A heat pipe reactor (HPR) is a kind of modular small reactor with broad application prospects, and its dynamic characteristics and nuclear power control are essential to the safe and stable operation of nuclear power plants. Taking the MegaPower HPR as an example, the dynamic characteristics of the HPR are analyzed, and its power control method is designed in this paper. Based on the lumped parameter idea, the equivalent processing of the structure of the HPR core is carried out, and the main parameters of the heat pipe heat exchanger are designed at first. A lightweight dynamic model of the HPR is established using a thermal resistance network, and the accuracy of the model is verified using the solution of the model under the steady-state full power condition. Then, the dynamic characteristics of the HPR without a controller are analyzed respectively with the disturbance reactivity and mass flow rate, indicating strong self-stability and self-regulation of the HPR. Finally, a reinforcement learning (RL) controller based on the twin delayed deep deterministic policy gradient (TD3) algorithm is designed for the HPR power control, and it is adjusted through appropriately setting states, network structures, reward functions, etc. To verify the performance of the controller, a step response simulation ranging from 100%FP to 90%FP, a compound conditions simulation, and a large load change simulation are carried out, respectively. The results show that the RL controller can find the optimal control strategy through training. Meanwhile, it significantly improves the dynamic and steady-state performance of nuclear power compared with uncontrolled case and PID controller case, and it has the ability of power control under all operating conditions.
Stall affects the safety of aircraft flight.Although the traditional stall warning system improves the safety by adopting the method of synchronizing the clock of multi-processors,the reliability of the system is reduced,and the complexity becomes high.To improve the reliability and reduce the complexity of the stall warning system,the inter-core data interaction and data consistency checking functions of heterogeneous dual-core processors are used to realize the high security design of the stall warning system.Firstly,a suitable processor is selected based on the overall design.Then,the inter-core communication mechanism is compared and selected based on the selected heterogeneous dual-core processor.Finally,the dual-core data transmission tasks are reasonably assigned.The test results show that by utilizing the shared memory communication mechanism in the dual-core processor for data transfer,the data transfer interaction is safer,faster,and more efficient.The method of consistency checking to the solved data in the same processor improves the correctness of the output instructions,enhances the safety performance of the system,and meets the requirements of the stall alarm system for high reliability and high security.In addition,the selection of heterogeneous dual-core processors for residual design is also applicable to other types of systems.
The status of research on high temperature measurement technology and development of temperature sensors is analyzed and summarized.Firstly,the situation of AMS 2750G standard is briefly introduced,as well as the status of research and application of the new concept of calibration of temperature measurement system,i.e.,online calibration.The concepts of offline calibration,online calibration,and the relationship between the two,as well as the development and application of portable online calibrators and thermocouples with calibration holes series are introduced.Then,the development and application of refractory metal thermocouple that tungsten rhenium thermocouple is elaborated in detail,including the characteristics and classification of tungsten rhenium thermocouple,the international leading anti-oxidation technology,and the performance of tungsten rhenium thermocouple at home and abroad is compared.Finally,the research and application of localization of imported temperature sensors are summarized,including the localization research of special thermocouples for multi-purpose furnace and carburizing furnace,thermocouples with calibrated holes,and special thermocouples for glow ion nitriding furnace,etc.,as well as the work of replacing precious metal thermocouples with inexpensive metal and refractory metal thermocouples.This research will provide new ideas for practitioners in the high-temperature measurement industry to select suitable temperature sensors.
Aiming at the problem of insertion and assembly of shaped components,a kind of insertion head that can stably insert and assemble shaped components is designed.Firstly,the ball screw sub drive system is applied to the design of the insertion head lifting mechanism,and the servo motor is selected through theoretical calculation.Then,ADAMS motion simulation software is used to simulate the lifting and rotating motion of the insertion head to verify the reliability of the calculation results and the stability of the structure.Finally,the insertion head is installed in the shaped insertion machine for the insertion test,the relevant data in the process of insertion movement is measured by NYCe motion control system.The test results show that:the maximum speed of the lifting movement of the insertion head is close to 1 m/s,and the one-way movement time is within 0.012 s,which meets the design requirements;the displacement change of the clamping jaw center of the rotating mechanism in the simulated movement process is kept within±0.015 mm,which indicates that the rotary movement is relatively smooth,and the accuracy is in line with the insertion requirements.The test results verifies the utility of the insertion head.The study provide a basis for the subsequent optimization of the performance of the insertion head and enhance the insertion efficiency.
