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| Moisture |
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There are several
different units used to present the moisture contained
in sf6 gas. Cigre however recomends the use of
ppmw(parst per million in weight). If you need a
conversion guide this is specified in the IEE standard
1125-1993.
CIGRE also recomends
the following specifications for SF6 dew point meters:
- Measuring range 10ppmw to 500ppmw.
- Accuracy +/- 20ppmw.
- Sensor resistant to oil traces and corrosive gases.
- Use of self sealing valve connections.
- Portable.
- Calibrated or field calibratable.
- SF6 gas release less than 1 bar litre per measrmt.
- Obtain results within 5 minutes.
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SF6 Analyzer
Leak
detection unit
Gas
multimeter
Online
monitoring of SF6 gas |
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Decomposition by-products |
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Gas flourides such as
SF4 and WF6, Oxiflourides like SOF2, SOF4 and SO2FO2,
oxide S=2 and hydrogen flouride HF are all decomposition
by- products. However, one or two of theese should be
selected as an indicator of the concentration of
decomposition products. SO2 and SOF2 are the best choice
due to the fact that the represent the biggest fraction
of decomposition products. |
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| CIGRE recomends the
following specifications for SF6 decomposition
by-products analysers: |
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- Measuring range up to 20ppmw
- Calibration for So2 and SOF2.
- Accuracy +/- 10%.
- Use ofsef sealing valve connections.
- Portable.
- SF6 gas release less than 1 bar litre per measrmt.
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| Sf6 percentage |
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| Air introduced by
handling and CF4 that is produced by arc erosion of
polymers is measured in SF6 gas concentration in %
volume. |
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| CIGRE recomends the
following specifications for SF6 % analyzers: |
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- Accuracy better than +/- 1% vol.
- Response time < 1 min.
- No recalibration required.
- Separate calibration for air and CF4 mix with sf6.
- Portable.
- SF6 gas release less than 0.5 bar litre per meas. |
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