GATRON | prod_EGS

Extraction Gas Sampler (EGS)
for Manual Gas-in-Oil Analysis

Application

Buchholzgas-Sampler - BGS

The EGS method is a simple and reliable way of obtaining a defined gas sample from an oil sample for gas chromatographic analysis of the gases dissolved in oil in order to obtain the individual gas contents, the total gas content, the solution pressure and the degree of gas saturation for transformer diagnostics on a quality-based criterion, the Natural Internal Standard (NIS).

Advantages of the EGS method

Minimisation of fault influences during sampling
Continuous hermetic conditions from oil sampling till gas dosing for GC analysis
Two-phase oil-and-air system is not a problem in case of gas separation processes in the oil during transport and storage
No additional equipment or time for gas extraction
No direct handling of the oil during extraction
No oil contamination in the laboratory
EGS can be used for complete laboratory analysis or on-site analysis of the fault gas part
Quality check possible without time delay and without external Standard (NIS)
Optional use of an auto-sampler for GC analysis in the laboratory
Access to the diagnostic service of GATRON GmbH or application of known monitoring criteria
Significant cost reduction
Oil sample available for selected oil parameters (DBPC, Furans)

Short description

EGS-Endverschluss

All data of a transformer is recorded in a form in relation to the seal number.
The preferred sampling option is "vessel bottom", where approx.1l of oil is drained before connecting the EGS.
When the EGS is completely filled with oil, wait until the oil flow temperature is constant, then close the EGS cocks.
The EGS filling tube is taken out of and the original seal (sample number, included septum, retaining ring) is used for final sealing.
Oil filling and air temperatures have to be recorded.
On-site analysis

Shake EGS by hand approx. 15 min, puncture seal till the septum and equalise pressures.
Dosing in portable GC and analysis of the fault gas sample (H₂, CO, CO₂, CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₆, C₃H₈).
Calculation of fault gas contents

Laboratory analysis

Record air pressure and put EGS into a transport container.
In the laboratory: Attach transport vessel to the horizontal shaker and keep the thermal and solution equilibrium for approx. 60 min.
In vertical position: puncture EGS seal after approx. 10 min of calming, measure the internal pressure via the septum and equalise pressures.
Dosing in GC and complete gas analysis (H₂, O₂, N₂, CO, CO₂, CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₆, C₃H₈).
Record laboratory temperature and air pressure, complete calculation of the final result including individual gas contents, total gas content, solution pressure, degree of gas saturation.
Quality check using the NIS criterion.

Sampling Management with EGS Techniques

1. Specification of sampling

	Power Transformers > 5 MVA	Small hermetical transformers < 5 MVA
Insulation liquid	> 1 t (free flow)	< 1 t (hermetic sealing)
EGS techniques Sampling volume	EGS-Oil-2 > 5 l	EGS-Oil-2 / EGS-P < 2,5 l (Preservation of hermetical conditions)	EGS-100 < 0,75 l (Preservation of hermetical conditions)
Volume of sample Analytical parameters	1,25 l VDE, DGA, Furans	1,25 l VDE, DGA, Furans	0,1 l DGA, Furans, possibly H₂O
Options	EGS-P Coupling at low temperatures (Filling Help)	Repatriation of external insulation liquid	Repatriation of catched insulation liquid (0,5 l)

2. EGS Technique Component

Service Box EGS-S	Sampling Box EGS-Oil-2
Sampling Box EGS-100	Oil Pump EGS-P

3. Transport Logistics

EGS-6T small sampling	EGS-20T big series sampling
Oil-3T small series sampling	Oil-15T big series sampling
EGS-Oil-1T single sampling (complete)	RSP-10 single sampling (resaturation)
EGS-100T4	EGS-100T7