In the field of nuclear sodium-cooled fast reactors,sodium pressure transmitters are essential for monitoring the pressure parameters of sodium process loop.The needs of high temperature,prevention of sodium liquid leakage,and detachable calibration of the sodium process loop are the main factors considered in the functional design of the sodium pressure transmitter.The study of the sodium pressure transmitter includes:the process connection is welded to prevent leakage of sodium liquid;the material used to receive the liquid is Austenitic heat-resistant stainless steel 316H,which solves the problem of high temperature and corrosion resistance;the separation structure consisting of positive and negative flanges of the remote transmission components realizes the function of removability;after the disassembling and separation of the transmitter's normal temperature components,the sealing design of the cavity structure formed by the high temperature components and the pipeline of the sodium liquid and the protection principle are analyzed.Sodium pressure transmitter for sodium bench high temperature impact test,separation mechanism disassembly and secondary installation impact error test are carried out.The test results all meet the requirements.The design and realization of the detachable sodium pressure transmitter meets the special needs encountered in the nuclear power sodium-cooled fast reactor demonstration project.The innovative design of its remote separation pressure transmission mechanism has reference for the application of pressure instruments in other fields.
In the digital protection system of nuclear power plant,the control layer communication undertakes important data and information transmission tasks to provide field data and protection output for the control unit,is an important part of the digital protection system of nuclear power plant.The existing control layer communication protocols can not meet the requirements of determinism,reliability,independence and real-time of nuclear power plant digital protection system.The designed control layer communication protocol adopts state-based,fixed communication period,redundant communication links,transmission of only fixed data sets,and fixed frame length and format.According to the requirements of nuclear power standards,the possible types of faults in the communication protocol are analyzed,and the error detection methods and corresponding processing measures are also given to meet the requirements of determinism,reliability,independence and real-time of the digital protection system of nuclear power plants.The communication protocol has been certified by authoritative organizations,and the hardware products involved have been authenticated as nuclear safety grade equipment,which can be subsequently applied to military,aerospace and other high-reliability industries.
With the goal of improving the obstacle avoidance ability of fixed-wing unmauned aerial vehicle(UAV)transmission line inspection and reducing the length of inspection path,a multi-objective inspection routes optimization method of fixed-wing UAV for transmission line based on improved particle swarm algorithm is proposed.Taking the minimization of line length and line threat as the objective function,combined with the length constraints of the trajectory segment and the maximum turning angle constraints,the fixed-wing UAV multi-objective inspection routes optimization model is constructed.The multi-objective function is used as the fitness function of the particle swarm optimization algorithm to find out the optimal transmission line inspection routes.Innovatively,by adjusting the inertia weights of particle swarm algorithm,introducing the strategy of comparing the values of adjacent fitness functions,and hybridization operation of genetic algorithm,the multi-objective inspection routes of UAV is optimally generated.The experimental results show that the method can effectively avoid all the obstacles existing in the inspection range.The inspection routes can cover all transmission lines within the inspection range.The-optimization effect is most appropriate when the trajectory points within a hundred square meters are set to 25.
1 概况 (1)《自动化仪表》创刊于1957年,系中国科学技术协会主管、中国仪器仪表学会与上海工业自动化仪表研究院有限公司合办、在我国自动化仪表行业具有专业技术权威的综合性科技期刊. 本刊采用大16开本,月刊,每月 20 日出版,国内外公开发行,邮发代号4-304,国外代号M721.
Aiming at the problems of large positioning error and low positioning accuracy of traditional natural gas leakage point localization methods,a natural gas leakage point localization method based on pipeline spatial data is studied.The embedded technology is used to construct a natural gas leakage detection system.Combined with the pipeline spatial data relationship,three base station nodes that meet the requirements and are closest to the unknown node location are screened out by the three-line edge localization method.The node vectors are computed by the least squares method,and the natural gas sensing node locations are solved.The weighted fusion algorithm is used to add spatial feature relationship weighting factors to each group of localization coordinates to realize the leakage point localization.The simulation test proves that the proposed method can make full use of the spatial relationship data features,reduce the localization error rate,detect the specific node location of the leakage point in a shorter time,and the detection performance is balanced and stable.This research can provide reliable technical support to help for pipeline natural gas leakage rescue work.
To optimize the peaking effect of supercritical coal-fired generating units,a 660 MW supercritical coal-fired generating unit is taken as the research object,and a proportional integral differential(PID)controller-based automatic control method is proposed for the deep peaking of 660 MW supercritical coal-fired generating unit.The dynamic model of the coal-fired generating unit is established,and a variable operating condition model is constructed;the dynamic characteristics of the 660 MW supercritical coal-fired generating unit in the deep peaking process are analyzed using the variable operating condition model;the PID controller is designed according to the analytical results to realize the automatic control of the 660 MW supercritical coal-fired generating unit in the deep peaking.The test results show that the proposed method has high flexibility in deep peaking,can meet the upward and downward peaking demand,and has a small gap with the set peaking demand;the wind and light discard rates are low,and the power is reduced after control.The test results prove that the proposed method has good deep peaking performance.
