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Dead-Time Effect Compensation Based on Additional Phase Current Measurements
PublikacjaThis paper proposes a new method of dead-time effect compensation. The proposed solution is based on additional phase current measurements realized by analog-to-digital converters. These measurements are carried out at the time instants specified by a pulsewidth-modulation (PWM) strategy. This makes it possible to estimate inverter currents at the commutation instants and, finally, to estimate the voltage error caused by dead time. This...
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Resonant Conditions in a Node with an SVC Compensator
PublikacjaThe primary purpose of installing static shunt compensators in power grids is to improve the voltage conditions. Additional reactive power sources increase the system’s voltage stability and enable faster system recovery after a voltage failure. This paper presents the impact of an SVC device’s structure and settings on impedance change in the supply system, and hence on the frequencies at which resonance phenomena can develop.
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THREE-LEVEL F-TYPE INVERTER
PublikacjaGiven the recent available IGBT switch modules up to 6.5 kV, 1200 A rating, the prospect of the diode-free variant topology of the three-level neutral-point-clamped (3-level, T-type) inverter in certain medium voltage applications is bright; due to its small part count and low conduction losses compared to the diode-clamped NPC inverter. However, within this voltage range, the input dc voltage rating of 50% of the switches per...
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Active Power Quality Controllers
PublikacjaDynamic Static Synchronous Compensator is the most important controller for distribution networks and probably in SEEN. It has been widely used since the 1990s to regulate system voltage precisely, improve voltage profile, reduce voltage harmonics, reduce transient voltage disturbances and load compensation. Rather than using conventional capacitors and inductors combined with fast switches, the D-STATCOM uses a power-electronics...
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Electrophoretic Deposition of Chitosan/Eudragit E 100/AgNPs Coatings for Controlled Release of Antibacterial Substance
PublikacjaThe development of bacterial infection of the tissues surrounding an implant is one of the leading causes of implant surgery failure. In order to prevent the deposition of bacteria on the implant surface and the formation of biofilm, coatings that exhibit antibacterial properties are manufactured. However, the problem is the controlled release of the therapeutic substance from the coating over the extended life of the implant [1],...
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Evolution of electrohydrodynamic flow of sduspended particles in a needle-to-plate negative DC corona discharge in air
PublikacjaCorona discharges are used for collecting dust in electrostatic precipitators (ESPs). The dust collection is mainlyrealized by the electric forces which move the ionized dust particles to the collecting electrodes. However, the presence of coronadischarge in the space between the charging and collecting electrodes in ESPs causes also the so-called ionic wind which set the gasmolecules and dust...
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A New Approach to the PWM Modulation for the Multiphase Matrix Converters Supplying Loads with Open-End Winding.
PublikacjaThis article presents three variants of the Pulse Width Modulation (PWM) for the Double Square Multiphase type Conventional Matrix Converters (DSM-CMC) supplying loads with the open-end winding. The first variant of PWM offers the ability to obtain zero value of the common-mode voltage at the load's terminals and applies only six switches within the modulation period. The second proposal archives for less Total Harmonic Distortion...
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Estimation of the uncertainty of the LEM CV 3-500 transducers processing function
PublikacjaThe paper presents the methodology for estimating uncertainty of a voltage transducer processing function based on the example of LEM CV 3-500 transducer. The analysis was performed using the method based on the GUM Guide propagation of uncertainty law and the Monte Carlo numerical method. The article also presents a comparative analysis of the results of a voltage measurement evaluation done using the Monte Carlo simulation method,...
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Conducted EMI Propagation Paths in DC-AC Hard Switching Converter
PublikacjaIn order to limit the electromagnetic interference (EMI) in power electronics devices, knowledge about the phenomena connected with EMI generation and propagation is necessary. This papers describes the propagation paths in the 3 phase voltage source inverter using wide-band simulation and laboratory test with the signal processing method Wiener filtering, where the transfer functions between voltage across switches and the perturbation...
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Harmonics produced by traction substations – computer modelling and experimental verification
PublikacjaVoltage and current harmonics have a detrimental effect on the components of a power system. Current harmonics may result in the overload and damage to power transformers. Voltage harmonics may result in, for example, damage to capacitor banks used to compensate reactive power. Devices which contribute to both current and voltage distortion include traction rectifiers. This paper presents results of the computer investigation of...
