Showing papers by "Georgia Power published in 1979"
TL;DR: This work presents mathematical models based on fuzzy set theory for physician aided evaluation of a complete representation of information emanating from the initial interview including patient past history, present symptoms, signs observed upon physical examination, and results of clinical and diagnostic tests.
38 citations
01 Apr 1979
TL;DR: In this article, a large-scale laboratory test was carried out to identify soil properties and cable heat flux values leading to moisture migration, and the results showed that accurate soil resistivities can be measured in the field as long as the field dry density and moisture content are carefully reproduced.
Abstract: Accurate measurements of soil thermal properties are essential for proper rating of under- ground power cables. The two most important soil pro- perties affecting cable ampacity are,thermal resistivi- ty and thermal stability. In the cable industry the most frequently used device for measuring the thermal resistivity is the thermal probe. Resistivity measure- ments made with a thermal probe are compared with val- ues using an ASTM guarded hot plate. The comparison of the data is excellent for dry soils and for soils with high moisture contents where moisture migration caused by a temperature gradient is not a problem. The dif- ference in resistivity measurements for soil with low moisture content results from moisture migration and it points out the difficulty of making accurate thermal resistivity measurements when moisture migration is present. Thermal resistivity measurements made in the field are compared with measurements taken on recompacted samples in the laboratory. Results show that accurate soil resistivities can be measured in the laboratory as long as the field dry density and moisture content are carefully reproduced. Ampacity calculations based on moist soil condi- tions can be inadequate if moisture migration in the soil takes place. A large-scale laboratory test pro- gram was carried out to identify soil properties and cable heat flux values leading to moisture migration. Results of the test program help identify drying times for the soil adjacent to the A knowledge of the drying time as a function of heat flux generated within the cable will help the utility en- gineers to identify the potential for a thermal run- away condition. Experimental thermal stability results are compared to a new theoretical study that models the heat and moisture transport process in the soil. surface of the cable.
12 citations
01 Apr 1979
TL;DR: In this article, the authors investigated the impact of lightning on the transmission lines near the substation and for direct lightning strokes to the substations and found that the damage at the Villa Rica Substation would be expected as a result of a direct substation stroke (shielding failure).
Abstract: Substantial lightning damage at Georgia Power Company's Villa Rica 500/230/46 kV substation in May of 1976 prompted a review of the EHV lightning protection. Although this subject has received attention in the past, improved knowledge and techniques will provide increased data for the many stress situations involved. Since twelve substations have either been constructed or are in progress, physical layouts for the "typical" stages of both the transmission and generation plant substation types have been derived. Specific configurations are simulated and subjected to surges initiated by lightning along the transmission lines near the substation and for direct lightning strokes to the substation. The results of this investigation have confirmed that the damage at the Villa Rica Substation would be expected as a result of a direct substation stroke (shielding failure). In addition, the excellent performance experienced with other stations for surges which enter from the lines was predicted. Specific application of arresters during the stages of growth of both the transmission and generating plant substations is presented.
1 citations