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An asset management tool using a simple technique for determination of maintenance priority level of medium voltage transformers is presented in this paper. Case studies during implementation of the decision tool on transformers with a decreased in oil quality are also discussed in this paper. Among the investigated cases, a transformer with a declined breakdown voltage and an excessive production...
In this paper, a computer program called Hybrid-DGA Interpretation software that has the ability to improve the accuracy Dissolved Gas Analysis (DGA) interpretation is presented. Four DGA interpretation methods are combined in this software: Key Gas, Rogers Ratio, IEC Ratio and Duval Triangle. The ability to combine more than one method increases the accuracy of fault prediction and saves computational...
Transformers are often the most valuable and indispensible asset in a substation and failures would result in undesirable disturbances and economic losses to energy systems. In order to prevent failures, the common practice in the industry is to monitor the condition of all transformers uniformly and routinely irrespective of the vulnerability of an individual transformer. Since transformers with...
This paper proposes a system of health-status-based condition detection and fault diagnosis of hydroelectricity production equipment. The proposed system has rational architecture and comprehensive functional modules, and aims at improving the health status of hydroelectricity production equipment and cuts down the cost of maintenance. The technical and managing systems, which are critical to the...
Applying transformer health and risk scores allows us to provide a basic asset ranking. Transformer health scores are not, by themselves, an indicator of a transformer problem but they do provide a relatively simple means for scoring large populations of transformers. However the results are not absolute and there is still a need for engineering judgment. Including an indication of consequence allows...
This paper introduced the concept of Proportional Hazards Model (PHM), it took advantage of the Weibull PHM to establish the failure rate model of transformer maintenance based on condition monitoring information. The failure rate threshold through the maximum availability method was determined, and then the maintenance decision model for the electric transformer was established. Finally, we used...
Transformers are a critical part of an electrical utility's asset base. Loss of a transformer in a utility, generation plant or process can cost many millions of dollars, depending on how long it is out-of-service. 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. This paper illustrates...
San Diego Gas & Electric (SDG&E) has committed to the construction of a comprehensive Transmission and Distribution Substation Condition Based Maintenance (CBM) project. The ultimate objective of this project is to extend the useful life and make greater utilization of its Transmission and Distribution Substation Assets. The transformer is the most expensive and critical asset in the substation...
Over the last decade there has been a renewed and increased interest in transformer life evaluation and monitoring. The main reason is that a large number of the transformers world population is approaching its expected end-of-life and the need increases for better methods to see whether the transformers are still fit for use or need to be retrofitted or replaced. In case of failure the possibility...
Power equipment with healthy condition is vital to security and stability of power grid. It is helpful to ensure power network secure and stable to grasp equipment status data immediately and comprehensively and to evaluate equipment status accurately. Information that reflects healthy status of substation equipment is analyzed. The CIM model is extended by following the semantic and grammar of CIM...
Chinese power industry developed rapidly recent years, and the problem of safety and reliability of power equipment is increasingly outstanding. The development of new test technology and the introduction of artificial intelligence (AI) are driving the monitoring and diagnosing method on insulation condition forward, and nowadays gradually changing the maintenance strategy from breakdown maintenance...
In this paper the basic management tools for asset and risk management were discussed. The structure and processes of asset management were shown. By the means of a risk matrix a good overview about the structure of the observed network is possible. For the equipment of high risk different measures can be applied to handle the risk. Besides preventing also reducing, transferring and finally accepting...
The condition-based maintenance of electrical transformer is a scientific overhauling management strategy prevailing domestically and abroad. This article depicts the failure diagnosing algorithm based on radial basis function (RBF), and by means of simulation, proves that the use of RBF method in condition-based maintenance of transformer obtains a comparatively good capability in classification,...
The need for improved performance of power systems in terms of reliability and higher productivity has necessitated more and more application of condition monitoring techniques, which can provide early warning of potential failure with the opportunity of organizing avoidance strategies to minimize loss of time and unexpected costs. Periodic condition monitoring tests have limitations such as continuous...
In order to take any proper maintenance actions the transformers conditions should be acquired. Since the transformer performance is limited by its main insulation condition, we focus on the thermal monitoring. As the transformer failure statistic rises, the root cause and ways to solve the problem should be found. Based on failure modes and effect analysis overloaded, external disturbances and ambient...
Power transformers are important and expensive components in electric energy networks. Unplanned outages of power transformers has a higher economical impact, which motivates, preventive tests and diagnosis for tapping the benefit of predicting condition to optimize maintenance and increase reliability of power system. Application of advanced diagnostic techniques for power transformers, provide the...
It is a common trend of power companies to progressively change its equipment maintenance strategies from relying on purely time-based preventive tasks to more condition-based predictive tasks. An important prerequisite of condition based maintenance is condition monitoring. Results of condition monitoring on power equipment form useful information in formulating asset strategies in the most cost...
Power transformers are usually very reliable and durable components of the power supply network. Unfortunately, when a fault occurs in a transformer, it can develop catastrophically and failures are usually very expensive, often resulting in the loss of what is the most expensive plant item in a substation [1]. In order to safeguard this valuable asset, various condition monitoring and diagnostic...
This paper deals with the practical importance of condition monitoring for power transformer in the electrical engineering field. A review has been made of the modern development in this technology. Some empirical relations have been established by using several practical data of different transformers. Practical test data of one of the State Electricity Boards of India has been taken & analysis...
In this paper, a methodology is developed to use data acquisition derived from condition monitoring and standard diagnosis for rehabilitation purposes of transformers. The interpretation and understanding of the test data are obtained from international test standards to determine the current condition of transformers. In an attempt to ascertain monitoring priorities, the effective test methods are...
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