Calculation of Ninimum Safety Distances for Live-Line Mintenance - A Statistical Mehod Applied to 765 kV AC Itaipu Lines
This paper presents a statistical method to calculate the miniumm safety distance for live-line maintenance. The method takes into account the complexity of the tower gap configuration and the presence of the lineman working at the line potential. It includes the inherent dispersion of the dieletric characteristics of the air gaps such as the probability of flashover and the tirnes-to-flashover. Laboratory tests were also performed to corroborate the results of the study, checking not only the performance of the various live-line tools but also the effectiveness of the by-passing insulators protective device and the occurrence of broken insulators in the string.
Switching and Lightning Impulse Discharge Characteristics of Large Air Gaps and Long Insulator Strings
Analysis of the influence of electrode shapes on the behavior of air gaps, both with and without insulator strings between the electrodes, is completed through the use of switching impulse tests. Results of a similar analysis for lightning impulse tests are also described. An attempt is made to correlate the behavior of air gaps in switching and lightning impulse tests to a factor k which characterizes the shape of the electrodes. Diagrams are given that express discharge voltages for switching and lightning impulse tests as a function of k.
Magnetic plasma confinement for laser ion source.
A laser ion source (LIS) can easily provide a high current beam. However, it has been difficult to obtain a longer beam pulse while keeping a high current. On occasion, longer beam pulses are required by certain applications. For example, more than 10 micros of beam pulse is required for injecting highly charged beams to a large sized synchrotron. To extend beam pulse width, a solenoid field was applied at the drift space of the LIS at Brookhaven National Laboratory. The solenoid field suppressed the diverging angle of the expanding plasma and the beam pulse was widened. Also, it was observed that the plasma state was conserved after passing through a few hundred gauss of the 480 mm length solenoid field.