Abstract
Transformer insulating oil is the core auxiliary material of power transformers, undertaking dual insulation and heat dissipation functions, and its performance directly determines the operational safety, stability and service life of power transformers. Over the past decade, driven by global energy transformation, UHV power grid construction upgrading and stringent environmental protection requirements, the technological R&D, product iteration and engineering application of transformer insulating oil have entered a high-quality development stage. Conventional mineral insulating oil has achieved comprehensive performance optimization through refining process upgrading and additive system innovation; new environmentally friendly ester oil represented by natural ester and synthetic ester insulating oil has broken through key technical bottlenecks and realized large-scale industrial application; functional insulating oil technologies such as nanomodified insulating oil and high-fire-point insulating oil have made important research progress and been gradually applied in special working conditions. At the same time, the matching detection, monitoring and operation maintenance technologies of transformer insulating oil have completed digital and intelligent upgrading with the development of IoT and big data technology. This paper reviews the technological development of transformer insulating oil in the past decade from the aspects of traditional mineral oil optimization, new environmentally friendly oil R&D, functional oil innovation and supporting technology upgrading, analyzes the current technical bottlenecks and industry demands, and looks forward to the future development trend of transformer insulating oil industry, aiming to provide reference for the technological R&D and engineering application of transformer insulating oil in the global power industry.
Keywords
Transformer Insulating Oil; Mineral Insulating Oil; Environmentally Friendly Ester Oil; Nanomodified Insulating Oil; UHV Transformer Insulating Oil; Insulating Oil Online Monitoring; Insulating Oil Operation and Maintenance; Technological Development
1 Introduction
Power transformers are the core equipment of power transmission and distribution systems, and their safe and reliable operation is the foundation of stable power grid operation. Transformer insulating oil, as the key internal medium of transformers, not only isolates live parts with different potentials to prevent electrical breakdown, but also transfers the heat generated by transformer core and winding operation to the outside, ensuring the equipment operates within the rated temperature range. Since the birth of mineral insulating oil in the late 19th century, it has been the main type of transformer insulating oil for more than a century due to its excellent insulation performance, low cost, mature production process and wide raw material sources.
In the past decade, the global power industry has undergone profound changes: the large-scale grid connection of renewable energy such as wind power and photovoltaic has put forward higher requirements for the overload capacity, temperature resistance and aging resistance of transformers and their matching transformer insulating oil; the construction of UHV transformer and smart power grids has raised the performance standards of UHV transformer insulating oil for high-voltage and large-capacity transformers; the "double carbon" goal has made environmental protection, biodegradability and low carbon emissions core indicators for transformer insulating oil selection; in addition, the application of transformers in special working conditions such as high altitude, high temperature, fire-prone areas and marine environments has put forward personalized performance requirements for transformer insulating oil.
Faced with the above new demands and challenges, the transformer insulating oil industry has launched in-depth technological R&D in the past ten years. On the one hand, it has carried out iterative optimization of traditional mineral insulating oil to make up for its shortcomings in fire resistance, aging resistance and environmental protection; on the other hand, it has accelerated the R&D and industrialization of new environmentally friendly ester oil, and developed functional transformer insulating oil adapted to special working conditions through material modification and composite technology. At the same time, the supporting insulating oil detection and insulating oil operation and maintenance technologies have also achieved digital and intelligent upgrading, forming a complete technical system from oil product R&D to application and maintenance. This paper systematically sorts out the technological development achievements of transformer insulating oil in the past decade and looks forward to its future development direction, so as to provide a reference for the technological progress of the power equipment auxiliary material industry.
2 Technological Optimization of Conventional Mineral Insulating Oil
Mineral insulating oil is refined from crude oil through distillation, solvent refining, hydrogenation and clay refining processes. It has the characteristics of low dielectric loss, good heat transfer performance and mature application technology, and still accounts for more than 80% of the global transformer insulating oil market share in the past decade. In response to the problems of poor fire resistance, easy aging and low oxidation stability of traditional mineral insulating oil, the industry has carried out a series of technological optimization and upgrading from raw material selection, refining process and additive R&D in the past ten years, significantly improving the comprehensive performance of mineral insulating oil.
