This shows that the influence of transformer leakage inductance is very important and should be paid attention to.
Research on Battery SOC Estimation Algorithm for Energy Storage Power Station
This paper takes the high-power lithium battery as the research object. The battery capacity is 40Ah. The state of charge (SOC) of lithium cannot be measured directly. We establish an equivalent circuit model of the battery and use Matlab/Simulink to simulate the equivalent circuit model of the battery. The simulation results and analysis show that the designed control strategy can accurately estimate the SOC of the battery and provide a theoretical basis for the designed algorithm in the practical application of energy storage power stations.
Analysis of Combined FM Application in Thermal Power Plant of Energy Storage System
With the increasingly strict assessment of grid AGC, the energy storage system's participation in AGC FM technology has ushered in a good development opportunity. This paper introduces the application status, basic principle and application effect of the largest energy storage system put into power plant in China. This paper analyzes the performance index and economic benefits of the integrated frequency modulation before and after the energy storage system put into operation.
300MW Class Units Circulating Pump for Heating Network Electric to Steam-Driven Comparative Study of Two Kinds of Economic Transformation Program
Jilin Province is located in the northern cold regions, winter heating period of up to five months, the thermal power plants in the larger proportion of the heating unit to improve the economy is a priority issue before us. Most thermal power plant in our province are used in electric network circulating pump run, a larger share of electricity plants, such as the use of steam-driven run, can reduce electricity consumption increased grid power plant, with better economic benefits, and whether the transformation potential, we need to demonstrate feasibility. To speed up the transformation project power industry the pace of industrial upgrading, power plant emissions-reduction targets.
Measurement and Numerical Simulation Analysis of Smoke Flow Field after Dust Collector Modification
The differential pressure of dust collector bag in a power plant was improved synthetically In this paper, the distribution of the smoke flow field in the unit dust collector system is numerically simulated and filed tested. The main technical parameters of the distribution of smoke flow field in the unit's overall dust removal system were measured on site. The actual operation results of the project show that the CFD calculation results are in good agreement with the actual situation, the airflow uniformity inside the modified dust collector is well, the dust removal efficiency is realized and the design expectation is achieved.
A Transmission System Planning Method Considering Combined Operation of Wind Farms and Energy Storage Systems
The ever-increasing penetration of wind power has resulted in new problems and challenges to the secure and economic operation of the power system concerned. Given this background, a bi-level transmission system planning model for this purpose is proposed. In the upper level, the objective is to minimize the total cost, the attained transmission planning scheme will be transferred to the lower level. In the lower level, the objective is to minimize the sum of the discharge cost of the energy storage system and the cost of abandoning the wind farm, the discharge cost of the energy storage system and the cost of abandoning the wind farm are transferred to the upper level as feedback. These two levels are implemented interactively and iteratively. Finally, the essential features of the developed model and adopted algorithms are demonstrated by a modified 18-bus test system.
Vibration Analysis and Treatment of a Heating Steam Extraction Pipeline of A 300MW Unit
After the 300MW condensing steam turbine of a power plant was delivered from the factory, it was retrofitted with medium and low pressure conduits for steam extraction and heating, and then the entire flow passage of the whole machine was reformed, and the heating capacity was considered. However, during the heating period, during the process of increasing the steam extraction, it was found that the unit's extraction pipeline and the medium and low pressure ducts were vibrating in the vertical direction. After analyzing and testing the on-site operating data, it was found that the main reason for the vibration was the discharge If the pressure is too low, the specific volume of steam will increase, which will reach the upper limit of the design flow rate of the pipeline at a low mass flow rate. The uneven media flow will cause the backlash motion of the pipeline to be unstable and vibrate, and the mediation control program was not readjusted after the flow part was remodeled. It is recommended that the power plant adjust the mid-range parameters and readjust the mediation control procedures. After the power plant takes advice, the site vibration problem can be resolved.
Day-ahead Scheduling of Islanding Microgrids Based on Wind Power Forecast
Wind power, as the main energy source of the island microgrid, has uncertain output. Reasonable setting of TOU price can improve adaptability to changes in wind power output. Based on the time series characteristics of wind speed, the EWMA is used to predict the wind speed day-ahead. Then through the method of distribution superposition fitting and roulette, the day-ahead forecast data of wind power considering power fitting error is obtained. As a reference, a new TOU price division method based on wind power output is proposed. At the same time, P2G and energy storage devices were introduced into the cogeneration system to achieve Gas-electric transformation functions. Combined with the heating and electric demand response of the user side, comprehensively considering the mutual conversion relationship between multiple energies. On the premise of considering economy and environmental protection, the Gurobi solver is called by Yalmip to get the start-stop status of the powerside unit and the user-side unit.
