Feng Y.,GuiZhou Power Grid Co.
Dianwang Jishu/Power System Technology | Year: 2011
Online static sensitivity analysis is one of the important constituent component in advanced application software for energy management system (EMS). To carry out online static sensitivity analysis in the EMS of dispatching center of China Southern power Grid (CSG), it is needed to make calculation of the full model of 500 kV/220 kV AC/DC hybrid power gird covering five provinces and districts, so it is necessary to consider various physical responses of generators in these provinces and districts and the interaction between AC and DC power networks, in addition, the good covergence of the calculation is to be ensured. To meet above-mentioned demands, the sensitivity algorithm for AC/DC hybrid power grid, in which the characteristics of PV and PQ nodes is taken into account, is adopted. The algorithm that considers quasi-steady physical response characteristics of generators can give sensitivity among AC components and that among AC and DC components. The presented online static sensitivity analysis software has been steadily and efficiently operated in the EMS of dispatching center of CSG more than three years, and operation experiences of this software show that it is practicable for scheduling and control of dispatching center.
Han S.,Zhejiang University |
Xu Z.,Zhejiang University |
Sun B.,GuiZhou Power Grid Co. |
He L.-Q.,Guizhou University
International Journal of Electrical Power and Energy Systems | Year: 2010
Utilizing the Hilbert-Huang transform (HHT) analysis techniques, the authors propose a practical method for detection and estimation of interarea oscillations in power systems from a nonlinear and nonstationary perspective. The methodological approach proposed here can analyze local dynamic behaviors and characteristics of nonstationary and nonlinear signals, better reflect the time-varying law of multi modes involved in oscillation process as well as the mutual influences among these modes, and improve the identification ability and processing effect. An initial application to the data acquired through the wide-area measurement system (WAMs) of Guizhou Power Grid in China is presented to verify the ability of estimating the time-varying characteristics inherent to the electromechanical oscillation processes. The preliminary test results prove the potential and feasibility of the proposed method, and suggest that it can be used as one of on-line identification methods in power system. © 2010 Elsevier Ltd. All rights reserved.
Teng Y.,Sichuan Electric Power Research Institute |
Xing W.,Xian Jiaotong University |
Zhang H.,GuiZhou Power Grid Co. |
Shi H.,Sichuan Electric Power Research Institute |
Jiao Z.,Xian Jiaotong University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015
Simulation models of double-fed induction generator and permanent magnet direct driven wind generator are built based on PSCAD/EMTDC software. The fault characteristics of wind generation system are studied, and the performances of relays in power systems with wind farm integration are analyzed. It can be concluded that the fault currents fed by wind generation are limited comparing with conventional synchronous generators. And the positive and negative sequence impedance of wind farm is not equal which is different from conventional power transmission system. Some widely used protection principles are studied and it is found that the distance relay and fault phase selector will be influenced by wind farm integration. Finally, some field fault data from recorder are used to verify the studies and analysis. The results show that the study and analysis conducted will be useful for the protection system setting and operation in power system with wind farm integration. ©, 2015, Power System Protection and Control Press. All right reserved.
Zhong Y.,Xian Jiaotong University |
Kang X.,Xian Jiaotong University |
Jiao Z.,Xian Jiaotong University |
Wang Z.,GuiZhou Power Grid Co. |
Suonan J.,Xian Jiaotong University
IEEE Transactions on Power Delivery | Year: 2014
Traditional distance relays often mis-operate for high transient resistance in phase-ground faults by measuring apparent impedance. To solve this problem, a novel distance protection algorithm is proposed in this paper. It is deduced in the RL lumped transmission line model and calculates the fault distance from the measuring point to the fault point by solving a linear differential equation. In addition, a protection criteria based on the comparison result between the calculated fault distance and the protective setting margin rather than the protective zone measured by apparent impedance is set up in this paper. As a result, the proposed method can avoid overreach for the given characteristics that the calculated fault distance is greater than the actual fault distance when the fault occurs next to the opposite terminal. Meanwhile, both the fundamental component and one decaying DC component are needed to solve the differential equation for the proposed distance algorithm, therefore it can trip the breaker fast during the fault transient period. Finally, EMTP simulation results verify the validity of the proposed distance algorithm on RL transmission line model. However, to put the proposed method into field use, the problem caused by the distributed capacitance of the transmission line on the proposed method will be further studied and solved. © 1986-2012 IEEE.
Tsinghua University and GuiZhou Power Grid Co. | Date: 2014-05-30
A method for obtaining a three-phase power flow of a power distribution network and a device for obtaining a three-phase power flow of a power distribution network are provided. The method comprises steps of: selecting a three-phase power transformer with an ungrounded neutral connection in the power distribution network; correcting a three-phase admittance matrix of the three-phase power transformer; and applying the three-phase admittance matrix to a preset algorithm to obtain a three-phase power flow of the power distribution network.