This is one convenient type of discharge reference source for Partial Discharge applications.
- It can be used to cross check electrical calibrators for partial discharge.
- It is suitable to connect in the high voltage test circuit.
- It is energized by the high voltage connection to the test circuit.
- The device consists of a stainless steel needle pointing at and into a stainless steel hemisphere.
- The HV is connected to the needle and the earth is connected to the 25mm radius hemisphere .
- The device produces corona discharges of practically constant magnitude, which is really a function of the needle radius and only slightly affected by the hemisphere radius.
- The pulse repetition rate corresponds to a few pules per cycle at inception voltage(5 kv rms) and increases progressively as the applied voltage is raised to 1.4 times inception voltage, without any significant effect on the discharge pulse magnitude.