Implementation of absorbing boundary condition (ABC) has a very important role in simulation performance and accuracy in finite difference time domain (FDTD) method. The perfectly matched layer (PML) is the most efficient type of ABC. The aim of this paper is to give detailed insight in and discussion of boundary conditions and hence to simplify the choice of PML used for termination of computational domain in FDTD method. In particular, we demonstrate that using the convolutional PML (CPML) has significant advantages in terms of implementation in FDTD method and reducing computer resources than using uniaxial PML (UPML). An extensive number of numerical experiments has been performed and results have shown that CPML is more efficient in electromagnetic waves absorption. Numerical code is prepared, several problems are analyzed and relative error is calculated and presented.

This paper considers the characteristics of satellite television transmission in the world. An overview of the development of satellite television is given through the following characteristics: broadcasting systems - analog and digital (SDTV, HDTV, UHDTV), frequency band (C, Ku, Ka), broadcasting standards (DVB-S, DVB-S2, DigiCipher, DSS), as well as the availability of TV services Free-To-Air TV (FTA) and PAY TV. All of these characteristics were considered both at the global and at the regional level: North America, South America, Europe, Africa, Russia, Asia, and Australia. The gathered data are presented in tabular form and presented graphically for the period from 1996 to 2018. Based on the presented results, an analysis of the development of satellite television transmission was carried out in accordance with the characteristics of the broadcast.

The increasing penetration of renewable energy sources (RES), such as photovoltaics (PV) and wind turbines, has brought many challenges to the grid due to their intermittency and variability. Battery energy storage systems (BESS) are considered as one of the most effective solutions to mitigate adverse impacts of RES integration and ensure stability and reliability. BESS offer several advantages over other energy storage systems, such as fast response, controllability, geographical independence and flexibility. This paper reviews techniques for optimal placement, sizing and operation of BESS. The optimization objectives and techniques have been classified into three categories. The advantages and disadvantages of different methods are emphasized. Additionally, this paper compares different battery technologies and discusses BESS applications.

This paper presents an experimental investigation of dynamic line rating (DLR) applied to aluminium conductor steel-reinforced (ACSR) overhead line conductors, with a specific focus on wind speed conditions up to 5 m/s. An experimental system was designed and implemented to provide controlled and repeatable cross-flow air conditions along a tested ACSR conductor, enabling direct measurement of wind speed in the immediate vicinity of the conductor surface. Conductor temperature, electrical current, voltage drop per unit length, the phase angle between them, and relevant meteorological parameters were continuously measured under controlled experimental conditions. Based on the measured data, the conductor heat balance was evaluated and the allowable current-carrying capacity was determined. The experimentally obtained conductor temperatures and ampacity values were compared with results calculated using thermal models and correlations recommended by IEEE, CIGRÉ, and IEC standards. The comparison demonstrates that, under low and moderate wind speed conditions, differences between standard-based predictions and experimental results can be significant, leading to deviations in the estimation of allowable current-carrying capacity. The results confirm the high sensitivity of DLR calculations to wind-related assumptions and provide an experimentally validated basis for assessing the applicability and limitations of existing standard thermal models for ACSR conductors under realistic operating conditions.

The convolutional perfectly matched layer (CPML) is currently, perhaps, the most efficient type of absorbing boundary condition in finite difference time domain method (FDTD) modeling of electromagnetic fields. The aim of this paper is to give a more detailed insight into parameter setting and absorption performance of CPML. In case of electromagnetic waves absorption for high-frequency impulsive source modeling, a proper choice of the CPML parameters is substantial. The numerical results show that stretching coefficient affects both absorption efficiency and dispersion. We demonstrate that, in order to eliminate dispersion, the stretching coefficient should be as small as possible. Additionally, the results have shown that a differentiated Gaussian pulse is a better choice than a regular Gaussian pulse in FDTD simulations.