Papers by Keyword: Power Flow

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Authors: Jun Chuan Niu, Guo Qun Zhao, K.J. Song
Abstract: A novel general model of the coupled flexible system is presented. Based on the description of state-space equation of the coupled system, the transmission channels of the power flow transmitted into the foundation are discussed in frequency domain, and then combined into a single function. The transmission characteristics of power flow and control strategies are discussed in detail. From numerical simulations presented, it is clear that the analytical model is effective and moment controls are able to achieve vibration cancellation substantially.
Authors: He Ye Xiao, Mei Ping Sheng, Ye Lei
Abstract: A new type dynamic vibration absorber, which consists of steel layer and variable cross section rubber layer fitted to plate by bolt through L-shape connection, is introduced firstly and applied to control vibration of plates at multi mode frequencies in this paper. The aim of the present paper is to study the energy absorbing ability of the new type dynamic vibration absorber and apply optimization method to obtain parameters of absorber which is excellent in absorbing energy. The coupling model of composite beam and plate is established by power flow method and energy of plate attenuated by absorber is analyzed. To improve energy dissipated by absorber, the particle swarm method is used to optimize parameters of absorber to minimize vibration energy of the plate. An experiment is executed to certificate the energy mitigated by absorber to validate analytical modeling method. The test data are consistent with the analytical results, demonstrating that the new type dynamic vibration absorber can suppress the vibration energy at every mode of plate and achieve a goal of multi-mode control.
Authors: Xiao Teng Wu, Li Jun Qin
Abstract: The allocation of power system loss under hybrid transmission modes was investigated. First, a concept and method for converting a bilateral transaction into its two equivalents pool transactions were proposed. Then, a model based on Shapley value was designed to allocate the power system loss in the framework of equivalent pool transactions. The Shapley solution in cooperative game theory was employed to allocate the power system loss to each load pool transaction that includes the equivalent ones. The proposed method is applicable for electricity markets containing pool and bilateral transactions. It satisfies electric circuit laws and provides economic signals to users. The effectiveness of the proposed method is verified by the IEEE 5-bus test system.
Authors: Xu Zheng, Jiang Hong Wang, Shuang Zhao, Mei Li, Bu Han Zhang, Ni Zeng, Ruo Xi Zhu, Yuan Fang Zeng
Abstract: A province in the central China faces the problem of energy shortage, 800kV Mengxi UHVDC project will effectively broaden the energy input channels of the province, enhance energy supply security, and reduce the pressure on coal transportation. This paper analyses the load, power supply and power shortage of a central province, and explored the role of Mengxi UHVDC project played in improving the energy demand in the Central China power grid. By comparing the different access plans to the grid, this paper demonstrated that it’s more appropriate to divide the Mengxi UHVDC into 1000kV and 500kV at the inverter side for consuming the power of UHVDC and protecting the normal power supply.
Authors: Yuferev Sergey
Abstract: In this paper, it is show how the second derivatives of the Hessian matrix influence on the convergence of the power flow calculation. Convergence conditions of the Combined Newton’s method using 14 nodes IEEE testing schemes are investigated. The method can be used to determine the control actions to pull the operating point into the feasibility domain.
Authors: Xiao Feng Zhang, You Gang Xiao, Liang Sun, Yu Shi
Abstract: In order to reduce aerodynamic noise in high-speed train cab,the SEA model of cab is established. The fluctuation pressures from train head surface are calculated by large eddy simulation method. Using fluctuation pressure as excitation force, power flow caused by airflow among sub-systems of SEA model of cab is obtained. Two schemes are put forward to reduce the aerodynamic noise in cab, namely interior decoration modification and windowpane thickness increase. The results show that when a layer of splint with 0.01 m thickness, 0.5 loss factor is added to the original decoration in cab, the overall sound pressure level (SPL) at driver head location will reduce 1.23 dB(A). When the cab windowpane thickness is increased to 5 mm from 4 mm, the overall SPL at the driver head location will reduce 0.87 dB(A).
Authors: Wen Bin Hu, Xian Shan Li, Ran Hu, Hua Jian Wan, Wei Wei Yao
Abstract: This paper proposed a fast weighting improving method based on an improved Newton's method with third-order convergence, made the intuitive geometric interpretation of the algorithm principle, and constructed a sum function of squared errors to obtain the optimal weighting factor. With a certain example being provided, the results showed that the improved algorithm requires less iterations and less calculating time than the classical Newtons method and the one in references. This improved algorithm is of widespread value in the analysis and calculation of power systems.
Authors: Gang Ji, Q. Zhou, Chun Wen Huang
Abstract: To adopting means to reduce power radiated from the hull, power injected by the shaft system and that radiated by the hull are analyzed for an underwater cylinder excited by the propeller/shaft system. As the power is injected by combination of the solely acting loads on the junction and there concurrent, power transmitted by each solely acting load, radiated by the hull and the concurrent power are compared to understand the mechanism of power transmission and transformation. In the comparisons, quantities are decomposed according to circum orders to understand the radiation modes. The conclusion drawn in the paper will provide some guidance for acoustic reduction by shaft isolation design.
Authors: Wei Xu, Xin Yong Xu, Zhen Yue Ma
Abstract: Basing on the theory of power flow, frequency response analysis was acted on in a hydropower house under dominant frequency with measured data of Three Gorges Station in spiral case and draft tube. Power flow in walls was calculated by APDL procedure and the properties were analyzed. The conclusion is that longitudinal wave is the main method in walls of the powerhouse, energy is reflected and stacked at the top of the walls. Displacement along the river changes and power flow in walls decays obviously. Intensity of vibration origin and distance between the vibration and the wall are both the influencing factors,increasing the stiffness of buttressed walls takes the role of limiting flexural wave and shear wave effect
Authors: Guang Hui Xu, Yan Yang Wang, Yi Nong Li, Wei Sun
Abstract: The vertical vibration of the in-wheel motor electric vehicle (IWM-EV) induced by large unsprung mass is analyzed based on power flow method. The simulation results show that due to the unsprung mass increase of IWM-EV, energy consumption of the suspension and wheel is increasing, which will cause adverse effects on not just the ride comfort but the maneuver stability. To decrease the effect, a new kind of vibration mitigation measure of the vehicle body absorber combined with an active hybrid control integrated the sky-hook and ground-hook methods is developed. The effectiveness of this measure is verified.
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