Filtry
wszystkich: 191
wybranych: 158
Wyniki wyszukiwania dla: DŁUŻNIK
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Wykorzystanie rejestracji przebiegów szybkozmiennych do weryfikacji modeli dynamicznych KSE
PublikacjaW referacie przedstawiono koncepcję narzędzia pozwalającego na weryfikowanie parametrów modeli dynamicznych elementów KSE. Narzędzie wykorzystuje program obliczeniowy PSLF, stosowany powszechnie przez operatora systemu przesyłowego. Nowatorstwo polega na wykorzystaniu dodatkowej aplikacji (programu w systemie MS Windows), która steruje pracą programu obliczeniowego. Powstaje w ten sposób tandem wygodnego interfejsu użytkownika...
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Weryfikacja działania blokad przeciwkołysaniowych na przykładzie zabezpieczeń firmy Siemens
PublikacjaReferat podejmuje tematykę działania zabezpieczeń impedancyjnych w czasie trwania synchronicznych i asynchronicznych kołysań mocy. W referacie analizowano działanie zabezpieczeń impedancyjnych generatora synchronicznego oraz linii blokowej. Wskazano na niebezpieczeństwo błędnego działania zabezpieczeń przy obecnie stosowanych sposobach ich nastawiania.
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The Influence of Limiters UEL and OEL (The power angle, stator's current and excitation current) ot the possibility of voltage collapse development
PublikacjaVoltage stability has been a major concern for power system utilities because of event of voltage collapses in the recent past. Sometimes, power system events have shown the need for generators to operate in the overexcited and underexcited region to support stable operation. Modern excitation systems include devices for controlling or limiting machine terminal voltage (overvoltage limiters), volts per hertz ratio (V/Hz limiters),...
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Wpływ obecnie stosowanych układów regulacji generatorów na możliwości pogłębienia awarii napięciowej
PublikacjaArtykuł przedstawia badania symulacyjne pracy generatora synchronicznego wyposażonego w wieloparametrowy regulator generatora o strukturach spotykanych obecnie w KSE. W pracy analizowano wpływu struktury i nastawień regulatora generatora synchronicznego na pracę systemu elektroenergetycznego w warunkach awarii napięciowej
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Praca regulatora generatora w warunkach sprzyjających powstawaniu lawiny napięcia - wybrane problemy
PublikacjaW referacie zwrócono uwagę na wybrane zagadnienia związane z pracą wieloparamatrowego regulatora generatora w warunkach awarii napięciowej. Przedstawiono wyniki analizy wpływu, tak często pomijanego elementu układu regulatora generatora, jakim jest stabilizator systemowy. Zwrócono uwagę na celowość automatyzacji procesu zaniżania mocy czynnej, dla zwiększenia możliwości generacji mocy biernej. Ponadto, wskazano błędy w strukturze...
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Uproszczone modelowanie linii kablowych wysokiego napięcia a napięcia indukowane w żyłach powrotnych – studium przypadku
PublikacjaLinie kablowe, obok linii napowietrznych, są jednym z podstawowych elementów składowych systemów elektroenergetycznych. Stosowane są głównie na terenach zurbanizowanych, gdzie prowadzenie linii napowietrznych jest mocno utrudnione lub wręcz niemożliwe. Linie kablowe wysokiego napięcia budowane są głównie z wykorzystaniem kabli, które oprócz żyły roboczej mają również współosiową żyłę powrotną. Istnieje kilka układów pracy takich...
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Selection of energy storage units by genetic algorithm for mitigating voltage deviations
PublikacjaIn recent years, energy storage units have become very popular. They are applied both for economic and technical purposes. Unfortunately, the cost of such devices is still high and selecting their proper location and rated power have to be performed precisely. In this paper, a Genetic-Algorithm-based optimization method for selecting the best configuration of energy storage units in the power network is proposed. The presented...
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Evaluation Of Single Pole Auto-Reclosing Effectiveness With Nonlinear Secondary Arc Model
PublikacjaThe paper discusses two evaluation methods of single pole auto-reclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a non-linear secondary arc implementation is presented. The authors indicate, that precise representation of secondary electric arc leads to more...
