Dissolved Gas Analysis Method
FINAL YEAR PROJECT 1 PROGRESS REPORT 1 AUTHOR’S NAME:Ruban s/o Paramasivam STUDENT ID:EP083765 REPORTING PERIOD:18TH JUNE 2012 - 15TH JULY 2012 SUPERVISOR’S:Mr. John Steven NAME PROJECT TITLE:Dissolved Gas Assay in free Abettor Faults SUBMISSION DATE:16TH JULY 2012 1. 0 Background of Studies Oil sampling assay is a useful, predictive, aliment apparatus for free abettor health. DGA is articular as one of the acceptable adjustment of oil sampling in evaluating abettor health. The breakdown of electrical careful actual central the abettor generates gases aural the transformer.
The character of gases actuality generated is advantageous in any antitoxin adjustment aliment program. DGA adjustment involves oil sampling adjustment and testing the sample to admeasurement the absorption of the attenuated gases. The two archetypal arch account of gas accumulation aural an operating abettor are electrical agitation and thermal decomposition. All transformers accomplish gasses to some admeasurement at accustomed operating temperature. Careful mineral oils for abettor are mixtures of abounding altered hydrocarbons and the atomization action for these hydrocarbons are complex.
During this process, alive hydrogen atoms and hydrocarbons bits are formed. These bits can amalgamate with anniversary alternative to anatomy gasses such as Hydrogen (H2), Methane (CH4), Acetylene (C2H2), Ethylene (C2H4), Ethane (C2H6) and abounding more. The gasses listed are advised combustible. The bulk at which anniversary gas are produced depends on the temperature. Therefore, the absorption of the alone attenuated gasses begin in abettor careful oil may be acclimated anon to appraise the abettor and advance any faults aural the transformer.
After samples accept been taken and analysed, the aboriginal footfall in evaluating DGA aftereffect is to accede the absorption akin of anniversary gasses. Basically, any aciculate access of the key gasses declared aloft indicates abeyant botheration aural the transformer. The blazon of faults which the key gasses can aftermath will be added discussed in the study. Abstract Assay 2. 0 Attenuated Gas Assay Ability Transformers are abounding with oil which acts as a dielectric average and additionally as a calefaction alteration abettor besides actuality an insulator to the transformer. The cloistral oil is fabricated up of saturated hydrocarbons.
These molecules are affiliated calm to anatomy a alternation admired address by carbon and hydrogen.  Table 1: Actinic anatomy of careful oil and accountability gases During accustomed use, there is a apathetic abasement of mineral oil which produces gases that deliquesce in the oil, but back there is a electrical fault, the oil starts to abase and temperature rises. Altered patterns of gases are generated due to altered intensities of activity blown according to the blazon of faults. This happens because of the burst alternation of the actinic anatomy of the careful oil.
Therefore, the burst alternation will anatomy its own actinic anatomy which is accepted as hydrocarbon gases or additionally accepted as accountability gases. It can be disconnected into 3 categories which is Thermal heating, Candelabrum and Arching, The best astringent acuteness of activity amusement occurs with arching, followed by thermal heating and the atomic astringent is Corona. Figure 1 illustrates the action of breaking alternation aural the careful oil actinic anatomy of the accountability arcing, thermal heating, and corona. Figure 1: Breaking alternation action of accountability arcing, corona, thermal heating and pyrolysis of cellulose
Gases which are produced by the abasement of oil because of the access of temperature may be acquired by several factors:  * astringent overloading * lighting * switching transients * automated flaws * actinic atomization of oil or insulation * overheated areas of the windings * bad access which accept a aerial acquaintance attrition The blazon of gases present in an oil sample makes it accessible to acquisition the blazon of accountability that occurs in the transformer. This is done by evaluating the absorption of gases present in the oil during maintenance.
The blazon of accountability and its characteristics are as beneath : * Arcing Arcing is the best astringent of all accountability processes. Large bulk of hydrogen and acetylene are produced, with accessory quantities of methane and ethylene. Arcing occurs in aerial accepted and aerial temperature conditions. Carbon dioxide and carbon monoxide may additionally be formed if the accountability complex cellulose. In some instances, the oil may become carbonized. * Thermal heating Atomization accessories accommodate ethylene and methane, calm with abate quantities of hydrogen and ethane.
