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Wyświetlanie 1-25 z 755
Tytuł:
Statistical analysis of supply voltage levels for rural customers
Autorzy:
Nęcka, K.
Trojanowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/410783.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
low voltage networks
supply voltage quality
Opis:
In the elaboration, levels of supply voltage at the ends of loaded low-voltage lines were statistically evaluated, describing them using basic statistical measures and examining the frequency distributions. Levels of voltages and time of their occurrence on the background of current regulations were also assessed. It was found out that in spite of the fulfilment of statutory requirements electricity consumers complained about the poor, in their opinion, quality of the voltage.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2016, 5, 3; 77-82
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long-Term Monitoring of Flicker and Some Other Parameters of Voltage Quality
Autorzy:
Krejci, P.
Santarius, P.
Gono, R.
Brunclik, Z.
Powiązania:
https://bibliotekanauki.pl/articles/136258.pdf
Data publikacji:
2016
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
flicker
unbalance
voltage harmonics
voltage quality
Opis:
In 1997 cooperation began between the Faculty of Electrical Engineering and Computer Science and the power company CEZ on a joint project that involved monitoring selected voltage quality parameters. Over the course of several years measurements were carried out at 59 points of the distribution system at a low voltage (LV) level and their power supply nodes at medium voltage (MV) and high voltage (HV) levels, which constituted more than 100 measured points. The measurements continued until 2012 (with a one-year break in 2009) and with a total scope of five cycles of three-year measurements. The last phase of the measurements was focused, inter alia, on the evaluation of 15th and 21st voltage harmonics. From 2013, the cooperation focused again on monitoring flicker in localities with the occurrence of elevated levels of this voltage quality parameter. At these sites, the monitoring of flicker was carried out for two weeks in spring and autumn for a period of three years. The basis for evaluating the quality parameters is the standard EN 50160. In addition the results of annual continual monitoring for one selected locality on MV level will be presented in the paper. In addition the possibility of utilization of intelligent electrometers for monitoring of some quality parameters will be referred in the paper.
Źródło:
Transactions on Environment and Electrical Engineering; 2016, 1, 3; 1-8
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of resistor-less first-order all-pass filter using single VDVTA (Voltage Differencing Voltage Transconducatnce Amplifier)
Autorzy:
Shaktour, M.
Powiązania:
https://bibliotekanauki.pl/articles/377724.pdf
Data publikacji:
2013
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
VDVTA
Voltage Differencing Voltage Transconductance Amplifier
Opis:
This paper presents a new realization of a first-order mixed-mode (Voltage input Current output) (MM) all-pass filter (APF) using the recently proposed modern active building block (ABB), namely the Voltage Differencing Voltage Transconductance Amplifier (VDVTA). The MM APF is made using minimum number of components, namely a single VDVTA and one grounded capacitor. The circuit does not use any external resistors and offers the advantages of current-tunable pole frequency, low input impedance and high output impedance. PSPICE simulation results are included to verify the workability of the circuit.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2013, 76; 271-274
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda oceny sytuacji napięciowej w sieci przesyłowej uwzględniająca działanie automatyki regulacyjnej
Method of voltage situation assessment in the transmission grid taking into account the regulation technology operation
Autorzy:
Jemielity, J.
Opala, K.
Powiązania:
https://bibliotekanauki.pl/articles/396860.pdf
Data publikacji:
2010
Wydawca:
ENERGA
Tematy:
SORN
napięcie
regulacja napięcia
Area Voltage Regulation System
voltage
voltage regulator
Opis:
Selected functions of the Area Voltage Regulation System (SORN) have been implemented in the Bydgoszcz Power Dispatch Centre (ODM) where the method of voltage situation assessment described in this paper has been utilised. The method of automated control over the ARNE and ARST regulation systems operation elaborated in the SORN system aims at supporting dispatchers during the ongoing regulation status assessment, danger conditions detection and counteracting the system malfunction results. This aim has been achieved by utilising the method of voltage situation assessment in the transmission grid which used normalized numerical indices describing the regulation nodes operation point. Next, the analysis of trends related to changes in these indices was used for detection with time advance of adverse changes in the voltage profile or reactive power reserves level. The described method employs the fuzzy inference system in order to generate prompts for Power Dispatch Centre (ODM) dispatchers. The limited SORN system functions fulfilled presently are to enhance the power system safety using the existing ARNE and ARST regulation systems infrastructure. Together with the latest modifications of the ARST system algorithms, the SORN system's basic duty is to prevent worsening or accelerating a voltage malfunction, which results from transformer regulation not being blocked on time.
