Showing papers by "Jovica V. Milanovic published in 1997"

Locating dynamic loads which significantly influence damping

Abstract: The paper proposes a techniques for locating loads where dynamics have a significant influence on the damping of power system inter-area oscillations. A feedback interpretation of load dynamics underlies this technique. It is shown that eigenvalue sensitivity and residues can be used to provide the desired information. This approach is applicable for the analysis of large systems. Use of these ideas allows limited resources to be devoted to obtaining good models of important loads, rather than trying to obtain adequate models of many extra loads.

Effect of load uncertainty on small disturbance stability margins in open-access power systems

Abstract: The paper is devoted to computation of the small signal damping bound caused by uncertainty in power system parameters (in particular in system load parameters). Methods of computation, reduction by means of revealing the most influential load parameters and expression in terms of security margins in the space of system parameters are addressed. The corresponding stability margin in the space of power system parameters can be taken into consideration in the procedures for finding the closest oscillatory stability boundary point and tracing these boundaries in given loading directions. The proposed method is tested on a realistic power system and results of simulation are presented and discussed. The techniques are not exclusive to but appear to be demanded by problems arising in open access grids.

Survey of power quality problems in Tasmania

Abstract: This paper presents results of the power quality survey in Tasmania. A questionnaire on the present status of power quality issues was prepared and distributed in the Hydro-Electric Corporation and major power users in Tasmania. Both utility and customer personnel were asked to indicate what power quality problems were and to identify the major causes of these problems.

Tuning of SVC stabiliser to compensate the influence of voltage dependent loads

Abstract: The paper explores the influence of power system loads on static VAr compensator (SVC) damping effectiveness. Equipped with properly tuned additional stabiliser SVCs have been successfully used for improving the damping of electromechanical oscillations in power system. The damping improvement is usually achieved through indirect voltage influence through voltage dependent loads. Tuning of additional compensator stabiliser (ACS) traditionally assumes that loads are statically voltage dependent. However load parameters are generally uncertain and loads often exhibit some dynamic response. This uncertain dynamic behaviour of loads can introduce an additional phase shift between voltage and load response and such can detune the ACS. Example of robust tuning of ACS to compensate influence of load dynamics and uncertainty is presented and discussed.