scholarly journals Effects of VA Rating on the Fault Diagnosis of Power Transformer Using SFRA Test

2021 ◽  
Vol 23 (5) ◽  
pp. 381-389
Author(s):  
Khalid H. Ibrahim ◽  
Nourhan R. Korany ◽  
Saber M. Saleh
Keyword(s):  
Fault Diagnosis ◽  
Power Transformer ◽  
Electrical Power ◽  
Mechanical Damage ◽  
Response Analysis ◽  
Electrical Power System ◽  
Statistical Parameters ◽  
Functional Interpretation ◽  
Emission Analysis ◽  
Main Challenge

The electric power transformer is an essential part of an electrical power system since it is used to step up or down voltage levels to maintain the system performance as well as possible. Frequency response analysis (FRA) is one of the most widely used techniques for detecting various types of mechanical damage in transformers. The equivalent circuit of the transformer will be represented by a complex network of R, L, and C elements in the FRA technique. For transformer faults diagnosis, various calculation techniques and diagnostic techniques may be used, such as acoustic emission analysis, thermal images of electromagnetic radiation, transformer temperature, and humidity analysis. SFRA test is one of these techniques that could be used to determine the fault type based on its response over a wide frequency range. The main challenge of the SFRA test is that the functional interpretation requirement for this test is not universally accepted Also statistical features are defined for this SFRA response to be used in fault detection and classification. In this paper, the effect of the transformer rating on the fault diagnosis techniques using SFRA is tested. Also, the effect of the transformer VA rating on the statistical parameters and the classification rules of fault diagnosis is discussed. Finally, the features used in fault diagnosis are ranked according to its independence of the transformer rating resulting in a more accurate matching fault diagnosis technique.

scholarly journals Frequency and time fault diagnosis methods of power transformers

2018 ◽  
Vol 18 (4) ◽  
pp. 162-167 ◽  
Author(s):  
Miroslav Gutten ◽  
Daniel Korenciak ◽  
Matej Kucera ◽  
Richard Janura ◽  
Adam Glowacz ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
High Voltage ◽  
Impact Test ◽  
Power Transformer ◽  
Short Circuit ◽  
Small Deformation ◽  
Short Circuit Current ◽  
Diagnostic Methods ◽  
Response Analysis ◽  
Short Circuit Currents

Abstract The authors describe experimental and theoretical analyses of faults of power transformer winding. Faults were caused by mechanical effect of short-circuit currents. Measurements of transformer were carried out in high-voltage laboratory. Frequency and time diagnostic methods (method SFRA - Sweep Frequency Response Analysis, impact test) were used for the analyses. Coils of transformer windings were diagnosed by means of the SFRA method and the time impact test. The analyzed methods had a significant sensitivity to a relatively small deformation of coil. In the analysis a new technique for analyzing the effects of short-circuit currents is introduced. This technique is developed for high-voltage transformers (different types of power). The proposed analyses show that it is necessary to analyze the value of short-circuit current. Short-circuit current represents a danger for the operation of the power transformer. The proposed approach can be used for other types of transformers. Moreover, the presented techniques have a potential application for fault diagnosis of electrical equipment such as: transformers and electrical machines.

scholarly journals The effects of drying time during manufacturing process on partial discharge of 83.3 mva 275/160 kv power transformer

2018 ◽  
Vol 218 ◽  
pp. 04008
Author(s):  
Siswanto ◽  
Agus Indarto ◽  
Radin Rahmatullah ◽  
Chairul Hudaya
Keyword(s):  
Manufacturing Process ◽  
Power Transformer ◽  
Partial Discharge ◽  
Electrical Power ◽  
High Standard ◽  
Electrical Power System ◽  
Drying Time ◽  
Standard Design ◽  
Cellulose Insulation ◽  
Discharge Test

Power transformer (PT), essential equipment in electrical power system proceeds complicated manufacturing process to meet high standard design. During manufacturing process of PT, the drying stage is of importance to remove excessive moisture contaminant on the solid insulation. This study investigated the effects of drying duration on partial discharge test of 83.3 MVA 275/160 kV PT. The partial discharge test measurements were carried out using IEC 60270 standards comprising of the capacitive network model based on the main quantity apparent charge concept. We found that the lowest partial discharge of 21 pC was achieved at 68 hours drying duration, while the highest value of 60 pC was reached at 81 hours drying time. The longer drying time may lead to initial degradation of cellulose insulation due to excessive heating. The amount of water extracted during drying effect to partial discharge also investigated. We conclude that the drying time at a higher and lower than 68 hours significantly contributes to the increased partial discharge values of PT.

