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• Structure characteristics of shipboard DC zonal electric distribution system. • Challenges in protection design about speed, selectivity and reliability. • Breaker coordination addressed from transverse and longitudinal directions. • Protection scheme based on the additional bus inductance. • Effectiveness and applicability in breaker failures and different operation modes. The shipboard DC zonal electric distribution system (DC ZEDS) has seen a recent explosion of interest for its high reliability and strong survivability. With multiple sources and zones, however, the complicated structure brings challenges to its protection design, in which the breaker coordination is one of the key issues. In this regard, this paper proposes a protection scheme based on the additional bus inductance (ABI) for the shipboard DC ZEDS, which meets the requirements on speed, selectivity and reliability in shipboard protection. The breaker configuration is analyzed based on the structure characteristics of DC ZEDS, and the breaker coordination is addressed from transverse and longitudinal directions. The ABI assists shipboard protection in identifying faults in different zones, improving operation speed and lessening fault severity. A reasonable simulation model has been built, in which breaker failures and different operation modes are considered. Simulation results are shown to verify the effectiveness and applicability of the proposed protection scheme. The sizing of the ABI is discussed in the paper to provide theoretical basis for engineering practice. [ABSTRACT FROM AUTHOR]

Orbital-scale East Asian summer monsoon (EASM) variability has been extensively investigated in Pliocene-Quaternary loess and marine sediments. In recent years, middle-late Miocene orbital-scale EASM variability has been depicted in lacustrine deposits from NE Tibetan basins, showing a dominant cyclicity of ∼100 kyr eccentricity. However, EASM variability during the early Miocene time remains poorly understood. Here, we investigate the sedimentary record of the early Miocene Xianshuihe Formation, Lanzhou Basin, in order to further constrain the NE Tibetan hydrological evolution and link it to orbital-scale monsoonal variability. By analyzing the lithology, magnetostratigraphy and cyclostratigraphic records of a 270-m section, we show that Lanzhou lake expansion cycles were consistently dominated by ∼100 kyr eccentricity forcing in early Miocene, except for the ∼20.8-19.8 Ma interval showing dominant obliquity control. These records are in agreement with deep-sea oxygen isotopic records, and are potentially linked to Antarctic ice sheet modulations related the precession amplitude modulation by eccentricity. A weakening of weathering intensity in Lanzhou Basin after 20.8 Ma may be attributed to orogenic barriers for westerly moisture and weakened surface temperature resulted from the rapid uplift of NE Tibet and surrounding mountains in the time interval of late Oligocene-early Miocene. • Eccentricity forcing Lanzhou lake evolution of ∼21.6-20.8 Ma and ∼17.2-19.8 Ma. • Obliquity forcing Lanzhou lake evolution between ∼19.8 and 20.8 Ma. • Weakening of the weathering intensity in Lanzhou Basin after 20.8 Ma. [ABSTRACT FROM AUTHOR]