Źródło:
Acta Energetica; 2010, 3; 19-29
2300-3022
Pojawia się w:
Acta Energetica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transfiguration of supplied-by-HV/MV transformer network to the supply radius
Autorzy:
Czepiel, S.
Powiązania:
https://bibliotekanauki.pl/articles/262797.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
power network transfiguration
voltage regulation
voltage drop
Opis:
A HV/MV transformer supplies a few power lines of known parameters and loads. These power lines can be substituted with the supply radius, at the end of which there is the equivalent load-receiver representing the entire load being transmitted by the transformer. The R and X parameters of this substitute supply radius are needed to calculate adjusting parameters of the voltage regulator which controls the HV/MV transformer. The presented method enables simple determining of the supply radius parameters R and X.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2008, 14, 1; 47-52
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved algorithm for the series step-up method based on a linear three-ports network
Autorzy:
Liu, Hao
Chen, Lixue
Wang, Xue
Yao, Teng
Gu, Xiong
Powiązania:
https://bibliotekanauki.pl/articles/2106422.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
voltage transformer
traceability method
calibration
high voltage
Opis:
Capacitive leakage and adjacent interference are the main influence sources of the measuring error in the traditional series step-up method. To solve the two problems, a new algorithm was proposed in this study based on a three-ports network. Considering the two influences, it has been proved that response of this three-ports network still has characteristics of linear superposition with this new algorithm. In this threeport network, the auxiliary series voltage transformers use a two-stage structure that can further decrease measurement uncertainty. The measurement uncertainty of this proposed method at 500/√3 kV is 6.8 ppm for ratio error and 7 μrad for phase displacement ( k = 2). This new method has also been verified by comparing its results with measurement results of the PTB in Germany over the same 110/√3 kV standard voltage transformer. According to test results, the error between the two methods was less than 2.7 ppm for ratio error and 2.9 μrad for phase displacement.
Źródło:
Metrology and Measurement Systems; 2022, 29, 2; 301--313
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Voltage Security Assessment of Power System
Autorzy:
Chowdhury, Amit Kumar
Mondal, Surajit
Alam, S. K. Mehboob
Pal, Jagadish
Powiązania:
https://bibliotekanauki.pl/articles/1193939.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
1P-1Q Method
Fast Decoupled Load flow
Voltage Collapse
Voltage Performance index
Voltage Stability
Voltage insecurity
Opis:
This paper deals with the security aspects of power system by evaluating the severity of transmission line outage. Voltage security assessment is made by determining the power flow in the line using load flow for each contingency. The severity of contingency is measured using a scalar index called Voltage performance index. 1P-1Q Method and Fast Decoupled load flow are used as approximate and exact load flow methods for Voltage security assessment respectively. Contingency analysis is carried out and ranked lists in the decreasing order of severity based on Voltage Performance Index values are prepared for standard test systems. The severity of line is evaluated and compared using these load flow methods.
Źródło:
World Scientific News; 2015, 21; 36-50
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple three-level neutral point voltage balance control strategy based on SVPWM
Autorzy:
Bo, G.
Shanmei, Ch.
Yi, Q.
