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Abstract. An adaptive protection scheme using digital relays is proposed for the protection of the distributed systems. Firstly, the impact of distributed generators on protection coordination is discussed. Then, an adaptive protection scheme is proposed for distributed systems with distributed generation (DG). Simulated results on an actual distribution system show that the proposed approach can perform adaptive primary and backup protection functions under both balanced and unbalanced fault conditions. Also, the proposed approach is adaptive to the fault types as well as capacities of DG. Compared with the traditional current protection scheme, the primary and backup protection regions have been extended considerably.

Abstract-This paper analyzes the current situation of shipwreck in the world today according to the data network of the world maritime shipwreck data, as well as the maritime report of International Maritime Organization, combined with a distinctive feature of the shipwreck which occurred in recent years, brings forward some precaution measures and finds out the root cause of maritime accidents. This paper points out that the root causes of sea accidents is ship management. Various factors, especially the major effect of the artificial factors are concluded through analysis of specific maritime cases. Sea accidents can be reduced by inspection and control of the ship, ship operating management and navigation, and improve the quality of personnel. This paper also puts forward rational proposals to prevent sea pollution, ensure safety of life at sea and enhance the overall safety of the shipping.