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The Current State-of-the-Art in the Determination of Pharmaceutical Residues in Environmental Matrices Using Hyphenated Techniques
PublicationSeveral thousand tons of pharmaceuticals and their transformation products (metabolites and degradation products) are introduced into the environment each year. They affect both human health and the environment, therefore, analytical procedures enabling the determination of a wide range of pharmaceuticals at trace levelswithminimal effort, time, and energy are required. Nowadays, hyphenated techniques are commonly applied in pharmaceutical...
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Control Systems of an Induction and Synchronous Motor Supplied by Current Source Converter Working as Generator
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How Important Is Research on Pollution Levels in Antarctica? Historical Approach, Difficulties and Current Trends
PublicationDespite the fact that Antarctica is a continent notably free from large negative impact of human activities, literature data can be the basis for concluding that this is not an area free from anthropogenic pollutants. Pollutants, which are identified in various elements of the environment of Antarctica, are mostly connected with long-range atmospheric transport (LRAT) and deposition in this area. The study presents: a historical...
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Remote sensing in laboratory diagnostics of reinforced concrete elements – current development and vision for the future
PublicationContinuous emergence of new concrete types and kinds of reinforcement, as well as technological solutions in the field of structural engineering have made great demand for diagnostic tests of reinforced concrete elements. New challenges and problems facing people require new more efficient tools for laboratory diagnostics than those commonly used. Remote sensing may be the answer to this demand. In this paper the author describes...
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The effect of the motor filters on earth fault current waveform in circuits with variable speed drives
PublicationIn circuits with variable speed drives distorted earth fault current flows. Earth fault current distortion influences the threshold of ventricular fibrillation. This paper presents earth fault current distortion in circuits with variable speed drives when motor filter is used. Two types of motor filter are analyzed. For every type of filter the effect of earth fault current distortion on ventricular fibrillation is evaluated.
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The adaptive backstepping control of PMSM supplied by current source inverter for the field weakening region
PublicationThe sensorless control system of permanent magnet synchronous motor PMSM supplied by current source inverter for field weakening operation is presented in this paper. The adaptive backstepping control system and the backstepping speed observer are presented. The control system is based on multi-scalar variables. The control variables are: dc-link voltage and the output current vector pulsation. The control system was named voltage...
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The effect of the motor filters on earth fault current waveform in circuits with variable speed drives
PublicationIn circuits with variable speed drives distorted earth fault current flows. Earth fault current distortion influences the threshold of ventricular fibrillation. This paper presents earth fault current distortion in circuits with variable speed drives when motor filter is used. Two types of motor filter are analyzed. For every type of filter the effect of earth fault current distortion on ventricular fibrillation is evaluated.
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Toxoplasma gondii recombinant antigens as tools for serodiagnosis of human toxoplasmosis: current status of studies
PublicationToxoplasma gondii is a parasitic protozoan which is the cause of toxoplasmosis. Although human toxoplasmosis in healthy adults is usually asymptomatic, serious disease can occur in the case of congenital infections and immunocompromised individuals. Furthermore, despite the exact recognition of its etiology, it still presents a diagnostic problem. Diagnosis of toxoplasmosis is mainly based on the results of serological tests detecting...
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Sensorless IPMSM drive with rotor position estimator based on analysis of phase current derivatives
PublicationThis paper describes a sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive designed for traction applications. Wide-speed sensorless operation is provided with the use of three methods of rotor position estimation designed for: a standstill, low- and high-speed range. The paper focuses on the high-speed estimation algorithm. The estimator uses the derivatives of motor phase currentsresulting from PWM modulation...
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The effect of current signal filtering method on the value of cutting power while sawing wood
PublicationThe goal of this work was to investigate an effect of various signal pre-processings on the outline of the electrical power curve and its influence on the measured cutting force estimation. Two signal processing methods were selected for the needs of the experiment, including digital filter and wavelet transform. The filter used was Butterworth, 3rd order band-stop with the cut-out band from 45 Hz to 55 Hz. The second approach...
