Small signal stability is an inherent characteristic of dynamic systems such as power systems. Pole positioning through power system stabilizers (PSS) is often used for improving damping in power systems. A well-designed PSS can be very effective in damping oscillations, especially local oscillations. However, designing PSSs for inter-area oscillations has been a very challenging task due to time-varying operating conditions affecting the oscillations. This paper explores the sensitivity relationship between oscillations and operating conditions, and employs the relationship to derive recommendations for operator's actions to adjust operating conditions for improving damping. Low damping is usually considered to be a result of heavy power transfer in long distance, while specific locations also have significant impact on damping of oscillations. Therefore, it is important to consider locations in deriving recommendations. This paper proposes the concept of relative modal sensitivity and presents its application in deriving recommendations for operator's action in damping control.

%B 2011 44th Hawaii International Conference on System Sciences (HICSS) %I IEEE %C Kauai, HI %P 1 - 9 %8 01/2011 %@ 978-1-4244-9618-1 %R 10.1109/HICSS.2011.469 %0 Conference Paper %B 2009 IEEE Power & Energy Society General Meeting %D 2009 %T Dynamic characterization of PMUs using step signals %A Ren, J. %A Mladen Kezunovic %A Stenbakken, J. %K AA05-003 %K AARD %K phasor measurement units (PMUs) %K Power system dynamics %X Performance evaluation of PMUs to confirm the consistency of phasor measurements is of a great importance since it promotes the interchangeability among PMUs from different manufacturers. This paper presents a method for evaluating the dynamic performance of PMUs when exposed to a step change of input signals. A phasor estimation scheme is proposed to achieve high accuracy of reference phasors. An interleaving technique applied on output phasors can equivalently increase the reporting rate and can precisely depict the PMU behavior under the step input. Four types of tests with balanced and unbalanced three-phase step signals are performed as reference signals to characterize the step responses. A set of programs are developed to automate step-based tests. Three commercial PMUs are selected to perform step tests using the dynamic test system developed at NIST. The test results are outlined at the end. %B 2009 IEEE Power & Energy Society General Meeting %I IEEE %C Calgary, Canada %P 1 - 6 %8 07/2009 %@ 978-1-4244-4241-6 %R 10.1109/PES.2009.5275535 %0 Conference Paper %B 2009 IEEE/PES Power Systems Conference and Exposition (PSCE) %D 2009 %T Fast parallelized algorithms for on-line extended-term dynamic cascading analysis %A Siddhartha Kumar Khaitan %A Chuan Fu %A James D. McCalley %K AA09-001 %K Power system dynamics %K RTGRM %X Very fast on-line computational capability to predict mid-term dynamic system response to disturbances and identify corrective actions is an important attribute of high-speed extended term (HSET) time domain simulation (TDS). Focusing on the development of computational speed, this paper propose a parallel strategy intended for deployment on the super computer, Blue Gene/L, to simulate the power system dynamics, which can be described as a set of differential algebraic equations (DAEs). To deal with DAE stiffness problems and fully capture benefits of explicit and implicit integration methods, the partition algorithm called recursive projection method (RPM) is employed. Additionally, good load balancing for parallel computation is achieved using waveform relaxation method (WRM) to separate the stiff parts of DAE. Multi-frontal massively parallel sparse direct solver (MUMPS) is utilized to solve the linear systems involved in the implicit methods. This paper reports on the design. %B 2009 IEEE/PES Power Systems Conference and Exposition (PSCE) %I IEEE %C Seattle, WA, USA %P 1 - 7 %8 03/2009 %@ 978-1-4244-3810-5 %R 10.1109/PSCE.2009.4840238 %0 Conference Paper %B 2009 IEEE/PES Power Systems Conference and Exposition (PSCE) %D 2009 %T The problem of initiating controlled islanding of a large interconnected power system solved as a Pareto optimization %A Vijay Vittal %A Gerald T. Heydt %K AA05-001 %K AARD %K Automatic Switchable Network (ASN) %K controlled islanding %K electricity markets %K Power system dynamics %K power system economics %XControlled islanding of a large electric power system is proposed under rare circumstances as a measure of last resort to avoid a catastrophic blackout. Controlled islanding appears to be more desirable than uncontrolled islanding. A separate power system operating objective is the retention of synchronous operation of the entire system to ensure the viability of power markets. The problem of when to initiate controlled islanding, accounting for power marketing objectives is formulated as a multiobjective optimization. Pareto optimization is applied in the form of the calculation of a Pareto surface. This formulation may allow power system operators to manage the multiobjectives of mitigating the possibility of a blackout versus the full enabling of power markets. This is a conceptual paper in which the analytical basis and the main points of the solution of when to initiate controlled islanding are outlined. The objective function recommended for the capture of transient stability is the transient stability load margin.

