High voltage testing of bus bars is a crucial step to ensure its safety and reliability in electrical systems. This involves applying high voltage to the bus bars to check for insulation integrity, potential weaknesses, or defects that could lead to electrical failures or hazards.
The only parameter that needs to be calculated in the busbar high voltage test is the leakage current with an IR test to ensure that the insulation is working properly. When the bus section CB is opened, the leakage current will be half as compared to the bus section CB closed condition.
* Preparation to be carried out before performing the HV test
All CT secondary circuits should be shorted, Isolated, and earthed properly
All VT secondary circuits should be open & all VT racked out
The BUS BAR for testing should be clean and free from dust and oil
All grounding switches of the BUS BARS should be in their open position
All grounding switches of the circuits should be in their open position
MV cables must be disconnected from SWGR, and inserted cables must be grounded & properly isolated from one another.
All the working activities in the SWGR room must be interrupted and the staff must be informed about the high voltage test.
* Preparation before applying the HV test
Case 1.
Insulation Resistance test Before & After HV Test when CB racked in & opened
High Voltage Test when CB racked in & opened
Case 2.
Insulation Resistance test Before & After HV Test when CB racked in closed
High Voltage Test when CB racked in & closed
Case 3.
High Voltage Test for VT when CB racked in & closed
Case 4. Measurements test for VT when CB racked in & closed
* Insulation Resistance test Before & After HV test
In all three cases, preconditions for IR will remain the same
1. CB racked in & opened.
2. VT racked out.
3. All Cable contacts are shorted and grounded.
4. Injection from required panel.
5. Apply 5 kV DC for 1 minute on one phase while grounding the other two phases.
Note:
In the case of the HV test the CB / VT status & Injected voltage magnitude will be varied according to the respective case.
Make sure there is no abnormal sound available during injection in any panel in the entire bus
* High Voltage Test of 13.8kV SWGR
Preconditions
1. All Cable contacts are shorted and grounded.
2. Injection from required panel.
3. Inject voltage for 1 minute on one phase while grounding the other two phases.
4. Test all cases for R- Y- B phases respectively
Case 1
CB racked IN & Opened
VT racked OUT
Inject 3 times to the rated Voltage
Case 2
CB racked IN & Closed
VT racked OUT
Inject 3 times to the rated Voltage
Case 3.
CB racked IN & Closed
VT racked IN
Inject 1.5 times to the Nominal Voltage
Case 4.
CB racked IN & Closed
VT racked IN
Inject Nominal Voltage & take measurements & make sure all VT circuits are perfectly working.
Wuhan Huayi electric power is a professional manufacturer of test equipment and also provides solutions for GIS/cable/transformer and other projects. Established in 2005, located in Wuhan, China.