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Dai F.,Wuhan University | Dai F.,Henan Electrical Power Dispatching Center | Cui T.,Wuhan University | Xu J.,Wuhan University | Sun Y.,Wuhan University
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011

According to the voltage stability analysis with short circuit capacity, an approach of voltage correction control based on comprehensive sensitivity analysis is proposed to improve the load-bus voltage and voltage stability margins after the great disturbance of power system. Based on the analysis of load-bus voltage and short circuit sensitivity, the comprehensive sensitivities are obtained and ranked to get the priorities of control variables. The bigger ones are then chosen to form the control variable set, which is applied to the improved genetic algorithm. Their variation spaces are shrunken according to the comprehensive sensitivity. With the consideration of voltage level, stability margin, grid loss, etc., the optimal control strategy is achieved. The analysis for a provincial power grid and the simulative verification demonstrate the effectiveness of the proposed approach.

Dai F.,Wuhan University | Dai F.,Henan Electrical Power Dispatching Center | Huang L.,Wuhan University | Xu J.,Wuhan University | Sun Y.-Z.,Wuhan University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

Voltage partitioning and pilot nodes selecting are the basis of secondary voltage control. For Henan power grid, an integrated partition method is proposed based on spectral coefficient averaging algorithm and fuzzy C-means clustering algorithm. An objective function based on controllability and representativeness of load node is adopted to find the pilot node of each voltage control area. The simulation result verifies the validities of the method and provides a theoretical basis for secondary voltage control in Henan power grid.

Song D.-W.,China Electric Power Research Institute | Ma S.-Y.,China Electric Power Research Institute | Li B.-Q.,China Electric Power Research Institute | Zhao X.-T.,China Electric Power Research Institute | And 4 more authors.
Lecture Notes in Electrical Engineering | Year: 2011

With real-time data from WAMS and EMS, the paper proposes a kind of comprehensive dynamic stability prevention and control method including low-frequency vibration monitoring, oscillation source search and dynamic stability control strategy. This method on one hand observes multiple oscillation modes and damping characteristics that may be existing in the power grid on line from EMS and through real-time small signal stability analysis, combining the sensitivity analysis, dynamic stability control aided decision for every kind of mode is generated. On the other hand, data from WAMS and online Prony calculating method are used to fast detect the occurrence of low frequency oscillation. Once it occurs, oscillation propagation way will be tracked by the algorithm based on transient energy function and dynamic hybrid simulation to identify possible initial oscillation point. Oscillation pattern matching calculations start to choose the feasible real-time auxiliary control strategy from the matching small disturbance mode. In ideal condition, initial point position and oscillation inhibit quell measures will be showed which provides online automatic monitoring method for preventing dynamic instability of power grid. The method gets practical application in Henan interconnected power grid. © 2011 Springer-Verlag Berlin Heidelberg.

Guo Y.,Tsinghua University | Wu W.,Tsinghua University | Zhang B.,Tsinghua University | Sun S.,Henan Electrical Power Dispatching Center
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

Power flow forecasting is a fundamental function in early warning and security countermeasure system (EWSC) for power grid. The ultra-short term and daily power flow forecasting methods are both presented. The factors affecting robustness and accuracy of the results of these two methods are analyzed. Power flow forecasting software is introduced which has been imbedded in a EWSC system. The recorded results from a provincial power grid are given and the practicality of the proposed method is validated. ©2010 State Grid Electric Power Research Institute Press.

Fu H.,Henan Electrical Power Dispatching Center | Ju P.,Hohai University | Sun R.,Henan Electrical Power Dispatching Center | Xie H.,Hohai University
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

By comparing the global modeling method of electric loads with the node modeling method, it can be concluded that the parameter accuracy of the global modeling method is a little better than that of the node modeling method, but the computing workload is much greater. Based on a comparison between three different error indices, the results show that they have roughly the same parameter accuracy, while the index of trajectory error squares behaves tolerably well. Then, three kinds of measurement variables are compared. The example shows that the sensitivity decreases with the relative generator angle, tie line power and key bus voltage. It has been found that the greater the sensitivity is, the higher will the accuracy be. ©2010 State Grid Electric Power Research Institute Press.

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