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Electromagnetic compatibility analysis of electric equipments

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Electromagnetic compatibility- EMC and functional safety can no longer be treated as two separate disciplines when electrical or electronic systems are considered performing safety-related functions. Furthermore the usual EMC approach to define immunity requirements on the basis of availability and economical conditions cannot be applied to immunity issues regarding safety-related systems. And on the other hand the approach within functional safety to emphasize the relevance of the SIL cannot be transferred in a simple way into the EMC area. An appropriate approach to combine both disciplines consists of the introduction of special immunity levels and test methods in connection with a particular performance criterion “Functional Safety". Streszczenie. Analizowano łącznie dwa parametry - kompatybilność elektromagnetyczną i funkcjonalne bezpieczeństwo. Zaproponowano metodę łączenia tych dwóch parametrów z uwzględnieniem aspektów ekonomicznych. (Analiza kompatybilności elektromagnetycznej i funkcjonalnego bezpieczeństwa w sprzęcie elektrycznym) Keywords: reliability, electromagnetic compatibility - EMC, electromagnetic field, ISDN modem. Słowa kluczowe: kompatybilnośc elektromagnetyczna, bezpieczeństwo funkcjonalne Introduction Reliable operation of electronic equipment at various technological and operation conditions requires safe operation on communication devices. Information transfer, automatic processing and data recording is exposed to detrimental influences from various sources. Disturbance effect of environments shows unwanted bonds, interference noise, resonance and transitional phenomena that may cause incorrect operation of electronic equipment, distortion and degradation of data transfer and its recording and in extreme cases also a destruction of the equipment. At failure, e.g. as a result of shift or interturn short-circuit at the winding of a transformer; the electromagnetic interference with other electrical equi[...]

Diagnostics of electric equipments by means of thermovision

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This paper analyses problems of thermovision diagnostics measurement. It examines basic principles and application of non-contact temperature measurement. Knowledge of problems of measurement in the infrared radiation allows us to use the thermovision diagnostic methods more effectively and to localise the disturbance which determines the quality of electric equipments in the inside distribution of electric energy. Abstract. Przedstawiono zasady diagnostyki termowizyjnej. Znajomość problemów pomiaru promieniowania podczerwonego pozwala na stosowanie termoizji w sposób bardziej efektywny I bardziej dokładnie lokalizować wady. (Diagnostyka urządzeń elektrycznych przy wykorzystaniu termowizji) Keywords: thermovision, emissivity, radiation, temperature, diagnostics, calculation Słowa kluczowe: termowizja, promieniowanie podcvzerwone. Introduction Fundamental for a non-destructive diagnostics of electrical equipments using thermovision, is the ability to record and to work infrared radiation (heating) to the form of real thermal images of objects, and on the basis of overheating of certain surround, for a detection of a failure (defect). With non-contact measurement it is able to detect the temperature distribution on the surface of objects using sensitivity measuring of a few Kelvin (or °C) decimal. Fig.1. [1] Infrared radiation is generated as a result of physical processes that take place in the object of radiation; moving atoms, molecules, vibration in crystal lattice, and transition of electrons from one energy level to another. The basic source of infrared radiation is elevated temperature of the source of radiation. Fig.1 Thermogram of electric wiring breaker Radiation of hot sources acts like (in respect of surrounding conditions), like visible light. To display temperature fields we can use visualization techniques used in optics. The only differences are materials used for elements of visualization systems, size of values[...]

Analysis of power transformers reliability with regard to the influences of short-circuit currents effects and overcurrents

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Abstract. This article deals with a description of methods of an experimental analysis (SFRA method, monitoring, thermovision) concerning the actual reliability of windings and magnetic circuit of the transformer, which is required in power transmission and power distribution companies all over the world. Streszczenie. Artykuł opisuje metodę eksperymentalnej analizy termowizyjnej niezawodności uzwojeń i obwodu magnetycznego transformatora. Analiza taka niezbędna jest do oceny jakości transformatorów rozdzielczych. (Analiza niezawodności transformatorów mocy z uwzględnieniem przetężeń i pradów zwarciowych) Keywords: Transformer, diagnostics, SFRA method, monitoring, thermovision. Słowa kluczowe: transformatory, termowizja, analiza niezawodności. Introduction Reliability of a techni[...]