2.1 Upgrading of Refining Process
The traditional solvent refining process has the problems of low oil yield, large solvent consumption and difficulty in removing polar impurities. In the past decade, hydrogenation refining technology has become the mainstream process for the production of high-grade mineral insulating oil, and has been continuously optimized and upgraded. The fully hydrogenated refining process can remove sulfur, nitrogen, oxygen and other heteroatoms in the oil, as well as aromatic hydrocarbons, colloid and other impurities that are easy to cause aging, and the saturation of the oil is significantly improved. The mineral insulating oil produced by this process has the advantages of high oxidation stability, low dielectric loss, good anti-aging performance and long service life. Compared with the traditional solvent refined oil, the oxidation induction period of fully hydrogenated mineral insulating oil can reach more than 1000 hours (GB/T 17623 standard), which is 3-5 times that of solvent refined oil, and the service life in the transformer can be extended to more than 30 years.
In addition, molecular distillation technology has been gradually applied in the deep refining of mineral insulating oil in the past decade. This technology can separate the light and heavy components in the oil at the molecular level, remove the low-boiling point volatile components and high-boiling point heavy components that affect the performance of the oil, and further improve the flash point, fire point and temperature resistance of mineral insulating oil, making it suitable for the operation of UHV transformer and overload transformers under high-temperature conditions.
2.2 Innovation of Additive System
Additives are the "core modifiers" of mineral insulating oil, which can effectively make up for the inherent performance defects of the base oil and improve the targeted performance of the oil. In the past decade, the R&D of mineral insulating oil additives has moved towards the direction of high efficiency, low dosage, multi-function and environmental protection, breaking through the technical bottleneck of single-function additives in the past, and developing a series of composite additives with synergistic effects.
Antioxidant additive: The traditional phenolic and amine antioxidants have the problems of easy volatilization and poor high-temperature stability. The new hindered phenol antioxidants and organic sulfur-phosphorus composite antioxidants developed in the past ten years have the characteristics of high antioxidant efficiency, low dosage (adding amount less than 0.5%) and good compatibility with base oil. They can form a stable protective film on the metal surface of the transformer, inhibit the oxidative decomposition of mineral insulating oil under high-temperature conditions, and significantly extend the oxidation induction period of the oil.
Metal deactivator: A new type of benzotriazole derivative metal deactivator has been developed to solve the problem of catalytic oxidation of the oil caused by copper, iron and other metal ions in the transformer. This additive can form a chelate with metal ions, isolate the contact between metal ions and oil, and reduce the oxidation rate of mineral insulating oil by more than 60%.
Pour point depressant and viscosity index improver: Aiming at the problem of high viscosity and poor fluidity of mineral insulating oil in low-temperature environments, the new polyacrylate and polyolefin pour point depressants have been optimized in molecular structure, which can effectively reduce the pour point of mineral insulating oil to below -45℃, and ensure the normal heat dissipation and insulation performance of the oil in high-altitude and cold regions.
Composite additive: The multi-functional composite additive integrating anti-oxidation, metal deactivation, anti-foaming and anti-corrosion has become the mainstream product. The composite additive can realize the synergistic effect of various single additives, avoid the mutual interference between different additives, and improve the comprehensive performance of mineral insulating oil with lower total adding amount, which is more in line with the environmental protection and high-efficiency requirements of the power industry.
2.3 Development of Special Grade Mineral Insulating Oil
In response to the demand of UHV power grid construction for high-voltage and large-capacity transformers, the industry has developed UHV transformer insulating oil with ultra-high insulation performance and low dielectric loss in the past decade. The oil has the characteristics of ultra-low water content (≤5 ppm), ultra-low dielectric loss (tanδ≤0.0005 at 90℃), high breakdown voltage (≥75 kV), and good compatibility with transformer insulation paper. It can meet the insulation and heat dissipation requirements of 1000 kV AC and ±800 kV DC UHV transformer, and has been successfully applied in a number of UHV power grid projects around the world.
