Multi-machine Electric Power System Research Articles

Harmony search algorithm for SVC controller tuning in voltage support mode

Static Var Compensator (SVC) in one of the most widely used FACTS devices in industry and real world power systems. The problem of finding optimal values of SVC parameters has been studied for years. Many different methods have been carried out to design SVC controllers. But trying to find better controller is still remains. In this scope, Harmony Search (HS) Algorithms method as a meta-heuristic optimization method is considered for tuning the parameters of SVC. A multi machine electric power system is used to test viability of SVC in voltage support under disturbances. Simulation results on a multi machine power system show the ability of SVC in control of voltage as well as stability enhancement. The results are carried out by numerical simulations by using MATLAB software.

Harmony search algorithm for STATCOM controllers tuning in a multi machine environment

This paper presents the application of static synchronous compensator (STATCOM) to voltage support in a multimachine electric power system. Harmony Search (HS) Algorithm as a meta-heuristic optimization method is considered for tuning the parameters of STATCOM. In order to evaluate the performance of STATCOM in voltage support, a multi-machine electric power system installed with STATCOM is considered as case study. The system under study is IEEE 14 bus standard system testing. The results are compared with the system without STATCOM. Several nonlinear time-domain simulation tests visibly show the ability of STATCOM in voltage support.

Harmony Search Algorithm for STATCOM Controllers Tuning in a Multi Machine Environment

This paper presents the application of static synchronous compensator (STATCOM) to voltage support in a multimachine electric power system. Harmony Search (HS) Algorithm as a meta-heuristic optimization method is considered for tuning the parameters of STATCOM. In order to evaluate the performance of STATCOM in voltage support, a multi-machine electric power system installed with STATCOM is considered as case study. The system under study is IEEE 14 bus standard system testing. The results are compared with the system without STATCOM. Several nonlinear time-domain simulation tests visibly show the ability of STATCOM in voltage support.

Multi-machine power system stabilizer adjustment using Simulated Annealing

In this paper, the authors are willing to find the optimal and robust design for power system stabilizers (PSSs) in a multi-machine power system. In this regard a new Meta heuristic method as Simulated Annealing (SA) is used. The PSS parameters are computed to assure maximum damping performance under different scenarios. A multi machine electric power system is used to illustrative the performance of proposed method. The efficacy of this technique in damping local and inter-area modes of oscillations in multimachine power systems is confirmed through nonlinear simulation results. Simulation results are carried out by numerical simulations on MATLAB software. Keywords: Multi Machine, Power System Stabilizer, Low Frequency Oscillations, Simulated Annealing

Multi-machine power system stabilizer adjustment using genetic algorithms

In this paper, the problem of tuning lead-lag power system stabilizer parameters of a multi machine power system is considered. This problem is formulated as an optimization problem, which is solved using Genetic Algorithms (GA). Simulation results show the effectiveness of the proposed Genetic Algorithms-based lead-lag power system stabilizer to damp the oscillation of multimachine system and work effectively under variable loading and fault conditions. The proposed GA-PSS is evaluated on the IEEE 14 bus test system as a multi machine electric power system.

Multi-machine power system stabilizer adjustment using genetic algorithms

In this paper, the problem of tuning lead-lag power system stabilizer parameters of a multi machine power system is considered. This problem is formulated as an optimization problem, which is solved using Genetic Algorithms (GA). Simulation results show the effectiveness of the proposed Genetic Algorithms-based lead-lag power system stabilizer to damp the oscillation of multimachine system and work effectively under variable loading and fault conditions. The proposed GA-PSS is evaluated on the IEEE 14 bus test system as a multi machine electric power system.

Transient stability improvement by nonlinear controllers based on tracking

This paper deals with the control problem in multi-machine electric power systems, which represent complex great scale nonlinear systems. Thus, the controller design is a challenging problem. These systems are subjected to different perturbations, such as short circuits, connection and/or disconnection of loads, lines, or generators. Then, the utilization of controllers which guarantee good performance under those perturbations is required in order to provide electrical energy to the loads with admissible stability margins. The proposed controllers are based on a systematic strategy, which calculate nonlinear controllers for generating units in a power plant, both for voltage and velocity regulation. The formulation allows designing controllers in a multi-machine power system without intricate calculations. Results on a power system of the open research indicate the proposition’s suitability. The problem is formulated as a tracking problem. The designed controllers may be implemented in any electric power system.

Neural network based on adaptive resonance theory with continuous training for multi-configuration transient stability analysis of electric power systems

This work presents a methodology to analyze electric power systems transient stability for first swing using a neural network based on adaptive resonance theory (ART) architecture, called Euclidean ARTMAP neural network. The ART architectures present plasticity and stability characteristics, which are very important for the training and to execute the analysis in a fast way. The Euclidean ARTMAP version provides more accurate and faster solutions, when compared to the fuzzy ARTMAP configuration. Three steps are necessary for the network working, training, analysis and continuous training. The training step requires much effort (processing) while the analysis is effectuated almost without computational effort. The proposed network allows approaching several topologies of the electric system at the same time; therefore it is an alternative for real time transient stability of electric power systems. To illustrate the proposed neural network an application is presented for a multi-machine electric power systems composed of 10 synchronous machines, 45 buses and 73 transmission lines.

