Le cout des bornes de traversee est relativement insignifiant, compare a celui des equipements de puissance pour lesquels elles permettent au courant de traverser la cuve metallique des appareils maintenue a la masse. Cependant, ces... more
Le cout des bornes de traversee est relativement insignifiant, compare a celui des equipements de puissance pour lesquels elles permettent au courant de traverser la cuve metallique des appareils maintenue a la masse. Cependant, ces bornes sont tres importantes car leur defaillance peut entrainer la destruction totale de l'appareil. Par consequent, la qualite de leur isolation doit etre aussi excellente que possible. Dans ce travail, des techniques spectroscopiques dans les domaines temporel et frequentiel sont utilisees pour le suivi des differentes etapes de fabrication d'une borne de traversee. Les resultats obtenus montrent que l'application de ces methodes a la surveillance de l'isolation des equipements de puissance durant la fabrication est extremement utile ; les mesures effectuees fournissent des informations sur la qualite de cette isolation. Les defauts de fabrication etant des contraintes fortes que l'on se doit d'apprehender systematiquement lors...
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Partial Discharge (PD) is one of the most important factors in the gradual destruction of transformer insulation, more importantly if the problem is not resolved can cause complete insulation failure. Physical localization of the fault... more
Partial Discharge (PD) is one of the most important factors in the gradual destruction of transformer insulation, more importantly if the problem is not resolved can cause complete insulation failure. Physical localization of the fault inside the transformers in terms of saving repair time and cost is important. In this paper, by modeling a high voltage winding of a power transformer as a single-layer disk winding with air core the localization of PD is investigated. In this configuration, winding consists of six disks. Here, by applying impulse voltage as PD signal to the beginning of each disk, the voltages are measured and saved online at the bushing and neutral ends of the winding. By using the curve fitting method, the equations of PD signals at these two ends are extracted, then by computing transfer function in Laplace domain the magnitude of this transfer function are saved as a reference diagram. We have done this for all 6 disks. When PD occurred at winding by measuring vo...
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Bushings are essential components of power transformers and are one of the common causes of catastrophic failure for transformers. The majority of bushings are as old as the transformers and therefore maintaining and monitoring of bushing... more
Bushings are essential components of power transformers and are one of the common causes of catastrophic failure for transformers. The majority of bushings are as old as the transformers and therefore maintaining and monitoring of bushing condition is essential. The power factor and capacitance (PF&C) are the best indicators of the bushing’s condition. Off-line measurement of the PF&C needs to remove the power transformer from the network and a normal capacitance (NC) must be installed in the substation. In this contribution a novel method for on-line measuring of PF&C for power transformer condenser bushings with the software, hardware and sensors used in this method are introduced. According to laboratory measurement results this method can be used with acceptable accuracy in measurement of PF&C to detect a change in the bushing oil level, an increase in the oil moisture of the bushing and the temperature variation of the bushing oil.
On line monitoring can give informations about the condition of transformers and constitute a data base for an expert system. Actually on line monitoring and diagnostics are performed separately on different parts of transformers and the... more
On line monitoring can give informations about the condition of transformers and constitute a data base for an expert system. Actually on line monitoring and diagnostics are performed separately on different parts of transformers and the detection of a relation between all monitored data is very complex. One of the methods that can help experts to interpret the data base is to develop a model of a transformer that simulates the behaviour of all important parts. The frequency response analysis method is one of the most frequently used diagnostic tools for investigating coil deformation. On-line measured transfer function with a suitable transformer model and the estimation of parameters can support the diagnostic. In this contribution, a new technique for on-line transfer function monitoring of power transformer through its bushing taps or non-invasive capacitive sensors which are installed on the surface of the low and high voltage bushings is presented. To evaluate the feasibility ...
Importance of monitoring and diagnosis systems for power transformer grows persistently. Increasing number of diagnosis techniques, sensors and measuring equipments lead to generate a huge amount of data that is complex to manage and... more
Importance of monitoring and diagnosis systems for power transformer grows persistently. Increasing number of diagnosis techniques, sensors and measuring equipments lead to generate a huge amount of data that is complex to manage and exchange. Also there are different parties involved in using and manipulating these data such as substation and power plants personals and field experts. Therefore it is required to use semantic based way of representing, reasoning and querying data. Our proposal for this task is to apply semantic web technologies to the monitoring and diagnosis of power transformers. In this paper we present a semantic based data model for a monitoring and diagnosis system for power transformer. The captured data from power transformer sensors will be integrated in this semantic data model for further manipulation and processing.
