Partial discharge measurements are conducted in frequency ranges which are partly covered by radio transmission. Further, impulse noise interference hamper sensitive measurements. Besides using small filters in the acquisition chain, power filters allow removing such disturbance from the high voltage supply. Power Diagnostix offers a range of different high voltage filters.
π-Filters are for three-phase systems up to 2 kV, whereas the single-phase T-filters are used for testing with higher voltages. Those filters are installed inline between voltage source and device under test.
T-filters with a built-in coupling capacitor are also referred to as TCC-filters. They are very useful for onsite tests with the ICMcompact. They serve to block noise resulting from the voltage source (e. g. a VLF source or a generator). In addition, those TCC‑filters can be used as a decoupling unit.
HV filters of different ratings (UN, IN) are available on request.
Ground Filter GF50
Partial discharge measurement requires a reasonable noise-free environment. Power Diagnostix‘ GF50 filter box is designed to reduce high frequent disturbance signals from the ground leads. It can be used for HF separation of the test specimen from the ground potential of the power supply or other HV equipment within the environment without influencing the power frequency. The efficiency strongly depends on the general earthing within the laboratory. A splitted ground lead or copper band can be connected to the multi contact connectors or alternatively to the wing screws beside.
Filter Models for Special Applications
Besides the standard HV filters, Power Diagnostix offers various filters for special high voltage applications, inlcuding e. g. line filters for cable testing, ground filters to block noise transmission via the earthing system, and filters with AC current and AC voltage measurement. With the latter a high voltage filter ist combined with a high voltage devider and a high current transformer in one unit; conventionally on rolls, or upside-down, as shown at the left-hand side.