On-line fault diagnostic for AC zonal marine distribution systems

This paper presents a new protection scheme for AC zonal distribution system proposed for future marine power systems based on active impedance estimation. This technique actively imposes small transient disturbances onto the system at a point of measurement to excite the system in real time and estimate the system impedance over a broad frequency range at that point. The identified impedance can be used for fault discrimination. The performance of this proposed technique is investigated by experiment. The scheme exploits the increased use of power electronic devices to provide a useful complement to traditional protection strategies and can also provide the necessary back up protection during extreme protection failure, without the need for communication channels.