Shipboard Medium-Voltage DC Integrated Power System Ⅱ: Protection and Fault Management Technology

The shipboard medium-voltage DC (MVDC) integrated power system (IPS) is the technological development direction of the shipboard IPS. As the second part, this paper focuses on the protection and fault management technology of the shipboard MVDC IPS, which includes four parts: fault characteristics analysis, protection principle, fault isolation scheme and reconfiguration method. First of all, the special technical requirements for the protection and fault management technology are analyzed. The shipboard MVDC IPS has high requirements for selectivity and speed. The protection and fault management scheme needs to fully consider the shipboard multiple operating modes and the transient response of multi-type power electronic converters. Then, the fault characteristics analysis method and the protection principle are summarized, and the limitations are outlined. Subsequently, the fault isolation scheme and reconfiguration method are comprehensive reviewed, and the detailed comparisons are made respectively. Finally, the future research trends of the protection and fault management technology of the shipboard MVDC IPS are pointed out. 1) Fault characteristics analysis. The fault transient characteristics analysis methods based on time-frequency domain transformation, nodal impedance matrix analysis, topology simplification, and pole-mode transformation analysis in multi-terminal DC (MTDC) transmission and distribution system provide important references for the shipboard MVDC IPS. However, the fault characteristic analysis model of the complex topology shipboard MVDC IPS containing multi-type power electronic converters, multiple system nodes and multiple operating modes still needs to be studied. 2) Protection principle. Intelligent protection methods require a large amount of training data, which limits the engineering applications. The shipboard MVDC IPS protection can draw on the existing MTDC transmission and distribution system protection method to a certain extent. However, due to the short ship cables, inconsistent DC line boundaries, multiple system nodes, and complex topology, more detailed and in-depth research is still needed. 3) Fault isolation scheme. The hybrid DC circuit breaker (DCCB) has the advantages of low on-state loss of mechanical DC circuit breaker (MCB) and fast breaking speed of solid-state DCCB, which is one of the main technological development directions of DCCB. Currently, the fault isolation scheme based on inductive DC fault current limiter (DCFCL) and DCCB is more suitable for the shipboard MVDC IPS. The simple topology and low cost-based current-limiting DCCB and the high reliability multi-port DCCB are the future research directions. 4) Reconfiguration method. Combining the advantages of centralized manner-based reconfiguration methods and distributed reconfiguration methods, the muti-level distributed reconfiguration method is a meaningful research direction. What is more, the objective function and constraints of the shipboard MVDC IPS reconfiguration method require further study. © 2024 China Machine Press. All rights reserved.