The medium voltage direct current (MVDC) electric networks are emerging in power distribution and collection. The MVDC is an attractive solution in the applications involving DC loads or sources where high energy efficiency and high power flow controllability are required. The emergence of MVDC networks strongly relies on the availability of the appropriate protection strategies and equipment. This article proposes a protection strategy for a multi-terminal radial MVDC network based on the principle commonly used in the existing AC distribution networks. The protection strategy involves a single DC circuit breaker (DCCB) and multiple DC fuses. The proposed strategy limits the quantity of sophisticated and costly DCCB used. The cost-effective DC fuses are proposed to protect the parts of the network where the expected short-circuit occurrence is limited and where the automatic reclosing is not mandatory. The article concludes that low grounding resistance is beneficial allowing to easily isolate the faulty circuit. The simulation models are developed allowing to confirm the theoretical analysis.
Piotr Dworakowski, Juan D. Páez, Wolfgang Grieshaber, Alberto Bertinato, Eric Lamard
Published in Elsevier International Journal of Electrical Power & Energy Systems (available here)