Pdf interpretation of dissolved gas analysis in transformer oil. The dielectric breakdown voltage is measured by applying a voltage between two electrodes under the oil. Improving the reliability of transformer gasinoil diagnosis,a ieee electrical insulation magazine 2005, 21. Dissolved gas analysis of transformer oil electrical4u. In addition, the assessment of the transformers potentialread. Effective maintenance of liquidfilled transformers begins with prevention of failure by testing transformer oil for unusual elements. The use of dissolved gas analysis dga as a method for determining the types of pending or occurring faults within power transformers has been in practice for many years. Dissolved gas analysis has been part of the transformer industry for many years as a valuable tool in monitoring the condition of power transformers.
Large oil filled electrical equipment, such as transformers and reactors, is a critical element of an electrical power system. In addition, dissolved gases are extracted from the oil sample, separated, and quantified in a gas chromatograph. When the fault is major, the production of decomposed gases are significant and they get collected in a. This analysis process consists of sampling and analyzing the oil to determine the kind and amount of gases in the oil. The university of new south wales, school of electrical engineering and telecommunications, sydney 2052, australia. Dissolved gas analysis was performed in all the oil samples from which the evolved gas concentration was quantified. The most important indicators are the individual and total combustible gas tcg generation rates based on the international electrotechnical commission iec 60599 and ieee c 57104 12 standards. Dga is considered the best method for determining a transformer s overall condition and is now a universal practice. The main findings of this thesis are outlined below. High energy faults not only degrade the transformers insulationoil, paper, wood etc but can generate metal. Dissolved gas analysis dga of the oil in the ltc is required. Power transformer fault severity estimation based on dissolved. Ieee guide for dissolved gas analysis in transformer load tap.
Fault detection techniques for transformer maintenance. Guest editorial understanding dissolved gas analysis dga. Metal in oil analysis of transformer oil is used to complement dissolved gas analysisdga. The hillside aluminium smelter is located in richards bay, 200 kilometers north of durban, kwazulunatal province, south africa. New guideline for interpretation of dissolved gas analysis in oil filled transformers. However, if this gas is left for a long time in the relay, some constituents will dissolve, modifying the composition of the gas collected. As use of dissolved gas analysis dga monitors increases as a growing component of transformer maintenance and reliability, it is imperative to understand the capabilities of monitors in their ability to align with conventional laboratory. This guide is intended for the application of dissolved gas analysis dga techniques on oil immersed transformers and reactors applied during factory temperature rise tests.
Detects most internal faults, some external faults and some operational errors. Dissolved gas analysis dga is proved accurate method all over the world for condition assessment of power transformer. Transformer condition monitoring transoil laboratory. The use of dissolved gas analysis dga as a method for determining the types. Transformer oil analysis tests identify whether the insulating properties are acceptable by measuring degradation and contamination of the oil. It may seem like a bold statement to say that dissolved gasinoil analysis dga is the most powerful tool in the industry, but i stand by it. The ieee transformers committee is presently analyzing over 500,000 sets of data for power transformers, but the majority of that data is still not for distribution transformers. Total dissolved combustible gas total gas content % kva rating.
Measurements of dissolved gas concentrations in the ltc oil are required to. Minimum detection limits for gases dissolved in oil, ppm astm d3612c compound detection limits, ppm signalnoise 3 h2 5 h2 0. Guest editorial understanding dissolved gas analysis. Identifies various gas ppm levels that are present in transformer insulating oil. Transformer oil analyst toa4 advanced diagnostic software for insulating fluid test data, including dissolved gas analysis, for highvoltage apparatus toa4 is a critical decision support tool that helps utilities and industrial facilities assess and diagnose the health of their highvoltage apparatus, such as power transformers. Dissolved gas analysis of transformer oil in todays modern electric power industry, transformer oil sampling and analysis has begun to enjoy wide popularity. The dissolved gas analysis dga is commonly used to diagnose these incipient faults within oil immersed transformer. Insulating materials within transformers and electrical equipment break down to liberate gases within the unit.
Oxides and water are analysed and reported under routine and dissolved gas analysis, trending of concentrations of furanic compounds in oil provide early indications of insulation degradation. Iec 60599 guide to the interpretation of dissolved and free. Mar 01, 2015 dissolved gas analysis in transformer oil 1. Dissolved gas analysis consists of sending transformer oil samples to a commercial laboratory for testing. By measuring the quantity and types of furans present in a transformer oil sample, the paper insulation overall dp degree of polymerisation can be inferred with a high degree of confidence. The third and most informative method for the detection of fault gases is the dissolved gas analysis dga technique. Generally you will see an increase of methane gas during the summer months. It is therefore prudent to periodically perform tests on the oil. However, in the absence of any other methods and limits, use the ones below as a beginning. The distribution of these gases can be related to the type of electrical fault, and the rate of gas generation can indicate the severity of the fault. Online analysis of oildissolved gas in power transformers using.
