AC and/or DC substantial power upgrading of existing OHTL corridors
The ever increasing difficulty to find new right of ways (ROW) for the construction of overhead transmission lines (OHTL) is forcing the study of possible alternatives for substantial power upgrading of existing AC line corridors. One possible solution is to modify existing OHTLs without major new construction. The authors discuss the two main methods of modification. Conversion of both double circuit and single circuit HVAC lines to bipolar and monopolar lines respectively; and substitution of both double circuit and single circuit old HVAC lines with new compact EHV lines having horizontal V assemblies and with the possible reutilization of existing tower location. The upgrading possibility offered by the above methods is analyzed with due considerations to the various design criteria relevant to conductors, structural/insulation/losses/environmental effects.
Aimed at the shortage of nearer covering distance,lower rate,lacking line-testing instrument in ADSL,an improved model about accessing network of ADSL2+ based on ATM core is brought forth in the paper.The principle and rationality of the model are analyzed,and the character is also discussed.At last,the application foreground of the technology is prospected.