Economic Benefit Analysis of "Direct Trading Model" DPV Project—Real Options Method
With the continuous advancement of market-oriented transaction of distributed photovoltaic (DPV) power generation, the "direct trading model" (DTM) as the most important market-oriented transaction model occupies an increasingly important position, but the DTM economic benefits affected by many uncertainties, the real option method (ROV) can calculate the value of uncertainty factors, so this paper uses the ROV method to evaluate the value of the DPV projects. This paper first constructs the revenue and cost model, then introduces ROV theory to construct the value model with risk factors; secondly, through empirical analysis, it proves that the ROV model can quantify the value of uncertainty factors, and can improve the accuracy of value assessment. Through the sensitivity analysis, we find the trend and degree of the influence of each factor on the value of the project. Finally, we put forward some suggestions for the research results.
Extracting Information on Wetlands in Northeast China Based on Time Series FY3/MERSI Data
Using Fengyun Medium Resolution Spectral Imager (FY3/MERSI) data from 2011 to 2018, this paper analyzed the characteristics of original spectra and the normalized difference vegetation index (NDVI) of lakes, reservoirs, rivers, paddy fields and swamps in Northeast China, A large-scale wetland extraction model was built using the decision tree classification method, and accuracy was verified in typical sites using China High-resolution Earth Observation System (CHEOS-1) data. The results showed that there were differences in the spectral curves and NDVI of different wetland types, especially the swamps, paddy fields and other landforms that showed a growth cycle with more significant differences in spectral curves and index curves than those of lakes, reservoirs and rivers. The total area of wetlands in Northeast China was 79,123.4 km2, including 5262.3 k m2 of lake and reservoir wetlands, 6514.7 km2 of river wetlands, 15284.7 k m2 of swamp wetlands and 52061.7 km2 of paddy fields. The accuracy verification showed that the area accuracy of wetlands was over 91.8%, the overall classification accuracy of wetlands was over 84.8% and the Kappa coefficient was over 0.6446.
Analysis of High Sulfur Coal Blending in Thermal Power Unit
In recent years, affected by the rising international energy price, coal price marketization and other factors, all provinces in the country are short of electric coal, and all power plants are taking multiple measures to ensure the purchase of electric coal and ensure the safe operation of the machine team leader cycle. In order to prevent the high temperature corrosion of the water wall of the unit burning high sulfur coal tangentially fired boiler, the main measures are to optimize the operation and adjustment, optimize the distribution of air and powder, avoid strong reducing atmosphere near the wall area of the water wall, and install wall wind to make the water wall form oxidation atmosphere; The water-cooled wall is applied with anti-corrosion, anti-wear and thermal spraying to isolate the reducing atmosphere from the metal material of the water-cooled wall, reduce the sulfur content of the coal entering the furnace and reduce the generation of H2S.
Design of Elevator Condition Monitoring and Fault Alarm System
The elevator condition monitoring and fault alarm system comprehensively uses a variety of detection technologies, and realizes the real-time monitoring of the position, speed and acceleration of the elevator car based on the elevator condition detection. With the integration of Internet of things technology, the remote warning of elevator fault is realized, which is convenient for elevator safety inspection and maintenance. The elevator safety management platform based on the Internet of things has been established to realize the special supervision of the supervision and management department on elevator safety.
Data Exchange Technology Across Networks Based on Trusted Computing
The authors analyze the existing technologies in the field of cross-network data exchange and their deficiencies in ensuring the safe transmission of data. We propose a technology to improve the security of data exchange across networks, which is based on trusted computing. We design an audit method of the data exchange to prevent the leakage of sensitive information, investigate the subject of the leak and ensure the integrity of the data transmission. We have proved the credibility of the method and the ability of data security protection in the process of cross network data exchange, by protecting data files and applications.
