Investigating the influence of zero sequence impedance in ship ungrounded electric networks

Prousalidis, J

dc.contributor.author	Prousalidis, J	en
dc.date.accessioned	2014-03-01T02:46:51Z
dc.date.available	2014-03-01T02:46:51Z
dc.date.issued	2010	en
dc.identifier.issn	1476-1548	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/32893
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-78649819030&partnerID=40&md5=2978c31d2e23fb5e9d26e80013cae7f6	en
dc.subject.other	Adverse effect	en
dc.subject.other	Analytical description	en
dc.subject.other	Analytical expressions	en
dc.subject.other	Electric networks	en
dc.subject.other	High impedance	en
dc.subject.other	Low resistance	en
dc.subject.other	Neutral points	en
dc.subject.other	Operating condition	en
dc.subject.other	Power supply	en
dc.subject.other	Representative case	en
dc.subject.other	Single-phase earth fault	en
dc.subject.other	Zero sequence impedance	en
dc.subject.other	Zero sequences	en
dc.subject.other	Capacitance	en
dc.subject.other	Electric lines	en
dc.subject.other	Ships	en
dc.subject.other	Transformer windings	en
dc.subject.other	Electric network analysis	en
dc.title	Investigating the influence of zero sequence impedance in ship ungrounded electric networks	en
heal.type	conferenceItem	en
heal.language	English	en
heal.publicationDate	2010	en
heal.abstract	In shipboard installations ungrounded earthing is selected because it provides continuous power supply, even in the case of single-phase earth faults, which cannot be accomplished by low resistance earthing in the neutral point of wye-connected generator or transformer windings. However the electric network is actually earthed via the high impedance capacitances of all the equipment installed onboard. Therefore, as already discussed in literature, the 'ungrounded' earthing type of shipboard installations has to be treated as 'grounded' via capacitive elements. This paper aims to show, for the first time, an analytical description of statements given in previous publications, ie, that in all analyses performed, it is the entire zero sequence (homopolar) impedance that has to be taken into account. This homopolar impedance includes, among others, leakage capacitances of the entire electrical installation. Therefore, an investigation of the influence of the zero sequence impedance is performed in representative case studies, all referring to unbalanced operating conditions. Within this frame, analytical expressions of voltages and currents with respect to zero sequence impedance are yielded. Moreover, the significant adverse effects of leakage capacitances on the occasion of an actual ship earthing network, are highlighted.	en
heal.publisher	INST MARINE ENGINEERING, SCI & TECHNOL	en
heal.journalName	Proceedings of the Institute of Marine Engineering, Science and Technology Part A: Journal of Marine Engineering and Technology	en
dc.identifier.isi	ISI:000282725600003	en
dc.identifier.issue	18	en
dc.identifier.spage	17	en
dc.identifier.epage	30	en