1 Introduction 2 Electromagnetic Transients 3 Synchronous Machine Modeling 4 Synchronous Machine Control Models 5 Single-Machine Dynamic Models 6 Multimachine Dynamic Models 7 Multimachine Simulation 8 Small-Signal Stability 9 Energy Function Methods Appendix A: Integral Manifolds for Model Bibliography Index

Power System Dynamics and Stability

Phasor Measurement Techniques.- Phasor Estimation of Nominal Frequency Inputs.- Phasor Estimation at Off-Nominal Frequency Inputs.- Frequency Estimation.- Phasor Measurement Units and Phasor Data Concentrators.- Transient Response of Phasor Measurement Units.- Phasor Measurement Applications.- State Estimation.- Control with Phasor Feedback.- Protection Systems with Phasor Inputs.- Electromechanical Wave Propagation.

Synchronized Phasor Measurements and Their Applications

A simple and novel approach in the design of an extended Kalman filter (EKF) for the measurement of power system frequency has been presented in this paper. The design principles and the validity of the model have been outlined. The performance of this filter has been compared with some of the existing methods for estimating the frequency of a signal under noisy conditions. The feasibility of the proposed filter has been tested in the laboratory under worst-case measurement and network conditions, which might occur in a typical power system. Also, the proof of the stability for the proposed filter has been discussed for a single sinusoid. It has been found that the proposed algorithm is suitable for real-time applications especially when the frequency changes are abrupt and the signal is corrupted with noise and other disturbances due to harmonics.

A novel Kalman filter for frequency estimation of distorted signals in power systems

In this paper, a new approach to adaptive underfrequency load shedding (UFLS), a procedure for protecting electric power systems from dynamic instability and frequency collapse, is presented. It consists of two main stages. In the first stage, the frequency and the rate of frequency change are estimated by the nonrecursive Newton-type algorithm. By using the simplest expression of the generator swing equation, in the second algorithm stage, the magnitude of the disturbance is determined. The UFLS plan is adapted to the magnitude estimated, obtaining in this way a more efficient system operation during emergency conditions. Results of procedure testing are demonstrated through the dynamic simulations by using: 1) a simple three-machine test system and 2) a ten-machine New England system

Adaptive underfrequency load shedding based on the magnitude of the disturbance estimation

Spread spectrum time domain reflectometry (SSTDR) and sequence time domain reflectometry have been demonstrated to be effective technologies for locating intermittent faults on aircraft wires carrying typical signals in flight. This paper examines the parameters that control the accuracy, latency, and signal to noise ratio for these methods. Both test methods are shown to be effective for wires carrying ACpower signals, and SSTDR is shown to be particularly effective at testing wires carrying digital signals such as Mil-Std 1553 data. Results are demonstrated for both controlled and uncontrolled impedance cables. The low test signal levels and high noise immunity of these test methods make them well suited to test for intermittent wiring failures such as open circuits, short circuits, and arcs on cables in aircraft in flight.

Analysis of spread spectrum time domain reflectometry for wire fault location

A new approach to the design of a digital algorithm for voltage phasor and local system frequency estimation is presented. The estimation problem is considered as an unconstrained optimization problem. The algorithm is derived using Newton's iterative method, very commonly used in load-flow studies. The algorithm showed a very high level of robustness as well as high measurement accuracy over a wide range of frequency changes. The algorithm convergence of order two provided fast response and adaptability. To demonstrate the performance of the algorithm developed, computer simulated, experimentally obtained and real-life data records are processed. The presented work is a part of a project concerning the application of microprocessors in frequency relaying. >

Voltage phasor and local system frequency estimation using Newton type algorithm

To avoid automatic reclosing on permanent faults, a new numerical algorithm for power transmission network arcing faults detection has been developed. Some important features of a long arc in air are investigated and used as a basis in the algorithm design. The fact that the nonlinear arc behavior influences other voltages and currents distorting them, offered an opportunity to detect the arc by measuring and processing the transmission line terminal voltage and current. A series of simulation studies have shown that the algorithm can be used as an effective tool for arcing faults detection. >

A new approach to the arcing faults detection for fast autoreclosure in transmission systems

Two numerical algorithms for fault location and distance protection which use data from one end of a transmission line are presented. Both algorithms require only current signals as input data. Voltage signals are unnecessary for determining the unknown distance to the fault. The solution for the most frequent phase to ground fault is presented. The algorithms are relatively simple and easy to be implemented in the on-line application. The algorithms allow for accurate calculation of the fault location irrespective of the fault resistance and load. To illustrate the features of the new algorithms, steady-state and dynamic tests are presented.

Distance protection and fault location utilizing only phase current phasors

In this paper a new numerical algorithm for arcing faults detection and fault distance estimation is presented. The solution is given in the time domain. It is based on the line terminal voltages and currents processing. A simple new mathematical model of arc voltage is introduced in the estimation. Thereby, the more accurate approach to fault location is derived, particularly for the close-in faults. The new algorithm can be utilized for blocking the automatic reclosing. The unknown model parameters, including the line resistance and inductance, fault resistance and arc voltage amplitude, are estimated by using the least error squares method. The new algorithm is successfully tested through computer simulation and laboratory tests.

Time domain solution of fault distance estimation and arcing faults detection on overhead lines

This paper introduces a new self-tuning digital signal processing algorithm for local power system frequency deviation measurement. The algorithm is derived using the nonrecursive least error square technique accompanied with an updating procedure, which generally improves the algorithm properties: the measurement range; the immunity to a random noise; and the accuracy. The algorithm developed takes into account the components of the fundamental frequency, the second through the M-th harmonics and a decaying DC component, so it could be used for the real-time distorted signals frequency estimation as well as for the harmonics measurement. To demonstrate the efficiency of the algorithm proposed, the results of the computer simulated, experimentally obtained and real-life data records tests are presented. >

Milenko B. Djurić

Papers

Voltage phasor and local system frequency estimation using Newton type algorithm

A new approach to the arcing faults detection for fast autoreclosure in transmission systems

Distance protection and fault location utilizing only phase current phasors

Time domain solution of fault distance estimation and arcing faults detection on overhead lines

A new self-tuning algorithm for the frequency estimation of distorted signals