A Method for Online Measurement of Dielectric Loss of HV Capacitive Equipment Insulation

It is still a major problem for research on online monitor dielectric dissipation factor of high voltage equipment insulation. In the field, new methods are paid attention by researchers especially. At present, there are no methods achieving the satisfactory measurement results. Based on the voltage and current at their respective zero crossed points, this paper proposes the integral measurement method which can be used to measure the dielectric dissipation factor of high voltage capacitive apparatus. The formula for dielectric dissipation factor angle computation is deduced by theoretical analysis and the computation results are achieved by digital simulation. Meanwhile, this paper explains the effect to measurements by system frequency, content of harmonic and zero-drift and draws the relevant error curves. It also proposes the measures to reduce the integral measurement method presented in this paper,which can convert measurement of small signal into that of big signal and accurately measure dielectric loss of capacitive apparatus. It also possesses great anti jamming ability under strong electromagnetic interference environment. The online measurement system can detect the dielectric dissipation factor of high voltage equipment by the integral measurement method.     

Application Research of MCU Technology in Online Test and Process Equipment for Vehicle & Motorcycle''s Accessory

Based on the discussion of MCU technology and its application in online test and process equipment for vehicle & motorcycle's accessory recent years,the paper elaborates the function of online test and process equipment for vehicle & motorcycle's accessory,brings up the hardware and software developing method which is applied to the C8051F020 MCU in electric controlling module of online test and process equipment for magneto.The test equipment has been made and tested the application effect of the MCU technology,on which works on with the real magneto product on line test in the factory,and this detected equipment is stability,unfailing apparatus through the real test.     

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This paper describes a digitization detection method harmonic analysis method which is used for detecting the dielectric loss of the electric equipments.The principle of this method and its characteristics of hardware circuits are introduced also.The testing results in the lab and the field show that this method can measure the dielectric loss rather stably and accurately.     

Real time self learning method of diagnostic knowledge in intelligent diagnosis system

Aiming at real time diagnostic knowledge accumulation and updating in intelligent diagnostic system, to simulate the process experts accumulate and update fault diagnostic knowledge, a new real time diagnostic knowledge self learning model is proposed based on pattern comparing and updating. Abnormal distribution test of hypothesis is used to compare real time equipment fault pattern to equipment normal pattern of contingent knowledge. The algorithm of sample size estimation algorithm is used to calculate the number of samples which is used to obtain necessary diagnostic efficiency. Real time model updating algorithm is used to adjust the diagnostic knowledge model to actual equipment on the spot. Analysis to actual test data of equipment shows that the method could achieve new diagnostic knowledge accumulation and be adaptive to actual equipment on the spot.     

The Electric Control System of Mechanical Transmission Test-bed With Mechanical Closed Cycle And Electric Colsed Cycle

This paper presented the principle and combinations of the mechanical transimssion test-bed with mechanical closed cycle and electric closed cycle. This system is composed of variable velocity driver, motor, generator, inverter and computer. It can be used both in mechanical closed cycle test-bed and electric ciooed cycle test-bed. The test-bed can keep a realting monitoring over the system and control the rotational speed and torque by computer. It can also simulate the real work condition of the test and to do the test. In this paper,the diminishable magnetization velocity modulation,invertiable control,the test data and curve,and the inverting efficiency as well as control scheme and presented.     

Analysis of spatial electric field with point-plateelectrodes configuration using finite element method

To investigate the spatial electric field with the point-plate electrodes configuration, variations of the electric field intensity are analyzed for absolute air dielectric and liquid dielectrics contained in air dielectric based on the finite element method of numeric computation. The results show that the electric field intensity of the spatial electric field is great non-uniform with the point-plate electrodes configuration for absolute air dielectric, and it can be increased rapidly at the nozzle point to achieve a maximum value. Single oil drop existed in air dielectric induces a biggish deformation of the gradient of the electric field intensity in its neighbor field. Many oil drops along with horizontal distribution have an obvious tensioning operation on the electric field, so the electric field intensity on the normal at the nozzle point has an evident augment for overlapping effects among the oil drops, and it can spread electric corona area of the total spatial electric field.     

OPTIMAL REACTIVE POWER FLOW BY SENSITIVITY METHOD

A new approach based on sensitivity method for the optimal power flow is presented in the paper. This method has the following advantages: it is suitable to solve a 200-node power system on the microcomputer; the convergence is easy to reach and the computation speed is quick; it is possible to reduce 8-14% power loss and to get maximum economic benefit by using this method; in power system dispatch center it can be used as an on-line voltage and reactive power control program to keep good voltage level. The proposed method has been proved successful by IEEE 118-node test system and the several real power systems such as 49-node, 61-node, 99-node and 200-node systems.     

