Measurement and simulation of the electric field of high voltage suspension insulator
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Measurement and simulation of the electric field of high voltage
Vassiliki T. Kontargyri, Ioannis F. Gonos*,y and Ioannis A. Stathopulos
The insulator strings, which are used for the suspension of overhead transmission lines, constitute one of the most important parts of
the transmission lines as they used to give support to electrical conductors and shield them from ground or other conductors as well
as they provide the necessary mechanical supports for the transmission lines against the worst likely mechanical loading conditions.
The number of the insulator units that consists the suspension insulator string depends on the operating voltage of the overhead
The calculation of the electric field and voltage distribution within and around high voltage insulators is a very important
parameter for the design of the insulators. High levels of the electric field are possibly responsible for audible noise, electromagnetic
pollution, partial discharge and premature aging of insulation. The assignment of the electric field distribution in an insulator string
is useful as it is an indication for flashover propagation. Hampton’s criterion shows that flashover cannot occur if the surface electric
gradient is sufficiently low . The flashover effects in insulators can cause the breakdown of a transmission system. Furthermore,
the knowledge of the electric field is helpful for the detection of defects in insulators .
Several methods such as finite difference method , boundary element method [4–6] and finite element method [7–13]
have been developed for the computation of electric fields and potentials along an insulator string. The simulation methods give the
possibility to examine the behaviour of models with very complex geometry without using analytical methods or experiments. The
electric field measurement along the insulator can also be found in many previous literatures such as references [6,14].
In this paper, the electric field distribution of a high voltage suspension insulator has been measured. In addition, the electric field
and potential distribution around and inside the insulator when it is stressed by power frequency voltage is examined using OPERA,
which is a suite of programs for two and three dimensional electromagnetic field analysis . The software package uses the finite
element method to solve the partial differential equations that describe the behaviour of electromagnetic fields. The critical points
affecting simulation accuracy are examined and the simulated results are compared with experimental results.