This paper presents an improved approach to reactive power planning in electric power systems (EPS). It is based on minimization of a transmission network’s active power losses. Some new limitations such as voltage instability detection and generator capability curve limit have been added to the existing method in order to improve the reliability of reactive power planning. The proposed method was tested on a model of the Slovenian power system. The results show the achievement of significant reduction in active-power losses, while maintaining adequate EPS security.
COBISS.SI-ID: 13301782
This paper discusses different methods for voltage-sag source detection. It is shown that methods known from the literature do not work well, particularly in cases of asymmetrical voltage sags. Therefore, generalized methods are proposed using a vector-space approach. All the discussed methods were tested by applying extensive simulations, as well as laboratory and field tests. The obtained results show that all the proposed methods are highly effective in all cases of voltage sags, whereas the overall effectiveness of those methods known from literature is mainly unacceptable.
COBISS.SI-ID: 13688086
This paper introduces a new method for evaluating the status of medium-voltage (MV) switching devices by defining two hybrid parameters. The device condition hybrid parameter (DCHP) and the device importance hybrid parameter (DIHP) are defined by using weighing factors. Three different methods were applied for determining the DCHP, while the DIHP is determined by using the differential evolution algorithm. The proposed approach was primarily developed for applying modern MV switching devices maintenance, but can also be used in network planning and for proper choosing of MV switching devices.
COBISS.SI-ID: 13164054
This paper introduces an analysis of electrical conditions in the area between the conductor and the insulator's upperfitting. The designing of a new composite post insulator is presented with the upperfitting made of insulating material. 3D analysis of electric-field strength in the insulator and its surroundings are also given. The results of this analysis are presented for both-new and old versions of a composite post insulator. 3D analysis shows that the new version has up to five times lower magnitudes of electric-field strength.
COBISS.SI-ID: 13352982
This paper presents application of multiobjective optimization methods on a capacitive divider finite element model. Modeling is based on the differential evolution algorithm (DE), including the concept of the Pareto nondominance. Through calculations, this concept allows differential evolution algorithm variation in order to achieve uniformly distributed results on the Pareto front, including the lowest population size as possible. Selection step, as a part of the differential evolution method, is properly modified to improve the convergence of the algorithm.
COBISS.SI-ID: 13078294