Advanced Materials Research Vols. 860-863

Abstract: The mixing degree of ammonia and exhaust gas has significant effect on the NO_x conversion efficiency of SCR (selective catalytic reduction) system. It is essential to investigate the structure of urea nozzle since it considerably impacts the atomization of urea water solution. This paper simulated the process of urea spray by the software FIRE and analyzed the influence of spray characteristics such as nozzle hole number, nozzle hole chamfering as well as the spray angle on the atomization of urea water solution. Simulation results can indicate the optimal nozzle for a certain circumstance which is beneficial to the engineering design.

Abstract: Fault diagnosis has long been recognised as one of the most effective methods of reducing operation and maintenance cost in rotating industry, especially in bearings. A method based on BP neural network modified by glowworm swarm optimization (GSO) was proposed for fault diagnosis of rolling bearings. Six fault features were selected as the input of network. GSO algorithm was applied to simultaneously optimize the initial weight and threshold values of BP neural network. The reliability of the proposed technique was confirmed by experimental data, which indicated the potential applications of this method in the field of rolling bearing fault diagnosis.

Abstract: In order to solve the domestic sub and super-critical unit import the high cost of procurement of high parameters of valves and valve operation in the common issues such as defects, and introduces the new valve of the Sino-ROK cooperative project--the labyrinth of high parameter control valve. First elaborates its structure characteristics, the core technology and application, and introduces concrete application for the settlement of condensate water pump recirculation valve defect. And we can see the labyrinth of high parameter control valve important role and development prospects in the future power plant.

Abstract: From studies of a reversible flow turbine for using in tidal power plants it was obtained a model with symmetrical blades that shows this characteristic. For the obtaining of more accurate results of this type of turbine it was proposed the manufacturing of a physical sample to be used in a testing bench at the Hydromechanical Laboratory of Small Hydropower Plants LHPCH, at Centro Nacional de Referências de PCH, (National Centre of Reference in SHP) CERPCH, in Universidade Federal de Itajubá (Federal University ofItajubá) UNIFEI, and also a mathematic sample modeled on CFD/CFX platform with the ANSYS software. This paper aims to describe one of the tests of the proposed rotor on mathematic model, to be used tidal power plants turbines.

Abstract: Monocrystalline Cu nanocolloid with 4.3 nm average particle size and 2.3～9.5 nm particle size distribution was successfully synthesized in situ by liquor-phase reduction synthesis, using copper acetate tetrahydrate as precursor, ascorbic acid as reductant, polyethylene sorbitan monooleate （Tween-80） as modifier, and liquid paraffin as solvent. The as-prepared copper nanocolloid was characterized by XRD, SAED, and TEM. Nano-lubricating oil with excellent dispersibility, chemical stability, and compatibility with other additives verified by TG-DSC, was achieved via adding as-prepared nano-copper into Mobil 1 5w-30 lubricating oil. The nano-lube’s physiochemical properties were characterized according to Chinese national standard. The tribological behavior of nano-lubricant was investigated on ball-on-disk UMT-Ⅱ tribometer and four-ball tribometer. The worn surface morphology was analyzed by means of SEM and EDS. Experimental results show as follows. The Mobil 1 5w-30 lube’s tribological property is markedly enhanced with the as-prepared copper nanocolloid as its additive. The as-prepared nano-Cu agglomerate discontinuous deposited, extrude, melt, spread, and form a film in micro-defects on the worn surfaces, then improve the friction-reducing, anti-wear ability, extreme pressure value, and extreme working ability of Mobil 1 5w-30 lubricant.

Abstract: Under power market environments, generator companies and power users are economic decision-makers and the ISO is the security decision-maker. The non-unique solution of security decisions may result in unfairness. At the same time, more and more power systems are operating near their security limits, thus the influence of uncertainty factors to security can not be ignored. To solve the above problems, the presented security pricing model in this paper suggests that security prices are calculated and released, which inducts and excites the market-participants separate decision-making, thus system security is maintained. Influences of the uncertainties of power loads and fault parameters to system security are taken into account. Furthermore, the system security and economy are unified in the model.

Abstract: Synchronized phasor measurement unit (PMU) has become the important monitoring device in power networks for high precision and accurate time tag of measurement data. This paper presents the PMUs suitable for smart substation which adopt embedded software-hardware platform. The differences between the common PMUs and PMUs for smart substation are introduced, and the software modules design is put forward, too. The key technology of PMUS is introduced including receiving and processing of sampling data message based on IEC 61850 standard and phasor calculation based on discrete Fourier transform.

Abstract: Inverter-based distributed generators (IBDG) have been integrated into distribution network increasingly. The characteristics of IBDG depend on its control strategy. This paper builds up the control scheme of IBDG considering specific control strategy. Theoretical analysis has been made on the fault response of IBDG and the inverters control system based on different degrees of voltage sag. A simulation model of power network with IBDG has been built in MATLAB for research. The simulation result has proved the correctness of the conclusions of the analysis.

Abstract: Against the background of the development of the smart grid, in order to promote the development of intelligent electricity in the residents side, developed a demand response based household electricity intelligent interactive terminal. The interactive terminal use configuration software as platform, combined with the existing peak-valley price and ladder price in Shanghai, consider of the real-time price mechanism and interruptible load mechanism of the demand response, cooperate with the intelligent socket which independently researched and developed, the intelligent interactive terminal is family oriented with information visualization, with a variety of control methods and easy to use. Through simulation and experiment, the terminal can achieve user-friendly, save energy, convenient supply company and user control, and improve the effect of users life habit.

Abstract: Topology adjustment is a main measure to limit short circuit current, but changes of power grid structure might bring deep impact on power system operation. Measures to limit short circuit current are difficult to apply online due to unable to completely evaluate its safety and feasibility. This paper presents an on-line decision support indicator system, which applied to evaluate online short circuit current level of power grid. Based on practical power grid model and typical cross-section, short circuit current level under the current and future maintenance mode is analyzed, decision support to limit short circuit current is given, and the effectiveness and feasibility of limiting measures are evaluated. Analysis results show that the index system is reasonable.