ELECTRICAL BREAKDOWN TIME DELAY IN COMMERCIAL GAS-FILLED SURGE ARRESTERS

This paper present the experimental results of electrical breakdown time delay of commercial gas-filled surge arresters manufactured by CITEL, SIEMENS and EPCOS as a function of relaxation time tau (memory curve) and applied voltage U-w. It was shown that for CITEL components mean value of electrical breakdown time delay, (t) over bar (d) insignificantly changes up to tau approximate to 700ms. For 700 ms < tau < 3 . 10(3) ms, (t) over bar (d) value rapidly increases and for tau > 3 . 10(3) ms (t) over bar (d) reaches saturation. Irradiation of CITEL components by gamma ray irradiation leads to significant decrease of (t) over bar (d) value for tau > 700ms. On the other hand, SIEMENS and EPCOS components show constant increase in (t) over bar (d) with the increase of tau until tau > 1s, when (t) over bar (d) value reaches saturation. The increase of applied voltage leads to significant decrease in (t) over bar (d) values up to U-w approximate to 300 V for all of the components, while for higher voltages such decrease is very small. Post-discharge mechanisms responsible for electrical breakdown time delay in these components were also analyzed.