Dissolved Gas Analysis Method

Last 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 Analysis in deciding Transformer Faults SUBMISSION DATE:16TH JULY 2012 1. 0 Background of Studies Oil testing investigation is a helpful, prescient, support device for deciding transformer wellbeing. DGA is recognized as one of the adequate strategy for oil testing in assessing transformer wellbeing. The breakdown of electrical protecting material inside the transformer produces gases inside the transformer.The character of gases being created is helpful in any preventive strategy support program. DGA strategy includes oil inspecting technique and testing the example to gauge the grouping of the broke up gases. The two run of the mill chief reason for gas arrangement inside a working transformer are electrical aggravation and warm disintegration. All transformers p roduce gasses somewhat at typical working temperature. Protecting mineral oils for transformer are blends of a wide range of hydrocarbons and the disintegration procedure for these hydrocarbons are complex.During this procedure, dynamic hydrogen iotas and hydrocarbons pieces are shaped. These pieces can consolidate with one another to shape gasses, for example, Hydrogen (H2), Methane (CH4), Acetylene (C2H2), Ethylene (C2H4), Ethane (C2H6) and some more. The gasses recorded are viewed as burnable. The rate at which every ga are created relies upon the temperature. In this manner, the centralization of the individual broke up gasses found in transformer protecting oil might be utilized straightforwardly to assess the transformer and propose any flaws inside the transformer.After tests have been taken and dissected, the initial phase in assessing DGA result is to consider the focus level of each gasses. Fundamentally, any sharp increment of the key gasses expressed above demonstrates p otential issue inside the transformer. The sort of deficiencies which the key gasses can deliver will be additionally examined in the examination. Writing Review 2. 0 Dissolved Gas Analysis Power Transformers are loaded up with oil which goes about as a dielectric medium and furthermore as a warmth move specialist other than being a protector to the transformer. The protected oil is comprised of immersed hydrocarbons.These atoms are associated together to frame a chain loved way via carbon and hydrogen. [1] Table 1: Chemical structure of protecting oil and flaw gases During ordinary use, there is a moderate corruption of mineral oil which produces gases that break up in the oil, however when there is an electrical shortcoming, the oil begins to debase and temperature rises. Various examples of gases are created because of various powers of vitality scattered by the kind of deficiencies. This happens as a result of the messed up chain of the compound structure of the protecting oil.T herefore, the wrecked chain will frame its own concoction structure which is known as hydrocarbon gases or otherwise called issue gases. It tends to be isolated into 3 classes which is Thermal warming, Corona and Arching, The most serious power of vitality dissemination happens with angling, trailed by warm warming and the least extreme is Corona. Figure 1 shows the way toward breaking chain inside the protecting oil substance structure of the deficiency arcing, warm warming, and crown. Figure 1: Breaking chain procedure of deficiency arcing, crown, warm warming and pyrolysis of celluloseGases which are delivered by the corruption of oil on account of the expansion of temperature might be brought about by a few components: [2] * extreme over-burdening * lighting * exchanging homeless people * mechanical imperfections * concoction disintegration of oil or protection * overheated regions of the windings * awful associations which have a high contact obstruction The kind of gases prese nt in an oil test makes it conceivable to discover the sort of shortcoming that happens in the transformer. This is finished by assessing the convergence of gases present in the oil during maintenance.The kind of shortcoming and its attributes are as beneath [3]: * Arcing is the most extreme of all flaw forms. Enormous measure of hydrogen and acetylene are created, with minor amounts of methane and ethylene. Arcing happens in high present and high temperature conditions. Carbon dioxide and carbon monoxide may likewise be shaped if the issue included cellulose. In certain occasions, the oil may become carbonized. * Thermal warming Decomposition items incorporate ethylene and methane, along with littler amounts of hydrogen and ethane.Traces of acetylene might be shaped if the flaw is serious or includes electrical contacts. * Corona is a low-vitality electrical issue. Low-vitality electrical releases produce hydrogen and methane, with little amounts of ethane and ethylene. Practically identical measures of carbon monoxide and dioxide may result from release in cellulose. 2. 