This paper adopts a new type of power electronics - soft normally open point (SNOP) to solve the bottleneck problem of bus/branch in distribution network, and improve the DG penetration capacity in ...flexible distribution network (FDN). Firstly this paper establishes the optimization model of the allowable capacity of DG in the FDN. A multi-population genetic algorithm (MPGA) is used to get the global optimal solution, in both traditional distribution network and FDN. Then this paper builds the system model of IEEE 33-bus distribution network to verify the conclusion, which finally proves that the application of SNOP in FDN will allow more DG accessing to the network. What is more, this method has certain reference value to determine the optimal capacity and access location of DG in the future FDN.
Soft normally open point (SNOP) is a power electronic device installed at normally open point (NOP) in a distribution network which can greatly promote the flexibility and controllability of ...distribution network. This paper firstly introduces the typical installation of SNOP, and takes the back to back MMC SNOP system as the studied case. Then the PQ-VdcQ strategy is described as steady-state control strategy of SNOP system, and the control principle of power flow on feeder is briefly illustrated. Lastly, the strategies of unbalanced current compensation and active power oscillating suppression are described for fault ride-through strategy. To avoid overcurrent, the unbalanced current compensation strategy is adopted. Simulation results verify the accuracy and effectiveness of the strategies adopted.
The use of soft normally open point (SNOP) instead of the traditional tie switch can realize the closed-loop operation of the urban distribution network and realize the controllability of the ...transmission power of the feeder. In this paper, for the 10kV AC feeders of the urban distribution network, the SNOP composed of the back to back voltage source converter (B2B-VSC) is used to flexibly interconnect the two feeders, then, based on the droop control, an active power real-time modulation strategy based on power equalization technology is designed. The active power distribution coefficient is used to realize the active power deviation control of the feeders, and the load balance between the feeders is realized. The PSCAD/EMTDC simulation software was used to build a two-feeder distribution system using SNOP flexible interconnection, and the original dual-loop control strategy was improved by using power balance technology. The simulation results show that the active power real-time modulation strategy based on power equalization technology can balance the load between feeders in real-time under the condition of local control, and improve the utilization and operational reliability of feeder equipment.
Soft Normally Open Point (SNOP) can flexibly interconnect multiple 10kV feeders through DC-Link, thus realizing closed-loop operation between different feeders. If SNOP is equipped with energy ...storage device, it can not only reduce the maximum power of feeder by power support between feeders, but also optimize the peak load shifting of multi-feed lines by energy storage device, which can further improve the utilization efficiency of 10kV equipment, and improve the operation of power distribution network. In this paper, a new peak-cutting and valley-filling technology is proposed for SNOP connected to multiple 10kV feeders. Firstly, an optimization model of peak-shaving and valley-filling based on minimum variance of daily load is established. Secondly, an improved particle swarm optimization (PSO) algorithm is used to solve the peak-shaving and valley-filling optimization model of flexible interconnected distribution network, and the flow chart of the algorithm is given. Finally, taking the DC distribution center with three feedbacks in Guizhou power grid as an example, the optimization technology of peak-shaving and valley-filling proposed in this paper is simulated, and the rationality and effectiveness of the optimization strategy are verified.
Provider: - Institution: - Data provided by Europeana Collections- Superinsulating state was experimentally observed for the first time only a
couple of years ago. The most important property of ...superinsulators, for
their use in electrical engineering, is the infinite electrical resistance.
The superinsulating state can be viewed as being dual to the superconducting
one, with both states subsisting only below certain critical values of the
same three parameters: temperature, applied voltage, and magnetic field
strength. Possible applications of superinsulators are for cable insulation
(especially of superconducting cables that have to be cooled to low
temperatures, at which both the superconducting and the superinsulating state
can exist), insulation of galvanic elements (for reducing leakage current
losses to a negligible level), and insulation of components in integrated
circuit technology (which could make dielectric layers even thinner). After
surveying general characteristics of insulating materials and the properties
of the superconducting state, the dissertation provides a description of
microscopic and macroscopic characteristics of the superinsulating phase. A
detailed review of radiation effects in materials is included, depending on
the type of radiation and the properties of the medium it traverses. Special
attention is given to the interaction of radiation with insulating materials,
emphasizing radiation damage in solid state insulators. The principles of
using Monte Carlo methods for simulating the passage of radiation through
matter are represented. Results of numerical simulations of radiation effects
in the analyzed superinsulating films are presented. Simulated radiation
transport included incident radiation energy losses through ionization,
phonon excitation, and atom displacement. The conducted numerical simulation
was linked to the theoretical model of the superinsulating phase, taking
account of all the specific traits of this state. It was noted that all three
modes of radiation energy deposition in superinsulators bring about either
transient or permanent changes of their properties. Radiation effects were
considered with respect to structural changes within the investigated films,
as well as the changes of electrical properties, such as the specific
electrical resistance and the current-voltage characteristic.