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Induced Sheath Voltages In 110 Kv Power Cables – Case Study
PublikacjaThe paper considers shock hazard due to induced sheath voltages in 110 kV power cables. Various configurations of the metallic sheaths bonding and earthing (single-point bonding, both-ends bonding, cross-bonding) are analysed. Taking into account shock hazard and ability of the system to power transfer an optimal configuration is proposed.
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Induced sheath voltages in 110 kV power cables – case study
PublikacjaThis paper considers electric shock hazard due to induced sheath voltages in 110 kV power cables. The purpose of this paper is to find an optimal configuration of the power cable system, taking into account electric shock hazard and ability of the system to transfer maximal power. A computer simulations on a computer model of the local power system, comprising high voltage power cables, were carried out. This model enables to analyse...
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Secondary arc modelling for single pole reclosing analyses
PublikacjaThe paper discusses two evaluation methods of single pole auto-reclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage calculation results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc model implementation is presented. The paper presents the study results for the three types of EHV transmission...
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Calculation of Induced Sheath Voltages in Power Cables – Single Circuit System versus Double Circuit System
PublikacjaThis paper presents comparison of values of induced sheath voltages in power cable metallic sheaths when one or two cables per phase are used. Calculation of voltages is performed for various phase sequences of the power cables. Three types of the sheaths bonding and earthing are considered. Shock hazard and voltage stress of non-metallic outer sheath of cables are evaluated. The proposed, optimal configuration of the power cable...
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Computer-aided Analysis of Induced Sheath Voltages in High Voltage Power Cable System
PublikacjaThis paper concerns the effect of configuration of high voltage power cables on induced voltages in their metallic sheaths. One, two or three cables per phase and phase sequence of the cables are considered. Computing of the voltages was performed for a normal operation and in case of earth fault. Various ways of the sheaths bonding are considered as well. Shock hazard and voltage stress of non-metallic outer sheath of cables are...
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DDQ-mediated synthesis of functionalized unsymmetrical disulfanes
PublikacjaWe developed a simple and efficient method for the synthesis of functionalized unsymmetrical disulfanes under mild conditions in good yields. The designed method is based on the reaction of bis(5,5- dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)disulfane with thiols in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). The developedmethod allows the preparation of unsymmetrical disulfanes bearing additional hydroxy, carboxy,...
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Ekwiwalentowanie farm wiatrowych
PublikacjaW artykule zaproponowano sposób modelowania i ekwiwalentowania dużych farm wiatrowych. Przedstawiono sposoby tworzenia modeli w celu ich wykorzystania do analiz stanów ustalonych i nieustalonych systemu elektroenergetycznego.
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Power and energy measurement problems in transmission line between Poland-Lithuania
PublikacjaThe paper discusses problem of power and energy metering in double circuit overhead transmission line. Considerations are based on example of transmission line connecting Polish substation Bis Elk and Lithuanian substation Alytus.
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Modification of the operating point of residual current transformers for high frequency earth fault currents detection
PublikacjaFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when earth fault current with high frequency components occurs. Serious hazard of electrocution exists then. One of the most important element of residual current devices is a residual current transformer with iron core. Tripping characteristic of residual current devices strictly...
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Problemy pomiarów mocy i energii w linii elektroenergetycznej Polska-Litwa
PublikacjaW referacie przedstawiono zagadnienia związane z pomiarem mocy i energii w linii dwutorowej. Rozważania oparto na linii łączącej stacje elektroenergetyczne Ełk Bis i Alytus.
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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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A new method of fault loop resistance measurement in low voltage systems with residual current devices
PublikacjaThis 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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Improving sensitivity of residual current transformers to high frequency earth fault currents
PublikacjaFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed...
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Use of AMI Meters in the Process of Low Voltage Grid Optimization
PublikacjaThis is a report of a project involving, inter alia, low voltage grid performance optimization with data from AMI meters . The study was supported with a European UPGRID grant, and executed by a consortium of companies from seven European countries, including Poland .