Traces of acetylene may be formed if the accountability is astringent or involves electrical contacts. * Candelabrum Candelabrum is a low-energy electrical fault. Low-energy electrical discharges aftermath hydrogen and methane, with baby quantities of ethane and ethylene. Comparable amounts of carbon monoxide and dioxide may aftereffect from acquittal in cellulose. 2. 1 How DGA Works DGA adjustment includes sampling of oil central the abettor at altered locations. Chromatographic assay will be done on the oil sample to acquisition the absorption of attenuated gas.
The gases are again separated, articular and quantitatively bent such that the DGA adjustment can again be activated in adjustment to access reliable assay . The extracted gases meant for assay purpose are Hydrogen (H2), Methane (CH4), Ethane (CH6), Ethylene (C2H4), Acetylene (C2H2), Carbon Monoxide (CO), Carbon Dioxide (CO2), Nitrogen (N2) and Oxygen (O2). These accountability gases can be classified into 3 groups which are apparent in Table 2. Group| Hydrocarbons & Hydrogen| Carbon Oxides| Non-fault gases| Gases| CH4,H2,CH6, C2H4,C2H2| CO, CO2| N2, O2| Table 2 :Fault Gases Group
Depending on the absorption of the attenuated gases, action of the abettor can be evaluated. This is accessible because anniversary blazon of accountability burns the oil in a altered way area it generates altered blazon of gases. Therefore, it is accessible to appraise the accountability abject on the gas appear and its absorption level. Table 3 : Affiliation amid Accountability blazon and Accountability gases 2. 2 DGA Analytic Methods Careful oil breakdowns to baby abundance of gases due to over electrical or thermal stress. Thus, the agreement of these gases plays a role in free blazon of fault.
Through DGA analytic methods, it is accessible to acquisition faults as discussed earlier. There are abounding methods in DGA and 5 methods will be advised in this abstract assay part. 2. 2. 1 Rogers Arrangement Adjustment The Roger’s adjustment utilizes four gases ratios: CH4/H2, C2H6/CH4, C2H4/C2H6 and C2H2/C2H6. Assay if faults are able via a simple coding arrangement based on ranges of the arrangement as apparent in tables beneath . Table 4: Gas Arrangement Codes  Table 5: Roger’s Arrangement Cipher  The aggregate of the coding gives 12 altered types of abettor faults. The blazon of faults based on the cipher is apparent in table 6 below: 
Table 6 : Classification based on Roger’s Arrangement Codes 2. 2. 2 IEC Arrangement Adjustment This adjustment originated from the Roger’s Arrangement method, except that the arrangement C2H6 /CH4 was alone back it alone adumbrated a bound temperature ambit of atomization . Here, the actual three gas ratios accept altered ranges of cipher as compared to the Roger’s arrangement adjustment and they are apparent in table 7. The faults are disconnected into nine altered types as listed in table 8.  Table 7: IEC Arrangement Codes  Table 8: Classification based on IEC Arrangement Codes 2. 2. 3 Doenenbury Arrangement Method
This adjustment utilizes the gas absorption from arrangement of CH4/H2, C2H2/CH4, C2H4/C2H6 and C2H2/ C2H4. The bulk of the gases at aboriginal charge beat the absorption L1 to as assertive whether there is absolutely a botheration with the assemblage and again whether there is acceptable bearing of anniversary gas for the arrangement assay to be applicative . Table 9 shows the key gases and their absorption L1 , and table 10 shows accountability blazon of specific ratios. Table 9: Absorption of L1 for Doernenburg Arrangement Table 10: Accountability assay for Doernenburg Arrangement Adjustment 2. 2. 4 Duval Triangle Adjustment M.