Research on Environmental Performance Evaluation of Petrochemical Enterprises Based on Balanced Scorecard-Entropy Method
Using the balanced scorecard method to select relevant indicators from the financial dimension and the non-financial dimension to build an environmental performance evaluation indicator system suitable for petrochemical enterprises. Taking Sinopec enterprises as an example, the specific data of each indicator obtained through Sinopec's financial statements, sustainable development reports, and social responsibility reports from 2011 to 2018 are evaluated and evaluated. It is concluded that the impact of the environmental performance of the corporate customer dimension is slowly increasing. The learning and growth dimension and the internal business process dimension are contributing more and more to the corporate environmental performance. The overall environmental performance of petrochemical enterprises shows a trend of increasing and slowing down year by year.
Practice and Thinking of Online Courses Based on "Dingtalk + Chaoxing" in COVID-19 Epidemic Situation
Since the outbreak of Novel coronavirus pneumonia (COVID- 19) at the beginning of this year, colleges and universities have actively responded to the call of "Suspension of classes and non-stop learning" by the Ministry of education, and have adopted online teaching methods to organize teachers and students to teach and learn. Under this background, the method of "DingTalk live broadcast + online interactive Chaoxing network teaching platform" is used for the online courses of "Single-chip microcomputer principle and interface technology" and “Database principle and Applicationâ€. Multiple ways combined the interaction are used to mobilize the classroom atmosphere in class, and homework and test are arranged to consolidate the learning points after class. Therefore, using this teaching mode can achieve good teaching and learning effect.
Study on Chromatographic Condition Assessment of Transformer Oil Based on Random Forest Model
In order to solve the problem that the accuracy of transformer condition assessment based on oil chromatographic data is not high, this paper adopts random forest to evaluate transformer state. In order to prevent the attribute values carried by the decision tree of the basic unit in the evaluation model from being too few and thus affecting the evaluation accuracy. The ratio of H2, CH4, C2H6, C2H4, C2H2, total hydrocarbon and various characteristic gases is used as the characteristic quantity, a stochastic forest optimization model for oil chromatography state assessment was constructedimmediately following the heading. It is compared with BP neural network and SVM, the test results of field oil chromatogram data show that the accuracy of random forest state assessment is 88.5%, which is better than BP and SVM, and the random forest assessment model has faster assessment speed, This paper provides technical support for the fast and accurate condition assessment of transformer.
A Newly Designed Method for On-Line Error Estimation of Smart Meter
The method of manual verification of smart meters used at the current stage usually suffers from high cost, poor efficiency, and small coverage. A new method is presented to solve the error of energy meter by iteration. Firstly, the daily electricity data is collected and sifted through to classify the data for light-load and no-load meters. Then, by applying the outlier line-loss rate treatment method, it can obtain the invariable-loss & line-loss rate & the suspected out-of-tolerance meter and their initial values. After that, the meter error, invariable-loss, and line-loss rate can be calculated by the improved meter error estimation model. Based on the computed results, the data with relatively high and low line-loss rate are removed. It is to guarantee that the line-loss rate of data is within a small range. The sifted process removes the outliers and avoids the mis-deletion of the valid data, which improves the calculation accuracy. The proposed method proves to be effective in out-of-tolerance meter search by verifying the data from two different scale distribute-electricity transformer districts (DETDs) and comparing with the traditional least-squares method (LSM). The algorithm is easily applicable to small computation burdens.
Research on Bearing Intelligent Diagnostic Technology Based on EMD and GA-BP
Bearings are the core components of rotating machinery and can have a significant impact on the equipment in the event of a failure. In this paper, an intelligent diagnostic technique based on the combination of EMD and GA-BP algorithm sifts with the rolling bearing fault identification and classification problem. First, the test data is processed by EMD method, the characteristic enhancement and extraction of micro-faults is realized, and the bearings are trouble shoot as training sets and test sets of BPNNs optimized by the built GA. The results show that the accuracy and convergence speed of this method are improved compared with the method of unutilized energy characteristics, and the identification and diagnosis of bearing fault can be effectively carried out.
