It is of great practical significance to study and protect the East Asian Maritime Cultural Routes Heritage. This is conducive to a profound understanding of the spirit of the East Asian region, especially traditional...It is of great practical significance to study and protect the East Asian Maritime Cultural Routes Heritage. This is conducive to a profound understanding of the spirit of the East Asian region, especially traditional Chinese marine culture, and the maintenance of peace and order in East Asia and the world as a whole. But at present, some problems increase the difficulty for the protection of East Asian Maritime Cultural Routes Heritage, for example, improper development and utilization in the process of urbanization, imperfection of the management mechanism, multiplicity of the ownership of the estate. Propose to carry out a survey of the East Asian Maritime Cultural Routes Heritage as soon as possible, build regional integration cooperation mechanism, improve the marine cultural heritage protection technology, perfect the relevant laws and regulations.展开更多
Electric power systems usually cover large geographical areas and transmission facilities are continuously increasing. These power systems are exposed to different environmental conditions which may cause faults to oc...Electric power systems usually cover large geographical areas and transmission facilities are continuously increasing. These power systems are exposed to different environmental conditions which may cause faults to occur on the system. Different types of studies are usually done on electric power systems to determine how the system behaves before, during and after a fault condition. The behaviour of variables of interest such as currents, voltage, rotor angle and active and reactive power under fault conditions are studied and observed to help determine possible causes of faults in a power system. The objective of this paper is to investigate a fault that occurred on the 330 kV transmission line between Ruacana power station and Omburu sub-station, the fault caused all the generators at Ruacana power station to trip and consequently caused a blackout at the power station that lasted for 6 h. Preliminary findings showed that the observed fault was an earth fault but the exact type of earth fault was however not known at the time. This research investigation sets out to determine the exact fault that occurred; the most probable cause of the fault, and propose possible solutions to prevent reoccurrence of such a fault. The section of the power network in which the fault occurred was modelled using DigSilent Power Factory software tool, and transient fault analysis was carried out on the model for different fault conditions. Results obtained were then compared with data obtained from NamPower records to ascertain the type of fault.展开更多
文摘It is of great practical significance to study and protect the East Asian Maritime Cultural Routes Heritage. This is conducive to a profound understanding of the spirit of the East Asian region, especially traditional Chinese marine culture, and the maintenance of peace and order in East Asia and the world as a whole. But at present, some problems increase the difficulty for the protection of East Asian Maritime Cultural Routes Heritage, for example, improper development and utilization in the process of urbanization, imperfection of the management mechanism, multiplicity of the ownership of the estate. Propose to carry out a survey of the East Asian Maritime Cultural Routes Heritage as soon as possible, build regional integration cooperation mechanism, improve the marine cultural heritage protection technology, perfect the relevant laws and regulations.
文摘Electric power systems usually cover large geographical areas and transmission facilities are continuously increasing. These power systems are exposed to different environmental conditions which may cause faults to occur on the system. Different types of studies are usually done on electric power systems to determine how the system behaves before, during and after a fault condition. The behaviour of variables of interest such as currents, voltage, rotor angle and active and reactive power under fault conditions are studied and observed to help determine possible causes of faults in a power system. The objective of this paper is to investigate a fault that occurred on the 330 kV transmission line between Ruacana power station and Omburu sub-station, the fault caused all the generators at Ruacana power station to trip and consequently caused a blackout at the power station that lasted for 6 h. Preliminary findings showed that the observed fault was an earth fault but the exact type of earth fault was however not known at the time. This research investigation sets out to determine the exact fault that occurred; the most probable cause of the fault, and propose possible solutions to prevent reoccurrence of such a fault. The section of the power network in which the fault occurred was modelled using DigSilent Power Factory software tool, and transient fault analysis was carried out on the model for different fault conditions. Results obtained were then compared with data obtained from NamPower records to ascertain the type of fault.
