Determinación de la función de la tensión de ensayo para impulsos tipo rayo con oscilaciones superpuestas en espacios de aire sometidos a campos eléctricos no homogéneos

Résumé

For verification of the proper design of high voltage installations, in relative to the correct insulation coordination, is necessary perform tests to demonstrate that a particular component is capable of withstand the representative electric stresses and surges, representatives for service. Tests to check withstand voltage levels are satisfied are performed in high-voltage laboratories using testing techniques to ensure reproducibility. Small differences in withstand voltage levels may force changes in design or manufacture, and therefore can have major economic impacts. Moreover, if different materials installed in the same electrical network have been tested according to different criteria, it can endanger own insulation coordination of the entire network. When testing materials with fast front lighting impulses, oscillations may appear in the pulse to be evaluated that must be considered to calculate the test voltage or the withstand voltage. This evaluation is provided in the international standards for testing, by the use of test voltage function, through a gradual change based on the frequency. However, there are some additional parameters to be taken into account when the function of the test voltage defined in new editions of the standards applied: The parameters that define the electrical configuration: the dielectric medium, the distance between the electrodes and the uniformity of the electric field. The parameters of lightning impulse: the polarity of the impulse, the maximum voltage Ue, the damping of the oscillation, the oscillation frequency or amplitude of the overshoot. The atmospheric conditions during the test: the temperature, absolute pressure and humidity whose influence on the impulses with oscillations is not sufficiently demonstrated.