Application of PSO Algorithm Based on Recognition in MPPT Control of Photovoltaic Array
Under the condition of local shadow, the P-U curve of photovoltaic array presents multi peak phenomenon. Traditional MPPT algorithm is easy to fail. PSO algorithm is suitable for the optimization of complex multi extremum system, so it is applied in multi peak global MPPT. In order to solve the problem of low precision and premature in PSO algorithm, this paper proposes a new PSO algorithm based on recognition. Through the introduction of awareness, compared with the set value, the particles with better awareness will directly enter the next better iteration, while the particles with poor awareness will be replaced by their historical optimal location, which continues to maintain the search accuracy and speed in the later stage of particle swarm, so as to improve the accuracy and speed of multi peak global optimization. Through the simulation of MATLAB/Simulink, the results show that under the condition of uniform illumination and variable shadow, the particle swarm optimization algorithm based on recognition can effectively improve the convergence speed and accuracy of system optimization.
Stator Winding Fault Diagnosis Method Based on Dc Side Current of Inverter
This paper analyzes the influence of the fundamental negative sequence component of the grid voltage on the output voltage of the variable frequency power supply, and points out that the fundamental negative sequence component of the grid voltage will not generate the fundamental negative sequence current component in the stator current of the induction motor, so when the stator winding fault is diagnosed, the influence of the negative sequence voltage of the grid does not need to be compensated. Based on the characteristic that the fundamental negative sequence current component in the stator current is converted into two times of the inverter output frequency component in the DC side current of the inverter, a stator fault diagnosis method based on the DC side current of the inverter is proposed. The method of connecting the short-circuit resistance between the two phases of the motor is used to simulate the nonmetallic short-circuit fault of the stator coil. The experimental results show that this method does not need to compensate the negative sequence voltage, and only needs to collect one current signal, and the algorithm is relatively simple, which is a simple and effective method.
Boiler Bypass Flue to Adjust Denitration Inlet Flue Temperature Automatic Control System Design and Analysis
Under low-load boiler operating conditions, the flue gas temperature at the inlet of the denitration system is lower than the normal working temperature of the catalyst. In order to ensure the reliable input of the denitration system, a bypass flue and an adjustment damper are added to the boiler economizer. Configure control logic and actual debugging to realize automatic control of the inlet temperature of the denitration system, and ensure that the denitration system can be continuously operating when the boiler is running in the 30% -100% load range.
Synthesis of C-H-O Symbiosis Networks Based on i-safe Index
The synthesis of C-H-O symbiosis network is considered in EIPs to reduce the amount of raw materials and waste discharge by using internal sources. In the conceptual design stage of C-H-O symbiosis networks, the concept of inherent safety index is introduced and safety factors are considered. Synthesis of C-H-O symbiosis networks based on i-safe index is proposed. Super-structure of C-H-O symbiosis networks was configured in EIPs, then optimization formulation was devised. A nonlinear programming (NLP) optimization model was established. A case study in Guizhou province shows that the method is useful in process decision-making, which could provide data support for early process decision making.
Prediction of the Spatial Structure of Cruise Market Based on Spatial Gravity Model—A Case Study of Shanghai Cruise Port
Spatial interaction between tourist origining region and destination is one of the key factors affecting tourism industry. Based on classical gravity models, this paper constructed a cruise market spatial gravity model to predict the cruise market demand. It is found that cruise tourism is rather and its elasticity is much higher than other tourism activities and cruise tourism is more easily to be replaced. Meanwhile the search index of cruise tourism in most regions is proportional to the overall tourism propensity, and the cruise tourism penetration rate decreases with distance from the cruise port studied. The largest market of Shanghai cruise tourism comes from the Yangtze River Delta region. Additionally, Cruise tourism and other tourism are positive correlated. Exotic cultures and the new modes of tourism are more attractive to tourists. However, the attraction for Midwest and North China and distance register a negative correlation with the share of the Shanghai cruise passenger market.
Influence of Wind Speed and Direction on the Combustion Parameters of the Exposed XPS Insulation Wall
Most of the fire accidents of exterior insulation in recent years started with the ignition of unprotected and exposed insulation materials. The fire spread on the thermal insulation layer will be affected by outdoor wind. In this paper, the influence of wind direction and wind speed on wall fire propagation characteristics was studied by carrying out medium sized experiments. The temperatures on the wall surface, radiation heat flux nearby, the infrared image and flame image were recorded during the tests with variation of wind direction and wind speed. It is found that with the increase of the angle between the wind direction and the wall, the surface temperature of the material, the radiation heat flux released decreases.This study results can provide valuable references for optimizing the fire safety design of exterior insulation layer.