Hardware in the loop test for plug-in hybrid electric vehicle

Mathematical modes of engine,cooperation of motor and batteries,automatic clutch and vehicle are built with analysis of configuration of plug-in hybrid electric vehicle (PHEV). Specifications of data input and output and signal characters are defined. Hardware in the loop (HIL) system based on MATLAB/xPC for PHEV is built up. The motor/engine drive shift control logic test of PHEV is carried with inputting real acceleration pedal data. Testing results show that automatic clutch acts abnormally. Bugs in control logic are found out. Road test results with revised control logic are very good.     

Flexible Field Calibration Solution of Environmental Test Equipment

In accordance with the shortage on the application of the traditional calibration Solution of environmental test equipment, this paper proposes a solution of flexible field calibration , which can be applicable to all sorts of environmental test equipments widely. The frame of system hardware and software is presented firstly through the system requirement analysis, then the key matter - - flexible calibration is analyzed and expatiated more deeply. Through actual test , it is shown that the solution put forward in this paper have notable applied values and spread significances.     

双层对向正反燃烧单体供热技术在烤烟烘烤中的应用研究

为提高烤烟烘烤中燃料利用率,降低烘烤成本,减少环境污染,研究采用1个供热炉设上下2个炉膛,实现正向和反向同时对向燃烧,对比研究了双层对向正反燃烧单体供热设备和普通加热设备烤房烤烟烘烤性能。煤的燃烧充分,传统烟气中所含CO、CH4、碳粉尘等可燃物能得到充分、高效燃烧及利用。空载测试升温速率60℃/h,比普通烤房提高34℃;烘烤实载时,各阶段实测温湿度与目标温湿度吻合度高,完全能满足烘烤工艺的控制要求。双层对向正反燃烧单体供热设备烤房平均每千克干烟耗煤量、耗电量、综合能耗成本分别比普通烤房减少0.31 kg、0.05 kWh和0.33元,降幅分别为17.73%、14.36%和17.46%;烘烤操作等日常用工成本较普通供热设备少0.52元,降幅43.93%,且对烟叶烘烤质量无明显影响。双层对向正反燃烧单体供热设备升温速度快,平面温度均匀,烘烤过程中温湿度控制精准,能有效降低烘烤能耗和用工成本。     

南美白对虾池塘养殖水质智能控制系统设计与开发

南美白对虾池塘养殖对于水体质量有着较为严苛的要求,残饵及生物排泄物的增多会大量消耗水体溶解氧,进而打破水体动态平衡,导致NH₃-N、NO₂-N等毒害成分升高,引起南美白对虾病害甚至导致死亡,造成养殖户经济损失并且阻碍了南美白对虾养殖产业的健康发展。针对上述问题,笔者研究并开发一种能够实时监测养殖池塘水质,并能根据南美白对虾生长习性智能控制增氧机、水泵等养殖设备的南美白对虾池塘养殖水质智能控制系统。系统具有控制智能、运行可靠、集成度高等特点,在养殖生产试验中取得了良好效果,保证了南美白对虾养殖过程的安全,有效降低了南美白对虾池塘养殖风险。     

Advancement of High Pulsed Electric Field for Inactivation of Microorganism

Inactivation of microorganisms can be realized by the accurately controlling the pulse electric field the strength and time for microorganism cell membrane. Use of high pulsed electric field for inactivation of microorganisms is one of the more promising nonthermal processing methods. Compare with pasteurization,it possesses the advantage of instant and even distribution throughout a conductive food system,short treatment time and very little heating of the medium in continuous processing. In addition, HPEF can decrease the loss of nutrition as little as possible. The author critically review the results of earlier experiment studies on HPEF,the mechanisms of inactivation by HPEF,and we suggest the future work that is required in this field.     

Model predictive control strategy of a medium hybrid electric vehicle

The intense coupled and nonlinear behaviors were observed on the tall long span tower line systems which were under the icing and wind loads in heavy icing areas. A set of stiffness equations of insulator, conductor and boundary conditions was deduced. Taking the ±800 kV UHV DC transmission line from Xiangjiaba to Shanghai as an example, the simplified numerical model of transmission tower, conductor, insulator and constraint was developed. The long span transmission tower line system models under seven loads conditions were analyzed by static nonlinear methods. It was found that the P Δ effect of tower components was small when the covered ice was uniformly distributed. The unbalanced wire loads on the tower would lead to twist effect when the covered ice was uneven distributed. The axial forces, moments at restraint nodes and the longest cantilever member were greatly affected by the P Δ effect, under which the unfavorable effect on the structure should be considered.     

