Fault Clearing Overvoltages on Long Transformer Terminated Lines
The results of Transient Network Analyzer (TNA) studies evaluating the feasibility of low-side switching long transformer terminated lines is reported. It is shown that overvoltages following line dropping and fault clearing can severely stress surge arresters and circuit brtakers exceeding capabilities specified in ANSI standards. These overvoltages are often not carefully considered in design studies, since the available literature on low-side switching of EHV transmission lines primarily deals with energizing the line and transformer.1,2,3,4
Field Tests of Low-Side Switching of EHV Transmission Line
Over 400 low-side switching operations energizing EHV transmission lines were carried out by the Department of Water and Power, City of Los Angeles. These extensive field tests included measurement of the magnitude and range of overvoltages produced under various system conditions and with different values of preinsertion resistors. The purpose of the investigation was to gain first-hand field experience with low-side switching operation and to confirm the validity of Transient Network Analyzer (TNA) studies conducted with similar circuit parameters.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.