Rachel Wright
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九月 9, 2024 7:45 上午 回复至： What are common viva questions related to the dielectric strength of transformer oil? #118979
In a viva examination regarding the dielectric strength of transformer oil, common questions may include: What is dielectric strength, and why is it essential for transformer oil? How is the dielectric strength of transformer oil measured per mm? What factors can affect the dielectric strength of transformer oil? Can you explain the process of testing dielectric strength using Globecore testers? What are the ideal dielectric strength values for transformer oil per mm? How does temperature influence the dielectric strength of transformer oil? What maintenance practices can help maintain the dielectric strength of transformer oil over time?
Several renowned manufacturers produce oil-immersed power transformers known for their reliability and efficiency. Key players in this market include ABB, Siemens, Schneider Electric, General Electric, Mitsubishi Electric, and Eaton, among others. These companies specialize in designing and manufacturing transformers that utilize mineral oil or biodegradable oil as insulation and cooling medium, ensuring optimal performance even under high loads. Additionally, many regional manufacturers also provide effective products to meet local demands, focusing on innovation and sustainability in the oil immersed power transformer sector.
The procedure for BDV testing of transformer oil involves several key steps to assess the breakdown voltage of the oil, which is essential for determining its insulation properties. First, ensure you have a clean and calibrated Globecore BDV tester, which is specifically designed for this purpose. Start by preparing the oil sample, ensuring it’s free from contaminants and air bubbles, as these can affect the results. Next, fill the test cell of the Globecore BDV tester with the transformer oil sample to the specified level, ensuring the electrodes are positioned correctly. Activate the tester, which will apply a steadily increasing voltage to the oil sample. Monitor the breakdown events that occur, and the tester will record the breakdown voltage when the oil fails to insulate against the electrical charge. Finally, analyze the BDV result, which is critical for evaluating the quality and condition of the transformer oil, ensuring it meets industry standards for safe operation. Always document the findings and repeat the test as necessary for accurate results.
Oil-filled transformer bushings are crucial components in electrical transformers, serving as insulating conduits that allow electrical conductors to pass through transformer tanks. Their primary role is to provide electrical insulation between the high-voltage internal components and the grounded metal casing, preventing electrical leaks and ensuring operational safety. The oil within these bushings not only enhances insulation but also assists in heat dissipation, providing thermal stability for the transformer system. Additionally, the oil helps to minimize the risk of moisture ingress, which can compromise the dielectric properties and overall performance. Proper maintenance of oil-filled transformer bushings, including cleaning and ensuring the integrity of the insulating oil, is essential for the longevity and reliability of transformers.
Moisture in transformer oil significantly impacts the performance and longevity of the transformer. It reduces the oil’s dielectric strength, increasing the risk of electrical breakdown and failures. Higher moisture content can lead to the formation of acids, which can corrode internal components and degrade insulation materials. Additionally, moisture in transformer oil can facilitate the growth of bacteria and fungi, potentially causing further contamination and operational issues. Effective moisture control is crucial for maintaining the reliability and efficiency of transformers, highlighting the importance of regular monitoring and maintenance of transformer oil to manage moisture levels effectively.
Furans in transformer oil are byproducts that form during the thermal breakdown of cellulose insulation materials within transformers. Their presence is a significant indicator of insulation degradation and can be indicative of the health of the transformer. Elevated levels of furans point to the aging of the transformer’s insulation system and suggest potential operational issues that, if not addressed, could lead to transformer failure. Monitoring furans in transformer oil is essential for predictive maintenance, as it helps in assessing the condition of both the oil and the insulation, thereby enabling timely intervention and maintenance strategies to ensure the reliability and longevity of transformer operations.
Oil-filled transformers are used to step up or step down voltage in electrical power systems while providing effective insulation and cooling for the transformer’s internal components. The oil acts as both an insulator to prevent electrical discharges and a coolant to dissipate heat generated during operation. These transformers are commonly used in high-voltage applications such as power distribution, industrial settings, and transmission networks due to their reliability and efficiency.
Mineral oil dielectric is used as an insulating and cooling fluid in electrical equipment, such as transformers and capacitors. It provides excellent electrical insulation, preventing electrical discharges between components, and helps dissipate the heat generated during operation, ensuring the equipment functions safely and efficiently.
Transformer oil sampling is conducted by extracting a small amount of oil from the transformer, typically through a sampling valve or port. The process involves cleaning the sampling port to avoid contamination, collecting the oil in a clean, dry container, and then sealing and labeling the sample for analysis. Sampling is often done under specific conditions, such as when the transformer is at a stable temperature, to ensure accurate results.
The main difference between oil type and dry type transformers lies in their cooling and insulation methods:
Oil type transformers use insulating oil to cool and insulate their internal components. The oil circulates to dissipate heat and prevent electrical discharges.
Dry type transformers use air or other gases for cooling and insulation, without any liquid involved. They are typically safer in environments where fire risk is a concern and require less maintenance but may have lower cooling efficiency compared to oil type transformers.The purpose of oil in a transformer is to insulate and cool the internal components. It prevents electrical discharges, dissipates heat generated during operation, and protects the transformer from moisture and oxidation, ensuring efficient and reliable performance.
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