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Selected Aspects of Biofuels Market and the Electromobility Development in Poland: Current Trends and Forecasting Changes
PublicationThis work presents basic information associated with markets of selected alternative fuels used in transport, such as methyl esters, conventional bioethanol and lignocellulosic bioethanol, and the market of electrical vehicles. Legal conditions, which stimulate development and regulate the mode of functioning of the liquid biofuel market until 2020 are discussed, based on provisions of EU directives. Data on biofuel production...
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Impact of digital signal processing on FOC current feedback in high-speed PMSM drive
PublicationIn applications where size and weight of the electric motor are among major design concerns, Permanent Magnet Synchronous Motors (PMSMs) with wide operational speed-range are commonly preferred. Due to limited inverter switching frequency, high-speed operation of a drive results in a low ratio between the switching frequency and the fundamental frequency of motor voltage. Such operating conditions have been recently identified...
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Sensors in River Information Services of the Odra River in Poland: Current State and Planned Extension
PublicationAccording to adopted in 2016 by the polish Council of Ministers assumptions for the plans for the progress of inland waterways in Poland for the years 2016-2020, with the perspective of 2030, assume that by 2030 Odra along its entire length and the Vistula from Warsaw to Gdansk, they will have become international shipping routes, which will be implemented system of River Information Services (RIS). Aspects of RIS sensor application...
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Sinusoidal Alternating-Current Voltammetry and Metrological Properties of a Flat Voltammetric Electrode in the Time Domain
PublicationIn this paper there were analyzed metrological properties of a flat electrode used to mark ions with the method of sinusoidal alternating-current voltammetry in the situation where on its surface an electrochemical reversible reaction of oxidizing / reduction takes place. The result of the analysis conducted is that such a voltammetric electrode functions like a converter type I. Metrological properties of such an electrode in...
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CFD-based evaluation of current-carrying capacity of power cables installed in free air
PublicationEvaluation of current-carrying capacity of power cables and selection of cross-sectional area of their conductors are mainly performed in accordance with requirements of EN, IEC or IEEE standards. However, these standards do not provide all methods of cables installation and location which occur in practice. Thus, in some cases, performance of advanced modeling of various thermal phenomena, affecting power cables current-carrying...
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Multiple output second-generation current conveyor utilizing high frequency output stage
PublicationIn this paper a multiple output second-generation current conveyor (MOCCII) is presented. The main advantage of the proposed general circuit architecture over a typical structure, well known in the literature, is the use of a high passband multiple output current mplifier block instead of cascaded current mirrors. It gives similar frequency responses for all the outputs of the current conveyor and also maintains simplicity of the...
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Recycling of Waste Rubber by the Manufacturing of Foamed Polyurethane-Based Composites—Current State and Perspectives
PublicationWorn car tires are disruptive waste, and the issue of their management is crucial for the natural environment. In many countries, the primary method of end-of-life tires utilization is energy recovery. However, more effective and beneficial for the environment is material recycling. Using them for the production of polymer-rubber composites seems to be an auspicious direction of research. Incorporation of ground tire rubber into...
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Current Status, Barriers and Development Perspectives for Circular Bioeconomy in Polish South Baltic Area
PublicationThe following article presents the current legal situation in Poland as well as in the European Union. Data on biomass production in the Polish South Baltic area were analyzed, along with an indication of the key sectors for the development of bioeconomy. Presentation of the current state of biomass management was made and areas necessary for development were indicated to facilitate the sustainable management of biomass and waste...
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Potential applications of by-products from the coffee industry in polymer technology – Current state and perspectives
PublicationCoffee is one of the most popular beverages in the world, and its popularity is continuously growing, which can be expressed by almost doubling production over the last three decades. Cultivation, processing, roasting, and brewing coffee are known for many years. These processes generate significant amounts of by-products since coffee bean stands for around 50% of the coffee cherry. Therefore, considering the current pro-ecological...
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Analysis of AC/DC/DC Converter Modules for Direct Current Fast-Charging Applications
PublicationThe paper is a comprehensive laboratory comparison study of two galvanic isolated solution off-board battery chargers: (1) Si-based cost-effective case, and (2) SiC-bidirectional ready for vehicle to grid concept case. All circuits are modular, and in both cases the DC/DC converter can be replaced according to the end user requirements (the coupled transformer remains the same and is constructed based on 12xC100 cores to avoid...