Design of nondestructive examination system for bridge cables surface defect

Aiming at the drawbacks of the current detecting methods, a nondestructive examination system design for bridge cables based on high speed digital signal processors chip DM642 is presented, and the hardware platform of the system is built. This examination system mainly consists of four parts: the image defaults acquisition part, DM642 hardware platform, creeping part and defaults locating equipment. The designed system is tested on the hardware platform based on digital image processing algorithm. The experimental results show that the detecting system has the advantages of high stability and reliability, real time, mass storage, and nondestructive examination, etc. This system uses high technology and has significant meaning on detecting the current bridge cables health, furthermore, this method can be used in other examination fields.     

LCL型CPT系统的参数设计方法及频率特性分析

以金鲳鱼为原料,固定小麦粉与水的质量比为2∶1,食盐添加量2%,微波真空度0.095 MPa,在单因素试验的基础上,通过正交试验对微波真空技术膨化鱼糜饼工艺条件进行优化。结果表明,鱼糜饼制作的最佳工艺条件为:鱼糜含量35%,膨化温度100℃,膨化时间20 min,鱼糜饼厚度2 mm,在该工艺条件下,制得的膨化鱼糜饼色泽金黄、质地酥脆、风味清香,成品膨化率可达到540%。     

西安地区智能通风冬季降温试验研究

利用冬季低温进行机械通风来降低粮堆温度是粮食储藏的重要技术,但选择适当的通风时机和适宜的通风方式,可以降低通风能耗,减少通风水分损失。试验表明:智能通风能够及时准确地把握有利的通风时机,自动控制通风设备的启停,提高通风效率,降低通风能耗和减少粮食水分损失。     

萌芽米工厂化生产关键设备及加工工艺研究

根据萌芽米的特性,研究了工厂化加工工艺,研制开发出适合萌芽米工厂化生产的关键设备。浸种催芽采用一体化智能仪表控制的冷热水循环系统,保证了催芽的恒温效果;芽体钝化采用高温高压的蒸汽,既保证了酶体的快速灭活,又起到灭菌的效果;干燥采用温室型太阳能干燥,既节能又保证萌芽米的商品性。经生产试验结果表明,设备的性能符合萌芽米的工业化生产要求。     

Load Forecasting Based on BP ANN for Economical Operation of Electric Boiler with Heat Reservoir Under Time-sharing price

Along with the generalization of DSM and time-sharing price system, the use of electric boiler with heat reservoir becomes more and more extensive. Load forecasting of heat supply system is an important base in the study of economical operation of electric boiler with heat reservoir under time-sharing price. The BP ANN modeling of the load forecasting for a 1200 kW electric boiler is discussed. The result of hourly heat load forecasting accords well with the real heat load.     

State of charge estimation of lithium iron phosphate batteriesbased on adaptive Kalman filters

The Kalman filter algorithm can be used to estimate the state of charge (SOC) of power batteries, however, it easily causes divergence due to uncertain of system noise and its estimation performance is affected by model. An adaptive Kalman filter algorithm is adopted to dynamically estimate SOC of lithium iron phosphate batteries for application in electric vehicles. At first, an equivalent circuit model, appropriate for SOC estimation is built after studying battery models. Then some charging and discharging experiments are carried out for parameter identification and the results are verified. At last, the adaptive Kalman filter algorithm is used on this model for on-line SOC estimation under unknown interfering noise. Simulation results show that adaptive Kalman filter method can correct SOC estimation error caused by tiny model error online, and the estimate accuracy is higher than Kalman filter method. Adaptive Kalman filter algorithm can also correct the initial error. Full-cycle test in electric vehicles proves that the algorithm is appropriate for SOC estimation of lithium iron phosphate battery.     

A NEW ON LINE AND REAL TIME METHOD FOR DETERMINING HARMONIC AND REACTIVE CURRENTS

According to the basic idea of phasar analysis and by applying a special multiplier, a new on line and real time method is derived for determining harmonic current and reactive current of an electric network. This method has a good dynamic response characteristic and solves for the first time the determining problem for the compensation system in single phase system,which is also appliable to the three-phase system.