Analysis of Distributorless Ignition Systems

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Ignition systems even in its simplest form represent electrical system which produces voltage waveforms in a form of pulses in complex shape. For the diagnosis of these systems is necessary to use such diagnostic systems, which allow to record these waveforms for next analysis. In the presented contribution we deal with possibilities of analysis and investigation of waveforms, primary and secondary circuit fully electronic ignition systems. Streszczenie. W artykule zaprezentowano system diagnostyczny do badania przebiegów napięciowych w układzie zapłonowym. (Analiza systemu zapłonowego bez rozrządu mechanicznego) Keywords: EFS ignition systems, diagnostics, LabVIEW system, high-voltage waveforms. Słowa kluczowe: system zapłonowy, diagnostyka. Introduction Distributorless ignition system (DIS) is ignition system which distributes high voltage to each spark plug without using mechanic distributor. High voltage shall be achieved to create a spark at the spark plug igniting the mixture through a high-voltage coil (transformer). High-voltage outlets in distributorless ignition system are directly applied to plugs, thus increasing the number of ignition coils. An immediate flash-over in the cylinders is necessary to determine by a separate switch controlling of transformer primary circuits. In practice are used two solutions which differ in the number of ignition coils. Basic characteristics of the EFS ignition system In EFS ignition system (or COP - Coil on Plug) are used coils which are creating only one spark for one spark plug at any given moment, thus that the number of ignition coils is corresponding with the number of engine cylinders Fig.1. Fig.1. Simplified scheme of the ignition EFS The engine operating parameter signals input into the control unit. EFS is not sufficient just with crank speed signals because each ignition coil receives one control pulse for two turns of crank but from the signal reference mark the control [...]

Analysis of thermal processes in oil distribution transformer DOI:10.12915/pe.2014.05.017

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Paper deals with the analysis of thermal processes in oil distribution transformers. By means of the mathematical analysis and experimental measurements it is possible to diagnose of power oil transformers in terms of mechanical strength of winding. Analysis of warming at varying loads is very importance, since allows determining the load capacity and overload of the transformer under various operating conditions and respecting the variable ambient temperature. Streszczenie. Artykuł dotyczy analizy procesów termicznych w rozdzielczych transformatorach olejowych. Za pomocą analizy matematycznej I pomiarów doświadczalnych można dokonać diagnozy olejowych transformatorów mocy pod względem wytrzymałości mechanicznej uzwojenia. Analiza nagrzewania się uzwojeń przy zmiennych obciążeniach jest bardzo ważna, gdyż pozwala na określenie nośności i przeciążenia transformatora w różnych warunkach eksploatacji w odniesieniu do zmiennej temperatury otoczenia. (Analiza procesów termicznych w rozdzielczych transformatorach olejowych). Keywords: transformer, thermal processes, thermovision, windings, temperature. Słowa kluczowe: transformator, procesy termiczne, termowizja, uzwojenia, temperatura. doi:10.12915/pe.2014.05.17 Introduction Electric energy lost in transformer in conversion of alternating current is converted into heat in winding, magnetic circuit and in other parts of the transformer. At the same time transformer heat´s up and the temperature of its individual parts can greatly exceed the ambient temperature. With increasing load and with emerging losses the temperature of the transformer rises, this all depends on cooling winding, magnetic circuit and other heated parts. As far as temperature, transformer is inhomogeneous element. Sheets of magnetic circuit are characterized by high thermal conductivity and relatively low thermal capacity. They are taking turns with layers of insulation (lacquer etc.), whose thermal[...]

Nondestructive diagnostics of electrical systems and equipments DOI:10.12915/pe.2014.03.041

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This paper analyses the problem of thermal sensors, it examines the principles, functions and application for a non-contact temperature measurements. The knowledge in measurements of infrared radiance allows us to use the methods of thermovision diagnostics more effectively and to localise the disturbance which determines the quality of connection in distribution of electric energy. For technical testing of electrical systems and equipment thermography is an important diagnostic method for determining of failure of electrical systems and equipment as well as for detection of worsened condition of these systems. Streszczenie. W artykule przedstawiono problematykę termicznych sensorów, zasady badań uwzgledniające bezdotykowe pomiary temperatury, ich funkcje oraz wnioski. Dotychczasowa wiedza o pomiarach w podczerwieni pozwala na efektywniejsze wykorzystanie metod termowizyjnych celem lokalizacji zakłóceń związanych z jakością połączeń odpowiadających za dystrybucję energii elektrycznej. Termografia jest nieniszczącą metodą diagnostyczną pozwalającą na badania instalacji elektrycznych i sprzętu w celu określenia uszkodzeń urządzeń i systemów elektrycznych, a także do wykrywania pogarszania się ich stanu. (Nieniszcząca diagnostyka systemów elektrycznych i urządzeń). Keywords: Thermovision, radiation, calculation, thermogram. Słowa kluczowe: Termowizja, promieniowanie, kalkulacja, termogram. doi:10.12915/pe.2014.03.41 1. Introduction In measurement of electrical equipment and wires we deal with warming of contacts, switches, power cables, clamps, contacts of fuses. In electrical substation, temperature of each object is measured, focusing on the expansion joints, junctions, bends and coats drivers. Thermovision is used to measure warming of connections and clamps in electrical machines, as well as to the measurement of electrical equipments in the internal and external electrical distributing systems. Fundamental for a non-destructive dia[...]