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Hydrogen sulphide electrocatalytic gas sensor
PublikacjaIn this article measurement results of the electrocatalytic gas sensor in different concentrations of hydrogen sulphide are presented. Working principle of such sensor is based on electric current acquisition, while voltage ramp is applied to the sensor. During voltage sweep oxidation and reduction reactions occurs on the sensor electrodes. Obtained current-voltage plot has unique shape connected...
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Space-vector pulsewidth modulation for a seven-level cascaded H-bridge inverter with the control of DC-link voltages
PublikacjaThe control strategy of DC-link voltages for a seven-level Cascaded H-Bridge inverter is proposed in this paper. The DC-link voltage balancing is accomplished by appropriate selection of H-Bridges and control of their duty cycles in Space-Vector Modulation (SVM) algorithm. The proposed SVM method allows to maintain the same voltage level on all inverter capacitors. Regardless of the balancing function, the...
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Grid-Forming Operation of Energy-Router Based on Model Predictive Control with Improved Dynamic Performance
PublikacjaThe focus of this study is on the grid-forming operation of the Energy Router (ER) based on Model Predictive Control (MPC). ER is regarded as a key component of microgrids. It is a converter that interfaces the microgrid (s) with the utility grid. The ER has a multiport structure and bidirectional energy flow control. The ER concept can be implemented in Nearly Zero-Energy Buildings (NZEB) to provide flexible energy control. A...
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Higher harmonics produced by traction substations – computer modelling and experimental verification
PublikacjaVoltage and current harmonics have a detrimental effect on the components of a power system. Current harmonics may result in the overload and damage to power transformers, although the rms value of load current does not exceed their current-carrying capacity. Voltage harmonics may result in, for example, damage to capacitor banks used to compensate reactive power. Devices which contribute to both current and voltage distortion...
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THE PHASE SHIFTERS INFLUENCE ON THE POWER SYSTEM STABILITY
PublikacjaThe paper presents the effect of phase shifters as FACTS devices on the possibility of improving the angle stability. Presented results obtained by the dynamic simulation performed on the mathematical model of the three machine system cooperating with the 400 kV network. The generative blocks models include turbine models with their controllers and models of synchronous generators with their excitation systems and voltage regulation....
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Niskonapięciowy filtr analogowy CMOS wykorzystujący konwerter ujemnoimpedancyjny
PublikacjaA low-voltage 3-order low-pass CMOS filter based on the novel current inversion type negative impedance converter (CNIC) is presented. It shows a badwidth of 10 MHz at 400 uW power consumption and 2 V supply voltage when realized in a 0.35 um CMOS process.
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Niskonapięciowy filtr analogowy CMOS oparty o konwerter ujemno-impedancyjny
PublikacjaA low-voltage 3-order low-pass CMOS filter based on the novel current inversion type negative impedance converter (CNIC) is presented. It shows a badwidth of 10 MHz at 400 uW power consumption and 2 V supply voltage when realized in a 0.35 um CMOS process.
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Speed sensorless ac drive with inverter output filter and fault detection using load torque signal
PublikacjaIn this paper, a sensorless induction motor (IM) drive using speed observer system is presented. The system includes load torque computation for gear fault detection. Nonlinear control method is adopted for controlling the motor over a wide speed range. An LC filter for smoothing current and voltage waveforms is used at the output of the voltage inverter. The use of filter imposes more building of the used observer to avoid using...
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Resonant DC link inverters for AC motor drive systems – critical evaluation
PublikacjaIn this survey paper, resonant and quasiresonant DC link inverters are reexamined for AC motor drive applications. Critical evaluation of representative topologies is based on simulation and waveform analysis to characterize current/voltage stress of components, control timing constraints and feasibility. A special concern over inverter common-mode voltage and voltage gradient du/dt limitation capacity is discussed for motor bearing...
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Electrophoretic deposition (EPD) of nanohydroxyapatite - nanosilver coatings on Ti13Zr13Nb alloy
PublikacjaTitanium and its alloys are the biomaterials most frequently used in medical engineering, especially as parts of orthopedic and dental implants. The surfaces of titanium and its alloys are usually modified to improve their biocompatibility and bioactivity, for example, in connection with the deposition of hydroxyapatite coatings. The objective of the present research was to elaborate the technology of electrophoretic deposition...