In addition, aiming at the application of transformers in marine, coastal and other humid and corrosive environments, the anti-corrosion mineral insulating oil with anti-humidity and anti-corrosion performance has been developed. By adding special anti-corrosion additives and optimizing the refining process, the oil can effectively prevent the corrosion of transformer metal parts by moisture and salt spray, and improve the operational stability of transformers in harsh marine environments, which is an important branch of mineral insulating oil technological optimization.
3 R&D and Industrial Application of New Environmentally Friendly Ester Insulating Oil
In the past decade, with the increasingly stringent environmental protection laws and regulations and the deepening of the green development concept, the R&D and industrialization of environmentally friendly ester oil have become the core development direction of the transformer insulating oil industry. Different from traditional mineral insulating oil, environmentally friendly ester oil has the characteristics of biodegradability, low toxicity, high fire resistance and good environmental compatibility. Even if it leaks during transportation and use, it will not cause pollution to soil and water sources, and has obvious advantages in fire safety. In the past ten years, natural ester insulating oil and synthetic ester insulating oil have become the main types of new environmentally friendly ester oil, and have achieved key technological breakthroughs and large-scale engineering application in the transformer insulating oil field.
3.1 Natural Ester Insulating Oil
Natural ester insulating oil is refined from renewable vegetable oils such as rapeseed oil, soybean oil and palm oil through degumming, deacidification, hydrogenation and esterification processes. It is a typical green and environmentally friendly transformer insulating oil with a biodegradability rate of more than 90% (OECD 301 standard), non-toxic to the environment and organisms, and its flash point is as high as 300℃ or more, and fire point is more than 330℃, which is a non-flammable insulating medium. It fundamentally solves the fire safety hazard of traditional mineral insulating oil transformers in fire-prone areas such as high-rise buildings, shopping malls, hospitals and data centers.
In the past decade, the technical R&D of natural ester insulating oil has mainly focused on solving the problems of high viscosity, poor low-temperature fluidity and easy hydrolysis in the early stage. Through the optimization of raw material selection (such as selecting high oleic acid vegetable oil as raw material) and the improvement of modification process, the viscosity of natural ester insulating oil has been reduced by more than 40%, and the pour point has been reduced to below -30℃, which significantly improves its low-temperature fluidity and heat transfer performance—two core performance indicators of transformer insulating oil. At the same time, the new anti-hydrolysis additive and molecular structure modification technology have effectively improved the hydrolysis resistance of natural ester insulating oil, making its stability in humid environments close to that of mineral insulating oil.
In terms of application, natural ester insulating oil has realized large-scale engineering application in the transformer insulating oil industry in the past decade. In Europe, the United States, Japan and other developed countries, more than 50% of urban distribution transformers have adopted natural ester insulating oil. In China, with the promotion of the green power grid concept, natural ester insulating oil transformers have been widely used in key projects such as data centers, high-speed rail stations and urban subways, and have been applied in 35 kV and 110 kV medium and high-voltage transformers, breaking the monopoly of foreign technologies and realizing the localization of natural ester insulating oil products in China's transformer insulating oil market.
3.2 Synthetic Ester Insulating Oil
Synthetic ester insulating oil is synthesized by the esterification reaction of polyol and fatty acid, which is an important type of environmentally friendly ester oil with the characteristics of good thermal stability, high oxidation resistance, low viscosity and good low-temperature fluidity. Its biodegradability rate is more than 80%, which is an environmentally friendly transformer insulating oil between natural ester oil and mineral oil. The flash point of synthetic ester insulating oil is about 260℃, and the fire point is more than 280℃, which has good fire resistance. At the same time, it has good compatibility with all kinds of transformer insulating materials (such as insulating paper, rubber, plastic), and can be directly used to replace mineral insulating oil in existing transformers without modifying the transformer structure, which has the advantage of convenient replacement and transformation, and is suitable for the upgrading and transformation of existing transformer insulating oil in the power grid.