Decentralized sliding mode block control of multimachine power systems

A decentralized sliding mode stabilizing excitation controller for multimachine Electric Power Systems (EPS) is designed. The block control approach is used in order to derive a nonlinear sliding manifold, on which the inherent plant model nonlinearities are compensated and the mechanical dynamics are linearized. A local Sliding Mode Speed Stabilizer (SMSS) and Sliding Mode Voltage Regulator (SMVR) control is designed to achieve attractiveness of the derived manifold, regulate the terminal voltage and stabilize the speed of each generation unit in spite of high level external disturbances. The simulation of the Western System Coordinating Council (WSCC) system exhibits the comparison between the traditional Automatic Voltage Regulator/Power System Stabilizer (AVR/PSS) and proposed SMSS/SMVR control schemes.

A Transient Stability Tool Combining the SIME Method with MATLAB and SIMULINK

This paper proposes an efficient educational tool for evaluating the transient stability of multi-machine electric power systems with possible future extensions to control (stabilisation). It uses the Single Machine Equivalent (SIME) transient stability method combined with SIMULINK to model transient stability phenomena, and the GUIDE (Graphical User Interface Design Environment) software of MATLAB. The resulting package validates the data and simulates the results by executing the SIMULINK model in the background in a user-transparent manner. It also provides the user with an extremely flexible tool, which enables him or her to enter, modify, and/or add on complexity to the existing model, thanks to the powerful hierarchical structure of SIMULINK. Considering the popularity and availability of MATLAB at the university level, this package should prove useful for pedagogical and research purposes, while at the same time having the look and feel of commercial packages.

A fuzzy approach in the determination of unstable machines

The aim of this paper is to present a fuzzy approach in the determination of the unstable machines in transient stability studies of multimachine electric power systems. This approach is based on the derivation of an index that can identify the unstable machine by using the values of the generator rotor angles and accelerations. The index actually computes the degree of instability of every system machine, when a three-phase fault is established on any power system location, causing no topological changes after its clearance. The unstable machine will be the one having the largest value of instability index. The derivation of this index is based on the principles of pattern recognition, fuzzy sets theory and the Taylor series expansion technique. Two examples illustrating the methods application are given, including the analysis of the interconnected Hellenic power system.

Determination of transient stability regions in state space using local Lyapunov surfaces

A new approach to the determination of stability regions of multimachine electric power systems is presented, using a Lyapunov function in conjunction with a certain class of unstable equilibrium points. The relevant Lyapunov surface is constructed for each fault, which is considered to be a local approximation to the stability region. Comparison shows that the conservative nature of the second method of Lyapunov is eliminated.

Modal Control Procedures for the Synthesis of Damping Actions in Multimachine Electric Power Systems

This paper deals with the synthesis of control actions in multimachine electric power systems, through modal (pole placement) techniques. The analysis is carried out with reference to a simplified linearized model, strictly oriented to the representation of the electromechanical oscillations. Particular reference is made to the synthesis of local additional feedbacks on machine excitation controls, or turbine controls, in order to achieve a desired improvement of oscillation dampings. After some comparison with other possible synthesis procedures, an iterative procedure is outlined, based on the inverse resolution of the characteristic equation for each assigned characteristic root; successful numerical applications are recalled. The considerations developed in the paper may look suitable also for the formulation and solution of more general synthesis problems.

Modal Control of Multimachine Electric Power System for the Stabilization of Poorly Damped Oscillations

The problem analyzed in this paper is the development of synthesis techniques for the stabilization |of poorly damped oscillations in multimachine power systems. Reference is done to a linearized model, where each machine is represented by a 2nd order model.A closed form analytic expression is deter mined for the feedback matrices leading to any placement of the system poles in the left half-plane of the complex plane. Particular attention is given to the case in which only a selected number of oscillation modes must be damped. For this case an ad-hoc synthesis procedure, based on the preventive construction of a simplified dynamic model retaining only the selected modes, is proposed.

Sensitivity Analysis of the Characteristic Roots of a Linear Time-Invariant Dynamic System: Application to the Synthesis of Damping Actions in Electric Power Systems

The sensitivity of the characteristic roots of a linear time- invariant dynamic system, versus parameter perturbations, may be defined in terms of the transfer matrix residuals; this result looks interesting also from a practical viewpoint, if suitable information on the residuals is experimentally available.The above property is then applied to multimachine electric power systems, with particular reference to the electromechanical oscillations damping.Some practical criteria are presented, both for the synthesis of damping actions and for identification purposes.The usefulness of such criteria has been recently confirmed by some successful applications, leading to the concrete solution of important practical problems.