Applied Mechanics and Materials Vols. 385-386

Abstract: Gas insulated switchgears occupy an important position in the power system.Insulating spacers are important parts in GIS, a research on the surface discharge characteristics is conducted, mainly using ultraviolet imaging technology, ultrasonic testing technology and pulse current method to test the whole discharge process. Based on the data analysis, get the following conclusion: 1) Ultraviolet photons indicator shows the "saturation" characteristic, when the voltage up to 68kV later, continue to increase the voltage, ultraviolet photon number increase is not obvious; 2) In the basin insulator defect, with discharge intensifies, charged particle collision more intense, the heat increase, so the local volume rapid expansion, the pressure increase lead to enhance the ultrasonic signal. These works provide a valuable reference for follow-up study of GIS.

Abstract: At present, the operational parallel compensating capacitors can only through the protection action for the information, so we can‘t location the fault capacitor. In order to obtain every parallel capacitor running status information and according to internal structure and the operation mode of film capacitor, this paper proposed a method of locating a capacitor, which can eliminate the affection caused by the environment and measurement error of sensor accuracy effectively. So we can locate the fault capacitor in complex environments running on the site.

Abstract: This paper presents fixed switching frequency direct power control (FSF-DPC) for three-phase AC/DC converter. Sensorless control strategies based on virtual-flux can optimize the performance of the system. In this paper, realization of pulse width modulation method for FSF-DPC is presented. The simulation results show that the system running performance is good.

Abstract: This paper mainly introduces an optimal design of PI control based on compensation to eliminating the interference and improving the performance of the system. With the mathematic model of shunt APF in d-p rotating coordinate, simulation indicates that there is a period disturbing signal in the current closed loop of shunt APF based on the conventional PI control, which obviously impacts on the current tracking performance of the system. So a new PI control based on compensation is put forward. Through the simulation in the platform of Matlab/Simulink, it turns out that this method can improve the current tracking performance of APF and stable performance of the system.

Abstract: In this paper, the hysteresis current control (HCC) technique based on space vector modulation (SVM) for active power filter (APF) is proposed. The switching control algorithms of the HCC based SVM manage to generate compensated current according to the reference current. Harmonics extraction is calculated for the power compensation based on the instantaneous active and reactive power theorem in time domain. A closed loop control system is carried out and the APF manages to generate better compensated harmonics currents to the power grid.

Abstract: The BD satellite navigation and positioning system (BDS) is a new generation of satellite navigation and positioning system developed by China independently. In order to get rid of the long-term reliance on the GPS system, research on the BD/GPS integrated navigation positioning algorithm is both inevitable and necessary, and analysis of the BD/GPS integrated navigation positioning accuracy is of great significance for the navigation and positioning applications. In this paper, the basic principles of the integrated navigation and positioning, observation equations and positioning algorithms were expounded, and the least squares algorithm was used to accomplish the positioning calculation. Base on the analysis of Positioning results, the integrated navigation and positioning accuracy of BD/GPS was given. The research results are importance to the application of the BD system.

Abstract: The imaging of the side of deep pipe is key problem of the detection implement in industry. With the help of tailor-made lamp-house, the side image of the deep pipe is detected by the CMOS chip. The CMOS chip is a little view field and large focal length, and it could convey the side information to the processor-SQ606. The image procession and photo and video files manipulation are fulfilled. With the telescopic barrels, the image of the side of deep pipe is satisfied.

Abstract: With the rapid development of modern electromagnetics, a lot of electromagnetic field numerical methods are maturing. 3D electromagnetic simulation software HFSS has two solutions including incentive solving and eigenmode solving. When solving the calculation of the structure of eigenmodes or resonant type can use eigenmode solver. Using matlab generate HFSS scripting language-based program to set eigenmode solution is a very convenient and very innovative approach. The program on a circular cavity modeling and eigenmode solution set simulation results meet the design requirements.

Abstract: A radial line slot antenna (CP-RLSA) is a slotted waveguide planar array for DBS reception. A number of designs have been devised, but these designs have pros and cons. In order to suppress grating lobes and increase the gain, this article will introduce a new wave material =1.06, arrange the angle and modify configurations of the slot sets. The results of experiment illustrate the validity of the design and analysis.

Abstract: The Cramer-Rao Lower Bound (CRLB) for the location accuracy of the netted radar is explored and the CRLB for the nonlinear filtering of a single radar is derived. The calculation process of the CRLB for the location accuracy of the netted radar is given by combining the above results. Simulation tests for the location and tracking accuracy of the netted radar under different conditions are conducted and several factors affecting the tracking accuracy of the netted radar are analyzed. The theoretical achievement derived in this paper can be used as a key theoretical basis for the evaluation of the performance of the netted radar.