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Wykorzystanie liczników AMI w procesie optymalizacji pracy sieci niskiego napięcia
PublikacjaPrezentowany jest opis projektu dotyczącego m.in. optymalizacji pracy sieci niskiego napięcia przy wykorzystaniu danych z liczników AMI. Prace były prowadzone w ramach europejskiego grantu UPGRID, realizowanego przez konsorcjum firm z siedmiu państw europejskich, w tym również z Polski.
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Wykorzystanie infrastruktury systemu ami w monitorowaniu i sterowaniu sieciami niskiego napięcia
PublikacjaW referacie przedstawiono wybrane zagadnienia z prac prowadzonych w ramach europejskiego grantu UPGRID realizowanego przez konsorcjum firm z siedmiu państw europejskich, w tym również z Polski, który dotyczy między innymi optymalizacji pracy sieci niskiego napięcia przy wykorzystaniu danych z liczników AMI.
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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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Methadone is substantially less effective than morphine in modifying locomotor and brain Fos responses to subsequent methadone challenge in rats
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Tri(mesityloxy)silanethiol - The First Structurally CharacterizedOrganoxysilanethiol (Contributions to the Chemistry of Silicon-SulfurCompounds. 77 [1])
PublikacjaTri(mezytyloksy)silanotiol (TMST) wyizolowano jako jedyny produkt reakcji pomiędzy disiarczkiem krzemu a 2,4,6-trimetylofenolem. TMSTkrystalizuje w układzie trójskośnym. Dobra jakość kryształów pozwoliła na udokładnienie grupy SH bez narzuconych więzów. Długość wiązania S-H określono na 1,29(4) ang., a kąt Si-S-H na 95,4(17) deg. Cząsteczki TMST nie tworzą wiązań wodorowych w kryształach.
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Delivery of Ancillary Services in Distribution Power Systems
PublikacjaOne of the technical and organizational challenges the power system faces in deregulated market conditions is to organize an ancillary services market. The growing share of distributed generation of variable (intermittent) energy sources and a change in the market position of consumers, causes the demand for distributed delivery of ancillary services. For this purpose, it is sought to use the ability of the regulatory measures:...
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Cross-border transmission line configuration influence on the electrical power and energy billing process
PublikacjaIn 2015 a connection between the Polish and Lithuanian power systems become fully operational. The connection consists of a 400 kV double circuit transmission line and a back-to-back HVDC substation located on the Lithuanian side. A magnetic couplings between the circuits of the transmission line cause that during power transmission a different values of active power losses are observed in both circuits. This situation may cause...
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Incomplete Cross-Bonding in the MV Line. Experience from the Operation of MV Single Cable Lines
PublikacjaCable lines are one of the basic components of power systems. Medium and high voltage cables mainly comprise a metallic sheath, which is concentric to the main core conductor. There are several operating schemes of such cable lines, which differ in the place of earthing of sheaths and the possible use of the sheaths and/or conductors crossing. The sheaths cross-bonding is typically done in two places of one cable line section,...
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Computer-aided analysis of resonance risk in power system with Static Var Compensators
PublikacjaStatic Var Compensators operation in a power system may significantly improve voltage profiles in nodes and the reactive power balance, as well as ensure greater system stability in emergency conditions. However these devices may be a cause of a resonance in the system. The aim of this paper is to call attention to the need to include resonance phenomena in a compensator’s location evaluation process. The analysis performed in...
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Influence of Shunt Compensation with SVC Devices on Resonance Risk in Power Systems
PublikacjaMany analyses are required to locate a new reactive power source in a power system. The choice of a location is a very complex matter which requires various aspects to be considered. Selecting a location also entails the necessity to assess it from the point of view of the selected compensator’s structure as well as the system’s performance in various states with the new device on. The paper presents the issues of assessing compensator...
