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.

Abstract In this paper, Huang’s Empirical Mode Decomposition approach is proposed for df / d t and active power imbalance in power system estimation. Applied approach implies availability of synchronized phasor measurement units. In addition to the successful applications in the analysis of nonstationary dynamic behavior of power system, identifications and analyses of low-frequency electromechanical oscillations and signals denoising, this approach also enables direct estimation of rate of change of a weighted average frequency (frequency of the center of inertia), as well as assessment of the overall imbalance in the power system. This demonstration is performed using computer simulation testing on the 39 Bus New England System and Western System Coordinating Council 118 bus test systems in the DigSILENT PowerFactory power system analysis software package. To validate the proposed approach the actual frequency information are used. Empirical Mode Decomposition approach is compared with Discrete Wavelet Transform, Method of Least Squares and the results from the DigSILENT PowerFactory. Also, performance of the empirical mode decomposition are compared with performances of the multivariate empirical mode decomposition and noise assisted multivariate empirical mode decomposition on both, simulated signals and field measurements. Applied approach is implemented in the MATLAB environment and results show very high accuracy.

The recent structure of the monitoring, protection, and control of the power systems includes GPS timely synchronized measurement units (Phasor Measurement Units). With the implementation of these units, Wide-Area Monitoring, Protection and Control Systems are required to perform fast and efficient identification of the disturbances that may lead to cascade propagation and blackouts in the power system. The requirements furthermore enable appropriate actions, preventive and corrective measures to minimize effects of the occurring disturbances. This paper proposes the application of the discrete Teager Energy Operator for the power system fault identification, localization, and classification. Identification and localization of the disturbances are performed with the analysis of available signals with the application of the Teager Energy Operator and comparison of its peak values at several points in the system. The proposed classifier of the disturbances is based on the Teager Energy Operator analysis of available signals and values of indicator of active power unbalance at several points in the system. Simulations are performed in the New England 39 bus test system using DIgSILENT Power Factory software. The performance and the comparison of the applied techniques are assessed through a large number of the simulated faults for the specific fault type. Fault identification and localization results are compared with the results obtained in the analysis performed with Discrete Wavelet Transform and Hilbert-Huang Transform indicating on satisfactory performance of the proposed approach. Furthermore, the proposed approach provides notable results in the fault classification performed according to 141 simulated faults. Teager Energy Operator in the proposed method outperforms other techniques with less computational work and faster estimation, enabling the development of a relatively simple algorithm for the fast and efficient identification, localization, and classification of the disturbances in power system.

The paper analyzes the problem of the construction of utility-scale solar photovoltaic power plants (US-PV). Two main problems of this construction are: occupying usable areas and the connection and integration of the power plant into the electricity system. The construction of US-PV power plants on water accumulations of existing hydro power plants was analyzed, as one of the solutions to these problems. The Jablanica Lake was taken as an example. Jablanica Lake is an artificial accumulation lake on the river Neretva with an area of 13 km2 within the hydroelectric power plant (HPP) Jablanica with 180 MW of installed power. It was shown that on a surface of less than 3% of the total area of the accumulation of HPP Jablanica, there could be built a floating photovoltaic (PV) plant with a power of 30 MW. This power would add another generator of 30 MW to HPP Jablanica, which would increase the current number of the 6 generators to 7. This would enable significantly better exploitation of the Neretva and Rama river basins, and increase production in the summer period with a decrease in lake level oscillations. Suitable locations for the installation of floating solar power plant were analyzed. Locations are selected on the basis of requirements for the preservation of existing lake functions, and provide the possibility of installing a 3 MW power plant. 10 of these plants, connected by a 20 kV power grid, represent one US-PV 30 MW plant, which at one point connects to the transmission network of 220 kV. The specifications of one 3 MW power plant are given in terms of the required area, number of modules and number of inverters. A preliminary techno-economic analysis of the total plant was carried out. In this analysis, the possible production, the indicative price of the plant, and the price of the produced kWh of electricity are calculated.