Powiązania:
https://bibliotekanauki.pl/articles/141238.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
space vector
neutral point voltage
voltage offset
PWM
Opis:
The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC) inverter, the effect of neutral point voltage balancing which is caused by voltage vector is analyzed, and the relationship of the voltage offset and neutral point voltage is studied in this paper. This paper proposes a novel neutral point balance strategy for three-level NPC inverter based on space vector pulse width modulation (SVPWM). A voltage offset is added to the modulation wave, and a closed-loop neutral point voltage balance control system is designed. In the control system, the dwelling time of synthesis voltage vectors for SVPWM is varied to solve the problem of the unbalance of the neutral point voltage, the sequence of the voltage vectors maintains unchanging. Simulation and experimental results show the neutral point voltage balancing control strategy based on SVPWM is effective.
Źródło:
Archives of Electrical Engineering; 2013, 62, 1; 15-23
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Voltage quality improvement using DVR
Autorzy:
Benachaiba, Ch.
Ferdi, B.
Powiązania:
https://bibliotekanauki.pl/articles/262805.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
Dynamic Voltage Restorer (DVR)
voltage sags (dips)
voltage swells
custom power
power quality
Opis:
The problem of voltage sags and Swells and its severe impact on sensitive loads is well known. To solve this problem, custom power devices are used. One of those devices is the Dynamic Voltage Restorer (DVR), which is the most efficient and effective modern custom power device used in power distribution networks. Its appeal includes lower cost, smaller size, and its fast dynamic response to the disturbance. This paper describes DVR principles and voltage restoration methods at the point of common coupling (PCC ). Simulation results are presented to illustrate and understand the performances of DVR in load voltage compensation.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2008, 14, 1; 39-46
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of ferroresonance phenomena in HV power networks
Autorzy:
Solak, K.
Rebizant, W.
Powiązania:
https://bibliotekanauki.pl/articles/410561.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
inductive voltage transformer
ferroresonance oscillations
high voltage networks
simulation
Opis:
Analysis of ferroresonance phenomena in high voltage (HV) power networks is presented in this paper. The adequate digital simulation model for investigation of ferroresonance oscillations in MATLAB/Simulink program was developed. In the paper HV power system configuration with circuit breaker grading capacitors was described and analyzed. The phase as well as open delta VT voltages and their spectra were considered as signals for ferroresonance detection. Additionally, the possibility of ferroresonance oscillations suppression was also studied.
Źródło:
Present Problems of Power System Control; 2015, 6; 5-14
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic Charge Carrier Transport Behaviors in Zirconium Oxide for Nuclear Cladding Materials
Autorzy:
Park, Il-Kyu
Lee, Sang-Seok
Mok, Yong Kyoon
Jeon, Chan-Woo
Kim, Hyun-Gil
Powiązania:
https://bibliotekanauki.pl/articles/351043.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zirconium
nuclear cladding
Zr oxide
capacitance-voltage
current-voltage
Opis:
Dynamic charge carrier transport behavior in the zirconium (Zr) oxide was investigated based on the frequency-dependent capacitance-voltage (C-V) and temperature-dependent current-voltage (I-V) measurements. The Zr oxide was formed on the ZIRLO and newly developed zirconium-based alloy (NDZ) by corrosion in the PWR-simulated loop at 360°C. The corrosion test for 90 days showed that the NDZ exhibits better corrosion resistance than ZIRLO alloy. Based on the C-V measurement, dielectric constant values for the Zr oxide was estimated to be 11.28 and 11.52 for the ZIRLO and NDZ. The capacitance difference between low and high frequency was larger in the ZIRLO than in the NDZ, which was attributed to more mobile electrical charge carriers in the oxide layer on the ZIRLO alloy. The current through the oxide layers on the ZIRLO increased more drastically with increasing temperature than on the NDZ, which indicating that more charge trap sites exist in the ZIRLO than in NDZ. Based on the dynamiccharge carrier transport behavior, it was concluded that the electrical charge carrier transport within the oxide layers was closely related with the corrosion behavior of the Zr alloys.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 3; 1063-1067
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Voltage stability in low voltage microgrids in aspects of active and reactive power demand
Autorzy:
Parol, M.