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Poor sensitization of 50-kHz vocalization response to amphetamine predicts rat susceptibility to self-administration of the drug
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Diverging changes in rat striatal extracellular dopamine and DOPAC levels and in frequency-modulated 50-kHz ultrasonic vocalizations rate during repeated amphetamine treatment
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Cross-Bonding of MV Cable Lines for Energy Losses Decrease
PublikacjaCurrently, almost all medium voltage cable lines (MV) operate with the return wires earthed at both ends of the cable. Such a way of operation causes that during normal states of operation as well as during disturbances, e.g. short-circuits, in the return wires induce currents whose values mainly depend on the currents flowing in the phase wires. These currents in normal operating states are a source of additional energy losses...
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Detection of high frequency current components by residual current devices
PublikacjaThe negative impact of current harmonics on the main components of residual current devices is presented. A solution for the improvement of the operation of residual current devices is proposed.
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Case studies of resonance phenomena in high voltage overhead power lines with shunt reactors
PublikacjaMisguided design of the towers of power transmission lines can lead to serious problems such as voltage asymmetry, overvoltages, electric arc extinction difficulties or resonance – in case of double circuit line with shunt reactors. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors.
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Rats showing low and high sensitization of frequency-modulated 50-kHz vocalization response to amphetamine differ in amphetamine-induced brain Fos expression
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Magnetic and capacitive couplings influence on power and energy measurement in double circuit high voltage overhead transmission line
PublikacjaThe paper discusses influence of magnetic and capacitive couplings on power and energy measurement in case of double circuit high voltage overhead transmission line. There are presented and discussed various factors influencing the power flow among the line‟s circuits. Mathematical model based calculations results are compared to the real transmission line measurements.
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Magnetic and capacitive couplings influence on power losses in double circuit high voltage overhead transmission line
PublikacjaPurpose – The paper aims to discuss problems of power and energy losses in a double-circuit overhead transmission line. It was observed from energymeters’ readings, that in such a line, active power losses can be measured as “negative”. The “negative” active power losses appear when the active power injected to the circuit is lower than the active power received at the circuit end. The purpose of this paper is to explain this phenomenon. Theoretical...
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Diversity of frequency-modulated 50-kHz vocalization response to intermittent amphetamine treatment in Sprague-Dawley rats
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Inter-individual diversity and intra-individual stability of amphetamine-induced sensitization of frequency-modulated 50-kHz vocalization in Sprague–Dawley rats
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N-acetyl cysteine does not modify the sensitization of the rewarding effect of amphetamine as assessed with frequency-modulated 50-kHz vocalization in the rat
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Energy losses reduction in the medium voltage cable line – case study
PublikacjaThe paper presents an analysis of energy losses in a power cable system, which is composed of two 30 kV cable lines. This cable system is located at the seaside holiday area, so the load profile during a year is specific. Energy losses related to reactive power transmission, as well as to currents induced in the sheaths of the cables, are subject to analysis. Measurements were made in the system in order to prepare a computer model...
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Morphine and methadone pre-exposures differently modify brain regional Fos protein expression and locomotor activity responses to morphine challenge in the rat
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The Quality of Life and Satisfaction with Continuous Glucose Monitoring Therapy in Children under 7 Years of Age with T1D Using the rtCGM System Integrated with Insulin Pump—A Caregivers Point of View
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Projekt UPGRID
PublikacjaMiędzynarodowy projekt UPGRID realizowany jest w ramach programu Horyzont 2020 (H2020). Program ten to największy jak dotąd program Unii Europejskiej (UE) w zakresie badań naukowych i innowacji. W projekcie UPGRID uczestniczy 17 partnerów z 9 krajów EU. Głównym celem projektu UPGRID jest rozwój funkcjonalności, które służą integracji sieci nn oraz SN ze stroną konsumencką. W ramach projektu wybrane technologie Inteligentnych Sieci...
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Diverse behavioral, monoaminergic and Fos protein responses to opioids in Warsaw high-alcohol preferring and Warsaw low-alcohol preferring rats
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Using anticipatory and drug-evoked appetitive ultrasonic vocalization for monitoring the rewarding effect of amphetamine in a rat model of drug self-administration
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Behavioral and arginine catabolism dissimilarities between Warsaw high alcohol preferring (WHP) and Warsaw low alcohol preferring (WLP) rats
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