1 How DGA Works DGA strategy incorporates testing of oil inside the transformer at various areas. Chromatographic investigation will be done on the oil test to discover the centralization of broke down gas.The gases are then isolated, distinguished and quantitatively decided to such an extent that the DGA technique would then be able to be applied so as to get dependable finding [6]. The separated gases implied for investigation reason for existing are Hydrogen (H2), Methane (CH4), Ethane (CH6), Ethylene (C2H4), Acetylene (C2H2), Carbon Monoxide (CO), Carbon Dioxide (CO2), Nitrogen (N2) and Oxygen (O2). These issue gases can be arranged into 3 gatherings which are appeared in Table 2. Group| Hydrocarbons and Hydrogen| Carbon Oxides| Non-issue Gases| CH4,H2,CH6, C2H4,C2H2| CO, CO2| N2, O2| Table 2 :Fault Gases GroupDepending on the centralization of the broke up gases, state of the transformer can be assessed. This is reachable on the grounds that each kind of shortcoming consumes the oil in an alternate manner where it creates distinctive sort of gases. In this way, it is anything but difficult to analyze the shortcoming base on the gas discharged and its fixation level. Table 3 : Relation between Fault type and Fault gases 2. 2 DGA Diagnostic Methods Insulating oil breakdowns to little amount of gases due to over electrical or warm pressure. In this manner, the sythesis of these gases assumes a job in deciding sort of fault.Through DGA demonstrative techniques, it is conceivable to discover blames as talked about before. There are numerous strategies in DGA and 5 techniques will be concentrated in this writing audit part. 2. 2. 1 Rogers Ratio Method The Roger’s strategy uses four gases proportions: CH4/H2, C2H6/CH4, C2H4/C2H6 and C2H2/C2H6. Conclusion if shortcomings are cultivated by means of a basic coding plan dependent on scopes of the proportion as appeared in tables underneath [4]. Table 4: Gas Ratio Codes [4] Table 5: Roger’s Ratio Code [4] The mix of the coding gives 12 distinct kinds of transformer issues. The kind of shortcomings dependent on the code is appeared in table 6 underneath: [4]Table 6 : Classification dependent on Roger’s Ratio Codes 2. 2. 2 IEC Ratio Method This strategy started from the Roger’s Ratio technique, then again, actually the proportion C2H6/CH4 was dropped since it just showed a restricted temperature scope of deterioration [3]. Here, the staying three gas proportions have various scopes of code when contrasted with the Roger’s proportion strategy and they are appeared in table 7. The deficiencies are isolated into nine distinct sorts as recorded in table 8. [4] Table 7: IEC Ratio Codes [4] Table 8: Classification dependent on IEC Ratio Codes 2. 2. 3 Doenenbury Ratio MethodThis strategy uses the gas fixation from proportion of CH4/H2, C2H2/CH4, C2H4/C2H6 and C2H2/C2H4. The esti mation of the gases from the start must surpass the focus L1 to as certain whether there is actually an issue with the unit and afterward whether there is adequate age of every ga for the proportion investigation to be relevant [5]. Table 9 shows the key gases and their fixation L1 [5], and table 10 shows issue sort of explicit proportions. Table 9: Concentration of L1 for Doernenburg Ratio Table 10: Fault analysis for Doernenburg Ratio Method 2. 2. 4 Duval Triangle Method M.Duval built up this technique during the 1960s. To decide if an issue exists in any event one of the hydrocarbon gases or hydrogen must be at L1 level or above and the gas age rate is at any rate at G2. [6] The L1 level and the gas age rate for this technique are appeared in table 11. Table 11: L1 cutoff points and gas age rate for Duval Triangle Methode Once an issue has been resolved to exist, to acquire analysis, ascertain the absolute aggregated measure of the three Duval Triangle gases (CH4, C2H2, C2H4) and gap every ga by the aggregate to discover the level of every ga of the total.Plot the rates of the aggregate on the triangle (Figure2) to show up at the determination [6] Figure 2: Duval Triangle Transformer Fault Diagnosis 2. 2. 5 Key Gas Method Figure 3 : Key Gases Diagnosis The standard of the Key Gas strategy depends on the amount of deficiency gases discharged from the protecting oil when an issue happens which thus increment the temperature in the force transformer. The nearness of the shortcoming gases relies upon the temperature or vitality that will break the connection or connection of the protecting oil concoction structure.This strategy utilizes the individual gas as opposed to the estimation of gas proportions for distinguishing deficiency. The huge and extent of the gases are called â€Å"key gases†. Figure 3 demonstrate these â€Å"key gases† and relative extents for the four general deficiency types [5]. 3. 0 Scheduled Work Task| Start Date| Duration ( days)| Remarks| Progress| Project Title Selection| 28. 05. 2012| 12| Proposed own task title and submitted it on fourth June 2012| Completed| Research for Project Proposal| 08. 06. 2012| 10| Journals and articles were perused through in IEEE, Science Direct, Scopus| Completed| Project Proposal| 14. 6. 2012| 3| Project Proposal was done dependent on the diaries and articles found. | Completed | Resear