Abstract: This study describes analysis of tower grounding
resistance effected the back flashover voltage across insulator string
in a transmission system. This paper studies the 500 kV transmission
lines from Mae Moh, Lampang to Nong Chok, Bangkok, Thailand,
which is double circuit in the same steel tower with two overhead
ground wires. The factor of this study includes magnitude of
lightning stroke, and front time of lightning stroke. Steel tower uses
multistory tower model. The assumption of studies based on the
return stroke current ranged 1-200 kA, front time of lightning stroke
between 1 μs to 3 μs. The simulations study the effect of varying
tower grounding resistance that affect the lightning current.
Simulation results are analyzed lightning over voltage that causes
back flashover at insulator strings. This study helps to know causes
of problems of back flashover the transmission line system, and also
be as a guideline solving the problem for 500 kV transmission line
systems, as well.
Abstract: This paper presents an application of particle swarm
optimization (PSO) to the grounding grid planning which compares to
the application of genetic algorithm (GA). Firstly, based on IEEE
Std.80, the cost function of the grounding grid and the constraints of
ground potential rise, step voltage and touch voltage are constructed
for formulating the optimization problem of grounding grid planning.
Secondly, GA and PSO algorithms for obtaining optimal solution of
grounding grid are developed. Finally, a case of grounding grid
planning is shown the superiority and availability of the PSO
algorithm and proposal planning results of grounding grid in cost and
computational time.
Abstract: Deep and radical social reforms of the last century-s
nineties in many Eastern European countries caused changes in
Information Technology-s (IT) field. Inefficient information
technologies were rapidly replaced with forefront IT solutions, e.g.,
in Eastern European countries there is a high level penetration of
qualitative high-speed Internet. The authors have taken part in the
introduction of those changes in Latvia-s leading IT research
institute. Grounding on their experience authors in this paper offer an
IT services based model for analysis the mentioned changes- and
development processes in the higher education and research fields,
i.e., for research e-infrastructure-s development. Compare to the
international practice such services were developed in Eastern Europe
in an untraditional way, which provided swift and positive
technological changes.