To solve the parameter identification problem of second-order time-lag system,a new method is proposed to estimate the unknown parameters of the system based on the step response.The method first solves the expression of the step response function of the second-order time-lag system;then the parameter estimation problem is transformed into a nonlinear minimization problem by defining the objective function.To solve the optimal solution of the objective function,a method of optimizing the objective function using differential evolutionary algorithm is proposed.In this method,the"either-or"strategy is adopted to minimize the influence of control parameter settings on the performance of the differential evolution algorithm.The parameter identification performance of the proposed method under different noise conditions is investigated seperataly through simulation experiments.The experimental results show that the proposed method has faster convergence speed,higher parameter estimation accuracy and better noise resistance.The proposed method can effectively solve the parameter estimation problem of second-order time-lag systems.
The central control room is the most important thing to protect the production operation.At present,the intelligent level of environmental monitoring and control inside the central control room of chemical enterprises is relatively low,the operating environment of personnel and equipment is not ideal,which leads the outstanding safety hazards.In view of the above problems,a set of center control room environment intelligent monitoring and control system based on STM32 and LabVIEW is innovatively designed.The lower computer of the system adopts STM32F429IG as the main control chip and realizes the collection of environmental parameters such as multi-point temperature,light intensity,number of people,and gas concentration in the central control room through sensors such as DS18B20,photosensitive resistor,and E18-D80NK,etc.The circuit is built by using TB6600HG,TPS92515 and other driver chips to achieve intelligent control of air conditioning,lighting,alarms,and other equipment.Through the RS-485 serial port,the data is transmitted to the upper computer monitoring platform to realize the real-time reading,display,and storage of each parameter.Test results show that the system runs stably,has good practicability and expandability,low development cost,and also provides a reference for other types of central control room environmental monitoring and control.The research has some inspirational significance for the extension of the research focus in the field of safety production from the traditional production area to the non-production area.
Power sensing data is a kind of time series data.The power system generates a large amount of data in operation,which leads to high system load and low query efficiency when querying the frequent items of data.To improve the quality of power transmission in the power grid,the query method for frequent items of power-aware data based on time-domain features is investigated.The power system topology is constructed to predict its operation state.According to the vertical continuity and horizontal continuity of the power grid,the transmission-active power sense data are collected directionally.Two sliding windows with the same three-axis acceleration are taken as the target area to extract the time-domain features of the power sensing data.The extracted time-domain features are input into a Bayesian classification algorithm and classified using a Bayesian classifier.Considering the logical sparsity degradation problem caused by the harmonic tremor effect,the frequent item query of power sensing data is realized by locking the category intervals with a larger frequency share.The experimental results show that the proposed methods's query rate is higher than 97%,the query of power sensing data is more than 180 items,the time overhead is 5 ms,and the memory overhead is 10 MB.The proposed method can effectively improve the query performance and query efficiency of the frequent items of power sensing data and improve the quality of power transmission in the power grid.
In order to achieve closed-loop accurate control of the electronic control air processing system of commercial vehicles,so that the safety and economy of the system can be improved,the temperature and humidity sensor is introduced into the air processing system of commercial vehicles.Together with the datas of the temperature and humidity and pressure,the high pressure dew point depress(DPD)can be real-time calculated and monitored using the Vogel-Tamma-Fullcher(VTF)equation.On this basis,a electronic control system for commercial vehicle air processing unit(APU)is designed,which is suitable for chassis domain controller or vehicle controller.Experimental results indicate that the system can effectively reduce the regeneration rate by about 4%,and the air compressor on-load rate of the commercial vehicle air processing system can be reduced by about 3%,under the China world transient vehicle cycle(C-WTVC).The dew point estimation is introduced into APU electrical control system,which realized real-time monitoring and stable control of DPD in air processing system,improved system safety and reduced the load of air compressor.
To better solve the problem of electricity information collection and processing during multi-source faults in the power grid,research is carried out on the data-driven-based power grid multi-source fault intelligent fusion technology of electricity information collection.The online operation mechanism of this technology is realized based on a priori knowledge and deep Boltzmann machine(DBM)model.After categorizing and processing the multi-source electricity information,the dynamic data and static data are acquired.The feature sets of different categories of electricity data are extracted by data driving,and the Kalman filter algorithm is used to remove the redundant features in the feature sets to complete the consistent feature description of electricity information,to obtain the fusion results of electricity information.The test results show that:the technology has good application performance;the test results of Davidson-Boulding index(DBI)are all below 0.017,which can effectively categorize the dynamic data and static data and deal with the abnormal data in the data;the results of coefficient of variation are all below 0.02.Using the electricity information fusion results obtained by this technology,it is possible to reliably predict electricity demand and identify abnormal electricity behavior.The application of this technology is effective.
