PROTECTION DEVICE OF SUBMODULE TO PREVENT DC FAULT AGAINST OVERVOLTAGE ON CAPACITOR

摘要

Disclosed is a protection device of a submodule (SM) against overvoltage on a capacitor to decrease a DC fault current, which is provided inside an arm of a modular multi-level converter and bypass a fault current when a DC fault of the modular multi-level converter occurs. The protection device comprises: a bypass circuit protecting an converter arm wherein submodules provided in a modular multi-level converter are connected in series by making a fault current of the converter arm bypass, and connected in series to the converter arm; a diode installed in the bypass circuit to make the fault current bypass; capacitors installed in the bypass circuit, protecting the submodules from damage caused by the fault current by storing/absorbing the fault current, and connected in series to the diode; and a resistance installed in the bypass circuit, suppressing overvoltage and voltage imbalance occurring in each phase of the capacitors of the submodules and in each arm, and connected in series to the capacitors.;COPYRIGHT KIPO 2016