Rokicki, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/140350.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
distributed generation
microgrids
voltage stability
voltage stability margin
indexes
Opis:
Low voltage microgrids are autonomous subsystems, in which generation, storage and power and electrical energy consumption appear. In the paper the main attention has been paid to the voltage stability issue in low voltage microgrid for different variants of its operation. In the introduction a notion of microgrid has been presented, and also the issue of influence of active and reactive power balance on node voltage level has been described. Then description of voltage stability issue has been presented. The conditions of voltage stability and indicators used to determine voltage stability margin in the microgrid have been described. Description of the low voltage test microgrid, as well as research methodology along with definition of considered variants of its operation have been presented further. The results of exemplary calculations carried out for the daily changes in node load of the active and reactive power, i.e. the voltage and the voltage stability margin indexes in nodes have been presented. Furthermore, the changes of voltage stability margin indexes depending on the variant of the microgrid operation have been presented. Summary and formulation of conclusions related to the issue of voltage stability in microgrids have been included at the end of the paper.
Źródło:
Archives of Electrical Engineering; 2016, 65, 1; 19-32
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Error analysis of the three-phase electrical energy calculation method in the case of voltage-loss failure
Autorzy:
Cheng, Han-miao
Wang, Zhong-dong
Cai, Qi-xin
Lu, Xiao-quan
Gao, Yu-xiang
Song, Rui-peng
Tian, Zheng-qi
Mu, Xiao-xing
Powiązania:
https://bibliotekanauki.pl/articles/221096.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
three-phase electrical energy meter
voltage-loss failure
voltage substitution
three-phase voltage unbalance
calculation error
Opis:
The single-phase voltage loss is a common fault. Once the voltage-loss failure occurs, the amount of electrical energy will not be measured, but it is to be calculated so as to protect the interest of the power supplier. Two automatic calculation methods, the power substitution and the voltage substitution, are introduced in this paper. Considering the lack of quantitative analysis of the calculation error of the voltage substitution method, the grid traversal method and MATLAB tool are applied to solve the problem. The theoretical analysis indicates that the calculation error is closely related to the voltage unbalance factor and the power factor, and the maximum calculation error is about 6% when the power system operates normally. To verify the theoretical analysis, two three-phase electrical energy metering devices have been developed, and verification tests have been carried out in both the lab and field conditions. The lab testing results are consistent with the theoretical ones, and the field testing results show that the calculation errors are generally below 0.2%, that is correct in most cases.
Źródło:
Metrology and Measurement Systems; 2019, 26, 3; 505-516
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic emission signals associated with prebreakdown state in air high voltage insulating systems
Autorzy:
Dobrzycki, A.
Opydo, W.
Zakrzewski, S.
Powiązania:
https://bibliotekanauki.pl/articles/97311.pdf
Data publikacji:
2015
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
high voltage insulating system
breakdown voltage
acoustic emission method
dielectric coatings
Opis:
The paper presents the method of acoustic emission (AE) in the study of the state of insulation systems with air as the high-voltage insulation. The tested object was a planar system of electrodes made of aluminum. In addition, the analysis of AE signals and the impact on these signals the presence of dielectric coating on the electrode surfaces of aluminum was tested. We examined the influence of saturation (seal) these coatings on the dielectric strength of the insulation system. The study was conducted at an air pressure values 1·105, 3·105 and 5·105 Pa. The strength of the electrical systems were tested at alternating voltage with a frequency of 50 Hz. Noted pros and cons of using the method of EA in the context of the assessment of high-voltage electric insulation devices. The presented results confirm the possibility of using acoustic emission method, not only for identifying vulnerable areas, but also to predict the time of of further use of high voltage device.
Źródło:
Computer Applications in Electrical Engineering; 2015, 13; 278-286
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of Graphene Based Flow Sensor
Autorzy:
Kowalski, A.
Safinowski, M.
Szewczyk, R.
Winiarski, W.