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Leakage Current Measurements of Surge Arresters
PublikacjaThe paper presents the methods of assessing the technical condition of varistor surge arresters used in laboratory tests and in operation—performed without disconnecting the arresters from the network. The analysis of the diagnostic methods was supplemented with the results of the measurements of the leakage current of arresters coming directly from their production and used in the power industry. Among the available methods of...
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Multiple reference frame theory in the synchronous generator model considering harmonic distortions caused by nonuniform pole shoe saturation
PublikacjaThe paper describes a synchronous generator model developed based on the multiple reference frame theory. The main physical phenomena included in the model are the machine armature non-sinusoidal voltage waveform and the influence of armature current in load conditions on the armature voltage waveform higher harmonic components. The modified multiple reference frame theory model is proposed. In this modified theory model the field...
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Buck-Boost Inverters with Symmetrical Passive Four-terminal Networks
PublikacjaAlternating Voltage Inverters (Converters) supplied by low-voltage sources DC (ex. fuel cell, photovoltaic cell) are most frequently realized on the basis of the three fundamental topologies: a) PWM voltage inverter with boost-converter" system, b) PWM voltage inverter with transformed converter DC/DC in the ,,boost-converter" system, c) PWM current converter. However none of these solutions is claimed to be the best and dominant...
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Optimized Space-Vector Modulation Schemes for Five-Phase Precision Low-Speed Drives with Minimizing the Stator Current Ripple
PublikacjaOne of the main ways to improve the quality of a precision electric drive is minimization of the stator current pulsations generated by the voltage inverter. The solution of this problem can be achieved by using of multiphase inverters, as well as improving control algorithms. This paper considers the influence of the space-vector modulation algorithm with different switching sequences of basic vectors on the stator current pulsations...
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Design of synchronous generator two inputs regulator based on hinf control theory.
PublikacjaThe power system is highly nonlinear system, its dynamics depends on system network configuration, system loading… etc. To overcome the above mentioned difficulties and fulfill the performance requirements the different control methods are considered and tested for design of synchronous generator control system. Application of the H optimization method to synchronous generator regulator based on measurement of generator voltage...
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Cost-Effective Piggyback Forward dc-dc Converter
PublikacjaThe novel piggyback dc-dc converter as a cost-effective solution is presented in this work. It provides a wide input voltage range of regulation with a low component count. The novel solution is an advanced forward dc-dc converter with an additional clamp output capacitor. The idea of such a type of converter is to transfer magnetizing energy of transformer to the output side, instead of using input clamp circuit. The design guidelines...
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Low cost set-up for supercapacitors parameters evaluation
PublikacjaWe propose a use of a power amplifier in the circuit of voltage to current converter (current driver) for supercapacitor charging/discharging in controlled conditions. The current driver is controlled by DAC output of DAQ board and voltage of DUT is measured and a control loop is realized by software. In the circuit the DC current method of evaluation of capacitance and equivalent series...
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An Implementation of a Compact Smart Resistive Sensor Based on a Microcontroller with an Internal ADC
PublikacjaIn the paper a new implementation of a compact smart resistive sensor based on a microcontroller with internal ADCs is proposed and analysed. The solution is based only on a (already existing in the system) microcontroller and a simple sensor interface circuit working as a voltage divider consisting of a reference resistor and the resistive sensor connected in parallel with an interference suppression capacitor. The measurement...
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Modeling the effect of parasitic capacitances on the dead-time distortion in multilevel NPC inverters
PublikacjaA simple model is derived and verified for evaluating the effect of parasitic capacitances on the dead-time related voltage distortion in multilevel NPC voltage source inverters. The model permits well-defined and precise compensation of dead-time distortion, exhibiting meaningful improvement on compensation methods neglecting the effects of parasitic capacitances. A simple formula is given for evaluating the capacitances as serial/parallel...
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Hydrogen Production via Biomethane Reforming in DBD Reactor
PublikacjaProduction of hydrogen from CH4:CO2 (70%:30%) mixture simulating dry biogas in a DBD reactor supplied with AC of 1.0-2.0 kHz or nanosecond negative pulses is presented. We have found that hydrogen production and methane conversion degree increase linearly with discharge power in the range of up to 50 W. Nanosecond voltage pulses are much more efficient in hydrogen production than sine AC voltage
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A method of self-testing of analog circuits based on fully differential op-amps with theTCBF classifier
PublikacjaA new approach of self-testing of analog circuits based on fully differential op-amps of mixed-signal systems controlled by microcontrollers is presented. It consists of a measurement procedure and a fault diagnosis procedure. We measure voltage samples of a time response of a tested circuit on a stimulation of a unit step function given at the common-mode reference voltage input of the op-amp. The fault detection and fault localization...
