There are many common methods for detecting partial discharge in power transformers, and in recent years, the internationally popular ultra-high frequency technology has been applied to research on partial discharge detection in GIS, transformers, motors, and cables. Today, the editor will mainly talk about the operating steps of a partial discharge laboratory?
1、 Preparation before operation
1) Ensure that all equipment to be grounded is grounded.
2) Ensure reliable interlocking actions.
3) Choose the appropriate voltage range and high voltage tap position. During the reactor switching process, there will be a buzzer alarm. Remember to perform high voltage operation strictly at this time, that is, press the high voltage "close" button.
4) All personnel should evacuate the experimental area.
2、 Operation steps
1) Before conducting partial discharge and voltage withstand tests, the outer sheath, armored steel strip, and copper strip shielding layer should be peeled off first, and then the outer semiconductor shielding layer should be peeled off with a peeling blade.
2) For 10kV cross-linked cables, the stripping length of the outer semiconductor shielding layer is 150mm-200mm. For 35kV cross-linked cables, the stripping length of the outer semiconductor shielding layer is 500mm-700mm. The base of the external semiconductor shielding and stripping section should be smooth, without semiconductor tips, and there should be no residual semiconductor traces on the surface of the insulator to prevent discharge.
3) The insulation medium used for testing in the oil cup (transformer oil, F113, silicone oil) should be filtered and dried, otherwise it will affect the accuracy of the test results.
4) The two ends of the cable should be placed in the oil cup terminal. When installing the proximal oil cup, the elastic copper needle should be pushed upwards with force to ensure good contact between the copper needle and the cable conductor core; When installing the remote oil cup, insert the cable end into the oil cup.
5) The cable end placed in the oil cup terminal should completely submerge the cut surface root of the outer semiconductor shielding layer to prevent discharge at the root.
3、 Precautions
1) The withstand voltage and partial discharge tests belong to high-voltage tests, and there should be no less than 2 people during the test. Full time operators should receive professional training and hold certificates to operate.
2) Prior to cable testing, personnel conducting partial discharge testing should inspect the surrounding safety conditions and take all necessary precautions to prevent unexpected situations from occurring.
3) Do not press the "high voltage tap" button directly under high test voltage to prevent cable breakdown.
4) At the end of the experiment, it is necessary to use a grounding rod to discharge the remaining charge of all live parts to ensure the personal safety of the tester.
5) Regardless of whether the laboratory is working or not, non laboratory personnel are not allowed to approach or linger, let alone enter. If there is any work contact, the consent of the laboratory personnel must be obtained before entering.
6) In the event of an accident, the main power supply and main power supply of the voltage regulator should be immediately cut off, and the scene should be protected,
7) Report immediately, superior supervisor. If there are casualties, rescue should be carried out first before reporting and analyzing the cause of the accident.
8) Partial discharge testing personnel should strictly follow this regulation for operation.
The above is the operation process of the partial discharge laboratory introduced by the editor, hoping to be helpful to everyone!
