Jia S.,Shandong Electric Power Research Institute
Advanced Materials Research | Year: 2012
This paper presents a novel and practical method for monitoring harmonic impedances of power systems seen at load serving substations. The method uses the natural load fluctuations measured at the substation for impedance estimation. It avoids the needs for intrusive disturbances and can be used for online tracking of impedance parameters. The method has been verified through several real field measurements. © (2012) Trans Tech Publications.
Liu F.,Shandong Electric Power Research Institute
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010
Thermal-hydraulics deviation used to cause furnace tube explosion in operation of supercritical pressure once-through boiler. Heat transfer calculation suitable for engineering application were employed to associated thermal-hydraulics inside the deviated tube with furnace burning conditions. Iterative computations were used to determine mass flux in the deviated tubes with the fundamental criterion of same pressure at both end of the averaged and deviated tube. A model coupled thermal processes of furnace gas with thermal-hydraulics inside the evaporating tube was developed to investigate the matching of combustion intensity with coolant mass flux in an evaporating tube. The model provides a detailed insight into impacts of deviated heat flux distribution, resistance deviation, abnormal blockage and inappropriately designed orifice on the deviated tube overheating, correlations of internal heat transfer coefficients are carefully selected to calculate tube wall temperature when the boiler operating at different pressures in the whole range of loads, it shows that the lower furnace tube is over-heated when the deviated heat flux coefficient reach 1.45 for a 1000 MW boiler operating at boiler maximum continuous rating (BMCR) load, the mass flux in the deviated tube decreases to 57% of average flux when deviation of local resistance increases to 0.292 MPa at 100% turbine heat acceptance (THA) load, and this leads to tube wall overheating as well. © 2010 Chinese Society for Electrical Engineering.
Liu F.-G.,Shandong Electric Power Research Institute
Ranshao Kexue Yu Jishu/Journal of Combustion Science and Technology | Year: 2010
Convection and radiation heat transfer have demonstrated different load characteristics in the furnace of a utility boiler, and ignoring convective heat transfer may give rise to deviation from the designed thermal properties of furnace. Based on the test data, this paper presents a coupled radiation and convection model of furnace in a supercritical pressure once-through boiler. Multi-dimensional minimization techniques are employed to draw compositional information about radiation and convection out of furnace load characteristics. Heat fluxes of 32 loads are predicted in 5 supercritical pressure boilers, and it is shown that the predictions are in good agreement with the actual values, indicating that the coupled convection and radiation model can accurately describe the furnace load characteristics. This model can be used to revise regulating parameters and give instructions for steam temperature control when boiler is in operation.
Du B.,Shandong Electric Power Research Institute |
Paital S.R.,University of North Texas |
Dahotre N.B.,University of North Texas
Optics and Laser Technology | Year: 2013
The study explores the synthesis of TiB 2 and TiC reinforced Fe-based nano-composite coating by laser surface engineering using Ti, B 4C and Fe powder mixture as precursor. The effect of laser scanning speed on the size, morphology, and amount of nano-sized ceramic reinforcements were studied at laser fluence of 1111 J/cm 2, 1667 J/cm 2 and 3333 J/cm 2 respectively. A bimodal microstructure with TiC and TiB 2 particles dispersed in fine α-Fe matrix was evolved in the laser processed coatings. Besides, the nature of formation of nano-sized ceramic phase was examined. The laser synthesized nano-composite coating yielded 3-5 times increase in microhardness. It appears that the presence of nano-sized TiB 2 and TiC particles coupled with the highly refined α-Fe matrix improves the hardness significantly. This coating offers the potential to increase the hardness and toughness simultaneously for developing wear-resistance coatings. © 2012 Elsevier Ltd.
Li T.,Shandong Electric Power Research Institute
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012
Intelligent power utilization is a topical and difficult subject in the study of smart grid. The flexible and interactive mode of power supply and consumption has become the trend of intelligent power utilization. A description includes the standards, system and terminal technology of advanced metering infrastructure, the bi-directional interactive operation mode and supporting technology of intelligent power utilization, and the interaction between users' power utilization environment and patterns, which constituting the flexible and interactive utilization of intelligent power. The current situation and development problems of these techniques at home and abroad are discussed. The development goals of flexible and interactive utilization of intelligent power are clarified. The development trends and technical study route of flexible and interactive utilization of intelligent power are elaborated. © 2012 State Grid Electric Power Research Institute Press.