Coordination protection for DC distribution network in DC zonal shipboard power system

In the DC zonal shipboard power system (DC-ZSPS), DC/DC power conversion module (DD-PCM) which is composed of ship service conversion module (SSCM) powers DC loads. This paper presents solutions to the coordination problems caused by the mismatch between the self-protection of DD-PCM and the time-overcurrent protection of the distribution network. The structure design of SSCM aims for the backup protection and the isolation of SSCMs one another. A current limiting control strategy of SSCM is presented to coordinate the time-overcurrent protection principle for the distribution network. A high fidelity DC-ZSPS model is established in PSCAD/EMTDC. Then, the faults in the SSCM and the distribution network are simulated. The results show that the method achieves rational coordination between the protection of DD-PCM and the downstream over-current protection and meets the requirements of selectivity and reliability.