Abstract: A gas insulated high voltage electrical device comprising: at least one conductor for conducting a high voltage current; a longitudinal enclosure for enclosing the at least one conductor, the longitudinal enclosure comprising an interior wall extending along a longitudinal axis; a particle trap formed on the interior wall and extending along the longitudinal axis, the particle trap comprising a part of the interior wall and a longitudinal shielding cover extending along the longitudinal axis to delimit a dielectrically shielding area in the enclosure for trapping particles; the shielding cover being made of an electrically conducting material and comprising at least two electrical connections to the interior wall spaced from each other along the longitudinal axis, the shielding cover comprising a mechanical resonating frequency that makes the shielding cover longitudinally oscillate when the high voltage current passes through the conductor.