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Exercise bike powered electric generator for fitness club appliances
PublikacjaA generator powered by a stationary bicycle for the purposes of generating electricity for fitness club appliances is considered. A generator is connected to a stationary bicycle in such a way as the circular rotation of the front wheel rotates the coils of wires inside the generator between the poles of the magnets inside the generator. The resulting Direct Current is channeled to the attached battery bank and converted into different...
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A method of measuring RLC components for microcontroller systems
PublikacjaA new method of measuring RLC components for microcontroller systems dedicated to compact smart impedance sensors based on a direct sensor-microcontroller interface is presented. In the method this direct interface composed of a reference resistor connected in series with the tested sensor impedance is stimulated by a square wave generated by the microcontroller, and then its voltage response is sampled by an internal ADC of the...
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Hybridized PWM Strategy for Three- and Multiphase Three-Level NPC Inverters
PublikacjaA simple hybridized pulsewidth modulation (PWM) algorithm for three- and multiphase three-level neutral point clamped (NPC) inverters is proposed. The proposed solution is based on classical space vector PWM (SVPWM) algorithms for two-level inverters but can also be based on sinusoidal PWM with min–max injection. An additional level of output voltage is obtained by modifying the resulting switching patterns taking into account...
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A 1-nS 1-V Sub-1-µW Linear CMOS OTA with Rail-to-Rail Input for Hz-Band Sensory Interfaces
PublikacjaThe paper presents an operational transconductance amplifier (OTA) with low transconductance (0.62–6.28 nS) and low power consumption (28–270 nW) for the low-frequency analog front-ends in biomedical sensor interfaces. The proposed OTA implements an innovative, highly linear voltage-to-current converter based on the channel-length-modulation effect, which can be rail-to-rail driven. At 1-V supply and 1-Vpp asymmetrical input driving,...
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Evaluation of expanded uncertainty of instantaneous power measurement in a bearing diagnostic system.
PublikacjaThe paper presents the issues concerning the estimation of the expanded uncertainty in the system for the diagnosis of rolling bearings, consisting of transducers: voltage and current voltage, which is used for diagnostic bearing motors method based on the measurement and analysis of the instantaneous power signal consumed by the induction motor. It presents the methodology for assessing the measurement uncertainty and presents...
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New type T-Source inverter
PublikacjaThis paper presents different topologies of voltage inverters with alternative input LC networks. The basic topology is known in the literature as a Z-source inverter (ZSI). Alternative passive networks were named by the authors as T-sources. T-source inverter has fewer reactive components in comparison to conventional Z-source inverter. The most significant advantage of the T-source inverter (TSI) is its use of a common voltage...
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Electroelastic biaxial compression of nanoplates considering piezoelectric effects
PublikacjaIn the present theoretical work, it is assumed that a piezoelectric nanoplate is connected to the voltage meter which voltages have resulted from deformation of the plate due to in-plane compressive forces whether they are critical buckling loads or arbitrary forces. In order to derive governing equations, a simplified four-variable shear deformation plate theory has been employed using Hamilton’s principle and Von-Kármán...
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Electro-mechanical shear buckling of piezoelectric nanoplate using modified couple stress theory based on simplified first order shear deformation theory
PublikacjaThis paper studies the electro-mechanical shear buckling analysis of piezoelectric nanoplate using modified couple stress theory with various boundary conditions.In order to be taken electric effects into account, an external electric voltage is applied on the piezoelectric nanoplate. The simplified first order shear deformation theory (S-FSDT) has been employed and the governing differential equations have been obtained using...
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Programmable Input Mode Instrumentation Amplifier Using Multiple Output Current Conveyors
PublikacjaIn this paper a programmable input mode instrumentation amplifier (IA) utilising second generation, multiple output current conveyors and transmission gates is presented. Its main advantage is the ability to choose a voltage or current mode of inputs by setting the voltage of two configuration nodes. The presented IA is prepared as an integrated circuit block to be used alone or as a sub-block in a microcontroller or in a field...
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Induction Generator with Direct Control and a Limited Number of Measurements on the Side of the Converter Connected to the Power Grid
PublikacjaThe article presents an induction generator connected to the power grid using the AC/DC/AC converter and LCL coupling filter. Three-level inverters were used in the converter, both from the generator side and the power grid side. The algorithm realizing Pulse Width Modulation (PWM) in inverters has been simplified to the maximum. Control of the induction generator was based on the Direct Field-Oriented Control (DFOC) method. At...