Duval developed this adjustment in the 1960s. To actuate whether a botheration exists at atomic one of the hydrocarbon gases or hydrogen charge be at L1 akin or aloft and the gas bearing bulk is at atomic at G2.  The L1 akin and the gas bearing bulk for this adjustment are apparent in table 11. Table 11: L1 banned and gas bearing bulk for Duval Triangle Methode Once a botheration has been bent to exist, to access diagnosis, account the absolute accumulated bulk of the three Duval Triangle gases (CH4, C2H2, C2H4) and bisect anniversary gas by the absolute to acquisition the allotment of anniversary gas of the total.
Plot the percentages of the absolute on the triangle (Figure2) to access at the assay  Figure 2: Duval Triangle Abettor Accountability Assay 2. 2. 5 Key Gas Adjustment Figure 3 : Key Gases Assay The assumption of the Key Gas adjustment is based on the abundance of accountability gases appear from the careful oil back a accountability occurs which in about-face access the temperature in the ability transformer. The attendance of the accountability gases depends on the temperature or activity that will breach the articulation or affiliation of the careful oil actinic structure.
This adjustment uses the alone gas rather than the adding of gas ratios for audition fault. The cogent and admeasurement of the gases are alleged “key gases”. Figure 3 announce these “key gases” and about accommodation for the four accepted accountability types . 3. 0 Scheduled Work Task| Start Date| Duration (days)| Remarks| Progress| Activity Appellation Selection| 28. 05. 2012| 12| Proposed own activity appellation and submitted it on 4th June 2012| Completed| Analysis for Activity Proposal| 08. 06. 2012| 10| Journals and accessories were browsed through in IEEE, Science Direct, Scopus| Completed| Activity Proposal| 14. 6. 2012| 3| Activity Proposal was done based on the journals and accessories found. | Completed | Analysis for Abstract Review| 19. 06. 2012| unknown| Journals and accessories were searched for the abstract review| Ongoing| Advance Report 1| 01. 07. 2012| 15| Anniversary advance appear the achievement of Final Year Activity 1| Completed| Analysis / Articulate Presentation Preparation| 17. 07. 2012| 24| Complete the abstract assay and accepting able for the articulate presentation while accomplishing analysis for the project| Incomplete| Articulate Presentation| 10. 08. 2012 / 29. 08. 012| -| Presentation of all the allegation and analysis and logbook to be submitted| Incomplete| Advance Report 2| 10. 08. 2012| 3| Anniversary advance appear the achievement of Final Year Activity 1| Incomplete| 4. 0 Conclusion In the end of this study, I’ll be able to actuate the pros and cons of all the altered types of DGA affection methods and be able to actuate abettor faults out of the analytic methods which are actual capital to anticipate abettor damage. Suggestions and recommendations will be accustomed to added advance the ability of those accessible analytic methods . 0 Reference 1. Church, J. O. , Haupert, T. J. and Jakob, Fredi (1987). “Analyze Incipient Faults with Dissolved-gas Nomograph. ” Elecrical World. Oct. Pgs. 40-44. 2. DiGiorgio, Joseph B. (1997). “Dissolved Gas Assay of Mineral Oil Careful Fluids. ” California: Northern Technology & Testing 3. Domun, M. K. (1996). “Condition Monitoring of Ability Transformers by Oil Assay Techniques. ” Proc. of the 11th Conference on Electric Ability Supply Industry (CEPSI). Kuala Lumpur, Malaysia 4. Siva Sarma, D. V. S. S. and G. N. S.
Kalyani, ANN Approach for Action Monitoring of Ability Transformers application DGA. 2004 IEEE Region 10 Conference, TENCON 2004. , 2004. C: p. 444-447. 5. C57. 104. 1991, I. , IEEE Guide for Interpretation of Gases Generated in Oil-Immersed Transformer, I. The Institute of Electrical and Electronic Engineers, Editor. 1992, The Institute of Electrical and Electronic Engineers, Inc p. 27 6. FIST3-31, Facilities Instructions, Standards and Techniques Volume 3-31 Abettor Diagnostics. 2003, Bureu of Reclamation Hydroelectric Analysis and Technical Services Group Denver. p. 5-13.
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