The paper reports on the solution, principles, and application results related to a system for diagnosing main transformers in power plants via the radiofrequency method. The subject of the diagnostics is the occurrence of partial discharge activity in transformers. The technical solution of the system is characterized in the introductory section of the article. There then follows a description of the operating principle and the implemented novel advanced methods for signal detection and source localization. The results obtained from practical application of the system within the diagnostics of high-power transformers are presented as well. Because ambient electromagnetic disturbance was recognized as a major issue during the system development, novel detection methods were proposed, implemented, and verified. The principal approach utilizes an external radiofrequency sensor to detect outer impulse disturbance and to eliminate disturbance-triggered acquisitions, and it also ensures direct real-time visualization of the desired impulse signals. The ability of weak signal detection was verified via artificial impulse signal injection into the transformer. The developed detection methods were completed with localization techniques for signal source estimation. The desired impulse signal was detected and localized during full operation of the main transformer, despite the presence of strong electromagnetic interference.

The authors present an analysis of conditions on the boundary between layers having varied electromagnetic properties. The research is performed using consistent theoretical derivation of analytical formulas, and the underlying problem is considered also in view of multiple boundaries including the effect of the propagation of electromagnetic waves with different instantaneous speeds. The paper comprises a theoretical analysis and references to the generated algorithms. The algorithms were assembled to enable simple evaluation of all components of the electromagnetic field in relation to the wave propagation speed in a heterogeneous environment. The proposed algorithms are compared by means of different numerical methods for the modelling of electromagnetic waves on the boundary between materials; moreover, the electromagnetic field components in common points of the model were also subject to comparison. When in conjunction with tools facilitating the analysis of material response to the source of a continuous signal, the algorithms constitute a supplementary instrument for the design of a layered material. Such design allows us to realize, for example, a recoilless plane, recoilless transition between different types of environment, and filters for both optical and radio frequencies.

We discuss the numerical modeling of electromagnetic, carbon-based periodic structures, including graphene, graphane, graphite, and graphyne. The materials are suitable for sub-micron sensors, electric lines, and other applications, such as those within biomedicine, photonics, nano- and optoelectronics; in addition to these domains and branches, the applicability extends into, for example, microscopic solutions for modern SMART elements. The proposed classic and hybrid numerical models are based on analyzing a periodic structure with a high repeatability, and they exploit the concept of a carbon structure having its fundamental dimension in nanometers. The models can simulate harmonic and transient processes; are capable of evaluating the actual random motion of an electric charge as a source of spurious signals; and consider the parameters of harmonic signal propagation along the structure. The results obtained from the analysis are utilizable for the design of sensing devices based on carbon periodic structures and were employed in experiments with a plasma generator. The aim is to provide a broader overview of specialized nanostructural modeling, or, more concretely, to outline a model utilizable in evaluating the propagation of a signal along a structure’s surface.

The authors report on an analysis of conditions on the boundary between layers having varied electromagnetic properties. The article presents an analysis of wave propagation in a layered material structure; the authors utilise analytical formulas based on Snell's law, and the analysis-related tasks are solved in the Matlab program. The underlying problem is processed for multiple boundaries, including the effect of the propagation of an electromagnetic wave at different instantaneous speeds. This paper presents the formalism for transmission of incident electromagnetic radiation through a finite number of layers having varied electromagnetic properties. The main algorithm was assembled to enable simple evaluation of all components of the electromagnetic field in relation to the speed of the wave propagation in a heterogeneous environment.