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Substation Automation Systems (SASs) are widely used for the purpose of control, protection, monitoring, communication etc. in substations to improve the reliability of the power system. SASs adopting IT based solutions such as Ethernet LAN have recently become more common, although hardwired control has been used in the past in earlier versions of SAS utilizing simple communication methods. Moreover, the IEC61850 standard has been issued as the new global communication standard for substations. The standard consists of ten parts, the final part being issued in 2005. Subsequently IEC61850 has been applied widely in SASs around the world.In this paper, we describe our experience of an IEC61850 based SAS, including system design and build methods. In addition, we also cover concepts for system build and detailed system configuration, the benefits of IEC61850, points to be considered for implementation of IEC61850 and issues that we have experienced in our practical application of the standard together with the measures that we have developed to overcome these issues.

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ABSTRACT. Movement of pack ice in Smith Sound in northern Bamn Bay was observed for April 1975 using the satellite imagery obtained by Landsat. Mean velocity was found to be directed to the south with a magnitude of 4 km d -1. The influence of the wind is discussed and the amount of ice transported from Smith Sound ev aluated. The findings show that on a daily average 600 km 2 of pack ice was carried out of the area.