JINSHANMEN TECHNOLOGY CO., LTD mainly produces oil immersed power transformers, dry-type power transformers, oil immersed three-dimensional coiled power transformers, dry-type three-dimensional coiled power transformers, mining explosion-proof dry-type transformers, mining explosion-proof mobile substations, amorphous alloy power transformers, on load capacity regulating power transformers, locomotive dry-type transformers, as well as prefabricated substations, modular substations, wind energy box type substations, high and low voltage switchgear and other transmission and distribution equipment. With rich experience in the power equipment industry, we are committed to providing professional technical support and high-quality products for global customers. The following is a detailed introduction to the oil quality judgment and oil leakage defect treatment of oil filled transformer, which is of great significance for the stable operation of power equipment such as 50 kva single phase transformer.
I. Application Advantages of Oil Filled Transformer
In the field of power equipment, oil filled transformer is widely used instead of dry-type transformer, which is mainly due to its unique performance advantages. These advantages ensure the stable and reliable operation of equipment under complex working conditions, and are also applicable to common models such as 50 kva single phase transformer.
Significantly improve electrical insulation strength: Effectively shorten the insulation distance, reduce the equipment volume on the premise of ensuring insulation performance, make the structure of products such as 50 kva single phase transformer more compact, and save installation space.
Optimize heat dissipation effect: Through the thermal cycle of transformer oil, the heat of the transformer body is efficiently transferred to the shell and radiator, greatly improving the heat transfer efficiency, increasing the allowable current density of the conductor, reducing the equipment weight, and ensuring the temperature stability of the oil filled transformer during long-term operation.
Extend service life: The oil-immersed sealed design reduces the oxidation rate of internal components, reduces the erosion of environmental factors on the equipment. Even the oil filled transformer operating at high frequency can achieve long-term stable service with reasonable maintenance.
II. Core Performance of Transformer Oil
Transformer oil in operation must have stable insulation performance and thermal conductivity, among which insulation strength, viscosity, pour point and acid value are the core indicators. Transformer oil is refined from petroleum, containing various hydrocarbons, resins, acids and impurities. Its performance is prone to oxidation under the influence of temperature, electric field, light and other factors. Under normal circumstances, the oxidation process is slow, and it can be used for more than 20 years with proper maintenance. However, pollutants such as metal impurities and gases will accelerate oxidation, leading to oil deterioration (darkened color, decreased transparency), increased moisture, acid value and ash content, and ultimately degradation and failure. For the transformer oil used in 50 kva single phase transformer, regular detection of these indicators is the key to ensuring equipment safety.
III. Causes and Stages of Transformer Oil Deterioration
The deterioration of transformer oil is divided into two stages: pollution and deterioration, with different causes and impacts:
Pollution stage: Mainly caused by moisture and impurities mixed into the oil, not oxidation products. Pollution will lead to the decline of oil insulation performance, reduction of breakdown electric field strength, and increase of dielectric loss angle, which directly threatens the insulation safety of oil filled transformer.
Deterioration stage: The core is the oxidation reaction of oil, and metal particles such as copper, iron and aluminum in the oil will accelerate this process. Even if the transformer is fully sealed internally, there is still about 0.25% volume of oxygen, and oxygen has high solubility in oil. Under the catalysis of moisture and acceleration of heat, oxidation will generate sludge. Under the action of electric field, these sludges form large particle precipitates, which concentrate in areas with strong electric field to form conductive "bridges". At the same time, they hinder heat dissipation, accelerate the aging of insulation materials, and lead to the decline of insulation resistance and insulation level.
IV. Judgment and Maintenance of Transformer Oil Quality
1. Judgment and Treatment of Insulating Oil Deterioration
The deterioration of insulating oil is manifested in the comprehensive change of physical and chemical properties, which in turn leads to the deterioration of electrical performance. It can be judged by detecting indicators such as acid value, interfacial tension and water-soluble acid value. The treatment method is regeneration treatment, which can effectively eliminate deterioration products. However, it should be noted that the regeneration process may lose natural antioxidants, and subsequent protection should be done well after treatment.
2. Judgment and Treatment of Insulating Oil Moisture Intrusion
Water is a strong polar substance, which is easy to ionize and decompose in the electric field. Trace moisture can significantly increase the dielectric loss of insulating oil. Whether it is damp can be judged by detecting the micro water content in the oil. For this problem, the pressure-type vacuum oil filtration method can effectively remove moisture and restore the insulation performance of the oil. This method is applicable to the oil quality treatment of various oil filled transformers.
V. Treatment of Transformer Oil Leakage Defects
Oil leakage is the most common defect of oil filled transformer, accounting for more than 90% of the total defects. Main leakage parts and proportions: more than 50% of the parts are radiator interfaces, flat butterfly valve caps, etc.; bushing and porcelain insulator leakage account for 16%; gas relay interface leakage accounts for 12%; in addition, there are leaks caused by inherent defects such as welds and sandholes during manufacturing. The following are the treatment schemes for two common types of leakage:
1. Treatment of Oil Leakage at Welding Joints
Causes: Poor welding quality (cold welding, incomplete welding, pinholes, sandholes), hidden dangers covered by welding flux and paint when leaving the factory, and weld cracking caused by electromagnetic vibration during operation. Treatment steps: First, comprehensively check the leakage points to ensure no omission; locate the source along the oil trace through cleaning; seal the leakage point with water-oil compatible supplement, which can achieve long-term anti-leakage after curing.
2. Treatment of Oil Leakage from Cast Iron Parts
Causes: Sandholes or cracks in cast iron parts. Treatment steps: For crack leakage, first drill a stop crack hole to avoid stress extension; drive lead wire or rivet the leakage point according to the crack condition; clean the leakage point with acetone, then seal it with water-oil compatible supplement and titanium steel glue. This scheme is also applicable to the repair of cast iron part leakage of small oil filled transformers such as 50 kva single phase transformer.
Conclusion
The oil quality state and sealing performance of the transformer directly affect the operation stability and service life of the oil filled transformer. Regular oil quality detection and timely treatment of oil leakage defects are the key links in power equipment operation and maintenance. With professional R&D and production capabilities, JINSHANMEN TECHNOLOGY CO., LTD provides global customers with various high-quality oil-immersed and dry-type transformers including 50 kva single phase transformer and supporting power transmission and distribution equipment, and also provides perfect technical support to help customers achieve safe and efficient operation of equipment.