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Impact of thermal backfill parameters on current-carrying capacity of power cables installed in the ground
PublicationProper design of power installations with the participation of power cables buried in homogeneous and thermally well-conductive ground does not constitute a major problem. The situation changes when the ground is non-homogeneous and thermally low-conductive. In such a situation, a thermal backfill near the cables is commonly used. The optimization of thermal backfill parameters to achieve the highest possible current-carrying capacity...
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Electrical safety in low-voltage DC microgrids with B-type residual current devices
PublicationResidual current devices (RCDs) are most popular devices used in low-voltage installations for protection against electric shock and fire. In cases of high risk of electric shock the application of RCDs is mandatory. Currently, the spread of local direct current (DC) microgrids is widely considered. This creates new challenges for protective systems, in particular those based on RCDs. The main purpose of the research is to test...
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Errors in the analysis of series resonant inverter/converter assuming sinusoidal waveforms of voltage and current
PublicationIn this paper the theory and simulation results of the series resonant inverter / converter are presented. In this work the authors carried out a detailed comparative analysis of results obtained using the method of AC analysis in the steady state for the first harmonic with the results of computer simulation. The AC analysis under certain conditions can lead to errors disqualifying this method. In particular, these errors appear...
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Current-based higher-order spectral covariance as a bearing diagnostic feature for induction motors
PublicationConducting the diagnosis of induction motors remotely by analyzing the supply current is an attractive prospect with the lack of access to the engine. Currently, there is no solution, based on analysis of the current, the credibility of which would allow its use in industry. The statistics of bearing failures in induction motors indicate that they constitute more than 40% of induction motor damage, therefore, bearing diagnosis...
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Remote sensing in laboratory diagnostics of reinforced concrete elements – current development and vision for the future
PublicationContinuous emergence of new concrete types and kinds of reinforcement, as well as technological solutions in the field of structural engineering have made great demand for diagnostic tests of reinforced concrete elements. New challenges and problems facing people require new more efficient tools for laboratory diagnostics than those commonly used. Remote sensing may be the answer to this demand. In this paper the author describes...
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Novel condition monitoring of induction motor bearings via motor current signature analysis
PublicationThe paper authors are researching the assessment of bearing conditions in induction motors. The methods developed by the authors are based on measurements and analysis of the motor supply current, which is particularly attractive in the absence of access to the engine. The article provides an overview of selected methods of induction motor bearings diagnostic based on Motor Current Signature Analysis (MCSA). However, there is no...
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Reactive extrusion of bio-based polymer blends and composites – Current trends and future developments
PublicationReactive extrusion is a cost-effective and environmentally-friendly method to produce new materials with enhanced performance properties. At present, reactive extrusion allows in-situ polymerization, modification/functionalization of polymers or chemical bonding of two (or more) immiscible phases, which can be carried out on commonly used extrusion lines. Although reactive extrusion has been known for many years, its application...
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Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers
PublicationPurpose: The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on...
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Disturbances of Earth magnetic field caused by eddy currents of airplane
PublicationThe uniform magnetic field of the Earth in the surrounding of a mobile, metallic object undergoes deformation by eddy currents. The influence of the moving, conducting object on the Earth's total magnetic field depends on the object's shape, position and speed of the changes relative to the magnetic field vector of the Earth, as well as the electric conductivity and the relative magnetic permeability of the material. Disturbances...
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Grinding specifics of plasma coatings melted with high-frequency currents
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Tripping of F-type RCDs for High-Frequency Residual Currents
PublicationResidual current devices (RCDs) are apparatus commonly used for protection against electric shock in low-voltage electrical installations. They protect people in the case of an earth fault or even in the case of direct contact with the live parts. However, to be effective protective devices, RCDs have to detect residual currents of various waveform shapes which appear in modern electrical installations. For this purpose, RCDs...
