With growing diffusion of DC microgrids, ground faults in the DC section of networks will become more and more likely. This is mainly due to the expected increase in size of such networks. Ground faults may involve significantly high currents, which may not be limited by front-end converters (FECs). The work presented in this paper is focused on the analysis of normal and faulty operation of a DC microgrid interfaced to a low voltage (LV) AC network by means of an IGBT FEC. Two different configurations of the LV star point of the transformer have been considered: connected to and isolated from the midpoint of the DC bus. Normal operation has been analyzed and the presence of high frequency homopolar currents has been detected in the first configuration. Ground faults of the positive pole have also been analyzed with decreasing values of fault resistance. DC values of the fault current and of the DC bus voltage have been analyzed. Moreover, the effect of the presence of a storage device has been investigated.

Currents, potentials towards ground and fault protection in DC microgrids

CARMINATI, MARCO MARIA;GRILLO, SAMUELE;RAGAINI, ENRICO;TIRONI, ENRICO
2014-01-01

Abstract

With growing diffusion of DC microgrids, ground faults in the DC section of networks will become more and more likely. This is mainly due to the expected increase in size of such networks. Ground faults may involve significantly high currents, which may not be limited by front-end converters (FECs). The work presented in this paper is focused on the analysis of normal and faulty operation of a DC microgrid interfaced to a low voltage (LV) AC network by means of an IGBT FEC. Two different configurations of the LV star point of the transformer have been considered: connected to and isolated from the midpoint of the DC bus. Normal operation has been analyzed and the presence of high frequency homopolar currents has been detected in the first configuration. Ground faults of the positive pole have also been analyzed with decreasing values of fault resistance. DC values of the fault current and of the DC bus voltage have been analyzed. Moreover, the effect of the presence of a storage device has been investigated.
Convegno Annuale AEIT
9788887237238
9788887237252
DC ground fault analysis, fault protection, microgrid, elettrici
File in questo prodotto:
File Dimensione Formato  
D1_02.pdf

Accesso riservato

: Post-Print (DRAFT o Author’s Accepted Manuscript-AAM)
Dimensione 333.57 kB
Formato Adobe PDF
333.57 kB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/877562
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 6
  • ???jsp.display-item.citation.isi??? 1
social impact