Powiązania:
https://bibliotekanauki.pl/articles/385013.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
graphene
flow
sensor
voltage
Opis:
This paper shows the research on a flow sensor based on graphene. Presented Results show the linear relation between voltage induced on graphene layer and flow velocity. The measurement shows that signal level is relatively low, and it is highly correlated with the time of the sample being submerged in water. A significant temperature dependency has been shown which indicates on necessity to develop a compensation system for the sensor. On the other hand, induced voltage is related to ion concentration of the liquid, so the sensor must be recalibrated for every working environment. The most important thing that turned out during research is that although the voltage signal itself is highly inconsistent, the difference between its value in steady state and for flowing liquid is always visible and correlated to the flow value – this property can be used in further deployment. Huge advantage of the sensor is also its scalability which opens so far unknown possibilities of applications.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2015, 9, 4; 55-57
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of voltage surge pulses on fusion of Saccharomyces cerevisiae protoplasts
Wpływ impulsów natężenia pola elektrycznego na fuzję protoplastów Saccharomyces cerevisiae
Autorzy:
Szopa, J.S.
Kowal, K.
Zwoliński, G.
Sikorski, L.
Mosiński, F.
Gańczyk, B.
Powiązania:
https://bibliotekanauki.pl/articles/1402007.pdf
Data publikacji:
1990
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
voltage
fusion
yeast protoplasts
Opis:
The effect of electric force pulses on the survival rate of protoplasts of auxotrophic haploid Saccharomyces cerevisiae yeasts was investigated. Increases of electric force were found to decrease the survival rate of protoplasts which was down to 50-60% at 22.5 kV/cm. 5 kV/cm pulses of electric force increase the frequency of haploid protoplasts fusion by about 50%.
Badano wpływ elektrycznych impulsów napięciowych na protoplasty auksotroficznych drożdży Saccharomyces cerevisiae. Protoplasty drożdży otrzymywano w wyniku trawienia ścian komórkowych wyciągiem enzymatycznym z Helix pomatia. Gęstość zawiesiny protoplastów zastosowanej do badania wpływu elektrycznych impulsów natężenia pola wynosiła 5 x 10⁷/cm³. Protoplasty stabilizowano za pomocą 0,6 M roztworu KCI. Stwierdzono, że ze wzrostem wielkości impulsu elektrycznego maleje liczba zregenerowanych protoplastów osiągając ok. 50% przeżywalności przy wartości 22,5 kV/cm natężenia pola. Wykazano, że impulsy natężenia pola w przedziale 2-7 kV/cm wpływają stymulująco na fuzję protoplastów drożdży Sac. cerevisiae. Optymalne natężenie pola wynoszące 5 kV /cm wywoływało zwiększenie zachodzących fuzji protoplastów o ok. 50%.
Źródło:
Acta Alimentaria Polonica; 1990, 16(40), 1-2; 39-44
0137-1495
Pojawia się w:
Acta Alimentaria Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An optimization model for reactive power control of super high voltage grid systems
Autorzy:
Shaban, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/377699.pdf
Data publikacji:
2012
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
MVAR
super high voltage grid systems
power control
voltage control
reactive power
Opis:
This paper develops an optimization model to control the excessive (MVAR) generation by super high voltage gird systems for maintaining the nodal voltages within the required acceptable margin. The model enhances an approximate solution on the condition of balanced real power. The pseudo-inverse method of optimization is implemented as an optimal optimization is implemented as an optimal means of solving non-square systems of equations based on LaGrange's theory of optimization. It recommends the locations and ratings of the minimum required reactors from the preinstalled ones that to be in service for optimum nodal reactive power and voltage controls.
Źródło:
Poznan University of Technology Academic Journals. Electrical Engineering; 2012, 69; 89-93
1897-0737
Pojawia się w:
Poznan University of Technology Academic Journals. Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Obliczanie asymetrii napięć w sieci niskiego napięcia wprowadzanej przez jednofazową mikrogenerację z wykorzystaniem równań rozpływu mocy
Computing voltage asymmetry making by one phase microgenerator in low voltage network by load flow equations
Autorzy:
Sobierajski, M.