Power transformers are one of the most important components of electric networks. These devices are very expensive and therefore diagnosis and monitoring systems will be valuable for preventing damage to these transformers. Statistical... more
Power transformers are one of the most important components of electric networks. These devices are very expensive and therefore diagnosis and monitoring systems will be valuable for preventing damage to these transformers. Statistical studies have shown that failures of bushings are one of the primary reasons for long duration outages of transformers. The use of data mining can improve the reliability and provide facilities to analysis of data that obtained from special sensor installed on power apparatus. It can also be used to extract information and knowledge that is not available and not visible from the data directly. Finding peculiarity data as a data mining technique will be useful to discover the possible change in bushing’s status. In this contribution, we describe an application of peculiarity oriented mining approach for analyzing of data that obtained from special sensor installed around the bushing’s surface. We propose a procedure for monitoring of transformers bushin...
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Interturn faults are a significant problem in power transformers that can eventually burgeon into catastrophic faults and likely result in an overall network failure. The main problem with SFRA as one of the well-recognized diagnostic... more
Interturn faults are a significant problem in power transformers that can eventually burgeon into catastrophic faults and likely result in an overall network failure. The main problem with SFRA as one of the well-recognized diagnostic tools for detecting winding faults is its restriction to the domain of offline testing since the method requires injection of a test signal into the
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Power transformers are one of the most important components of electric networks. These devices are very expensive and therefore diagnosis and monitoring systems will be valuable for preventing damage to these transformers. The aim of... more
Power transformers are one of the most important components of electric networks. These devices are very expensive and therefore diagnosis and monitoring systems will be valuable for preventing damage to these transformers. The aim of this contribution is to study the current situation in monitoring and diagnostic software systems for high voltage transformers and introducing software modules and techniques that will be useful for this purpose.
Conference Record of the 2004 IEEE International Symposium on Electrical Insulation, Indianapolis. IN USA, 19-22 September 2004 ... A Procedure for Diagnosis and Condition based Maintenance for Power Transformers ... Alireza Setayeshmehr,... more
Conference Record of the 2004 IEEE International Symposium on Electrical Insulation, Indianapolis. IN USA, 19-22 September 2004 ... A Procedure for Diagnosis and Condition based Maintenance for Power Transformers ... Alireza Setayeshmehr, Alireza Akbari, Hossein ...
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Abstract: Power transformers are one of the most important and expensive components in electric energy networks. The majority of them have been in service for many years under different environmental, electrical, and mechanical... more
Abstract: Power transformers are one of the most important and expensive components in electric energy networks. The majority of them have been in service for many years under different environmental, electrical, and mechanical conditions. To extend transformers life as long ...
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ABSTRACT Interturn winding faults are one of the most prevalent and potentially destructive electrical faults in power transformers. This contribution is an initiative to explore the potential of the sweep frequency response analysis... more
ABSTRACT Interturn winding faults are one of the most prevalent and potentially destructive electrical faults in power transformers. This contribution is an initiative to explore the potential of the sweep frequency response analysis (SFRA) method in detecting interturn winding faults and also identifying the most appropriate measurement configuration for making sensitive frequency response measurements. This application enables timely warning of the rising failure and so is of particular importance, as these kinds of defects, if left undetected, can propagate and lead to catastrophic phase–ground or phase–phase faults which can finally cause the breakdown of the whole transformer. In this paper contribution is made to a better understanding of the transformer performance and modification of the transformer winding frequency response in the presence of interturn faults. The paper includes a full description of the details of the SFRA method and measuring procedure, along with principal experiments conducted on a 100 kVA distribution transformer. A large number of measurements with different transfer functions, various terminal configurations and three categories of measurement types was conducted to identify the most appropriate configuration for making SFRA measurements. The experimental results proved that the identified measurement configuration is sensitive to detect unambiguously interturn faults even down to 0.2% shorted turns along the winding.