Aiming at the problems of large size and long preheating time when traditional turbidity sensor is applied to groundwater in-situ monitoring,a new type of turbidity sensor suitable for groundwater in-situ monitoring is designed.The sensor is based on the principle of 90° scattered light measurement and adopts a flexible glass optical fiber bundle as the light guide material,which significantly reduces the size of the sensor.In addition,the sensor compensates for the luminous intensity of the light source by dynamic monitoring,which effectively shortens the preheating time of the sensor and further improves the measurement accuracy of the sensor.The measurement principle and design method of the sensor are introduced,and the performance of the sensor is verified in combination with the needs of groundwater in-situ monitoring and the requirements of relevant specifications.The sensor has a measurement repeatability of 0.41%,a drift of 0.46%,a linearity error of 0.47%,and can better withstand a 0.5 MPa water pressure environment.The test results show that the sensor has high measurement accuracy,good stability,strong water pressure resistance,and can be suited for in-situ turbidity monitoring of groundwater.
To reduce the impact of new energy access on the power system,the automatic control method of load frequency of power system based on compressed sampling is studied.The sparse representation of the collected new energy generation output power signal is carried out by using the matched tracking algorithm,and the low-dimensional measurement value is obtained by projecting the sparsely represented signal to the measurement matrix.The reconstructed output power of the new energy generation is obtained by using the L1 paradigm optimization method within the range of the measured values.The deviation of this power and desired power is used as a perturbation term to access the load frequency control model based on proportional integral(PI)controller.The variable domain method is utilized to adjust the input and output domains of the PI controller.According to the fuzzy reasoning,the expansion factor is defined,and the variable domain fuzzy PI controller is constructed to act on the load frequency control model to complete the automatic control of the load frequency of the power system.The experimental results prove that the output power after control of this method is stable,the regional control deviation and frequency deviation under load disturbance are small,and the accuracy of automatic control of power system load frequency can reach up to 99%,which is practical.
The wind turbine vibration signal is mixed with many sound signals,and the signal band is disturbed by noise,resulting in poor fault diagnosis of wind turbine.To this end,an online fault diagnosis method of wind turbine based on the separation and purification of sound vibration signal is proposed.The factors leading to the interference of wind turbine acoustic vibration signal are analyzed.Empirical mode is used to decompose the initial wind turbine online fault signal into two parts:high-frequency component and low-frequency component.A wavelet threshold algorithm is used to remove the high-frequency component noise and do reconstruction processing with the low-frequency component to derive the actual fault vibration signal of the wind turbine.A back propagation(BP)neural network training model is established,and the optimal weight matrix and bias vector of the network are derived using particle swarm optimization algorithm,and the location and type of fault data are diagnosed by the network training algorithm.The experimental results show that the proposed method has high accuracy in online fault diagnosis and can ensure its training efficiency and convergence speed,which is of high practical value.
To avoid power users from being defrauded during the transaction process,it is necessary to monitor the whole green power transaction settlement process.A security monitoring model of green power transaction settlement process based on multi-timescale coupling is proposed.Based on the sequence data fusion method of time smooth regularization,the green power transaction data of multi-timescale are fused.Based on the data fusion results,the specific process of green power transaction settlement is analyzed,and the Monte Carlo simulation method is innovatively adopted to establish the transaction model.Through the Markov random field model,a security monitoring model is established according to the characteristics of the green power transaction settlement process to realize the security monitoring of the green power transaction settlement process.The experimental results show that the application of the proposed model can cover the entire green power transaction process and monitor the 24-hour security posture of green power transaction with high accuracy.The study provides a reference for analyzing the security risks in the settlement process of green power transaction.
Blast furnace blower dial system introduces hot air from other blast furnaces into the duct of the faulty blast furnace through the dial contact pipe,to prevent the slagging in the air outlet due to the emergency shutdown of the blast furnace blower.In the case of bidirectional measurement and limited straight pipe section,a programm of matching a bidirectional flowmeter and restriction orifice plate is proposed to meet the process requirements and save cost.In the choice of bidirectional flowmeter,more consideration is to meet the process under the premise of convenient construction and installation and subsequent maintenance.In the choice of supporting secondary meter not only consider the accuracy and cost,but also innovative use of a differential pressure transmitter to complete the measurement of bidirectional flow.In about 1 year after the project is put into operation,the working condition runs well.The programme idea has universality,suitable for popularization and application.
