Power System Steady State Stability Research Articles

Hybrid Power System Frequency Control including Wind Farm using Battery Storage System

Fixed speed wind turbine-squirrel cage induction generator (FSWT-SCIG) based wind farm (WF) is increasing significantly. However, FSWT-SCIG have no frequency control capability, which creates a significant problem on power system steady-state stability. This paper represents a new operational strategy to control frequency of the entire power system including large-scale FSWT-SCIG based WF by using battery storage system (BSS). The proposed cascaded control of BSS is designed to provide effective amount of real power during steady-state period to damp frequency fluctuations. To evaluate the validity of the proposed system, simulation studies are executed on a reformed IEEE nine-bus power system with three synchronous generators (SGs) and SCIG-based WF along with BSS. The simulation results indicate that the proposed system can be an effective solution to reduce frequency fluctuations of the hybrid power system during steady-state condition.

Исследование позиционной модели энергетической системы

The position model specific features are investigated; the eigenvalues and eigenvectors of the small perturbation equation matrix are analyzed, and a criterion of limiting operation modes in terms of aperiodic steady-state stability is obtained, which generalizes the classic Wagner - Evans criterion for complex multimachine systems. It has been found that the position model, i.e., a model in which the powers and torques of generators depend only on the relative angles of machine rotors, implicitly uses the distributed slack bus philosophy, and its limiting modes in terms of aperiodic steady-state stability are exactly identical with the limiting modes of a load flow model with a distributed slack bus in which the coefficients characterizing the participation of nodes in active power balancing are assigned to be directly proportional of the synchronous machines’ inertia constants. It has been found from a comparative analysis of the limiting mode parameters in the position model and the model with an infinite bus that the position model yields a conservative (underestimated) assessment of the electric power system steady-state stability margin. It is shown that the steady-state stability margins are estimated in the most adequate manner by means of the load flow model with an infinite bus, in the limiting modes of which the relative power loss increments do not exceed unity for all nodes.

STEADY STATE STABILITY ANALYSIS AND ENHANCEMENT OF THREE MACHINE NINE BUS POWER SYSTEM USING TCPS FACTS DEVICE

Power System stability study is the important parameter of economic, reliable and secure system planning and operation. Studies are important during the planning and conceptual design stages of the project as well as during the operating life of the plant periodically. This paper presents the power system steady state stability analysis for IEEE9 bus test system and examines influence of TCPS FACTS device based controller on test system. It is assumed that system under study has been perturbed from a steady state equilibrium that prevailed prior to the application of the disturbance. If system is stable, we would expect that for temporary or permanent disturbance, system will acquire initial or new operating state after a transient period. The stability study is accessed using Lyapunov’s first method. The effectiveness of damping controller in enhancing the steady state stability is investigated by incorporating available constraints. For analysis MATLAB software is employed. The conclusions have been drawn here, based on theoretical and mathematical analysis so as to provide an insight and better understanding of steady state stability of considered multi machine power system.

Effects of Synchronous Machine Saturation, Circuit Parameters, and Control Systems on Steady State Stability

Analysis of elementary power system configuration by means of idealized model illustrates some of the fundamental stability properties of power system. Instability in a power system may be manifested in many different ways, depending on the system configuration and operating mode. Analysis of synchronous machine performance, including saturation effect, is very important. Synchronous machine performance is greatly influenced by its iron saturation. The developed synchronous machine model, and hence the power system model, which takes this saturation effect into account will also depict the effects of the control systems on power system steady state stability. The objective of this paper is to provide an overview of the power system stability phenomena, which is also dependent on the synchronous machine circuit parameters with and without automatic voltage regulator and governor systems.

Synchronizing and damping torque coefficients and power system steady-state stability as affected by static VAr compensators

The utilization of static VAr compensators (SVC) for supplying reactive power at certain points of an electric power system is an efficient way for fast control of transient and steady-state voltage changes following short-circuits, load rejection, opening of severely loaded transmission circuits, etc. Other SVC applications include the increase of power transmission capacity through interconnections between areas of a power system and the damping enhancement of local or inter-area electromechanical oscillation modes. This paper fundamentally deals with these last two issues by analyzing the results of synchronizing and damping torque coefficient calculations for a generation station connected radially to a much larger power system. The results presented pertain to a double-circuit, 800 km, 500 kV transmission system during a one-circuit out contingency.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Power system steady-state stability and the load-flow Jacobian

The relationship is presented between a detailed power system dynamic model and a standard load-flow model. The linearized dynamic model is examined to show how the load-flow Jacobian appears in the system dynamic-state Jacobian for evaluating steady-state stability. Two special cases are given for the situation when singularity of the load-flow Jacobian implies singularity of the system dynamic-state Jacobian. The standard load-flow Jacobian can provide information about the existence of a steady-state equilibrium point for a specified level of loading or interchange. There are two very special cases when the determinant of the standard load-flow Jacobian implies something about the steady-state stability of a dynamic model. Both of these cases involve very drastic assumptions about the synchronous machines and their control systems. The load level which produces a singular load-flow Jacobian should be considered an optimistic upper bound on maximum loadability. >

Power system steady state stability assessment using catastrophe theory

Catastrophe theory is a mathematical techique for the qualitative analysis of system equations, defining the jump phenomena and sudden changes caused by smooth alterations in the situation. This theory has been applied previously to the study of steady state stability of power systems. The paper presents a new algorithm to derive the appropriate catastrophe manifold to which the power systems can be fitted. The algorithm is deduced in terms of relevant system parameters that can be helpful for online steady state stability assesment.

Controller Designs for Power System Stability Enhancement Using Static Phase Shifters

This paper presents a digital simulation study of the use of a static thyristor-controlled phase shifter as an effective power controller to enhance system stability and to damp the line electromechanical oscillations, hence to improve AC tie line capacity. A dynamic model of the static phase shifter is incorporated in the integrated power system dynamics; the unified state space form is used to investigate digital and analog control laws to transform static phase shifters into viable tools in enhancing interconnected power system steady state stability.

The Use of Dynamic Equivalents in the Analysis of Power System Steady State Stability

Frequently in the analysis of the steady state stability of a power system large portions of the system remain unchanged while parameters in one or a few machines and their associated control systems are altered and the effect on the total system examined. The section of the system in which the parameters are to be altered can be designated as the study system while the remainder of the system can be designated as the external system. This paper describes a procedure to form a low order mathematical equivalent of the external system which can be simply linked to a complete model of the study system. Stability can then be determined by an eigenvalue analysis of the resulting lower order system.

Effect of Different Types of Regulators on Power System Steady State Stability

ABSTRACT This paper presents a comparison of the various types of regulators namely the current-actuated, the voltage-actuated the load angle-actuated and the rotor angle-actuated regulators, for a single machine infinite bus system. The same study is extended to a two machine system. The stability limit is given as the angle at which the critical eigenvalue of the system matrix changes sign.

Effect of Intermittent Regulation on Power System Steady State Stability

ABSTRACT Thin paper presents a study of a simple intermittent regulator on a single machine infinite bus system. The method of analysis usedis Z-transform analysis. The power system is analysed as a feedback sampled-data control system.