This paper introduces a new method for mitigating inter-area oscillations of a large scale interconnected power system by means of generation re-dispatch. The optimal mitigation procedures are derived by searching for the shortest distance from current operating condition to a targeted operating condition with the desired damping ratio of the oscillation mode. A sensitivity-based method is used to select the most effective generators for generation re-dispatch and decision tree is trained to approximate the security boundary in a space characterized by the selected generators. The optimal operational rules can be found by solving an optimization problem where the boundary constraints are provided by the decision tree rules. This method is tested on a Western Electricity Coordinating Council (WECC) 179-bus simplified model and simulation results have demonstrated the validity of the decision-tree-based method and shown promising application in real time operation.

%B 2011 IEEE/PES Power Systems Conference and Exposition (PSCE) %I IEEE %C Phoenix, AZ, USA %P 1 - 8 %8 03/2011 %@ 978-1-61284-789-4 %R 10.1109/PSCE.2011.5772564 %0 Conference Paper %B IEEE Power and Energy Society (PES) General Meeting %D 2011 %T The influence of topology changes on inter-area oscillation modes and mode shapes %A Yousu Chen %A Jason C. Fuller %A Ruisheng Diao %A Ning Zhou %A Zhenyu Huang %A Francis K. Tuffner %K AA07-001 %K AARD %K Automatic Switchable Network (ASN) %K damping %K power grid operations %K Power system stability %K WECC %XThe topology of a power grid network is a piece of critical information for power grid operations. Different power grid topologies can change grid characteristics, inter-area oscillation modes, mode shapes, and even the robustness of the power system. This paper presents some preliminary study results, based on an approved WECC operating case and a modified low damping WECC system, to show the impact of topology changes resulting from N-1 contingencies on power system modes and mode shapes. The results show that topology changes can have very different impact on modal properties in a power system: some result in an unstable situation, while others can improve small signal stability. For the former, the studies show about a 4.5% damping reduction, so a 5% damping margin would be required to ensure the system can sustain the contingencies. For the latter, those topology changes could be used as a control method to improve small signal stability. Mode shapes normally do not change when there is an N-1 topology change. These observations suggest that the inclusion of topological information is useful for improving the accuracy and effectiveness of power system control schemes.

%B IEEE Power and Energy Society (PES) General Meeting %I IEEE %C Detroit, MI, USA %P 1 - 7 %8 07/2011 %@ 978-1-4577-1000-1 %R 10.1109/PES.2011.6039904 %0 Report %D 2010 %T Modeling and Studying FIDVR Events %A WECC Modeling Group %K composite load model %K FIDVR %K FIDVR Composite Load Model %K RTINA %K WECC %X The objective of this paper is to inform the operating and planning entities within WECC on the development of the composite load model, the model applicability to the studies of Fault-Induced Delayed Voltage Recovery (FIDVR), and potential implications to the reliability criteria. The paper also makes recommendations on improving FIDVR monitoring, load model validation, steps towards load model implementation, and reliability criteria review. %I Western Electricity Coordinating Council %8 12/2010 %G eng %9 WECC %0 Journal Article %J IEEE Transactions on Power Systems %D 2010 %T Probing Signal Design for Power System Identification %A John W. Pierre %A Ning Zhou %A Francis K. Tuffner %A John F. Hauer %A Dan Trudnowski %A William A. Mittelstadt %K AA07-001 %K AARD %K Automatic Switchable Network (ASN) %K WECC %X This paper investigates the design of effective input signals for low-level probing of power systems. In 2005, 2006, and 2008 the Western Electricity Coordinating Council (WECC) conducted four large-scale system-wide tests of the western interconnected power system where probing signals were injected by modulating the control signal at the Celilo end of the Pacific DC intertie. A major objective of these tests is the accurate estimation of the inter-area electromechanical modes. A key aspect of any such test is the design of an effective probing signal that leads to measured outputs rich in information about the modes. This paper specifically studies low-level probing signal design for power-system identification. The paper describes the design methodology and the advantages of this new probing signal which was successfully applied during these tests. This probing input is a multi-sine signal with its frequency content focused in the range of the inter-area modes. The period of the signal is over 2 min providing high-frequency resolution. Up to 15 cycles of the signal are injected resulting in a processing gain of 15. The resulting system response is studied in the time and frequency domains. Because of the new probing signal characteristics, these results show significant improvement in the output SNR compared to previous tests. %B IEEE Transactions on Power Systems %V 25 %P 835 - 843 %8 05/2010 %N 2 %! IEEE Trans. Power Syst. %R 10.1109/TPWRS.2009.2033801