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Chen L.,Yunnan Electrical Power Experiment Institute Co. | Zhou F.-R.,Yunnan Electrical Power Experiment Institute Co. | Ma Y.,Yunnan Electrical Power Experiment Institute Co. | Deng H.-M.,State Grid Electric Power Research Institute of China | Wang S.-H.,North China Electrical Power University
Gaoya Dianqi/High Voltage Apparatus | Year: 2013

In this paper, the discharge facular region in the ultraviolet (UV) images was extract with digital image processing algorithm, and the facular area parameter was defined, in the high voltage laboratory, the corona discharge character at the high voltage side of 10 kV, 35 kV and 110 kV composite insulator were studied, the relation curves of facular area and apparent discharge was obtained. The corresponding experiment data was fitted with the CFTOOL function toolbox in MATLAB, research showed that the facular area to gain had approximate exponential relationship, and the facular area to the observe distance had approximate power function relationship. On that basis, this paper established the curves of facular area with the distance under different discharge intensity with the gain was 50%, 60%, 70% and 80%, then a discharge quantification estimation model is established with the LS-SVM (least squares support vector machine, LS-SVM) regression algorithm, testing showed that it has good prediction accuracy.

Wang D.,Chongqing University | Wang D.,Southwest Jiaotong University | Guo C.,Yunnan Electrical Power Experiment Institute Co.
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2010

Continuum modeling is applied to study the electromechanical dynamics of large-scale power system, which emphasizes the propagation process of electromechanical disturbance in entire power system. The spatial difference treatment is carried out for the nonlinear partial differential equations, which describe the electromechanical wave propagation, and the connection topology of power network is presented by the formative differential equation set to rationally treat with the line branching. According to Gauss function, the inertia of generator rotor is distributed continuously along the lines connected to it, showing its geographical location in power system. Dynamic simulation of disturbance propagation is carried out for the modified New England 10-machine 39-bus system with the continuum modeling approach and the conventional modeling technique(PSS/E software package) respectively, and the characteristics of electromechanical disturbance propagation in power system are investigated. The disturbance propagation times by both approaches are nearly same.

Li Y.,Southwest Jiaotong University | Wang D.,Southwest Jiaotong University | Guo C.,Yunnan Electrical Power Experiment Institute Co. | Li Y.,Yunnan Electrical Power Experiment Institute Co.
POWERCON 2014 - 2014 International Conference on Power System Technology: Towards Green, Efficient and Smart Power System, Proceedings | Year: 2014

Decoupled control of active power in doubly-fed induction generation (DFIG) makes it impossible to respond to electromechanical dynamics of power grid. When wind power's penetration ratio increases rapidly in power grid, the effect that wind power cannot participate in frequency regulation becomes more and more severe. Based on the DFIG model in Matlab/Simulink platform, wind turbine model with additional virtual inertia to participate in frequency regulation is built firstly in this paper, and then these wind turbines are connected to a 2-area 4-machine model in order to analyze the feasibility of DFIG participation in frequency regulation. Next, taking a local part of Yunnan Power Grid as the example, analyzed are the impact of wind power upon power grid frequency under different penetration ratio at different wind speeds, steady-state operation and sudden load change conditions. With the increasing of penetration ratio of wind power, some traditional wind turbines are replaced by DFIGs which can participate in frequency regulation, and the minimal proportion of DFIG needed to participate in frequency regulation under different wind power penetration circumstances. The conclusions indicate that it is important to dispatch reasonably the proportion of DFIG participating in frequency regulation under the condition of high wind power penetration ratio in order to make full use of wind power output and ensure the steady operation of power grid with high wind power integration. © 2014 IEEE.

Wang D.,Southwest Jiaotong University | Guo C.,Yunnan Electrical Power Experiment Institute Co.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2012

Continuum electromechanical wave theory is a novel modeling approach for studying the electromechanical dynamic characteristics of large-scale power systems. Based on the theoretical derivation, the equations and their propagation characteristics of electromechanical wave in the continuum model and electromechanical disturbance in the discrete model for power system are studied in this paper. At the same time, the one-to-one correspondence relations of those main physical parameters, including propagation velocity, critical velocity, propagation constant, characteristic impedance, reflection coefficients, in the two models are also analyzed profoundly. The results show that the propagation of electromechanical disturbance between the two models of power system have the almost same physical properties, which proves the continuum model is a kind of approximate method of the discrete model, and can be completely utilized to describe the dynamic characteristics and the internal mechanism of electromechanical disturbance propagation in a vaster spatial dimension.

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