Distributed detection of leakage current and fault current, and detection of string faults

US9594126B2 · kind B2 · utility

Assignee

• SMA Solar Technology AG · DE

Inventors

• Andreas Falk · Kassel, DE
• Mario Willenberg · Paderborn, DE

Key dates

• Filing date: Jan 28, 2015
• Grant date: Mar 14, 2017
• Expiry date: May 16, 2035

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/50
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

For monitoring an inverter that includes separate input-side connectors for multiple direct-current generators with regard to the occurrence of a critical fault current, differential currents in at last two pairs of input lines are measured separately in the inverter. The at last two pairs of input lines conduct the currents that are fed in at different input-side connectors, and all pairs of input lines in their entirety transmit all currents that are fed in at the connectors. The differential currents are compared with a limit value separately for each pair of input lines. A case of the limit value being exceeded is recognized as a fault. In addition, a sum of simultaneously occurring differential currents in all pairs of input lines is determined and the sum is compared with a further limit value, wherein a case of the further limit value being exceeded is also recognized as a fault.