Infrastructure of a distribution systems is facing major challenges with deregulated power system. Reactive power compensation can reduce energy losses in system, improve voltage profile and release feeder capacity. Installation of capacitors in distribution network is ensuring more efficient systems, but also provides economic benefit to utility and users. Vital task for capacitor implementation is to determine the best locations and size of capacitors. Hence, capacitor placement has an important role in distribution system planning. In this paper, using the professional software tool DigSILENT Power Factory, optimal capacitor placement is analysed in real low voltage distribution network. Results and analysis show that by optimal capacitor placement annual losses and adequate size for installed capacitors can be calculated. The capacitor placement problem consists of objective function which is composed of power losses and capacitor installation costs subject to bus voltage constraints. Optimization placement calculation is compared to installation of four capacitors in given case study distribution grid. Simulation results show that with appropriate software techniques optimal capacitor placement can be achieved in distribution grid.

Ferroresonance is a nonlinear dynamic phenomenon that appears in the electric power system between a non-linear inductances and system capacities excited by a sinusoidal voltage source. The most common non-linear elements of the electric power system are the iron core inductances of power and measuring transformers, reactors, etc. in which saturation of non-linear elements can occur. As a consequence of ferroresonance there may be a significant increase in the voltage value and under the certain conditions an excessive increase of the current value across the transformer terminals. This phenomenon can lead to damage of the measuring transformers and other equipment used in the network. Ferroresonance is one of the most common low-frequency electromagnetic transient phenomena that appear in the isolated power networks. Therefore, special attention must be on analyzing the probability of ferroresonance occurrence in electric power systems. In this paper, ferroresonance measurement results will be given. The waveform of the phase to ground voltage and wave form of the open delta voltage is obtained. Also, the Fourier transformation is performed on these signals. Proposed

The city of Sarajevo as the capital and the largest administrative and economic center in Bosnia and Herzegovina represents one of the most polluted cities in Europe in terms of the concentration of PM10 (particulate matter 10). Scientific and professional communities have particularly been focused on identifying the causes of this situation, and on the introduction of the system of measures to reduce PM10 values to below the limit values. This paper analyzes the impact of meteorological variables (wind speed, humidity, temperature and pressure) to the concentration of PM10 in the city of Sarajevo by using the Wavelet Coherence approach (WTC). Available data indicate actual values recorded in the Federal Institute for Hydrometeorology in 2012. The results of the analysis show the different effects that certain meteorological parameters have on the concentrations of PM10 particles in a time period of one year. It can also be concluded that this approach is very useful in terms of the practical interpretation of available data and it offers a clearer picture of the impact of meteorological conditions on the concentrations of PM10 particles.