In the past decade, the technological development of synthetic ester insulating oil has focused on the optimization of synthesis process and the improvement of high-temperature stability. The new catalytic esterification technology and molecular distillation purification process have reduced the content of free acid and moisture in synthetic ester insulating oil, improved the insulation performance and thermal stability of the oil, and its oxidation induction period can reach more than 800 hours, which is higher than that of natural ester oil. In addition, the modified synthetic ester insulating oil developed by introducing special functional groups into the molecular structure has further improved its high-temperature resistance and anti-aging performance, and can operate stably for a long time at a temperature of 180℃, which is suitable for high-temperature and overload transformers in renewable energy power generation systems such as wind power and photovoltaic, and has become a key supporting transformer insulating oil for new energy power generation.
In terms of application, synthetic ester insulating oil is mainly used in medium and high-voltage transformers, mobile transformers and special transformers in the transformer insulating oil market in the past decade due to its excellent comprehensive performance. It has been widely applied in wind power bases, photovoltaic power stations and UHV power grid supporting projects, and has become an important choice for high-performance transformer insulating oil.
3.3 Other New Environmentally Friendly Insulating Oil
In addition to ester insulating oil, the industry has also carried out R&D of other new environmentally friendly transformer insulating oil in the past decade, such as vegetable oil-based modified insulating oil, alkylbenzene insulating oil and fluorinated insulating oil. Among them, alkylbenzene insulating oil has good insulation performance, low temperature fluidity and oxidation stability, and its biodegradability is better than that of mineral insulating oil, and has been applied in some special transformers such as railway transformers and marine transformers. Fluorinated insulating oil has ultra-high thermal stability and chemical stability, and can operate at high temperatures of more than 200℃, but its high cost and low biodegradability limit its large-scale application in the transformer insulating oil market, and it is only used in a small number of high-end special transformers at present.
Vegetable oil-based modified insulating oil is a new type of transformer insulating oil developed by compounding natural vegetable oil with mineral insulating oil and adding special modifiers. It combines the environmental protection and fire resistance of environmentally friendly ester oil with the low viscosity and mature application of mineral insulating oil, and has the advantages of low cost and easy promotion. It has become a research hotspot in the low-voltage distribution transformer insulating oil field in recent years, and has achieved small-scale trial application in some regions.
4 Innovation of Functional Transformer Insulating Oil Technology
In the past decade, with the diversification of transformer application scenarios and the improvement of performance requirements, the R&D of transformer insulating oil has moved from the traditional "insulation + heat dissipation" dual functions to the direction of multi-functionalization and customization. By means of nanomaterial modification, composite blending and functional group introduction, the industry has developed a series of functional transformer insulating oil with special performance such as nanomodified insulating oil, high-fire-point flame-retardant insulating oil, anti-aging long-life insulating oil and anti-pollution insulating oil, which have made important progress in adapting to special working conditions and improving the operational reliability of transformers, and enriched the product system of the transformer insulating oil industry.
4.1 Nanomodified Insulating Oil
Nanomodified insulating oil is a new type of functional transformer insulating oil prepared by adding nanomaterials with special properties (such as TiO₂, Al₂O₃, SiO₂ metal oxide nanoparticles, carbon nanomaterials, ceramic nanoparticles) into the base oil (mineral insulating oil, environmentally friendly ester oil) through a special dispersion process, and realizing the performance improvement of the oil through the nano-effect. It is one of the most important research directions of transformer insulating oil technology in the past decade, and has become a hot spot in the field of power equipment insulation materials at home and abroad.
Nanomodified insulating oil has significant advantages in core performance indicators of transformer insulating oil such as insulation performance, heat transfer performance and anti-aging performance: the nanomaterials dispersed in the oil can capture the free electrons generated during the partial discharge of the transformer, inhibit the development of electron avalanche, and significantly improve the breakdown voltage of the oil (the AC breakdown voltage can be increased by 20%-50% compared with the base oil); the high thermal conductivity of nanomaterials can improve the thermal conductivity of the oil by more than 30%, enhance the heat dissipation effect of the transformer, and improve the overload capacity of the transformer; the nanomaterials can also absorb the free radicals generated during the oxidation of the oil, inhibit the oxidative decomposition of the oil, and improve the anti-aging performance of the oil.
