Conference paper
Metal Oxide Surge Arrester (MOSA) have
been used for telecommunication and power lines transient
protection. MOSA has dynamic characteristics that are
significant for overvoltages coordination studies regarding
fast front surges. Several models with acceptable accuracy
have been proposed to study the frequency-dependent
behaviour of MOSA. These models differ in calculation and
adjustment of the model parameters, some models needs
iterative procedure and other models the necessary data are
not reported in the manufacturers’ data sheets. A simplified
model by Pinceti has been used to study protection of
overhead transmission line against direct lightning strike. In
this paper, simulations have been performed using the
Alternative Transients Program version of Electromagnetic
Transient Program (ATP-EMTP) and the results were
compared with the ones of manufacturer’s data sheet and
found to be satisfactory. Pinceti model has a small relative
error of 2.26% for fast transient surge (1/2μs) and of 1.05%
for slow transient lightning surge (8/20μs) respectively when
compared our results with the results from manufacturers’
data sheet. The simulations were performed for a 3kV
TRANQUELL MOSA and its effective protection when
applied to the end of 1km line and lightning strike of
0.11/20μs a typical subsequent return stroke current was
injected at the middle of the line. It has been observed that,
the significant dynamic characteristics of MOSA are that
the peak of the voltage wave occurs before the peak of the
current wave and that the residual voltage across the MOSA
increases as the time to crest of the MOSA discharge current
decreases.
Sida-SAREC