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Properties of chitosan/CuNPs coatings electrophoretically deposited on TiO2 nanotubular oxide layer of Ti13Zr13Nb alloy
PublikacjaCoatings based on chitosan/CuNPs (chit/CuNPs) were obtained by a one-step electrophoretic deposition (EPD) on nanotubular oxide layer of Ti13Zr13Nb alloy. The deposition was carried out for 1 min applying voltages of 10 and 20 V with and without the addition of dispersing agent (Polysorbate 20) to the suspension. The coatings obtained for the lower voltage were more uniform than for the higher voltage. By adding a dispersing agent,...
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Single-Phase 15-Level Switched-Capacitor Boost Multilevel Inverter Topology for Renewable Energy Applications
PublikacjaGalvanic isolation is a vital part of a grid-connected solar PV system. With the growth of multilevel inverters for grid-connected applications, the multilevel inverters having isolation are not sufficiently discussed in the literature. In this paper, a 15-level isolated multilevel inverter topology requiring only thirteen switches is proposed. The envisaged configuration includes two cells, designated as upper and lower cells....
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Impact Assessment of Electric Vehicles Integration and Optimal Charging Schemes Under Uncertainty: A Case Study of Qatar
PublikacjaThe integration of electric vehicles (EVs) is rapidly growing compared to conventional vehicles in Qatar. To assess how these electric vehicles will impact Qatar’s distribution network, it is necessary to accurately model EV loads. However, EV loads exhibit uncertainties due to driving behaviour in charging time, state of charge (SOC), number of trips, and distance travelled. This necessitates the development of a probabilistic...
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Virtual Space Vector Pulse Width Modulation Algorithm for Three-Level NPC Converters Based on the Final Element Shape Functions
PublikacjaThe paper puts forth a novel idea for the computation of Nearest Three Virtual Space Vector Pulse Width Modulation for the three level NPC converters. The computations are based on the concept of final element shape function widely used in the domain of finite element analysis. The proposed approach significantly frees the computations from the use of trigonometric functions, which simplifies the computations and permits easier...
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An Extended Control of the Input Angle for Matrix Converters Connected with the Non-Unity Power Factor Loads.
PublikacjaThis paper proposes a novel PWM modulation algorithm for Multiphase Conventional Matrix Converters (MCMC), with 3 inputs and k outputs, using the transfer function of the load angle. The proposed approach extends the range of power angle control at the input during the operation with a maximum voltage transfer ratio. The proposed concept is based on the Direct Analytic Voltage PWM (DAV--PWM) modulation with an elliptical trajectory...
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Przekształtnik prądu jako sterownik w układach napędowych z silnikami indukcyjnymi
PublikacjaThe circuits used for power conversion applied in drives with electric machines are classified into two groups: voltage source inverters (VSI) and current source inverters (CSI). Application of the current source inverter results in better properties of drive than application of voltage source inverter because there is no output filter. The development of power electronics and especially the IGBTs, in which on/off-times are very...
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Study of Metrological Properties of Voltammetric Electrodes in the Time Domain
PublikacjaMetrological properties of voltammetric electrodes, in the situation where on their surface an electrochemical reaction of oxidizing/reduction takes place, were analyzed in this chapter. The properties of electrodes on which a reaction controlled by ion transport process takes place were taken into consideration. Also, it was analyzed how the electrode’s shape and the voltage polarizing the electrode influence this electrode’s...
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Uncertainty estimation of loop impedance measurement determined by the vector method
PublikacjaThis article presents a detailed analysis of uncertainty estimation of loop impedance measurement determined by the vector method. The analysis includes the following estimates: resistance variance, voltage variance and time measurement variance. This paper presents a methodology for estimating the combined standard uncertainty of loop impedance by the vector method. The vector method allows to determine loop impedance based on...
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Measurement methods for assessing insulation condition of underground pipelines
PublikacjaThe paper discusses the most frequently applied measurement methods for assessing the quality of external insulation along pipelines and detecting defect locations in the protective coating. The quality of coating along a given pipeline section under investigation is assessed by determining unitary resistance of the coating, which is calculated on the basis of measurement results obtained along a pipeline subjected to cathodic...