The operation is fully owned and operated by bhp billiton. Testing has shown that the causes for generation of various gases are the same, whether the fluid in question is conventional transformer oil or beta fluid. Taking the concentration of key gases co, co 2, h 2, c 2 h 6, c 2 h 4. Since it was difficult to deduce the inaccuracies of distinct instruments and human errors of each data set from different sources, a 95% confidence level was assumed to cater for these uncertainties. High energy faults not only degrade the transformers insulationoil, paper, wood etc but can generate metal particles that will disperse in the oil.
So in order to protect from faults, transformer oil testing is required. As use of dissolved gas analysis dga monitors increases as a growing component of transformer maintenance and reliability, it is imperative to understand the capabilities of monitors in their ability to align with conventional laboratory results and detect gas related changes from a baseline. Comparative study and analysis of dga methods for transformer mineral oil. Astm d3612a 15 gas chromatography for the energy industry july 17, 20. The presence of certain gases often indicates an abnormality that could lead to failure if ignored, and advances in gas analysis are making the detection of future transformer. This guide is not manufacturer specific, rather category specific. Furthermore, the dissolved fault gases in oil were measured by both the online dga monitoring system and the oil analysis laboratory, and the dga results were also compared. Practical experience gained from dissolved gas analysis at an. The transformers fluid not only serves as a heat transfer medium, it also a part of transformers insulation system. Metal in oil analysis of transformer oil is used to complement dissolved gas analysis dga. Power transformer fault severity estimation based on. Product information dissolved gas analysis and supervision.
Much in the same way that a doctor can analyze a patients blood to determine certain. Kraft paper, in conjunction with insulating oil, is used to insulate the conductors. The types and concentration of furans in an oil sample. In substation, transformer is the most efficient and costly equipment. Power transformers faulting usually manifests when the electrical and thermal insulation withstand limits are being exceeded. The analysis of gases from petroleum products has been performed for decades using gas chromatography. Transformer oil sample analysis is a useful,predictive, maintenance tool for determining transformer health.
Dissolved gas analysis guide for transformers filled with. It may seem like a bold statement to say that dissolved gasinoil analysis dga is the most powerful tool in the industry, but i stand by it dga is the most costeffective tool to detect a wide range of problems in the early stages and then throughout deterioration until an outage is required. Monitoring and maintaining insulating oil quality and the integrity of a transformer are essential in ensuring reliable plant operation. These gases can be detected in transformer insulating oil using sensitive and reliable dissolved gas analysis dga techniques for determining the type of pending or occurring fault. A powerful maintenance tool for transformers, tjh2b na techcon, 2004. Transformer oil gas analysis includes backflush valve and methanizer bypass. In todays modern electric power industry, transformer oil sampling and analysis has begun to enjoy wide popularity. Fr3 generates similar amounts of fault gases to gemini x under sparking faults. This means that the guidelines for interpretation of dissolved gas analysis dga for conventional transformer oil can be followed when working with beta fluid. A dissolved gas analysis consists of sending transformer oil samples to a commercial laboratory for testing. Transformer oil gas analysis cont manual sample handing. Dissolved gas analysis iec 60567 gas in oil symbol limit result hydrogen h2 100 ppm 52 methane ch4 120 ppm 47 ethylene c2h4 50 ppm 8 ethane c2h6 65 ppm 159 acetylene c2h2 of methods available to analyze the content of gases in oil, but a dissolved gas analysis is preferred since only a dissolved gas analysis can provide the truest and most accurate results.
East tx dissolved gas analysis fluid quality analysis limits additional fluid quality tests notes. The primary differences between the analysis of dissolved gases produced in beta fluid and with mineral oil are in the solubilities of the gases in the oil. Study of dissolved gas analysis under electrical and. Basics, maintenance, and diagnostics ix contents continued page 6. Oil analysis services identifies the three main types of pcb i. Page 1 transformer nameplate, identification name, oil and gas results and any notable comments and deficiencies. Silicone oil dissolved gas analysis is in the beginning stage, and the suggested methods and limits below are subject to change as we gain more experience. Gray transformer chemistry services introduction the fault free operation of power transformers is a factor of major economic importance and safety in power supply utilities and industrial consumers of electricity. Dissolved gas analysis dga is one of the most useful techniques to detect incipient faults in power transformers. Low oil levels due to improper flow of oil through radiators. Dec 08, 2018 by measuring the quantity and types of furans present in a transformer oil sample, the paper insulation overall dp degree of polymerisation can be inferred with a high degree of confidence.