In the past decade, the research of nanomodified insulating oil has mainly focused on the selection of nanomaterials, the optimization of dispersion process and the research of stability mechanism—the key technical points of nanomodified insulating oil R&D. The industry has developed a series of high-performance nanomaterials such as graphene oxide modified nanomaterials, and developed a special surface modification and ultrasonic dispersion process, which solved the problems of agglomeration and poor dispersion stability of nanomaterials in the oil that have long plagued the nanomodified insulating oil industry. At present, nanomodified insulating oil based on mineral insulating oil and environmentally friendly ester oil has completed laboratory research and small-scale pilot test, and has been tested and applied in 10 kV and 35 kV distribution transformers, showing good application prospects in the transformer insulating oil market.
4.2 High-fire-point and Flame-retardant Insulating Oil
Aiming at the fire safety requirements of transformers in fire-prone areas such as data centers and nuclear power plants, the industry has developed high-fire-point flame-retardant transformer insulating oil with higher fire resistance performance on the basis of environmentally friendly ester oil in the past decade. The flash point of this type of transformer insulating oil is more than 350℃, and it has the characteristics of self-extinguishing after leaving the fire source, no toxic gas release during combustion, and can effectively prevent the spread of fire. The high-fire-point flame-retardant insulating oil is mainly prepared by compounding ester oil with phosphorus-based, halogen-free flame retardant additives and molecular structure modification, has good compatibility with transformer insulating materials and does not corrode metal parts, which is the ideal transformer insulating oil for key fire protection places such as data centers, nuclear power plants and chemical plants. At present, the high-fire-point flame-retardant transformer insulating oil has completed the type test and has been applied in a small number of high-end special transformer projects.
4.3 Anti-aging and Long-life Insulating Oil
In response to the demand for long service life of transformers in UHV and smart power grids (the design service life is more than 40 years), the industry has developed anti-aging long-life transformer insulating oil in the past decade. This type of oil is based on fully hydrogenated mineral insulating oil or synthetic ester insulating oil, and is added with high-efficiency anti-oxidation, metal deactivation and anti-aging composite additives. Its oxidation induction period is more than 1500 hours, and the thermal stability temperature is more than 150℃. It can inhibit the aging of the oil and insulating paper at the same time, and realize the "oil-paper synergy anti-aging" effect, significantly extending the service life of the transformer. At present, the anti-aging long-life transformer insulating oil has been applied in 220 kV and 500 kV high-voltage transformers, and the operation test shows that its performance is stable and the anti-aging effect is significant, which is an important functional innovation of transformer insulating oil technology.
5 Upgrading of Insulating Oil Detection and Operation & Maintenance Technology
The performance of transformer insulating oil changes continuously during operation, and the timely and accurate detection of oil performance parameters is the key to judging the operating state of the transformer and carrying out predictive maintenance. In the past decade, with the development of digital, intelligent and Internet of Things (IoT) technologies, the insulating oil detection and insulating oil operation and maintenance technology of transformer insulating oil have realized the transformation from off-line sampling detection to insulating oil online monitoring, from single parameter detection to multi-parameter comprehensive analysis, and from passive maintenance to predictive maintenance, forming a complete intelligent operation and maintenance system of transformer insulating oil matching the development of smart power grids.
5.1 Innovation of Insulating Oil Online Monitoring Technology
The traditional off-line sampling detection has the problems of long detection cycle, large human error and inability to reflect the real-time performance of transformer insulating oil. In the past decade, the insulating oil online monitoring technology of transformer insulating oil has achieved rapid development, and a series of insulating oil online monitoring sensors and systems with high precision, high stability and strong anti-interference have been developed, realizing the real-time monitoring of key performance parameters of transformer insulating oil such as water content, dielectric loss, breakdown voltage, dissolved gas, acid value and oxidation degree.