An Improved Object Detection Method for Automatic Electrical Equipment Defect Detection
Employing computer vision and machine learning on equipment defect detection has become an important trend of electric power inspection. This paper presents a new electrical equipment default detection method based on improved YOLOv3. By combining abundant geometric measures, Complete IOU(CIOU) make the bounding box regression during NMS more accurate. Focal loss function, which focus on differentiate between easy and hard examples, is employed to deal with the class imbalance problem. Experiment results show that the proposed approach obtains competitive performance compared with state-of-the-art deep learning object detection methods.
Experimental Study on Energy Consumption Distribution of Electric Forklift
In this paper, the energy consumption and its distribution of forklift in various working conditions are analyzed through experiments, and the main factors of energy consumption are found, which can find a breakthrough for system energy saving and provide theoretical basis for subsequent research. According to the measured battery output voltage and current of the electric forklift, the walking system accounts for about 42.7% of the overall energy consumption of the hydraulic system, the steering system accounts for about 13% of the overall energy consumption of the hydraulic system, the pitch system accounts for about 0.3% of the overall energy consumption of the hydraulic system, and the lifting system accounts for the largest proportion of the overall energy consumption of the hydraulic system, reaching about 44%.
Reliability Analysis of Flexible Multiple State Switch Based on Bayesian Network Method
In order to accurately establish the reliability model of flexible multiple state(FMSS) switch and excavate the weaknesses of component reliability, a method of reliability modeling of FMSS based on Bayesian network is proposed in this paper. Firstly, a multi-state reliability model is established by Markov process. Then, the Bayesian network of MMC is established. The correctness of the model is verified by examples. The reliability of SM, MMC and FMSS is calculated. The influence of submodule redundancy on FMSS is analyzed. The weak link of FMSS is analyzed. The research results in this paper can provide support for the application of FMSS in distribution network.
Analysis of the Coupling Laws of Disaster Inducing Factors of Frozen Rain and Snow Disasters in Southern China—Taking Changsha City as an Example
In order to study the causes and laws of freezing rain and snow disasters in southern China caused by coupling of multiple disaster inducing factors, the meteorological observation data of the severe rain and snow freezing disasters in Changsha in January 2008 was analyzed in this paper. The fluctuation characteristics of typical disaster inducing factors and disaster factors coupling law were studied, and the following conclusions were drawn: (1) Temperature-humidity coupling system will promote the occurrence of freezing disasters such as glaze, freezing fog, freezing rain and sleet; (2) Wind and precipitation are important causes for the occurrence of freezing disasters, and their coupling effect will lead to typical disasters such as snow drift and rain-wind phenomenon, which will aggravate freezing disasters; (3) Daily maximum temperature, daily minimum temperature and the average temperature are significantly negatively correlated with the degree of freezing disasters, and the effects of humidity and precipitation on freezing disasters are significantly positively correlated. The results showed that the coupling analysis of disaster inducing factors could provide a powerful tool for the freezing disasters prevention and emergency management.
Study on the Effects of the Aging by Accelerated Weathering on the Intumescent Fire Retardant Coating for Steel Elements
This paper reported the results of an experimental study of degradation in fire protection performance of intumescent coating for steel elements after different times of accelerated weathering aging. The physical and chemical changes of the coatings during the aging process were investigated. After aging the surface of the samples were found to become rough, powdered and embrittled; the fire resistance time decreased and the char layer morphology changed significantly. Due to the oxidation, decomposition and hydrolysis reactions in the main components of the coating, such as the resin and the fire retardant system, the content ratio and composition of the coating changed. Then the concerted expansion reaction may not occur between the ingredients when heated, which led to the deterioration of the fire resistance performance of the coating.
Calculation and Optimization of Volumetric Efficiency of Aviation External Gear Pump
The power consumption of aviation gear pump has a direct impact on the performance of aero-engine. To improve the efficiency of aviation external gear pump, this paper analyses the leakage of gear pump, and calculates the leakage of axial, radial clearance, gear face meshing clearance, and the elastic loss of liquid compression. Mathematical models of volumetric efficiency are established including the effect of temperature and pressure. Comparing the theoretical value with experimental results, the effectiveness of the models is verified with the error less than 5%. On this basis, the design variables of gear pump are optimized with the maximum theoretical displacement as the optimization objective function. The simulation results show significant volumetric efficiency improvement of the external gear pump. And some suggestions on actual products design and analysis in the aviation fuel device are proposed accordingly.