Detection down to parts per million ppm levels is generally achievable by gas chromatography 2 and requires extraction of an oil sample of the transformer for laboratory analysis 3. The oil sample is analysed in the laboratory using gas chromatography technique. It has been proven that the generation of certain gases within a transformer is an excellent indicator that a failure is pending. Practical experience gained from dissolved gas analysis at. Along with the oil sample quality tests, performing a dissolved gas analysis dga of the insulating oil is useful in evaluating transformer health. Dissolved gas analysis dga of mineral oil used in transformer. All limits are based upon standards widely accepted throughout the industry. This provides a more visual idea of determining the trending of these gases. Product information dissolved gas analysis and supervision of.
Dissolved gas analysis dga is the study of dissolved gases in transformer oil. Study of dissolved gas analysis under electrical and thermal. The presence of certain gases often indicates an abnormality that could lead to failure if ignored, and advances in gas analysis are making the detection of future transformer problems an. Iec 60599 guide to the interpretation of dissolved and. Dissolved gas analysis dga has been proven an effective method to diagnose the internal fault of transformers for decades. A good oil analysis program provides equipment owners the ability to determine the current condition of a transformer and schedule prevetive maintenance so as to avoid possible failures in future. In this method a sample of the oil is taken from the unit and the dissolved gases are extracted. Ieee guide for dissolved gas analysis in transformer load. Dissolved gas analysis of transformer oil based on deep belief. Jun, 2016 it may seem like a bold statement to say that dissolved gas in oil analysis dga is the most powerful tool in the industry, but i stand by it dga is the most costeffective tool to detect a wide range of problems in the early stages and then throughout deterioration until an outage is required.
It contains recommended procedures for sampling, recommended actions based on interpretation of results, and a bibliography of related literature. Detailed procedures for interpreting dissolved gas analysis results are described in this guide. The purpose of this guide is to assist the responsible parties who are in charge of the operation and maintenance decisions in evaluating the condition of an ltc without the need to deenergize the. New oil should have a minimum dielectric strength of 35 kv by astm methods of testing. For many years the method of analysing gases dissolved in the oil has been used as a tool in transformer diagnostics. Dissolved gas analysis dga test of transformer oil. Pdf evaluating transformer condition using dga oil analysis. Astm d3612a 14 gas chromatography for the energy industry july 17, 20.
General types of load tap changer ltc mechanisms, breathing configurations, and electrical designs, described for reference for determining methods of testing and evaluating dissolved gases in mineralbased transformer oils in ltcs, are discussed and recommended in this guide. Under normal operating conditions, oil insulated power transformers generate gases very slowly, as a result of the transformer ageing and experiencing a relatively constant load. Gases generate by degradation of fluid or cellulose. We use capillary column chromatography to determine the pcb concentration in oil. Transformer oil gas analysis manual sample handing. When gas in oil analysis indicates the presence of a possible fault, metal in oil analysis will help determine the fault type and pinpoint its location. Transformer oil analysis dissolved gas analysis of mineral oil.
However, this technique was not applied specifically to transformer mineral oil until the late 1960searly 1970s and is now commonly called dissolved gas in oil analysis dga. Then the extracted gases are separated, identified, and quantitatively determined. The testing results show that the detection limit of every analyte component is lower than 0. Whenever a transformer undergoes abnormal thermal and electrical stresses, certain gases are produced due to the decomposition of the transformer oil. The most important indicators are the individual and total combustible gas tcg generation rates based on iec 60599 3 and ieee c 57 104 4. Valve option 752 automate two valves 78900047 configured per. Blockage of natural air flow preventing sufficient cooling. Dga results of oil samples drawn from transformers of different. The large gas bubbles rise quickly to the relay and exchange little gas with the oil so that the gas that collects in the relay is initially far from being in equilibrium with the gases dissolved in the oil. Using dissolved gas analysis to detect active faults in oil. It is therefore prudent to periodically perform tests on the oil to determine whether. Insulating materials within transformers and electrical equipment break down to. Regular sampling and testing of insulation oil taken from transformers is a valuable. Dissolved gases reveal your transformers state of health.
This guide is intended for the application of dissolved gas analysis dga techniques on oilimmersed transformers and reactors applied during factory temperature rise tests. Practical experience gained from dissolved gas analysis at an aluminium smelter ian. Dissolved gas analysis iec 60599 for many years the method of analysing gases dissolved in the oil has been used as a tool in transformer diagnostics in order to detect incipient faults, to supervise suspect trans. Effective transformer maintenance depends on dissolved gas analysis.
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