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Modeling the impact of surface currents in a harbor using graph theory
PublicationEnsuring security in a harbor requires research into its infrastructure using spatial environmental data. This paper presents a methodology that defines the design of a graph for modeling the interactions between surface currents and moving objects. Combining this graph with port charts that integrate electronic navigation charts with coastal orthophotographs allows us to perform a multidimensional analysis. In addition, the complete...
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Measure small currents without adding resistive insertion loss
PublicationFloating current to voltage converter can be inserted in-line with no voltage drop and no need for a ground reference.
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Tripping of F-type RCDs for high-frequency residual currents
PublicationResidual current devices (RCDs) are apparatus commonly used for protection against electric shock in low-voltage electrical installations. They protect people in the case of an earth fault or even in the case of direct contact with the live parts. However, to be effective protective devices, RCDs have to detect residual currents of various waveform shapes which appear in modern electrical installations. For this purpose, RCDs are...
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The determination and identification of stray current source influences on buried pipelines using time/frequency analysis
PublicationZaprezentowano metodę detekcji źródła interferencji prądów błądzących na rurociągach podziemnych w aglomeracjach miejskich z wykorzystaniem łącznej analizy czasowo-częstotliwościowej mierzonych sygnałów. Badania przeprowadzono na rurociągu podziemnym zlokalizowanym w sąsiedztwie dwóch trakcji elektrycznych: tramwajowej i kolejowej. Wyniki analiz zaprezentowano w formie spektrogramów, które ilustrują zmiany spektralnej gęstości...
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Estimation of interior-permanent-magnet-synchronous-motor rotor position by analysis of phase-current derivatives
PublicationThis paper describes an algorithm for estimation of IPMSM rotor angular position. The algorithm uses derivatives of motor phase currents resulting from PWM modulation to obtain the rotor position. The presented method is designed for medium- and high-speed range, since it is based on determination of the EMF vector. Calculation of the motor position is performed in every PWM cycle. The standard SV-PWM method is used to determine...
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Residual Current Devices Operational Characteristics within the Frequency Range 50 Hz to 1000 Hz.
PublicationW artykule przedstawiono charakterystyki działania powszechnie stosowanych wyłączników różnicowoprądowych przy prądach różnicowych w zakresie częstotliwości 50÷1000 Hz. Częstotliwość wyższa niż 50 Hz wpływa niekorzystnie na prąd zadziałania wyłączników, a w skrajnych przypadkach mogą one w ogóle nie reagować na wolno narastający prąd różnicowy.
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On the Use of Automatic Cuts Algorithm for T0 – T – Φ Formulation in Nondestructive Testing by Eddy Current
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Optoelectronic properties of the metal-tetracene interface investigated by current noise measurement under monochromatic irradiation.
PublicationZaprezentowano badania prądów ograniczonych elektrodowo w warstwach tetracenu. Szczególną uwagę zwrócono na zależność szumów elektrycznych od przyłożonego napięcia i padającego światła.
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Computer aided registration of current pulses in polyethylene insulation during the first stage of electrical treeing.
PublicationW referacie przedstawiono aplikację w programie Labview do automatycznej rejestracji impulsów prądowych zjawisku drzewienia elektrycznego w izolacji polietylenowej.
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Bibliometric analysis of artificial intelligence in wastewater treatment: Current status, research progress, and future prospects
PublicationWastewater treatment is an important topic for improving water quality and environmental protection, and artificial intelligence has become a powerful tool for wastewater treatment. This work provides research progress and a literature review of artificial intelligence applied to wastewater treatment based on the visualization of bibliometric tools. A total of 3460 publications from 2000 to 2023 were obtained from the Web of Science...
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Harmonic analysis of the current of an electric system simulating the electrode process in conditions of linearly changing potential
PublicationAnalizowany był prąd elektrycznego modelu symulującego pierwszorzędową reakcję elektrodową zachodzącą w warunkach liniowo zmieniającego się potencjału z nałożonym sygnałem sinusoidalnym. Pokazano, że transformacja Fouriera nie odzwierciedla zmian amplitudy składowych komponentów w funkcji potencjału. Także matematycznie wykazano, że zastosowanie transformacji Gabora do analizy spektralnej pozwala uzyskać poprawną dekompozycję częstotliwościową....