Numerical Study on the Unsteady Film Cooling Characteristics of Turbine
In view of the main flow pulsation phenomenon and the new pulsating film cooling mode in the aeroturbine engine, the numerical calculation method is used to study the film cooling characteristics under the condition of the main flow velocity pulsation and cooling gas velocity pulsation with the classical circular film hole as the research object. In order to eliminate the influence of other factors on the film cooling characteristics of turbine blades as much as possible, a circular film hole of flat plate model similar to the small curvature section of turbine blades was established, and the influence of different cooling air pulse frequency, blowing ratio and mainstream pulse frequency on the film cooling characteristics was analyzed in depth. The results show that: with the increase of cooling air pulse frequency, the film cooling efficiency of cooling gas pulsation scheme can be achieved approximately the steadystate condition with blowing ratio of 1.0 while only half of the cooling air flow is consumed; at high blowing ratio, the cooling effect will be better when using the cooling air pulsating film cooling scheme compared with the steady-state scheme; in the main pulsating frequency range of the study, the frequency of main flow pulsation has little effect on film cooling efficiency.
Analysis of Problems in Application of "Mine Ventilation" Project Teaching
In order to better improve the quality of teaching, from the original teacher-centered to student-centered transfer, it is urgent to carry out the reform of teaching methods and methods. Taking the course of "mine ventilation" as an example, this paper studied the problems existing in the process of implementing project-based teaching, and put forward reasonable and feasible Suggestions according to the problems. This paper discussed the necessity of carrying out project-based teaching research in the course of "mine ventilation". The traditional teaching way and the effect of project teaching method has carried on the contrast analysis, the results show that the project teaching in the course of "learning" of mine ventilation applications have more advantages than the traditional teaching way, mainly reflected in the student's study enthusiasm, significantly improve grades, hands-on practice ability and problem solving skills, etc. This paper analyzed three problems of project-based teaching and put forward corresponding solutions.
The Production Performance Evaluation of Hydraulically Fractured Wells in the East Sulige Field Using Machine Learning
The paper presents a comprehensive workflow to integrate the machine learning algorithm with the Monte Carlo simulation, and a field example is provided to demonstrate that the proposed workflow could reasonably capture the behaviour of well production data. The workflow helps engineers in learning valuable lessons from their historical operations to optimize the future hydraulic fracturing treatments in the Sulige gas field.
Optimization Algorithm Study of Operation Energy Consumption in Water Flooding System
Oilfield flooding is one of the methods which replenish energy to stratum, improve the recovery factor of oil exploitation in the development of oilfield. The energy consumption of water injection is also part of the totle energy consumption. Oilfield flooding is one of the methods which with the great mass oilfields that in China have entered the later development period, the cost of oil exploitation is rising, and the water injection in the same way. It is an effective way to reduce the cost of water injection by using computer technology to optimize operation control of oil field water injection system. Water injection system analyzed in this paper is suitable by combining multiple centrifugal pump and frequency converter in the composition of water injection station as the water system, optimization mathematical model is established for water injection system, using c++ optimization software is compiled, selects the improved constrained variable dimension method was used to solve the model, the optimization result is applied to a production plant of daqing oilfield water injection system. After adopting the optimized pumping measures, the system efficiency is increased by 1.8% when meeting the water injection requirements, and the operation cost is saved by about 10,000 RMB per day, which reduces the production cost of the oilfield.
Research on Lean Operation and Maintenance Technology of Intelligent Electric Energy Meter Based on Artificial Intelligence
The existing power metering device does not realize on-line monitoring, operation health evaluation and dynamic inspection of equipment in the process of operation and inspection. The purpose of this paper is to solve the technical problems of online monitoring and evaluation of the operation status of the electric energy metering device, analyze the technical difficulties encountered in the process of realizing the lean operation and maintenance of the electric energy metering device and the supporting technologies available at this stage in detail, and propose a lean operation and inspection technology of the electric energy metering device to improve the working efficiency and level of intelligence management.
