Advanced Materials Research Vols. 986-987

Abstract: The equivalent salt deposit density (ESDD) is an important characteristic of our country which is used to measure insulator deposition level. The contamination of the insulator would reach saturation after a period of time.In order to increase the specific creepage distance, disc suspension porcelain insulator lower surface inward concave, which makes the rain washing the upper surface difficult, that cause the saturation time of lower surface longer than upper surface .For studying the operation insulator contamination saturation time and reflecting the ESDD of the actual operation line accurately,this paper adopts a comparison method between empty hanging insulator surface and operation insulator surface to measure the ESDD , the field experimental results further verify that the saturated time of disc suspension insulator lower surface is longer, so as to lay the foundation for the ESDD measurement.

Abstract: Because the shortcomings of the common asymmetrical half-bridge circuit can't achieve soft switch and has DC bias for the transformer, the paper studies a new asymmetrical half-bridge circuit. Compared with the traditional asymmetrical half-bridge circuit, the circuit is added an auxiliary switch and diode by the composition of the slip. Thus the converter can achieve the control strategy of symmetric PWM. At last the simulation results show that the theoretical analysis is correct.

Abstract: Embedded remote economized power controller based on Ethernetadopts uses the embedded technology to realize intelligent control. It cuts the TCP/IP protocol and realizes point-to-point communication through UDP hole punching technology.It goes beyond the LAN limit and follows the principle of energy conservation.This economized power controller has very high practical value.

Abstract: As one of the most essential part in a battery management system for a lithium battery, cell balancing determine its performance and lifetime. A new “flying capacitor” method is presented in this paper. Where, a clock-switched circuit changer matrix makes the charges flow from the high-voltage cells to the low-voltage cells. Some super-capacitors buffer the charge and redistribute energy of the cells in the battery. The implementation is also low-cost and its design period is short. The result shows that the method is feasible.

Abstract: In the power system electromagnetic transient simulation, the establishment of a stable power transformer simulation model is crucial. Therefore, the high frequency strictly passive model of the transformer is investigated, which is suitable for the lightning strokes. The proposed model is introduced based on two-port network theory where its scattering parameters are measured through network analyzer firstly, and then the scattering parameters are transformed into the impedance parameters, finally the transformer T-equivalent circuit is established. The image method is used to fit frequency dependent impedance parameter, and according to different types of the parameter, the combination of circuit elements R, L, C is needed. By using the image method the values of the elements achieved are all positive and the strictly passive conditions of the circuits are guaranteed. Furthermore, the experiment and simulation results of a 10kV single-phase transformer under lightning overvoltage is presented, confirming the validity of the proposed method.

Abstract: The method of self-energy extracting has been adopted in high voltage thyristor device more and more widely. In consequence of the existing insufficient of high heat loss and large variation range of storage voltage value, this paper designs a novel comprehensive draw-out power circuit which is suitable for almost all kinds of working conditions of thyristor. The circuit includes voltage draw-out power module, current draw-out power module and the coordination control module between them. The principle of each module has been detailed analyzed and the calculation formulas of the corresponding parameters have been concisely given. At last, every conclusion drawn in this paper has been verified in simulation.

Abstract: Because of the dynamic characteristics of the streamer discharge, the acquisition of time parameters is very important to the streamer discharge simulation in the rod-plate air gap. This paper raises a new method to get the time parameters and charge development in the discharge of air gas, and the comparison of our results and the test results shows that the new method is very suitable and correctly to describe the stream discharge process.

Abstract: To solve the problem about vehicles passing deceleration strip consumming a large amount of energy , it can improve the efficiency of the deceleration strip generating electricity by improving the existing mechanical power or gas-liquid pavement power transmission part,using the buffer device and conversion device to change the stress state of rack and pinion,combining the working characteristics of one-way clutch with bevel gear transmission characteristic.The result shows that the power generation device design is reasonable and the economical profit is remarkable.

Abstract: Analysis the important significance of transformer short-circuit current calculation for the stable operation of power system. Lead to three different types of transformer short-circuit current calculation methods, this literature uses a simplified example to compare the characters among three methods. Meanwhile, calculation by using the theory to get a quantitative range of simplified method. The calculation results and theory support each other, finally, summarizing the application range of the three methods, and offering a reference for reasonable selection of short-circuit current methods.

Abstract: The installation of super capacitor in urban rail transit system allows the recovery of the braking energy for increasing the energy efficiency as well as a better pantograph voltage profile. An energy control strategy of the energy storage system which is suitable for the urban railway transit is proposed in this paper. Then, the methodology of capacity configuration is put forward based on the simulation platform in Matlab environment. Ultimately, the capacity configuration results of super capacitor energy storage system are determined based on parameters of an actual metro line under different traffic conditions.