Radiation-induced changes were compared for various types of radiation and
different superinsulating film thicknesses. Investigation and analysis
conducted in the dissertation suggest that for certain energy ranges, fluence
levels and types of radiation considerable effects in superinsulators are to
be expected, even at nanometer thickness. Based on the conclusions about
radiation effects in superinsulating films, methods for radiation hardening
of complex structures comprising these films are proposed in the
dissertation.- Superprizolatorsko stanje je po prvi put eksperimentalno uočeno pre svega
nekoliko godina. Za elektrotehničke primene, najznačajnija osobina
superizolatora je beskonačna električna otpornost. Superizolatorsko stanje
moguće je shvatiti kao dualno superprovodnom, pri čemu oba opstaju samo do
određenih kritičnih vrednosti ista tri parametra: temperature, primenjenog
napona i jačine magnetnog polja. Moguće primene superizolatora su za
izolaciju kablova (pogotovo superprovodnih kablova, čija konstrukcija
podrazumeva hlađenje do niskih temperatura na kojima se održavaju i
superprovodno i superizolatorsko stanje), galvanskih elemenata (čime bi
gubici usled struja curenja mogli da se svedu na zanemarljiv nivo) i
komponenti u tehnologiji integrisanih kola (što bi omogućilo izradu znatno
tanjih dielektričnih slojeva). Nakon razmatranja opštih karakteristika
izolatorskih materijala i osobina superprovodnog stanja, u radu je dat opis
mikroskopskih i makroskopskih karakteristika superizolatorske faze. Detaljno
su razmotreni efekti zračenja na materijale, u zavisnosti od vrste zračenja i
osobina materijalne sredine kroz koju ono prolazi. Posebna pažnja posvećena
je interakciji zračenja sa izolatorskim materijalima, sa naglaskom na
radijaciona oštećenja u čvrstim izolatorima. Izloženi su principi Monte Carlo
metoda simulacije prolaska zračenja kroz materijal, koje se zasnivaju na
numeričkoj simulaciji slučajnih veličina na osnovu poznatih raspodela.
Prikazani su rezultati numeričkih simulacija dejstva zračenja na analizirane
superizolatorske filmove, kojim su obuhvaćeni gubici energije upadnog
zračenja putem jonizacije, fononskog pobuđivanja rešetke i izmeštanja atoma
materijala. Numerička simulacija sprovedena u radu dovedena je u vezu sa
teorijskim modelom superizolatorske faze, uzimajući u obzir sve specifičnosti
ovog stanja. Uočeno je da svaki od tri vida deponovanja energije zračenja u
superizolatorima dovodi do specifičnih promena njegovih fizičkih osobina,
koje mogu da budu prolazne ili trajne. Efekti zračenja razmatrani su sa
stanovišta strukturnih promena unutar ispitivanih filmova, kao i promena
električnih osobina, kao što su specifična električna otpornost i
strujno-naponska karakteristika. Radijacione promene su upoređene za razne
tipove zračenja i debljine filmova superizolatorskih materijala. Ispitivanja
i analiza sprovedeni u disertaciji ukazuju da se za određene energetske
opsege, flunse i vrste zračenja mogu očekivati znatni efekti u
superizolatorima, cak i pri nanometarskim debljinama ovih materijala.
Zaključci o dejstvu zračenja na filmove u superizolatorskom stanju omogućili
su da u disertaciji budu predložene metode radijacionog očvršćavanja
složenijih struktura u kojima bi se našli filmovi superizolatora.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Relacja mówiona zarejestrowana w ramach Programu Historia Mówiona realizowanego w Ośrodku "Brama Grodzka - Teatr NN" ...(www.historiamowiona.teatrnn.pl)- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: Grodzka Gate – NN Theatre - Data provided by Europeana Collections- Relacja mówiona zarejestrowana w ramach Programu Historia Mówiona realizowanego w Ośrodku "Brama Grodzka - ...Teatr NN" (www.historiamowiona.teatrnn.pl). Wyraża ona wyłącznie subiektywne wspomnienia i poglądy świadka historii, które nie mogą być utożsamiane z oficjalnym stanowiskiem Ośrodka.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Relacja mówiona zarejestrowana w ramach Programu Historia Mówiona realizowanego w Ośrodku "Brama Grodzka - Teatr NN" ...(www.historiamowiona.teatrnn.pl)- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Mikronukleus-test pokazao se osjetljivim pokazateljem oštećenja u limfocitima periferne ljudske krvi te se primjenjuje kao biološki dozimetar posumnja li se na prekomjerno izlaganje ionizirajućem ...zračenju. Mikronukleusi kao mjera oštećenja kromosoma često se rabe za procjenu učinaka zračenja u biološkim sustavima. Ovdje je istraženo djelovanje pulsnoga elektronskoga snopa od 8 MeV, dobivenog s pomoću elektronskoga akceleratora marke Microtron, na nastanak mikronukleusa u rasponu brzina doza od 35 Gy min-1 do 352.5 Gy min-1. Brzine doza mijenjale su se mijenjajući brzinu ponavljanja pulsa (tzv. pulse repetition rate, krat. PRR). Za mjerenje apsorbirane doze pri različitim PRR-ovima rabio se Frickeov
dozimetar. Dozimetrijska su mjerenja također poslužila za ujednačavanje doze elektronskoga snopa. Za istraživanje utjecaja brzine doze, uzorci krvi ozračeni tako da apsorbiraju dozu od (4.7±0.2) Gy pri različitim brzinama doze, a zatim se s pomoću mikronukleus-testa utvrdilo citogenetsko oštećenje. Pokus s pulsnim snopovima energije 8 MeV upućuje na neovisnost broja mikronukleusa o brzinama doze u rasponu ispitanome u ovom istraživanju. Naše ranije istraživanje utjecaja doze pulsnoga elektronskoga zračenja energije 8 MeV upozorilo je na linearni do kvadratni odgovor izmjerenih parametara. Stoga se akcidentalna doza može procijeniti s pomoću linearnih do kvadratnih parametara odgovora na dozu, bez potrebe za korekcijom s pomoću brzine doze.
Provider: - Institution: Grodzka Gate – NN Theatre - Data provided by Europeana Collections- Relacja mówiona zarejestrowana w ramach Programu Historia Mówiona realizowanego w Ośrodku "Brama Grodzka - ...Teatr NN" (www.historiamowiona.teatrnn.pl). Wyraża ona wyłącznie subiektywne wspomnienia i poglądy świadka historii, które nie mogą być utożsamiane z oficjalnym stanowiskiem Ośrodka.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
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