Numerical Simulation of Thermal Performance for the Reaction Tubes in a Miniaturized Methanol Synthesis Reactor
The reaction of methanol synthesis via hydrogen and carbon dioxide which has a broad application prospect in the energy field should be carried out in a reasonable temperature range. Thus, a comprehensive thermal analysis under different work conditions for the reaction tube which is the really reaction place in the miniaturized methanol synthesis reactor is of great significance to its temperature control and thermal design. In this paper, the thermal analysis models of reaction tube in methanol synthesis reactor via hydrogen and carbon dioxide are established, through numerical simulation, the thermal performance results which include the molar ratio of methanol synthesis and temperature distribution inside reaction tubes changing with the reaction tube diameter, inlet gas temperature, and space velocity are obtained. Based on the results, the change laws of the methanol synthesis molar ratio and temperature distribution change with the three parameters are summed, which provide a reference to the thermal design and working conditions setting for the miniaturized methanol synthesis reactor of hydrogen and carbon dioxide.
On the Relationship Between Contemporary Environmental Security and Human Health
Due to the deteriorating global ecological environment, the current outbreak of new coronary pneumonia has spread rapidly to all countries in the world, and it is constantly increasing its proliferation in posing a serious threat to human survival and development. This article intends to reveal the importance of protecting the ecological environment for human health from the close relationship between the environment and human health, and the deterioration of the ecological environment that caused various pollution and disasters has created serious harm to human health. At the same time, it analyzes the major problems between contemporary environmental security and human health, and proposes effective measures to address environmental security and human health in response to these problems, and calls on all countries in the world to work together to build a community of human ecological fate to ensure ecological security and human health, which is going to expand a broader living space for mankind and create better conditions for development.
Research and Application of a New Electric Coupling Device
With the increase in the size of the distribution network, as the overhead cable that accounts for the largest proportion in the urban power grid, the importance of electricity inspection and phase detection is also increasing. In order to avoid the shortcomings of traditional electroscope and the possible serious consequences caused by incorrect phase-detecting, this paper proposes a new type of electric coupling device, introduces the structure and performance of the device, and analyzes its advantages and practical applications. This electric coupling device can measure, calculate, analyze and report the real-time status of transmission line operation, and it can fully meet the requirements of engineering that is economical and practical, safe and reliable, and intuitive judgment.
Research on Influencing Factors of Heat Transfer Performance of Vertical Single U-Tube for Ground Source Heat Pump
The heat transfer performance of the buried heat exchanger is a key factor affecting the efficiency of the ground source heat pump. In this paper, the heat transfer model of the vertical single U-type heat exchanger is first established under the condition of variable heat flow to make it closer to the actual operating conditions, for simplicity The calculation process and the calculation time are saved. The boundary element method is used to analyze the heat resistance of the buried heat exchanger, and then the numerical simulation software is compiled to simulate the heat transfer performance of the buried heat exchanger. The results of the study show that the soil temperature changes within a range of 1.5m from the buried tube heat exchanger. The hole spacing of the buried tube heat exchanger cannot be less than 4m in practical applications; when the soil thermal conductivity increases by 25%, The heat transfer per unit depth of the buried tube heat exchanger increases by 14.8%; When the diameter of the drill hole is increased from 160mm to 300mm, the heat transfer per unit depth of the hole increases by 8.2%.
Research on the Application Prospect of Energy Blockchain in Power Grid Enterprises
Blockchain technology used widely in the financial field. As a representative of payment tools, Bitcoin impacted the monopoly of traditional finance and currency. As the key technology of Bitcoin operation, blockchain technology also has broad prospects in the energy field. Based on the analysis of the application prospects and related influences of blockchain technology in the field of energy and power, this paper puts forward an application model suitable for power grid enterprises and gives corresponding countermeasures and suggestions.
Research of Harmonic Index and Testing Method Based on Virtual Instrument
In view of the practical problems such as the imperfect harmonic testing and evaluation methods of the variable frequency speed regulation system and the high operating cost, a harmonic evaluation index system including 9 indexes is established, and the calculation method of each index is clarified. At the same time, the harmonic testing and analysis method of the variable frequency speed regulation system based on virtual instruments is proposed. The Labview software platform is combined with an external data acquisition module to replace the traditional testing instruments for harmonic testing and signal acquisition, processing and analysis. On the basis of theoretical research, an experimental platform was built to conduct verification experiments, and then the application experiments of 2 working conditions were carried out. The results shows that the test method was correct and feasible. Based on the experimental results, further analysis of the impact of harmonics on the performance of the variable frequency speed control system, and the corresponding law of influence will be obtained, which will provide guidance for the subsequent development of harmonic prevention and other related work.
