Applied Mechanics and Materials Vols. 543-547

Abstract: The randomness and fluctuation of wind results in wind power generation with strong uncertainty. To ensure the power system operate safely and reliably, research on the impact of grid connected wind power on power system is necessary. From the perspective of system relay protection, system peaking, transmission capacity planning and reliability planning, this paper introduces the impact of centralized wind power integration on power system.

Abstract: To solve the effect that the multi threading task can be achieved by the TFT of color screen, we adopt MSP430F5438 as the main controller, the main equipment of its hardware system was built by the TFT of touch screen, and the task driving function was completed by using buttons and wireless communication module and other peripherals. And we have developed the application program based on UC/OS operating system utility with the kernel structure and characteristics of UC/OS. It can be realized these function, such as digital tube display, TFT display task, multi-tasking, wireless communication, the task driving system, touch screen and low power verification task. The experimental results show that it completely meets the desired design goals, it works reliable and stable.

Abstract: 270V high voltage DC power supply system with grid of light weight, uninterrupted power supply and a two power density higher characteristic, in recent years become a hot research topic in domestic and international air supply system.[ To ensure the high voltage DC bus power quality, for the safe operation of the aircraft is very important. Single phase aeronautical static inverter as a typical aircraft power system load, the input current ripple of the serious pollution of the high voltage DC power supply. Therefore, the harmonic pollution problem of how to control the high voltage DC power supply system has been increasingly concerned aviation power researchers.

Abstract: The electromagnetic characteristic of sensitive field of Electrical Capacitance Tomography (ECT) was compared with that of Electrical Resistance Tomography (ERT) applying Finite Element Method.The math model of ECT and ERT were deduced respectively, then their electromagnetic characteristics of sensitive field and their relationship were evaluated using finite element method, which laid the foundation of theory for information fusion in ECT&ERT-compound system.

Abstract: In this paper, a new BIST structure is presented, which is generated by the LFSR modified. There is no redundant single input jump test incentive, all possible test vector combinations are covered, the testing power is reduced. Moreover, the testing time do not increase and fault-coverage rate won't be affected. Experiment results on the integrated circuit 74HC42 show that the switching activity reduction can be achieved up to 64% while achieving high fault coverage, especially suitable for BIST of Integrated circuits.

Abstract: Traditional frequency power and test equipment cannot meet the requirements. This paper discusses in detail the composition of FM type series resonance test device, technical principles, characteristics and advantages. And also introduces wiring method, test methods, test standard. The instance proves that discharge test of large transformer using the FM series resonance device is convenient and accurate.

Abstract: With the development of national economy, the progress of science and technology and the height of the production process automation, various nonlinear loads in power grid grow rapidly together with a variety of complex, precise and sensitive power equipment. The above-mentioned two aspects of contradiction is more and more prominent and the requirement of users for power quality is also higher. In such situation, this paper discusses the related theory and its control technology in the field of power quality, analysis the development trend of power quality management and control in our country, which has a strong practical significance. This paper expounds the main problems affecting the quality of electric energy, and analyze in detail the way to improve the quality of electric energy, and then give a preliminary discussion on the development direction of this field.

Abstract: According to the 66kV transformer blackout phenomenon, the oil chromatogram data analysis, found that the transformer existed temperature (676 °C) and low energy discharge defect. Through measuring the harmonic content to and analyzing the load condition, test results show that the grid was injected harmonic currents by the substation non-linear loads, its 5 times,7 times, 11 times, 13 times harmonic were higher than the state standards, this shows that the harmonic is the cause of the chromatographic data of transformer oil abnormal

Abstract: Metal oxide surge arresters cavity invasion along the humid, causing flashover discharge incidents, through the structure and assembly of metal oxide surge arresters construction process, discusses the causes MOA damp for various reasons. Test methods can be found listed MOA cavity invasion humid, and described the purpose of the various test methods and their respective advantages and disadvantages, while noting that the invasion is suspected cavity defects humid or with a family of metal oxide surge arresters, various test cycle should be shortened and comprehensive analysis, judgment, to prevent accidents of various test data.

Abstract: This paper briefly expounds the determination of transformer pressure value, and introduces the principles of power frequency ac withstand voltage, variable frequency series resonance withstand voltage and multi-frequency induced withstand voltage. It also expounds the ac withstand voltage wiring method, and demonstrates a simple way in withstand voltage test on low voltage winding.