The core technological breakthroughs of insulating oil online monitoring technology in the past decade mainly include: the development of micro-nano sensor technology, which miniaturizes the detection sensor and improves its sensitivity and anti-interference ability; the application of optical detection technology (such as infrared spectroscopy, Raman spectroscopy), which realizes the non-contact and non-destructive detection of oil parameters, avoiding the pollution and loss of the oil sample; the development of wireless communication technology (5G, LoRa), which realizes the real-time transmission of insulating oil online monitoring data to the smart power grid platform, and realizes the remote monitoring and early warning of the oil state. At present, the multi-parameter insulating oil online monitoring system of transformer insulating oil has been widely applied in UHV transformer, large-capacity power plant transformers and key substation transformers, and has become an important part of the state monitoring system of smart power grids.
5.2 Development of Rapid Detection Technology
Aiming at the demand of on-site rapid detection of transformer insulating oil in power grid operation and maintenance, the industry has developed a series of portable rapid detection instruments in the past decade, such as portable dissolved gas analyzer, portable water content detector, portable dielectric loss tester and so on. These instruments have the characteristics of small volume, light weight, fast detection speed and simple operation, and can complete the detection of key parameters of transformer insulating oil on site in a few minutes, which solves the problem of long off-line detection cycle and improves the efficiency of insulating oil operation and maintenance.
In addition, the intelligent oil sample detection robot has been developed and applied in some large substations in recent years. The robot can realize the automatic sampling, automatic detection and automatic data upload of transformer insulating oil, completely replacing manual operation, and improving the accuracy and efficiency of insulating oil detection, which is the important development direction of insulating oil detection technology in the future.
5.3 Intelligent Operation and Maintenance Based on Big Data and AI
In the past decade, with the construction of smart power grids, the insulating oil operation and maintenance of transformer insulating oil has entered the era of intelligent operation and maintenance based on big data and artificial intelligence (AI). By collecting the insulating oil online monitoring data of transformer insulating oil, the operating data of the transformer and the environmental data of the substation, and establishing a big data analysis model, the AI algorithm can realize the comprehensive analysis and evaluation of the oil state, predict the potential faults of the transformer (such as partial discharge, overheating, insulation aging) in advance, and put forward targeted insulating oil operation and maintenance suggestions, realizing the transformation from "post-maintenance" to "predictive maintenance" and "condition-based maintenance" in the insulating oil operation and maintenance field.
At present, many power grid companies at home and abroad have built the intelligent insulating oil operation and maintenance platform of transformer insulating oil, which integrates data collection, analysis, early warning and maintenance decision-making. The platform can realize the unified management of the transformer insulating oil state of all transformers in the power grid, improve the level of refined insulating oil operation and maintenance of the power grid, and reduce the failure rate of transformers caused by oil performance degradation.
6 Industry Development Trends and Challenges
6.1 Development Trends
Driven by the global energy transformation, stringent environmental protection requirements and continuous technological progress, the transformer insulating oil industry will show the following development trends in the future, which will guide the subsequent R&D and application of mineral insulating oil, environmentally friendly ester oil and nanomodified insulating oil:
Green and low-carbonization: Environmental protection will become the core indicator of the development of transformer insulating oil, and environmentally friendly ester oil such as natural ester and synthetic ester insulating oil will gradually replace traditional mineral insulating oil and become the mainstream product of the transformer insulating oil market, especially in urban distribution transformers and special working condition transformers. The R&D of new biodegradable, non-toxic and low-carbon transformer insulating oil will become the focus of the industry.
High performance and functionalization: With the development of UHV transformer, high-capacity and high-temperature transformers, the performance requirements of transformer insulating oil will be further improved, and the R&D of high-voltage resistant, high-temperature resistant, anti-aging and long-life functional transformer insulating oil will be accelerated. Nanomodified insulating oil, high-fire-point flame-retardant insulating oil and other new functional oil will realize large-scale engineering application in the transformer insulating oil market, and the customization of transformer insulating oil for special working conditions will become a new development direction.
Digital and intelligent: The matching insulating oil detection and insulating oil operation and maintenance technology of transformer insulating oil will be further integrated with digital technologies such as IoT, big data, AI and digital twin. The full-life cycle management of transformer insulating oil from production, transportation, filling to operation and replacement will be realized, and the intelligent level of the whole industry chain of transformer insulating oil will be continuously improved.
