East China Electric Power Design Institute

Shanghai, China
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Jiang H.,Tongji University | Li S.,Tongji University | Zhu Y.,East China Electric Power Design Institute
Journal of Constructional Steel Research | Year: 2017

To improve the seismic performance of high-rise building structures with outriggers, a new structure with energy-dissipation outriggers installed using buckling restrained braces (BRBs), which replace the ordinary diagonal bracing, is proposed in this study. To verify the seismic performance of the new structure, a case study was carried out. Two high-rise structures, one with conventional outriggers, the other with energy-dissipation outriggers, were designed. The numerical models for the two structures were established with the aid of a commercial software, Perform-3D. The responses of the two structures under frequent earthquakes, basic earthquakes, and rare earthquakes were analyzed and compared. The results show that compared to the ordinary structure, the seismic performance of the new structure is improved significantly. Under frequent earthquakes, both structures remain basically elastic, and the responses of the two structures are almost identical. Under basic earthquakes and rare earthquakes, the BRBs in the new structure yield initially and dissipate a large amount of the input energy to provide adequate protection to the main structural members. Furthermore, the influences of the strength and layout of BRBs on the seismic performance of the new structure were investigated, providing reference for engineering applications. © 2017 Elsevier Ltd

Menhas M.I.,Shanghai University | Wang L.,Shanghai University | Fei M.-R.,Shanghai University | Ma C.-X.,East China Electric Power Design Institute
International Journal of Automation and Computing | Year: 2011

Coordinated controller tuning of the boiler turbine unit is a challenging task due to the nonlinear and coupling characteristics of the system. In this paper, a new variant of binary particle swarm optimization (PSO) algorithm, called probability based binary PSO (PBPSO), is presented to tune the parameters of a coordinated controller. The simulation results show that PBPSO can effectively optimize the control parameters and achieves better control performance than those based on standard discrete binary PSO, modified binary PSO, and standard continuous PSO. © 2011 Institute of Automation, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.

Li G.J.,Shanghai JiaoTong University | Ma F.,Arizona State University | Choi S.S.,Nanyang Technological University | Zhang X.P.,East China Electric Power Design Institute
IET Power Electronics | Year: 2012

A three-phase unified power quality conditioner (UPQC) with cross-phase connection is investigated. The UPQC is designed to mitigate voltage sags/swells, including those resulting from single-phase faults. Based on an analysis of the configuration of the conditioner, multi-loop control schemes are proposed for the voltage and current compensation strategies. The practicability of the topology and the effectiveness of the control schemes are verified through simulations using PSCAD/EMTDC. The results demonstrate the proposed control strategy for the cross-phase-connected UPQC is capable of regulating load terminal voltage and compensating load current changes simultaneously and effectively. © 2012 The Institution of Engineering and Technology.

Fan H.,Shanghai JiaoTong University | Zhou H.,East China Electric Power Design Institute | Wang J.,East China University of Science and Technology
Energy Conversion and Management | Year: 2014

The pyrolysis of three municipal sewage sludges was carried out using a slowly heating and gas sweeping fixed-bed reactor in the temperature range between 300 °C and 700 °C. The study was aimed to characterize the gaseous and liquid products derived from three different sewage sludges and mainly to discuss the varieties of sewage sludges on the yields and compositions of the gaseous and liquid products. The pyrolysis in this reactor was observed to produce high yields of liquid (above 40 wt.% at 700 °C) that contained high proportions of oxygen-containing compounds and nitrogenated compounds, with minor monoaromatics and aliphatic compounds. The gas and liquid yields correlated with the volatile matter contents in the sludges. For all three sewage sludges, the oxygenated compounds were the principal liquid compounds which could be produced at a low temperature of 300 °C, while more of nitrogenated compounds and other compounds were formed at 700 °C depending on the varieties of sewage sludges. © 2014 Elsevier Ltd. All rights reserved.

Chen J.,Tongji University | Yuan S.,East China Electric Power Design Institute
Journal of Engineering Mechanics | Year: 2014

Solving the Fokker-Planck-Kolmogorov (FPK) equation is one of the most important and challenging problems in highdimensional nonlinear stochastic dynamics, which is widely encountered in various science and engineering disciplines. To date, no method available is capable of dealing with systems of dimensions higher than eight. The present paper aims at tackling this problem in a different way, i.e., reducing the dimension of the FPK equation by constructing an equivalent probability flux. In the paper, two different treatments for multidimensional stochastic dynamical systems, the FPK equation and the probability density evolution method (PDEM), are outlined. Particularly, the FPK equation is revisited in a completely new way by constructing the probability fluxes based on the embedded dynamics mechanism and then invoking the principle of preservation of probability. The FPK equation is then marginalized to reduce the dimension, resulting in a fluxform equation involving unknown probability flux caused by the drift effect. On the basis of the equivalence of the two treatments, this unknown probability flux could be replaced by an equivalent probability flux, which is available using the PDEM. An algorithm is proposed to adopt the data from the solution of the generalized density evolution equation in PDEM to construct the numerical equivalent flux. Consequently, a onedimensional parabolic partial differential equation, i.e., the flux-equivalent probability density evolution equation, could then be solved to yield the probability density function of the response of concern. By doing so, a high-dimensional FPK equation is reduced to a one-dimensional partial differential equation, for which the numerical solution is quite easy. Several numerical examples are studied to verify and validate the proposed method. Problems to be further studied are discussed. © 2014 American Society of Civil Engineers.

