How to eliminate the interference problem in the partial discharge tester test

(1) External interference

1. Interference not related to power supply voltage

This interference has nothing to do with the power supply voltage (the voltage applied to the tested product), and it does not change with the increase or decrease of the power supply voltage. It is produced by: opening and closing operations of electrical switches, arc welding, crane starting, brushes of rectifier motors, flashing lights, radio electromagnetic waves, and various industrial interferences. These interferences invade through the power supply, test circuit and ground wire.

2. Interference related to the power supply voltage

This type of interference generally increases as the power supply voltage increases. It can be generated from various parts of the test area. For example: test transformer, high-voltage lead, end of the test sample, poor contact of high-voltage line, contact of insulating objects in the high-voltage test area with ground (or grounded metal objects), poor grounding of metal objects in the test area, and induced discharge of other objects, etc. Wait. The intrusion path of interference related to the power supply voltage can intrude into the test circuit through the power supply, high-voltage wire, space and ground wire.

(2) The method of partial discharge tester to eliminate external interference

1. Eliminate interference that has nothing to do with the power supply voltage: measures should be taken in terms of power supply, space, and grounding methods. In order to eliminate the interference of electromagnetic waves in space, the laboratory should be shielded. For the interference invaded by the power supply, isolation transformers and filtering devices are generally installed at the power inlet. To eliminate the interference from the grounding grid, one-point grounding should be adopted.

2. Measures to eliminate interference related to the power supply: the high-voltage wire can be thickened (with a thicker snake-skin tube, thin iron cylinder or aluminum tube); anti-corona cover is added to the end of the tested product; various lines in the test area And metal objects should be well grounded; the insulating objects in the test area are strictly prohibited from contacting the metal grounding body; there should be no screws, ground wire ends and other metal objects on the ground under the high voltage line.