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Wireless power transfer (WPT) technology has been popularized due to its convenience, safety, and unmanned nature. To improve the transmission performance of couplers and reduce the magnetic field, the designers of such couplers often adopt a combination of coils and substrates: however, the non-ferromagnetic substrate often leads to the enhancement of coil equivalent resistance and the decrease of the efficiency of a WPT system. In the present work, the effect of a substrate on coil equivalent resistance is evaluated by finite element simulation. The effects of the distance between a substrate and a coil and the number of turns of coil on the equivalent resistance of coils are studied. Based on the calculation method of alternating current resistance for Litz-wire, the equivalent resistance reduction method involving use of a coil with substrates is proposed to significantly reduce equivalent resistance of the coil with its substrate. A high-power-density coupler is designed based on the above method. The power densities of a transmitting coil and a receiving coil are only 0.542 W/cm 3 and 0.81 W/cm 3 respectively. When the transmission distance is 200 mm, a power transmission of 3.61 kW is realized, and the efficiency of the coupler and system reaches 94.61% and 92.56%, respectively. • The more coil turns, the greater effect of non-ferromagnetic substrate on resistance. • The change of substrate size will significantly affect the coil equivalent resistance. • The mutual inductance of coupler with substrate hardly affects the coil equivalent resistance. • Increasing strand number of Litz wire significantly reduce coil resistance with NFMS. • The proposed coupler structure achieves high power density and high efficiency. [ABSTRACT FROM AUTHOR]

The technology in which low-voltage power lines are used as communication channels is a hot spot in current information transmission research. Signal transmission on 220 V/380 V low-voltage power lines is quite different from high-voltage power line carrier communication. It is characterized by low line impedance, strong signal attenuation, large interference, and large time-varying characteristics. In this paper, we apply the ant colony algorithm to low-voltage power line carrier communication signal transmission, and the characteristics of conventional low-voltage power line channels and the test results based on the ant colony algorithm are analyzed. The research results show that noise interference usually has multiple noise sources, and the power line attenuation is usually above 20 dB. The attenuation increases with the increase of frequency. Because the load presents different properties to the power line, it may attenuate greatly at certain frequencies. The attenuation amplitude is the largest when it is less than 100 kHz, and the attenuation amplitude becomes relatively stable when it is greater than 500 kHz. The longer the signal transmission distance, the more severe the signal attenuation, so the signal transmission distance is usually not higher than 1 000 m. Ant colony algorithm can effectively improve the transmission performance of low-voltage power line carrier communication signals, and it can well overcome different types of noise interference. [ABSTRACT FROM AUTHOR]

Abstract: lEC 61850 “Communication networks and systems in substation” is not only the most advanced and universal standard for communication but also a comprehensive system oriented standard for substation automation system (SAS). This paper proposes a transmission solution for communication scheme which combines Multicast Sampled Value (MSV) and Generic Object Oriented Substation Event (GOOSE) information in one network (Transmit MSV and GOOSE simultaneously with a network transmission line). MSV and GOOSE are described detail in the next context, and then the traffic flow and the delay of the two messages are estimated respectively. In this article, transmission performance tests based on the architecture of a single network are designed and implemented. The single event and multi-event tests show that the latency of the packets is quite small and the real-time performance satisfies the requirement of the intelligent substation. [Copyright &y& Elsevier]

Abstract: Energy consumption is becoming a fundamental topic also for telecommunication networks, where the implementation of “green” infrastructures is required. In this paper, we report a numerical investigation about energy saving in a transport network both exploiting the transmission properties that permit to reduce the number of in-line equipments (optimizing wavelength path assignment) and switching off optical links when the traffic load decreases. In particular, we investigate a European transport network based on transmission and the Italian network based on the transmission. [Copyright &y& Elsevier]

This paper focuses on an experimental investigation of a novel friction drive, a magnetic belt drive (MBD), in which an additional frictional force between the belt and pulleys is provided by the usage of magnetic belt and magnets. The effective tension, elastic creep rate, and transmission efficiency of a prototype of the MBD were measured by experiments against a few running parameters, such as initial tension, input torque, and magnetic flux density. The results demonstrate that the MBD has better contact conditions and transmission performances than conventional belt drives in terms of the above measures. [ABSTRACT FROM AUTHOR]