- Test objective:
1. This test aimed to test if bus bar will withstand its withstand voltage after being installed in the site or it will breakdown and to check the vacuum bottle integrity, also to measure leakage current and insulation between CB and ground.
- Testing equipment required:
1. AC HI-voltage injection machine
2. Earthing Rod or Ground Discharge stick (coming with high pot tester)
3. Megger 5KV DC Supply
- Mechanical and visual inspection:
1. All safety rules should be taken into consideration.
2. breaker cleaning and housekeeping.
3. Check all shipping devices removed.
4. Inspect ground to switchgear ground bus.
5. Ensure the adequate clearance (distance) between circuit test ends and to other Ground objects and other phases (not under the test) and also with other electrical equipment's to prevent flashover.
- Test connection and test procedure
1. Test VCB withstand voltage: VCB should be close , inject voltage as per FAT value.
• NOTE: When we conduct the HIPOT Test for one phase, the other remaining phases should be connected to the Ground.
• Use a Ground discharge stick with high-tension Electrical for discharge the voltage from the system after each High potential Test.
2. Test CB withstands voltage: VCB should be open, inject voltage as per FAT value.
3. Measure insulation after the high voltage test with CBs close and open status then inject 5 KV for 1 minute then record the value and compare it with the value before the high voltage test.
NOTE:
Use a Ground discharge stick with high-tension Electrical to discharge the voltage from the system after each High potential Test.
Wuhan huayi electric power provide the HIPOT test kit for testing VCB,there are so many models to be selected based on your test requirements.
There is the model 10KVA 100KV AC hipot test set can meet the test normally. There are 3 types test transformers, dry type, oil filled or SF6 gas filled.
There are 2 types of controller, manual type and automatic type.