Lightning trip-out risk evaluation of a 220kV transmission line in Shiyan
The lightning trip-out accidents of Shiyan transmission lines occur frequently. The lightning parameters, lightning faults and geography of 220kV shi-xuan transmission line have been collected. The lightning striking simulation model has been built by using electromagnetic transient calculation software ATP-EMTP and multi-wave impedance model. The lightning withstanding level of tower and the lightning trip-out rate have been calculated. The actual operation of the transmission line has been considered in order to evaluate the risk of lightning trip-out. The results can provide guidance for the lightning protection of transmission linewhich locates in mountains.
Self-starting Kerr-lens mode locking of a Nd:YAG-laser
Abstract The operation of an end-pumped Kerr-lens mode-locked self-starting Nd:YAG laser is reported. Without an intracavity aperture near bandwidth-limited pulses with a pulse length of 6.7 ps were generated. The maximum average output power exceeded 675 mW at a repetition rate of 106 MHz and a pump power of 2 W.
Self-starting mode locking of a cw Nd:YAG laser using cascaded second-order nonlinearities.
The nonlinear mode variations induced by the equivalent third-order susceptibility resulting from cascaded secondorder nonlinearities in an intracavity lithium triborate crystal are exploited for mode locking of a cw Nd:YAG laser. The loss modulations are provided by a slit, as in the Kerr-lens mode-locking scheme. The mode-locking process is self-starting and produces nearly transform-limited pulses of 14-ps duration with 0.5-W average power.