Procedure & Test for SF6 Circuit Breaker

* Physical Inspection
1. Wiring correctness
2. Check damage for
Control cubical & components
Main Body
3. Auxiliary contact of CB for all three Phase

* Electrical Test
1. Insulation Resistance Test
Insulation resistance between Phase to Ground & Phase to Phase when CB is in a Close Position
Insulation resistance between Phase to Pole when CB is in an Open Position
Apply 5kV DC for 1 minute for the insulation resistance test & the value should be greater than 100Mohms

2. Resistance of Closing & Tripping coil
Resistance of closing & tripping coil is necessary to calculate & it will reveal the health of both coils.

3. Current for Closing & Tripping Coil
Calculate the current for tripping and closing the coil during both operations.

4. Breaker Mechanism
. Check the manual operation of CB & it should be Ok
. The Breaker status should be correct

5. Spring Charge Motor Current Measurement & Timing
. Calculate the starting & Running Motor current at the  Nominal Voltage & Frequency value
. Also,  calculate the spring charge timing for CB and it should be in accordance with the FAT report.

6. Circuit Breaker Timing Test for Multiple input Voltage
Breaker Trip Timing is the most important test for CB because all the fault clearance time is directly related to the tripping time of the CB. To calculate the CB closing & tripping time apply multiple input voltage as 80V, 100V, 120V, 140V etc,  and measure the result & it should be according to the FAT report & equal in value for all voltage ranges.
There are few steps that need to be followed for the calculation of closing & tripping time for CB.
. Measure the CB closing time for all voltage level
. Measure the CB tripping time for all voltage level both from Trip Circuit 1 & Trip Circuit 2 respectively
. Measure the CB Close-Open time at nominal voltage level both from Trip Circuit 1 & Trip Circuit 2 respectively
. Measure the CB Open-Close time at nominal voltage level both from Trip Circuit 1 & Trip Circuit 2 respectively.