Abstract-Transformers are a critical part of an electrical utility's asset base. On-line monitoring and diagnostics is a useful tool to help operators to manage their assets and make decisions on continuing operation, maintenance or replacement. Dissolved Gas Analysis (DGA) is the heart of on-line monitoring as it is a well-established method of transformer diagnosis. DGA techniques are simple, inexpensive, and widely used to interpret gases dissolved due to the deterioration of the insulating oil of power transformers and hence to diagnosis, possibility of various type of faults in power transformer. Various diagnostic criteria based on gas analysis have been developed. In this paper, the application of many AI techniques have been presented such as Artificial Neural Network (AAN), Fuzzy Interface System (FIS), Genetic Algorithm (GA), Extended Relation Function (ERF), Bayesian Network (BN), Self Organizing Map (SOM) and Discrete Wavelet Network (WNs) Transforms, which can be used to increase the efficient and accurate diagnosis for off line and on line monitoring of power transformers.Index Terms-Power Transformer, Dissolve Gas Analysis, Artificial Intelligence Techniques.
I. INTRODUCTIONPower transformers play an important role in both the transmission and distribution of electrical power system. It is very essential oil-insulated components in power systems and its operational state determines the safety of the whole power system. Failure of a transformer may cause long interruptions in power supply and require expensive repairs. An incipient fault in a transformer should be detected as early as possible, preventing the transformer from further deterioration. Diagnostic approaches can be divided into two groups: on-line and off-line. Transformer ageing process of insulating oil and cellulose materials has been monitored by many different techniques such as Dissipation factor, capacitance, Breakdown voltage of oil and paper, Degree of polymerization (DP), Total combustible Gases (TCG), furan analysis, Interfacial Tension (IFT) analysis etc. Dissolved Gas Analysis is most widely method to detect incipient faults in oil filled transformer and Electrical equipment. Dissolved gas analysis is made on the basis of the standard IEC60599 standards [1]. Several diagnosis methods, such as the Rogers and Duval Triangle methods, are available to identify the different types of fault occurring in service such as arcing, partial discharges, or hot spots. DGA includes detection, quantification and characterization of the Gases. These gases, called characteristic gases, include, Hydrogen (H2), Methane (CH4), Ethane (C2H6), Ethylene (C2H4) and Acetylene (C2H2), and Carbon Oxides such as CO and CO2. The nature and the amount of the individual component gases extracted from the oil may be indicative of the type and degree of abnormality. The DGA data provides information about the condition of the transformer and advance warning of developing faults, monitoring the rate of fault development, confirm the presence of faults, conve...