SO2 MEASUREMENT IN SF6 GAS

The concentration of SO2 is an indicator for the presence of decomposition products in SF6 gas. The SO2 measurement in SF6 gas in the GIS equipment which is energized condition is easy way to analyze the abnormalities.

Gastec Detector Tubes

Gastec Tube

Gastec Detector Tubes are used for the rapid measurement of SO2 in SF6 gas. These Pre-calibrated, direct-read detector tubes offer distinct lines of demarcation for easier viewing and color charts. Each tube contains detecting reagents that are especially sensitive to the target substance and quickly produces a distinct layer color change. 

Gastec Gas Sampling Pumps

Gastec Gas Sampling Pumps are used to take the sample of SF6 gasCollect the SF6 gas in a polythene bag from the equipment Non returnable value. Take a fresh Detector Tubes and broke two edges and fix one edge with Gas sampling pump, insert the other end  in to gas collected polythene bag. Then pull the gas Pump handle.  Now gas will accumulated in the gas tube. If SO2 presence in the SF6 gas, the tube in side Blue color will be change in to Yellow. 

HYUNDAI 380KV CB PROBLEMS

Problem -1

A Circuit Breaker opened from the remote end for some outage work . After complete the work breaker was tried to close again, but "R" phase CB pole not closed and other two poles are closed . 

Immediately Pole Discrepancy Stage -1 operated and closed breaker poles are opened. 

CB was taken outage for further investigation.

1.+ve & -ve is checked across contact K1 - ok.

2. Individual coil resistance - ok

3. Function of K1 checked - ok

4. CB was closed by manually press the closing coil nob. Again locally CB was tried to close. All three phases are closed. We thought there is struck up in the close coil nob. So again CB tried to close but this time same problem happened.   

5. Resistance checked between point A & B 

R- Phase = 90 ohms Y= 40 ohms B= 40 ohms

The resistance R1 not shown in the drawing . So we desired wire problem between coil and point 'A'. Then the R1 was found between between coil and point 'A'. 

A wire connected in the resistance was found disconnected. And circuit taken full resistance value. So the enough current was not flowing through the coil to pickup. 

Problem -2

When close the CB ,  " R" Pole oil pressure comes to "0" point. Pole was not closed. Same PD- Stage 1 operated and other poles are tripped.

After long investigation found the closing coil nob is in middle position. So when ever close comment came total compressed pressure was relished thorough a valve. Then oil pressurizing  motor automatically ON but oil pressure was not increased.

 Then closing coil nob was properly pulled out. Oil pressure was increased by manually up 10Mpa. Then motor was ON and pressure got normal.

The same problem will happened if CB close with "0" pressure.