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Statements

Subject Item
n2:RIV%2F00177016%3A_____%2F12%3A%230000718%21RIV13-MSM-00177016
rdf:type
n3:Vysledek skos:Concept
dcterms:description
DC currents in power grids are mainly caused by geomagnetic activity especially during magnetic storms. It is desirable to monitor these currents to prevent saturation of transformers, which may cause blackout. However, adding DC current sensors to existing installations would be very costly. We suggest to convert some of the existing current transformers to fluxgate DC current sensors by injecting AC excitation current into their secondary winding. We successfully tested this concept on 500 A current transformer. The achievable accuracy is 10% for DC currents and 1.5% for AC currents, which is sufficient for protection and monitoring purposes. We analyze the DC current sensitivity dependence on the (changing) grid impedance, and we show that the sensitivity can be stabilized by controlling the secondary voltage component at the excitation frequency. Excitation current injected into the grid also depends on the grid impedance, but for realistic conditions it is below 2 A. DC currents in power grids are mainly caused by geomagnetic activity especially during magnetic storms. It is desirable to monitor these currents to prevent saturation of transformers, which may cause blackout. However, adding DC current sensors to existing installations would be very costly. We suggest to convert some of the existing current transformers to fluxgate DC current sensors by injecting AC excitation current into their secondary winding. We successfully tested this concept on 500 A current transformer. The achievable accuracy is 10% for DC currents and 1.5% for AC currents, which is sufficient for protection and monitoring purposes. We analyze the DC current sensitivity dependence on the (changing) grid impedance, and we show that the sensitivity can be stabilized by controlling the secondary voltage component at the excitation frequency. Excitation current injected into the grid also depends on the grid impedance, but for realistic conditions it is below 2 A.
dcterms:title
Measurement of DC Currents in the Power Grid by Current Transformer Measurement of DC Currents in the Power Grid by Current Transformer
skos:prefLabel
Measurement of DC Currents in the Power Grid by Current Transformer Measurement of DC Currents in the Power Grid by Current Transformer
skos:notation
RIV/00177016:_____/12:#0000718!RIV13-MSM-00177016
n3:predkladatel
n19:ico%3A00177016
n4:aktivita
n20:I
n4:aktivity
I
n4:dodaniDat
n14:2013
n4:domaciTvurceVysledku
n15:1305565 n15:5916925
n4:druhVysledku
n7:D
n4:duvernostUdaju
n12:S
n4:entitaPredkladatele
n10:predkladatel
n4:idSjednocenehoVysledku
148868
n4:idVysledku
RIV/00177016:_____/12:#0000718
n4:jazykVysledku
n6:eng
n4:klicovaSlova
power grid; DC current; current measurement; instrument transformer
n4:klicoveSlovo
n5:instrument%20transformer n5:current%20measurement n5:DC%20current n5:power%20grid
n4:kontrolniKodProRIV
[BC4D0525CD3C]
n4:mistoKonaniAkce
Praha
n4:mistoVydani
Praha
n4:nazevZdroje
EMSA 2012 - 9th European Magnetic Sensors & Actuators Conference
n4:obor
n9:JB
n4:pocetDomacichTvurcuVysledku
2
n4:pocetTvurcuVysledku
3
n4:rokUplatneniVysledku
n14:2012
n4:tvurceVysledku
Draxler, Karel Styblíková, Renata
n4:typAkce
n17:WRD
n4:zahajeniAkce
2012-01-01+01:00
s:numberOfPages
1
n18:hasPublisher
Česká technika - nakladatelství ČVUT
n8:isbn
978-80-01-05078-1