%B 2009 IEEE/PES Power Systems Conference and Exposition (PSCE) %I IEEE %C Seattle, WA, USA %P 1 - 7 %8 03/2009 %@ 978-1-4244-3810-5 %R 10.1109/PSCE.2009.4839928 %0 Conference Paper %B 2009 North American Power Symposium (NAPS) %D 2009 %T Wide-area dynamic security region %A Yuri V. Makarov %A Pengwei Du %A Shuai Lu %A Tony B. Nguyen %A James W. Burns %A Jim Gronquist %K AA07-002 %K AARD %K phasor measurement units (PMUs) %K Power system dynamics %K power system security %XThis paper proposes a practical method to determine the wide-area dynamic security region of electrical power systems. The boundary of the security region can be approximated using its piecewise-linear approximation. The goal of this approximation is to find a minimum set of hyperplanes that describe the boundary with a given accuracy. Offline computer simulations are used to generate experimental data to build a set of hyperplanes, which form the Security Region for the Wide-area Interconnection. The hyperplanes will be used in real time with State Estimation data and PMU information to evaluate the current security margin and operational transfer capability, to determine the most limiting elements of the grid, and to select optimal remedial actions. Numerical simulations carried out on the WECC system have demonstrated the effectiveness of this approach.

%B 2009 North American Power Symposium (NAPS) %I IEEE %C Starkville, MS, USA %P 1 - 6 %8 10/2009 %@ 978-1-4244-4428-1 %R 10.1109/NAPS.2009.5484095 %0 Journal Article %J IEEE Transactions on Power Systems %D 2008 %T Multifrontal Solver for Online Power System Time-Domain Simulation %A Siddhartha Kumar Khaitan %A James D. McCalley %A Qiming Chen %K AA09-001 %K AARD %K Automatic Switchable Network (ASN) %K dynamic simulations %K Power system dynamics %XThis paper proposes the application of unsymmetric multifrontal method to solve the differential algebraic equations (DAE) encountered in the power system dynamic simulation. The proposed method achieves great computational efficiency as compared to the conventional Gaussian elimination methods and other linear sparse solvers due to the inherent parallel hierarchy present in the multifrontal methods. Multifrontal methods transform or reorganize the task of factorizing a large sparse matrix into a sequence of partial factorization of smaller dense frontal matrices which utilize the efficient Basic linear algebra subprograms 3 (BLAS 3) for dense matrix kernels. The proposed method is compared with the full Gaussian elimination methods and other direct sparse solvers on test systems and the results are reported.

%B IEEE Transactions on Power Systems %V 23 %P 1727 - 1737 %8 11/2008 %N 4 %! IEEE Trans. Power Syst. %R 10.1109/TPWRS.2008.2004828 %0 Conference Paper %B 2008 IEEE Power and Energy Society General Meeting %D 2008 %T Use multi-dimensional ellipsoid to monitor dynamic behavior of power systems based on PMU measurement %A Jian Ma %A Yuri V. Makarov %A Miller, Carl H. %A Tony B. Nguyen %K AA07-002 %K AARD %K phasor measurement units (PMUs) %K Power system dynamics %XThe paper discusses a new idea of the multi-dimensional characteristic ellipsoid (CELL) approach to monitor dynamic behavior of an interconnected power system using phasor measurement unit (PMU) measurement. The multi-dimensional minimum volume enclosing ellipsoid (MVEE) is extracted based on phasor measurements to represent the feature of dynamic behavior of power systems. The orientation matrix of MVE describes the shape and orientation of the CELL. Extreme events can be identified by tracking the volume change of the CELL with respect to time. Some feature indexes that can be used to determine the disturbance are also proposed to interpret the dynamic behavior of the power system, and to determine the decision trees for extreme event identification procedure. This method will be a useful tool for providing wide-area situational awareness for grid operators, identification of system disturbances and detection of system stresses and their locations.

%B 2008 IEEE Power and Energy Society General Meeting %I IEEE %C Pittsburgh, PA, USA %P 1 - 8 %8 07/2008 %@ 978-1-4244-1905-0 %R 10.1109/PES.2008.4596578 %0 Conference Proceedings %B IEEE Power Engineering Society Summer Meeting %D 2000 %T Transmission voltage recovery following a fault event in the Metro Atlanta area %A Taylor, L.Y. %A Hsu, Shih-Min %K FIDVR %K FIDVR-001 %K load modeling %K Power system dynamics %K RTINA %XThis paper describes a multiple contingency fault and breaker failure event at two Metro Atlanta 230 kV substations. After the fault activity, the transmission system in the Metro Atlanta area experienced a voltage depression lasting around 15 seconds, followed by a voltage overshoot. Over 1900 MWs of load was lost. Evidence suggests that the majority of the load was dropped due to the operation of induction motor protection removing the motors from the extended low voltages. Dynamic simulations using aggregate load models that included the effect of induction motors and distribution system impedances were used to recreate the response of the transmission system. Real world data, including a plot from a data fault recorder, is presented and compared to the dynamic simulations. This paper describes the event, and the study techniques required to simulate the observed transmission system behavior. The effectiveness of new bus arrangements, enhanced relaying, and dynamic and static MVAr support toward mitigating the voltage depression is also discussed.

%B IEEE Power Engineering Society Summer Meeting %V 1 %P 537-542 vol. 1 %8 08/2000 %G eng %3 IEEE Power Engineering Society Summer Meeting, 2000 %R 10.1109/PESS.2000.867642