Rojewski, W.
Powiązania:
https://bibliotekanauki.pl/articles/266966.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
mikrogeneracja
asymetria napięć
sieć niskiego napięcia
microgeneration
voltage asymmetry
low voltage network
Opis:
Przyłączanie do sieci niskiego napięcia 1- fazowych mikrogeneratorów powoduje wzrost asymetrii napięcia definiowanej jako stosunek wartości skutecznej składowej symetrycznej przeciwnej napięcia do składowej symetrycznej zgodnej. W pracy przedstawiono model matematyczny pozwalający wyznaczać współczynnik asymetrii napięć w oparciu o analityczne rozwiązanie równań węzłowych rozpływu mocy.
Connection of one phase microgenerator to the low voltage network makes the increase of voltage asymmetry. The voltage asymmetry is defined as the quotient of negative and positive voltage components. The mathematical background of exact calculation of the asymmetry quotient are presented in the paper.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2013, 33; 95-98
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ zjawisk ferrorezonansowych na pracę bezpiecznika przekładnika średniego napięcia
The effect of ferroresonance phenomena on operation of the fuse to medium voltage measuring transformer
Autorzy:
Tłustochowicz, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/267582.pdf
Data publikacji:
2010
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
ferrorezonans
bezpiecznik przekładnika
przekładnik napięciowy
ferroresonance
voltage transformer’s fuse
voltage transformer
Opis:
Bezpieczniki przekładnikowe stanowią zabezpieczenia obwodów uzwojeń pierwotnych przekładników napięciowych od skutków zwarć. W praktyce eksploatacji sieci elektroenergetycznych średnich napięć z przekładnikami obserwowane są przypadki zadziałań bezpieczników przekładnikowych w następstwie zjawisk ferrorezonansowych. Przyczyną zjawisk ferrorezonansowych w przekładniku jest najczęściej nagły wzrost napięcia na jego uzwojeniu pierwotnym, wywołany przez przepięcia łączeniowe lub atmosferyczne. Wobec zmniejszenia się w tych warunkach indukcyjności magnesowania przekładnika może wystąpić sytuacja, w której indukcyjność ta z pojemnością doziemną systemu elektroenergetycznego stworzą obwód rezonansowy. W większości przypadków skutkuje to niekontrolowanym wzrostem prądu w obwodzie pierwotnym przekładnika, czego konsekwencją może być zadziałanie bezpiecznika przekładnika. Wieloletnia eksploatacja przekładników w systemach elektroenergetycznych średnich napięć z izolowanym punktem neutralnym potwierdza przypadki takich zdarzeń.
Measuring transformer fuses are used to the protection of primary winding of voltage measuring transformers against the ef-fects of short-circuits. In practice, under operating conditions of medium voltage networks with voltage measuring transfor-mers, there have been observed some cases of fuse maloperation resulting from the ferroresonance phenomena. The reason of ferroresonance phenomena in voltage measuring transformer is mostly a step-wise change of voltage across its primary winding, due to switching overvoltages or lightning surges. Under these circuimstances, the magnetizing inductance of vol-tage measuring transformer is significantly diminished, so a resonance circuit may be formed with the capacitance of power system versus earth. In most cases it results in an uncontrolled rise of the current in primary winding of voltage measuring transformer and consequently-maloperation of the fuse protection. Long-lasting observations on operation of voltage measur-ing transformers in medium voltage power system with isolated neutral point have confirmed the events of cases being considered in this paper.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2010, 28; 131-134
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power losses and windings temperature of an induction machine under voltage subharmonics
Autorzy:
Gnaciński, Piotr
Pepliński, Marcin
Hallmann, Damian
Powiązania:
https://bibliotekanauki.pl/articles/1819114.pdf
Data publikacji:
2020
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
induction motors
interharmonics
power quality
thermal stresses
voltage fluctuation
voltage waveform distortions
Opis:
This paper deals with the effect of voltage subharmonics on power losses and heating of an induction motor. An increase in power losses in stator and rotor windings and their impact on windings temperature is presented for subharmonics of various frequencies. The results of this study’s investigations are provided for subharmonics occurring as a single power quality disturbance and combined with voltage deviation. The appropriate electromagnetic computations were performed with the finite element method, and thermal ones – with an analytical method.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 63 (135); 51-57
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
International standardization in the design of “Shore To Ship” - power supply systems of ships in port
Autorzy:
Tarnapowicz, D.