Xie Q.,Tongji University | Wang Y.,East China Electric Power Design Institute
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

Complicated interactions exist in the flexible bus connected substation equipment under earthquake. In this paper, firstly, the flexible bus was simplified as a cable. By introducing deformation compatibility condition between the substation equipment and the flexible bus, the tension and tension stiffness of the cable were derived. Then a mathematical model for analyzing the dynamic interaction between the equipment and the cable was proposed and solved by using the Runge-Kutta method. The following case study and parametric analysis showed that due to the interconnection by the cable, the seismic response of the coupling system, which was different from that of the independent equipment, exhibited strong nonlinearity and the tension in the cable varied abruptly under earthquake action. The results demonstrated that the interaction between the flexible bus and the equipment should be considered in the seismic design of substation equipment and the mathematical model derived in this paper could be used to analyze the seismic response of the equipment in random frequency interconnected by the flexible buses. © 2010 Chinese Society for Electrical Engineering.

Chen J.,Tongji University | Wu M.,East China Electric Power Design Institute
Asia-Pacific Journal of Atmospheric Sciences | Year: 2012

We have proposed in a previous study a non-stationary wind model to represent the typhoon record as a summation of a time-varying mean wind speed (TVM) and a stationary turbulence. This note further suggests a quantitative scheme, rather than the previous qualitative method, to find the best TVM for any given wind record. Trial TVMs are first extracted from the wind record by a data-processing technique named empirical mode decomposition. For each TVM, its corresponding turbulent component is computed by removing the TVM from the original wind record, and the degree of stationarity of the turbulence component is checked. The best TVM is taken as the one that leads to the maximum degree of stationarity. The degree of stationarity of turbulence is quantified by two indicators: β the ratio of horizontal wind variability and wind speed; and γ the ratio of friction velocity at different Reynolds averaging periods. The applicability of the suggested scheme is validated with 550 typhoon and 3300 monsoon records of 10 minute duration and at different measurement heights. Threshold values for the two stationary indicators β and γ are determined using field measurements and their sensitivities to the Reynolds averaging periods are discussed. Observations in this study demonstrate that the suggested scheme is proper for finding the TVM of a wind record. For a stationarity quantification of 10 minute duration record, the γ indicator with 30 second Reynolds averaging period is recommended. © The Korean Meteorological Society and Springer 2012.

Chen J.,Tongji University | Yuan S.,East China Electric Power Design Institute
Probabilistic Engineering Mechanics | Year: 2014

Engineering structures usually exhibit hysteretic property when they are subjected to disastrous loadings such as earthquakes, strong wind and huge waves. The solution of FPK equation related to such complex systems are of great significance but is still an extremely challenging problem. In the present paper, the FPK equation for hysteretic systems is studied and the dimension is reduced to render an efficient numerical solution. The equivalence of probability flux in two different treatments, i.e., in the FPK equation which is based on the state space description and in the generalized density evolution equation which is mainly based on the random event description, are first examined. Then the FPK equation for additively excited multi-degree-of-freedom structures exhibiting nonlinear behaviors, including hysteresis together with strength degradation and stiffness degradation, is discussed. By invoking the basic idea of equivalence of probability flux, an equivalent probability flux due to drift could be constructed by the probability density evolution method (PDEM) instead of the direct coupled high-dimensional integral. Numerical implementation procedure is outlined. Two numerical examples are illustrated. Problems to be further studied are discussed. © 2014 Elsevier Ltd. All rights reserved.

Liu M.-X.,East China Electric Power Design Institute | Xu L.,East China Electric Power Design Institute | Yang P.,East China Electric Power Design Institute
Gaodianya Jishu/High Voltage Engineering | Year: 2010

To study whether UHV AC transmission lines impact on the security and stability of East China Power Grid, combined with actual UHV power transmission projects related to the UHV substations located in East China, the situations with single and multi-faults were calculated with power system simulation software BPA, and the security and stability of East China Power Grid after constructing the UHV AC transmission system were analyzed. The results of analysis show that the system will lose its transient stability when overhead fault happens on Xuzhou-North Nanjing 1000kV double-circuit transmission line, the voltage of substation buses sliding with divergent rotor angle. Among the three corresponding control schemes, one is chosen as the commendatory scheme. The mechanism of the aforementioned N-2 fault particularity is further analyzed, in which voltage stability problem is possibly caused by heavy active power or deficient reactive power under the district-classified and level-classified operation mode of East China Power Grid.

Xie Q.,Tongji University | Wang Y.,East China Electric Power Design Institute
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2011

In order to study the dynamic interaction of substation equipment interconnected by flexible buses subjected to earthquakes, a shake table test on a full scale model was carried out. After comparing the seismic behavior of the independent equipment with that of the equipment interconnected by the flexible buses of different slackness, the dynamic interaction mechanism of the coupling system was given and the theoretical model for analyzing the seismic interaction was also verified. When the slackness of the flexible bus is large, the difference of the seismic response between the independent equipment and the equipment interconnected by flexible buses is small. On the contrary, when the slackness of flexible bus is small, the interaction between substation equipment and flexible buses is large. An impact tension will happen in the flexible bus when the coupling system is subjected to severe ground motion, which will have a negative influence on the equipment. Therefore, the dynamic interaction of the equipment interconnected by flexible buses should be considered in the seismic design of substation equipment. © Chin. Soc. for Elec. Eng.

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