Transient Process Of Power System Research Articles

Evaluation of the effect of wind-operated power plants on the total inertia of an electric power system

This paper is aimed at determining the effect of a variable number of Type 4 wind turbines in the total generation of the corresponding electric power system on the parameters of an asynchronous regime of such a system. Processes occurring in an electric power system were simulated using an all-mode real-time simulation complex of electric power systems constituting a multi-processor software and hardware system. A model of an electric power system was developed, which, in addition to conventional power sources, included a wind-operated power plant combining a variable number of Type 4 wind turbines. The automatic control system of the simulated wind-operated power plant comprised a control loop (in terms of active power and voltage) equipped with an additional regulator of virtual inertia. An analysis of changes in the parameters of the asynchronous regime using a virtual inertia algorithm showed that the time of its advancement along the protected line was reduced maximally by 0.1 s. However, the time of the first cycle of asynchronous motion between two generators in the post-emergency regime increased by 2 times. Thus, for a wind-operated plant with a capacity of 100 MW, the time of asynchronous motion was 0.36 sec and 0.74 sec without using and when using a virtual inertia algorithm, respectively. It was experimentally confirmed that an increase in the power of a wind-operated power plant leads to a decrease in both the time of advancement of the asynchronous regime and the time, during which conventional generators transit from the synchronous regime. The latter was evidenced by the effect of Type 4 wind turbines on the value of total inertia, which ranged from 8.746 to 5.478 s. A study of the virtual inertia algorithm confirmed its impact on the electromechanical transient processes in power systems. The most favourable effect was noted at a virtual inertia value of 2 s and a wind-operated power plant capacity of 100 MW.

Mathematical modelling of transient processes in power systems considering effect of high-voltage circuit breakers

Mathematical modelling of transient processes in power systems considering effect of high-voltage circuit breakers

Особенности применения пакета MATLAB/simulink для анализа статической устойчивости синхронных генераторов в энергосистеме

MATLAB/Simulink is widely used for calculation and analysis of stable and transient processes in power systems. For this purpose there is a range of mathematical models in the package which can be applicable to resolving simulation issues. The package models have some distinctive features, and they are different from commonly known ones which makes them harder to use and creates difficulty in configuring them and comparing the results of modeling. In the view of this situation the research in specific features of applying MATLAB/Simulink is of the utmost importance, particularly for the analysis of the static sustainability of synchronous generators working in parallel with the power system. The paper provides a review of the most widespread elements of the power system, some features of the equivalent circuits which they are based on, and there is also an example of parameterization and some recommendations on how to configure them in the package. The modeling of steady state and the comparison between the regime parameters have also been made. The results might be useful for studying the specific features of application of the package Matlab/Simulink for power engineering, the recommendations presented below may be used for modeling steady and transient regimes of power systems.

Analysis of Transients Processes in Motor Load at Switching on to Reserve Power Supply Source

The work is devoted to analysis of transient processes in power systems with synchronous and inductions motors at short-time electrical power failure in supply network for determination of conditions for the success of fast-acting automatic switchover to a backup power supply source. The analysis is performed using a mathematical model of the network section, a result of which was received dependences to the current and torque of the motor load from the phase shift angle between the backup power supply voltage and voltage on the section, which lost power.

Stabilization of transient processes in power systems by an eigenvalue shift approach

A new approach to stabilize power system transient processes is presented. It uses the idea that left shifts of the dominant state matrix eigenvalues, computed along the integral trajectory, will provide better damping of the resulting transient processes. Those shifts are made by varying the power system controllable parameters in the direction of maximal joint displacement of selected (dominant) eigenvalues. The effectiveness of the proposed technique is demonstrated by its application to the problem of voltage stability control.

Transient Stability of Dissipative Power Systems

Stability criteria for on-line analysis of transient processes in power systems are discussed. A method to approximate separation manifolds by energy surfaces of corresponding conservative systems is derived by using the theory of differential manifolds in the spirit of Its applications in classical mechanics. Closed form stability criteria, stability region estimates which are expressed explicitly in terms of system parameters, and simple algorithms suitable for on-line implementation are obtained when the Method is applied to the transient stability problem in power systems. A structure preserving Model of Multimachine systems with electromechanical damping is employed in the analysis. Physical insight is preserved through considerations of energy surfaces in the direction of a faulted system trajectory. Additional research will be required in order to extend the approach to other types of dissipation forces and to verify its applicability to on-line assessment of power systems stability.

An approach to the evaluation of electromechanical transient processes in power systems

The paper presents an approach to the evaluation of electromechanical transient processes in power systems. On the basis of identification of the physical properties of the system considered, for an adequately chosen time interval, quasilinearization and decomposition of the original system of nonlinear differential equations into subsystems is performed. A linear transformation is introduced which transforms the state matrix of the sub-systems into diagonal form. These simplifications enable the use of numerical integration schemes based on difference state equations, which have an elementary form. As a result, a model is formed which is very suitable for numerical treatment. The integration is performed without numerical instability, quickly and effectively, with the desired simulation accuracy, and with low memory requirements.