The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 2026
Filed:
Sep. 13, 2024
Hitachi Energy Ltd, Zürich, CH;
Sasitharan Subramanian, Ludvika, SE;
HITACHI ENERGY LTD, Zürich, CH;
Abstract
Embodiments herein provide a protection method of protecting a Modular Multilevel Converter (MMC) for Direct Current (DC) fault protection in a symmetrical monopole configuration. The MMC for each of at least one phase comprises a leg, which comprises a first branch and a second branch comprising director valves connected in series. Further, legs of the MMC are connected in series between DC poles. The method comprises measuring DC pole voltages relative a common ground and accordingly determining a DC fault identifying a DC pole to ground fault of one of the DC poles. Upon determining the DC fault, the method comprises controlling the director valves of the second branch for each leg to bypass the DC poles through the second branch for protecting a DC pole other than the DC pole identified with the DC fault.