Low Inductance Fuses for Protection and Disconnection in DC Networks

Development of renewable energies will be possible because of progress in electrical power converters. But, even if reliability of converters is highly secured, some mis-operations or failures may occur. Generally, these mis-operations and failures lead to a high current short circuit and then, electrical fuses are able to bring an efficient solution to protect equipment and persons. Unfortunately, fast-acting fuses are components which size depends on rated current (cross section) and voltage (length) they have to cut: higher is the voltage, longer is the fuse. And a longer fuse will increase the inductance of the circuit, and then increases the commutation-time of electronic switches. Engineers are facing the problem of choosing between: (a) Accept to not protect the equipment. (b) Protect the equipment but reduce its performances. (c) Not develop any converter. Mersen is studying fuses, specifically designed for this kind of converters, both guarantying safety of equipment and keeping the inductance at low values. Of course, these fuses will not reduce energy consumption by themselves, but they are crucial components for equipment that will reduce energy consumption.” The paper will present the different kinds of faults depending on the source, i.e., internal fault, external fault and up-stream fed fault. It will also describe what will be the specificities needed for a protection device, i.e., fuse. And what is the investigation-plan carried out by Mersen for proposing the right fuse.