Zaneta Eleschova

Impact of fault location on transient stability of synchronous generator

This paper presents the impact of fault in various lengths of power line on transient stability of synchronous generator. The same events on two power lines are compared by means of transient simulations, the difference is at fault distance on assessed power lines considering the generator. In the first part are compared fault impacts and fault tripping in the fast zone of distance protection. Fault tripping by protection failure at the end of the assessed power line is compared in the second part. All simulations are mutually compared in terms of significance of their impact on transient stability of synchronous generator.

Analysis and mitigation of ferroresonant oscillations in power system

The aim of the paper is the review of analysis and mitigation of ferroresonant oscillations. The application of harmonic balance method and bifurcation theory was used to analyse a ferroresonant circuit. The derived closed-form solution is useful mathematical method to find turning points which define boundaries between safe (normal) and ferroresonant region as a function of system parameters. The influence of load on mitigation of ferroresonant oscillations was verified using Matlab/Simulink.

Verification of steady state model of power autotransformer

This paper deals with the model of three-winding autotransformer for steady state analyses and for different types of step-voltage regulator. The paper is focused on comparison of two types of three winding transformer model and on verification of these models by means of measurement of distributing transformer. The analyzed transformer is installed and operated in the electric power station Stupava.

Methodology of global assessment of operational states of power system using deterministic approach

Currently a great attention is paid to the increase of security and operation of power system. Several large system failures occurring worldwide over the previous decades affirm significance and need to develop this philosophy. There are examples of it such as power system failures of blackout type in USA, Italy or a splitting into islanding operations in a synchronically interconnected power system in Europe. The reason for occurrence of such failures is a conjunction of several events, nevertheless, all the cases show the only common violated indicator which is a failure to meet the performance of security criterion N-1. This article deals with the methodology based on analysis of the results of simulated calculations of N-1 events with the aim to obtain a more complex view of the use of security criterion N-1 in comparison with the current methods and procedures being in practice. The methodology is based on deterministic approach arising from calculations of steady states with global assessment of operational states of power system. The objective of the article is to comprehensively consider operational states from the view of wider use of the results of security criterion N-1 in comparison with procedures currently being in place.