Dariusz Sajewicz

This paper presents a theoretical and numerical extension of Budeanu’s power theory for three-phase three-wire systems supplied by symmetrical nonsinusoidal voltages and feeding unbalanced linear time-invariant loads. The proposed formulation combines the classical Budeanu framework with the Currents’ Physical Components (CPC) theory to provide a physical interpretation of Budeanu distortion power. Five mutually orthogonal components of the load current are distinguished, namely the active, scattered, Budeanu reactive, Budeanu-complemented reactive, and negative-sequence unbalanced currents. Consequently, Budeanu distortion power is shown to be an orthogonal combination of three powers (scattered, Budeanu-complemented reactive, and negative-sequence unbalanced) and not merely a residual obtained from the apparent, active, and reactive powers. The theoretical formulation is verified numerically using three illustrative delta-connected load configurations fed by a voltage composed of the 1st, 5th, and 7th harmonics. In all examples, the sum of the proposed components reproduces exactly the line currents calculated directly with Ohm’s law and Kirchhoff’s current law, and they distinguish the physical mechanisms responsible for each contribution to distortion power. The analysis is restricted to 3-p 3-w circuits fed by symmetrical nonsinusoidal voltages and loaded with linear time-invariant (LTI) elements, which are not sources of harmonics; consequently, it does not directly address asymmetrical supply conditions, four-wire systems, time-varying loads, or nonlinear loads with harmonic generation.

This paper contains the design of active optical lenses used for the detection of arc flashing emissions. The phenomenon of an arc flashing emission and its characteristics were contemplated. Methods of preventing these emissions in electric power systems were discussed as well. The article also includes a comparison of commercially available detectors. An analysis of the material properties of fluorescent optical fiber UV-VIS-detecting sensors constitutes a major part of the paper. The main purpose of the work was to make an active lens using photoluminescent materials, which can convert ultraviolet radiation into visible light. As part of the work, active lenses with materials such as Poly(methyl 2-methylpropenoate) (PMMA) and phosphate glass doped with lanthanides, such as terbium (Tb³⁺) and europium (Eu³⁺) ions, were analyzed. These lenses were used to make optical sensors, which were supported by commercially available sensors in their construction.

Celem artykułu jest wykazanie skuteczności nowo opracowanych metod detekcji uszkodzeń opartych na analizie danych z rejestratorów zakłóceń. W trakcie prac badawczych wyekstrahowano najbardziej istotne cechy sygnałów prądów w dziedzinie częstotliwości. Pozyskane cechy stanowiły podstawę budowy probabilistycznego klasyfikatora zdarzeń awaryjnych. Detekcja uszkodzeń dotyczy wykrywania: pękniętych prętów wirnika i stopnia jego degradacji oraz awarii łożysk na wale silnika. Przeprowadzone badania potwierdzają wysoką skuteczność wykrywania uszkodzeń we wszystkich rozpatrywanych obszarach.

Celem pracy jest wykazanie skuteczności nowo opracowanych metod detekcji uszkodzeń opartych na prostym podejściu statystycznym obejmującym liniową analizę dyskryminacyjną i przetwarzanie sygnałów. Przeprowadzone badania potwierdzają wysoką skuteczność wykrywania uszkodzeń we wszystkich rozpatrywanych obszarach. (Wykrywanie zdarzeń awaryjnych w sieciach SN na podstawie analizy danych z rejestratorów zakłóceń.

The article provides a theoretical basis for a method allowing to calculate probability of effects of electric shock, as well as a method for determining probabilistic characteristics of random touch current values and of human body impedance in a person who suffered from specific effects of electric shock. Results of example calculations are presented, including probabilities of occurrence of sensory symptoms, exceeding the letgo threshold, and development of ventricular fibrillation, as well as probabilistic characteristics of random touch current values and of impedance of human body in people who experienced specific effects of electric shock.

Shock safety modelling of indirect contact with low-voltage electric devices: The article presents a shock safety model of an indirect contact with a low-voltage electric device. This model was used for computations and analyses concerning the following: the probabilities of appearance of the particular shock protection unreliability states, electric shock states (ventricular fibrillation), contributions of the unreliability of different shock protection elements to the probability of occurrence of these states, as well as the risk of electric shock (and the shock safety), and contributions of the intensity of occurrence of damages to different shock protection elements to this risk. An example of a possibility to reduce the risk of an electric shock through changing the intensity of occurrence of damages to the selected protection elements was provided.

Shock safety modeling method for low-voltage electric devices: The article describes a shock safety modeling method for low-voltage electric devices, based on using a Bayesian network. This method allows for taking into account all possible combinations of the reliability and unreliability states for the shock protection elements under concern. The developed method allows for investigating electric shock incidents, analysing and assessing shock risks, as well as for determining criteria of dimensioning shock protection means, also with respect to reliability of the particular shock protection elements. Dependencies for determining and analysing the probability of appearance of reliability states of protection as well as an electric shock risk are presented in the article.