Simulation Analysis of Emulsion Droplet Excited by Chaotic Frequency Pulse Electric Field
The frequency of the chaotic pulse electric field is random in a limited range, which can be adjusted and controlled, thus can effectively cover the harmonic resonance frequency of the droplets in the oil, and realize the efficient coalescence and demulsification of the droplets. In this study, the chaotic frequency pulse electric field is constructed by embedding the chaotic sequence into the pulse interval with the Chaotic-Pulse-Position Modulation method, and the vibration dynamics simulation model of the emulsion droplet in the chaotic frequency electric field is established. The vibration dynamics response of the emulsion droplet under the action of the chaotic frequency pulse electric field is obtained by numerical calculation, and the dynamic analysis, phase diagram analysis and maximum Lyapunov exponent calculation of the response output are carried out. It is found that under the action of chaotic frequency pulse electric field, the emulsion droplet can obtain large tensile deformation at high frequency, but relatively small at low frequency, and the fluctuation is stable, which can qualitatively and quantitatively identify the chaotic vibration characteristics of the droplet.
Application of BP Neural Network in Cross- Sensitivity Solution of Temperature and Strain of FBG Sensor
Fiber Bragg grating (FBG) sensor has the advantages of long transmission distance and less channel occupied by data acquisition instrument, so it can be used for strain measurement of power engineering and electronic engineering and so on. FBG is sensitive to both strain and temperature, that is, both changes can change the central wavelength of the grating. In structural health monitoring, the load on the tested part is complicated, and the temperature also changes greatly in the long-term monitoring process. If the FBG sensor is fixed on the tested component, it will inevitably be affected by the combined action of temperature and strain at the same time, making the test result produce error or deviation. In this paper, the temperature compensation of FBG strain sensor is analyzed and studied. Based on the calibration data, the FBG strain sensor temperature compensation is realized by BP Neural Network Algorithm. The research results of this paper can be used as a reference for health monitoring of large-scale structures using FBG sensors.
A Random Switching Frequency De-Re- Coupling Current MPC Method for Single-Phase MC
Model predictive control (MPC) is a highlighted control method for power electronic realm. For Matrix Converter (MC) with bidirectional switches and difficulty model, MPC has a complex structure and control process. A random switching frequency de-re-coupling current MPC method is proposed in this paper for a single-phase MC. A voltage function is obtained by the simplified and decoupled discrete-time model of MC, and a random switching frequency generating strategy is inserted to modulate function and to improve harmonic of MPC variable switching frequency. The principle effectiveness and advantages of the proposed method such as THD, settling times and static errors are verified by simulation results comparing with the conventional MPC and de-recoupling fixed switching frequency current MPC methods.
Research on Assistant Decision of Transient Stability Based on Trajectory Sensitivity
In order to improve the execution rate of the power system dispatch plan, a dispatch plan assisted decision-making considering transient safety and stability constraints is proposed. First, the principles for formulating power system transient stability control scheduling are given. Then, through the topological analysis of the expected fault location, decouple the unstable faults, formulate appropriate multi-fault adjustment timing according to the severity of the fault, and decompose the prevention and control problems of multiple fault constraints into several single fault stable control decision problems. In the end, a preventive control adjustment strategy that satisfies all transient stability constraints is obtained. Combined with parallel computing technology, the algorithm has the feasibility of online application.
Coordinated Control of Independent Microgrid Based on SOC Deviation Rate
System failure due to high failure rate of independent microgrid energy management system (EMS) in high altitude and cold area, considering the difference in charge state (SOC) between multiple energy storage devices in the system, a power coordinated control strategy based on the SOC deviation rate of energy storage devices is proposed, adjust the output power of the energy storage converter according to the difference in SOC of each energy storage device, reduce the difference in SOC of each energy storage device, after the system EMS fails, the operation status of the energy storage equipment is consistent to ensure the normal operation of the system. The RT-LAB simulation platform is used to establish a simulation model and design a digital control system. The control system can quickly carry out power coordination control according to the SOC state of energy storage devices, so it makes the devices output power differently according to the SOC level, reduces the SOC difference of energy storage devices, makes the devices SOC reach the same, and verifies the feasibility and effectiveness of the coordination control strategy.