In this paper, a new multi-objective model for electricity market clearing, considering both voltage and dynamic security aspects of the power system, is proposed. The objective functions of the proposed model include offer cost, voltage stability margin (VSM) and corrected transient energy margin (CTEM). A new solution method incorporating the lexicographic optimization and augmented @?-constraint method is proposed to solve the multi-objective optimization problem. The New England test system is used to demonstrate the performance of the proposed method. The proposed strategy is also compared with the conventional @?-constraint technique.

Multi-objective electricity market clearing considering dynamic security by lexicographic optimization and augmented epsilon constraint method

This paper presents a decision tree based method for out-of-step prediction of synchronous generators. For distinguishing between stable and out-of-step conditions, a series of measurements are taken under various fault scenarios including operational and topological disturbances. The data of input features and output target classes are used as the input-output pairs for decision tree induction and deduction. The merit of decision tree based detection of transient instability lies in robust classification of new unseen samples. The performance of the proposed method is verified on two test cases including a 9-bus dynamic network and the practical 1696-bus Iran national grid. The simulation results are presented for various input features and learning parameters.

Transient Instability Prediction Using Decision Tree Technique

This paper presents a new approach to identify fault types and phases. A transmission line fault classification method based on a radial basis function (RBF) neural network with orthogonal-least-square (OLS) learning procedure was used to identify various patterns of associated voltages and currents. The RBF neural network was also compared with the back-propagation (BP) neural network in this paper. It is shown that the RBF approach can provide a fast and precise operation for various faults. The simulation results also show that the proposed approach can be used as an effective tool for high speed relaying.

A Fault Classification Method by RBF Neural Network with OLS Learning Procedure

Various transmission line fault location algorithms have been proposed in the past depending on the measurements available. These algorithms perform well when the measurements utilized are accurate; they may yield erroneous results when the measurements contain considerable errors. In some cases, there are redundant measurements available for fault location purposes, and it may be possible to design an optimal estimator for the fault location based on nonlinear estimation theories. This paper aims at proposing a possible method for deriving an optimal estimate of the fault location that is capable of detecting and identifying the bad measurement data, minimizing the impacts of the measurement errors and thus significantly improving the fault location accuracy. The solution is based on the distributed parameter line model and thus fully considers the effects of shut capacitances of the line. Since field data are not available, case studies based on simulated data are presented for demonstrating the effectiveness of the new method.

Optimal Estimate of Transmission Line Fault Location Considering Measurement Errors

Application of wavelet fuzzy neural network in locating single line to ground fault (SLG) in distribution lines

An accurate algorithm for locating double phase-to-earth faults on transmission lines of nondirect ground neutral systems is presented. The algorithm employs the faulted phase network and zero-sequence network as the fault location model. It effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The technique embodies an accurate location by measuring only one local end data. The algorithm is used in a procedure that provides the automatic determination of faulted line and phase, rather than requires engineer to specify them. Simulation results have shown the effectiveness of the algorithm under the condition of earth faults.

Transmission line fault location for double phase-to-earth fault on non-direct-ground neutral system

A new dynamic equivalent power system (DEPS) model for fast first swing transient stability assessment is proposed in this paper. The DEPS model makes use of the phenomenon that during a fault on a large power system, there are many generators that are only lightly disturbed when compared with severely disturbed machines. The method substitutes these less disturbed machines by one equivalent generator but allows some model parameters to become time dependent. The crucial feature is that a novel method of classification of the less disturbed machines based on a Taylor series expansion which achieves a very rapid assessment of first swing critical clearing time (CCT) has been developed. This method is fundamentally different from other published dynamic equivalent techniques, such as the extended equal area criterion method and the identification of coherent generators, and both reliability and efficiency are better. With this DEPS model the efficiency of the traditional first swing transient stability analysis could be fundamentally improved. Extensive tests performed on several IEEE test systems show that the proposed model is suitable for fast transient stability assessment in large systems. >

Fast transient stability estimation using a novel dynamic equivalent reduction technique

Fuzzy logic controller for enhancing oscillatory stability of AC/DC interconnected power system

This paper introduces a new conception of corrected potential energy function and its application to on-line fast transient stability margin assessment. Traditionally, transient stability margin is evaluated by the corrected kinetic energy and the potential energy in transient energy function methods. The corrected potential energy is used for transient stability margin assessment instead of potential energy. The main attraction is that the sum of the corrected kinetic transient energy and the corrected potential transient energy is conservative along post fault trajectories. Simulation results on the 10-generator New England test power system show that the transient energy margin obtained is more efficient and more suitable for assessment of stability limit parameters.

http://ieeexplore.ieee.org/iel4/5865/15678/00726889.pdf

Fang Da-zhong

Papers

Transmission line fault location for double phase-to-earth fault on non-direct-ground neutral system

Fast transient stability estimation using a novel dynamic equivalent reduction technique

Fuzzy logic controller for enhancing oscillatory stability of AC/DC interconnected power system

Corrected transient energy function and its application to transient stability margin assessment

A fast approach to transient stability estimation using an improved potential energy boundary surface method