Localization and industrialization: In developing countries represented by China, the localization of high-end transformer insulating oil products (such as UHV transformer insulating oil, natural ester insulating oil, synthetic ester insulating oil) will be further realized, the industrial chain will be improved, and the independent innovation capability and international competitiveness of enterprises will be enhanced. The scale and intensification of the transformer insulating oil industry will be further improved, and the market concentration will be continuously increased.
6.2 Current Technical Challenges
Although the transformer insulating oil technology has achieved great development in the past decade, there are still some technical bottlenecks and challenges that restrict the further development of the transformer insulating oil industry, especially in the R&D and application of environmentally friendly ester oil and nanomodified insulating oil:
The performance of new environmentally friendly ester oil needs to be further improved: Natural ester insulating oil still has the problems of high viscosity and poor low-temperature fluidity in low-temperature environments; synthetic ester insulating oil has high production cost, which limits its large-scale promotion in the transformer insulating oil market; the long-term operation stability of new environmentally friendly ester oil in high-voltage and large-capacity transformers still needs to be verified by more engineering practice.
The industrialization technology of nanomodified insulating oil is not mature: The nanomaterials in nanomodified insulating oil still have the problems of long-term dispersion stability and agglomeration; the interaction mechanism between nanomaterials and oil, insulating paper and metal parts is not clear; the production cost of nanomodified insulating oil is high, and the industrialization process in the transformer insulating oil market is slow.
The integration of insulating oil online monitoring technology needs to be improved: The insulating oil online monitoring sensors of transformer insulating oil have the problems of low precision, poor stability and short service life in harsh environments; the compatibility and data fusion of multi-parameter insulating oil online monitoring systems need to be further improved; the big data analysis model and AI algorithm of transformer insulating oil state need to be optimized and improved by more engineering operation data.
The compatibility of transformer insulating oil and new insulating materials needs to be studied: With the development of new transformer insulating materials (such as nano-modified insulating paper, high-temperature resistant polymer materials), the compatibility between transformer insulating oil and new insulating materials needs to be in-depth studied to realize the synergy and common progress of oil and material performance, which is the key to the further upgrading of transformer insulating oil technology.
7 Conclusion
Over the past decade, driven by the upgrading of the power industry and the increasingly stringent environmental protection requirements, the technological development of transformer insulating oil has achieved remarkable achievements in the global market: the conventional mineral insulating oil has realized comprehensive performance optimization through the upgrading of refining process and the innovation of additive system, and the UHV transformer insulating oil has met the development demand of UHV power grids; the new environmentally friendly ester oil represented by natural ester and synthetic ester insulating oil has broken through key technical bottlenecks, realized localization and large-scale engineering application, and become an important force for the green development of the transformer insulating oil industry; the functional transformer insulating oil technologies such as nanomodified insulating oil and high-fire-point flame-retardant insulating oil have made important research progress, and laid a solid foundation for the application of transformers in special working conditions; the supporting insulating oil detection and insulating oil operation and maintenance technology of transformer insulating oil has realized digital and intelligent upgrading, and formed a complete intelligent operation and maintenance system matching the smart power grid.
In the future, with the deepening of global energy transformation and the continuous development of UHV and smart power grids, the transformer insulating oil industry will face new development opportunities and challenges. The industry should focus on the development direction of green low-carbonization, high performance functionalization, digital intelligence and localization industrialization, accelerate the R&D of key core technologies, solve the technical bottlenecks of new environmentally friendly ester oil and functional transformer insulating oil, improve the digital and intelligent level of insulating oil detection and insulating oil operation and maintenance technology, and strengthen the research on the compatibility of transformer insulating oil and new insulating materials. Through continuous technological innovation and engineering practice, the comprehensive performance of transformer insulating oil will be further improved, the service life of transformers will be extended, and the safe, stable and green operation of the power grid will be guaranteed, so as to provide strong technical support for the high-quality development of the global power industry and the transformer insulating oil industry.