Fault Location Techniques in Electrical Power System-A Review

2017 ◽  
Vol 8 (1) ◽  
pp. 206 ◽  
Author(s):  
Hui Hwang Goh ◽  
Sy yi Sim ◽  
Mohamad Amirul Hafiz Mohamed ◽  
Abdul Khairi Abdul Rahman ◽  
Chin Wan Ling ◽  
...  
Keyword(s):  
Fault Detection ◽  
Power System ◽  
Fault Location ◽  
Electrical Power ◽  
Electric Power System ◽  
Electrical Power System ◽  
System A ◽  
Main Challenge ◽  
Distribution Line ◽  
Continuous Power

<p>Electric fault is the main challenge in the process of providing continues electric supply. Fault can occur at anytime and anywhere. Due to the fault causes are mainly based on natural disaster or accident. Most fault occurrence hardly predicted nor avoided. Therefore, a quick response fault detection is necessary to ensure that the fault area is maintained to ensure a continuous power supply system. Hence, a system is required to detect and locate the position of the fault in the power system especially in the transmission line and distribution line. This paper will review the type of fault that possibly occurs in an electric power system, the type of fault detection and location technique that are available together with the protection device that can be utilized in the power system to protect the equipment from electric fault.</p><p> </p>

Power Transformers Condition Assessment of GI Simangkuk Switchyard Sumatra Interconnection in Indonesia

2012 ◽  
Vol 452-453 ◽  
pp. 975-979 ◽  
Author(s):  
Josep Franklin Sihite ◽  
Takehisa Kohda
Keyword(s):  
Power Systems ◽  
Power Transformer ◽  
Electrical Power ◽  
Aging Effect ◽  
Diagnostic Methods ◽  
System Stability ◽  
Power Transformers ◽  
System Control ◽  
Electrical Power System ◽  
Power Utility

The electricity needs of Indonesia grow an average 10% each year. Therefore, PLN (Perusahaan Listrik Negara) as the only power utility business in Indonesia, has a master plan to develop new power plant, switchyard and transmission system. One of the new developed systems is GI Simangkuk switchyard of Sumatra interconnection system. This switchyard is prepared to improve reliability of Sumatra interconnection system. This site utilizes power transformers of 275 kV. Power transformer is one of the main equipments in power systems. When a failure occurs in a power transformer, the whole system will be failed and the electricity could not be delivered to customer. Each utility has to assure their reliability in order to maintain electrical power system stability by assessing transformer condition. There is an increasing need for better diagnostic and monitoring tools to assess the condition of transformers. Modern power transformers are equipped with software and computer system control. The reliability of this computer systems are needed to evaluate for assurance of system safety. This paper describes the need of assessment and maintenance of power transformers such as outages effect of failures, high cost of maintenance and replacement, increase of world demand, aging effect and used of old transformer, and computer protection system failure. Monitoring and diagnostic methods of transformers assessment have been developing in recently years. They can be separated into traditional and non-traditional methods that have been used in many years and are still in research stage. In this paper we propose a new approach in order to assess power transformer condition by using fault tree analysis.

scholarly journals Adaptive ANN based differential protective relay for reliable power transformer protection operation during energisation

2019 ◽  
Vol 8 (4) ◽  
pp. 307
Author(s):  
Azniza Ahmad ◽  
Mohammad Lufti Othman ◽  
Kurreemun Khudsiya Bibi Zainab ◽  
Hashim Hizam
Keyword(s):  
Power Transformer ◽  
Electrical Power ◽  
Circuit Breaker ◽  
Inrush Current ◽  
Electrical Power System ◽  
Transformer Protection ◽  
Protection Scheme ◽  
Internal Fault ◽  
Magnetizing Inrush Current ◽  
Harmonic Restraint

Power transformer is the most expensive equipment in electrical power system that needs continuous monitoring and fast protection response. Differential relay is usually used in power transformer protection scheme. This protection compares the difference of currents between transformer primary and secondary sides, with which a tripping signal to the circuit breaker is asserted. However, when power transformers are energized, the magnetizing inrush current is present and due to its high magnitude, the relay mal-operates. To prevent mal-operation, methods revolving around the fact that the relay should be able to discriminate between the magnetizing inrush current and the fault current must be studied. This paper presents an Artificial Neural Network(ANN) based differential relay that is designed to enable the differential relay to correct its mal-operation during energization by training the ANN and testing it with harmonic current as the restraining element. The MATLAB software is used to implement and evaluate the proposed differential relay. It is shown that the ANN based differential relay is indeed an adaptive relay when it is appropriately trained using the Network Fitting Tool. The improved differential relay models also include a reset part which enables automatic reset of the relays. Using the techniques of 2nd harmonic restraint and ANN to design a differential relay thus illustrates that the latter can successfully differentiate between magnetizing inrush and internal fault currents. With the new adaptive ANN-based differential relay, there is no mal-operation of the relay during energization. The ANN based differential relay shows better performance in terms of its ability to differentiate fault against energization current. Amazingly, the response time, when there is an internal fault, is 1 ms compared to 4.5 ms of the conventional 2nd harmonic restraint based relay.

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