German-Galkin, S.
Powiązania:
https://bibliotekanauki.pl/articles/410120.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
Shore to Ship system
High Voltage Shore Connection
Low Voltage Shore Connection
Opis:
The decisive source of air pollution emissions in ports is the berthed ships. This is primarily caused by the work of ship’s autonomous generator sets. One way of reducing the air pollution emissions in ports is the supply of ships from electricity inland system. The main problem connected with the power connection of ships to the inland network is caused by different values of levels and frequencies of voltages in these networks (in various countries) in relation to different values of levels and frequencies of voltages present in the ship’s network. It is also important that the source power can range from a few hundred kW up to several MW. In order to realize a universal „Shore to Ship” system that allows the connection of ships to the electricity inland network, the international standardization is necessary. This article presents the current recommendations, standards and regulations for the design of „Shore to Ship” systems.
Źródło:
Management Systems in Production Engineering; 2018, 1 (26); 9-13
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The study of electronic voltage transducers operation in conditions of dips and interruptions of measured voltage
Autorzy:
Kaczmarek, M.
Szczesny, A.
Nowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/201639.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
voltage transducer
voltage interruptions and dips
power quality
reliability of power supply
Opis:
The aim of the paper is to present a response on dips and on interruptions of the measured voltage by means of electronic voltage transducers and inductive voltage transformers. Results of laboratory studies show high overvoltages generated in both a primary and secondary side of inductive VTs during the above mentioned conditions. Overvoltages in secondary circuits may damage measuring or protection apparatus connected to the secondary side of the VT. Using electronic voltage transducers enables users to avoid these problems.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 3; 645-649
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Praca bezpiecznika przekładnika średniego napięcia w warunkach ferrorezonansu
Operation of fuses to medium voltage measuring transformers under ferroresonance condictions
Autorzy:
Tłustochowicz, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/268080.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
ferrorezonans
bezpiecznik przekładnikowy
przekładnik
przepięcie
ferroresonance
voltage transformer's fuse
voltage transformer
overvoltage
Opis:
Obserwowane są przypadki działania bezpieczników średnich napięć chroniących przekładniki napięciowe od skutków przetęSeń podczas ferrorezonansu napięć. W artykule przed-stawiono wyniki badań symulacyjnych wpływu zjawisk ferrorezonansowych na pracę bezpiecznika SN. Ferrorezonans moSe wystąpić w wyniku nagłej zmiany napicia pracy przekładnika, której przyczynami mogą być przepięcia łączeniowe lub atmosferyczne. Wyniki badań symulacyjnych nie wykluczają moSliwości działania bezpiecznika przekładnika SN w następstwie zjawisk ferrorezonansowych, powodowanych przepięciem. Przypadki takich zdarzeń są rejestrowane w praktyce eksploatacji sieci średnich napięć i potwierdzone badaniami laboratoryjnymi.
There are observed some cases of maloperation of fuses, which are used to the protection of medium voltage measuring transformers against results of overcurrents at voltage ferroresonance. The paper presents results of simulation study of the effect of ferroresonance phenomena upon medium voltage fuse operation. The ferroresonance may occur at a sudden change of measuring transformer operation voltage, which may result, e.g. from switching overvoltages or lightning surges. Simulation study has not excluded maloperation of a fuse to medium voltage measuring transformer resulting from ferroresonance phenomena. Such events have been registered in practice, in operation of medium voltage networks and confirmed by laboratory experiments.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2009, 26; 117-120
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza pracy przekładników napięciowych podczas pomiaru napięć odkształconych
Measurements of non-sinusoidal voltages with a voltage transformer
Autorzy:
Kaczmarek, M.
Nowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/155751.pdf
Data publikacji:
2009
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
przekładnik napięciowy
błąd napięciowy
błąd kątowy
jakość energii
napięcie odkształcone
voltage transformer
voltage error
phase displacement
power quality
non-sinusoidal voltage
Opis:
W ocenie jakości energii elektrycznej ogromne znaczenie mają cechy metrologiczne przekładnika, czyli wartości jego błędów napięciowego i kątowego [1]. W artykule zostały przedstawione zastosowane metody pomiarowe oraz wyniki przeprowadzonych analiz umożliwiające określenie dokładności przekładników napięciowych podczas pomiaru napięć odkształconych. Stwierdzono, że podczas takich pomiarów następuje pogorszenie właściwości metrologicznych przekładników napięciowych, co prowadzi do zmniejszenia ich dokładności przy ocenie jakości energii elektrycznej.
Metrological properties of a measuring transformer such as a voltage error and phase displacement are of significant importance in assessment of electric power quality both in steady and transient state [1]. In the paper the method and results of laboratory investigations of the voltage transformer accuracy during measurements of non-sinusoidal voltages are presented. The laboratory tests based on two medium-voltage transformer models and a voltage transformer of type UDZ 24 produced by ABB company were carried out in the measuring circuit shown in Fig. 1. The measurements were taken in the full range of supply voltages and loads of the secondary winding of the voltage transformers in accordance with the standard for determining the accuracy of the inductive voltage transformers [4]. The voltage error and phase displacement of the voltage transformer determined for measurements of non-sinusoidal voltages, shown in Figs. 2 - 5, were compared with the corresponding errors measured for sinusoidal voltages (presented in Table 1). The influence of the conductive disturbances on the voltage transformer errors was determined as the differences between these values. The results of the laboratory investigations show that the metrological properties of a voltage transformer were worse when it was used for measurements of non-sinusoidal voltages. The increase in errors results in the decrease in the accuracy of the power quality determination. In some cases this worsening of the metrological properties causes the decrease in the voltage transformer accuracy class [4].
Źródło:
Pomiary Automatyka Kontrola; 2009, R. 55, nr 1, 1; 5-7
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling and Performance Evaluation of an Electromagnetic Voltage Regulator via Series Compensation
Autorzy:
Brito, Vinícius Henrique Farias
Oliveira, José Carlos de
Santilio, Fabricio Parra
Powiązania:
https://bibliotekanauki.pl/articles/136200.pdf
Data publikacji:
2020
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
computational modelling
distribution system
electromagnetic voltage regulator
performance evaluation
power quality
voltage regulation
Opis:
Although there currently exists a wide range of voltage regulators that are commercially available, the search for devices with a simpler physical design remains the focus of research studies. Following this line, an electromagnetic voltage regulator (EVR) arrangement has been proposed. The EVR is constituted of an autotransformer that supplies, via discrete taps, a series transformer that injects voltage for regulating the feeder voltage. Even though its operating principle is shown as being similar to that of other devices on the market, the physical arrangement and operating strategy of EVR show novelties which result in properties such as: economic attractiveness, constructive simplicity, and operational reliability. Moreover, when installing voltage regulators, efficacy studies must be carried out to optimize equipment design. In this context, this paper aims at evaluating the factors that influence the effectiveness of the EVR in restoring voltage variations according to the determinations imposed by regulatory agencies. The ultimate goal of this study is to determine the voltage deviation range that the EVR is able to restore. To achieve this goal, a mathematical modeling of the EVR is given and study cases are computationally carried out to investigate its performance when connected to a typical distribution feeder.
Źródło:
Transactions on Environment and Electrical Engineering; 2020, 4, 1; 12-17
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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