Using non-destructive methods for measurement of reinforcement corrosion in practice DOI:10.15199/40.2017.3.1

  The paper deals with a description of selected methods, by which it is possible to detect the corrosion loss of steel reinforcement, based on the recorded change in electrical resistance at the time. By verification the suitability of using these methods in previous researches [1, 5, 7, 15] we prepared new samples with required dimensions withinproject APVV- 14-0772. Formation and progression of corrosion [2, 3, 6, 8-10, 13, 14] we will monitor on samples of reinforcing steel in the form of separate bars and in bars embedded in concrete. There will be also used samples of structural steel. Part of the samples will be exposed to the atmospheric environment and the remaining samples will be subjected to accelerated tests in climatic chambers. Real type of corrosion (uniform corrosion, non-uniform corrosion, pitting corrosion, etc.) of samples will be assessed visually and by means of scanning electron microscopy (SEM). Keywords: corrosion, reinforcement, reinforced concrete, non-destructive methods, electrical resistance W artykule opisano wybrane metody umożliwiające wykrywanie korozji stali zbrojeniowej na podstawie zarejestrowanych zmian oporności elektrycznej w czasie. Po weryfikacji przydatności stosowanych w poprzednich badaniach metod [1, 5, 7, 15] w ramach projektu APVV-14- 0772 przygotowane zostały kolejne próbki o odpowiednich wymiarach. Początek oraz postęp korozji [2, 3, 6, 8-10, 13, 14] będą monitorowane na próbkach stali zbrojeniowej, zarówno na samych prętach, jak i na prętach umieszczonych w betonie. Zostaną również wykorzystywane próbki ze stali konstrukcyjnej. Część próbek będzie wystawiona na działanie środowiska atmosferycznego, a pozostałe zostaną poddane przyspieszonym testom w komorach klimatycznych. Typ korozji (jednolita, nierównomierna, wżerowa, itd.) próbek będzie określany wizualnie oraz za pomocą mikroskopu skaningowego (SEM). Słowa kluczowe: korozja, zbrojenie, żelbet, metody nieniszczące, opór elekt[...]

Analysis of transformer condition by frequency and time methods DOI:10.15199/48.2019.09.08

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Maintenance diagnostics of transformers considering to the influence of short-circuit currents during the operation should be carried out to increase the reliability in real trouble-free process. The short-circuits in operation are commonly created by different line faults, etc. in mechanical damage of insulation, an electric insulation, an electric insulation breakdown on over voltage, wrong operation and in the next case row [1]. The short-circuit currents cause a progressive serious disrepair of the transformer, because there are high currents in it which are awfully rising winding temperature, what it can cause damage their insulation. Much more danger is high electro-magnetic forces, which can be the reason for the devastation of transformer. Considering a significance of power three-phase transformers in the electric system, their price and possible damages arising in accidents, it is necessary to pay attention to higher prevention of these devices. Windings of the transformers should be designed to avoid various mechanical or thermal deteriorations caused by short-circuit currents occurring in operation. Besides the permanent deformation effects of shortcircuit currents, there are also gradual aging process of the electrical device, which can worsen its mechanical properties. Heat shocks can cause decrease of mechanical strength of transformer and consequent unexpected damage of transformer during the operation. To prevent a damage state of transformers, it is performed different types of the measurements that should illustrate an actual condition of the measured equipment. It is therefore important to choose a suitable diagnostics for the right prediction of such conditions. The theory of mechanical forces effect on transformer winding during short-circuit For a better comprehension this relation between transformer damage and short-circuits currents effects, it is needed focused on mechanical forces effect on tr[...]

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