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Selectivity of lithium electrodes: correlation with ion-ionophore complexstability constants and with interfacial exchange current densities
PublicationMembranowe elektrody selektywne na jony litu oparte na dwóch różnych dicyk-lohesyloamidowych jonoforach poddane zostały systematycznym badaniom. Potencjometrycznie wyznaczono wartości współczynników selektywności. Wartości stałych trwałości kompleksów z jonami litu, sodu i potasu wyznaczono metodą membran "sandwichowych". Transfer ładunków przez membranę oraz przez granicę faz membrana/roztwór badano metodą spektroskopii impedancyjnej....
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RCDs Tripping in the Range from DC to AC 50 kHz for Slowly Rising Residual Current
PublicationThe wide use of power electronic converters means that in many low-voltage systems earth fault currents containing components from DC to AC of various frequencies have to be taken into account. Due to the tendency to increase the modulation frequency in converters, components of higher frequencies may be in the order of several tens of kilohertz. Therefore, it is very important to verify the behavior of devices for protection against...
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Evaluation of applicability of classic methods of a fault loop impedance measurement to circuits with residual current devices
PublicationMeasurement of fault loop impedance in low voltage grids and systems is in most cases performed to verify the effectiveness of protection against electric shock by automatic disconnection of supply. For the sake of measurement accuracy, it is advisable to perform it using large current. Unfortunately, in circuits with residual current devices which are very widely used nowadays, a large measurement current may trigger those devices...
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The effect of PWM frequency on the effectiveness of protection against electric shock using residual current devices
PublicationW referacie przedstawiono analizę widmową odkształconego prądu ziemnozwarciowego z obwodu silnika o regulowanej prędkości obrotowej za pomocą przemiennika częstotliwości. Oszacowano wpływ tego odkształcenia na próg fibrylacji serca. Analizowano skuteczność ochrony przeciwporażeniowej wykorzystującej wyłączniki różnicowoprądowe przy różnych wartościach częstotliwości PWM przemiennika. Przedstawiono charakterystykę działania zaproponowanego...
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High step-up continuous input current LCCT-Z-source inverters for fuel cells
PublicationFalowniki typu Z (ZSI) przeznaczone są do układów wymagających szerokiej zmiany wzmocnienia napięciowego, np. w energetyce odnawialnej. Ostatnio zaproponowano w literaturze zmienione struktury - falowniki typu Trans-Z (TZSI) oraz typu T (TSI) - w których dzięki zastosowaniu dławików sprzężonych uzyskano lepsze wzmocnienie niż w ZSI. W tym artykule przedstawiono ideę rozszerzonej struktury TZSI. Zaproponowano dwie nowe struktury...
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The effect of PWM frequency on the effectiveness of protection against electric shock using residual current devices
PublicationW artykule przedstawiono analizę widmową odkształconego prądu ziemnozwarciowego z obwodu silnika o regulowanej prędkości obrotowej za pomocą przemiennika częstotliwości. Oceniono skuteczność ochrony przeciwporażeniowej wykorzystującej wyłączniki różnicowoprądowe przy różnych wartościach częstotliwości PWM przemiennika. Przedstawiono charakterystykę działania proponowanego wyłącznika różnicowoprądowego.
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A new method of fault loop resistance measurement in low voltage systems with residual current devices
PublicationThis paper presents a new method of fault loop resistance measurement in low voltage systems with residual current devices. The method enables measuring fault loop resistance without nuisance tripping of residual current devices, by application an unconventional waveform of measurement current. It is important for proper verification of the effectiveness of protection against electric shock.
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Verification of safety in low-voltage power systems without nuisance tripping of residual current devices
PublicationLow-voltage power systems require initial and periodical verification to check the effectiveness of protection against electric shock. As a protection in case of fault, automatic disconnection of supply is most often used. To verify such a protection measure, the earth fault loop impedance or resistance is measured. This measurement is easy to perform in circuits without residual current devices. When residual current devices are...