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Current Status of Material and Technology Development for Transformer Insulating ComponentsI. Introduction In power systems, transformers serve as one of the core pieces of equipment, and their operational reliability is directly linked to the security and stability of the power grid. Transformers contain a large number of conductive components internally; to ensure that short circuits or breakdowns do not occur between these components, a high-performance insulation system is essential. Transformer insulating components are tasked not only with electrical isolation but also with maintaining long-term stability under conditions of high temperature, intense electric fields, mechanical stress, and complex environments. Consequently, the selection of insulating materials and technological advancement have always been critical topics in transformer manufacturing and R&D.
In recent years, with the development of smart grids, ultra-high voltage (UHV) transmission, and the integration of new energy sources, transformer capacity and voltage levels have continuously increased. This has placed higher technical demands on insulating components. The application of new insulating materials, optimization of insulation structures, and innovation in manufacturing processes have driven the continuous progress of transformer insulation technology. II. Primary Functions and Classification of Transformer Insulating Components The core function of transformer insulating components is to prevent discharge or breakdown between conductors at different potentials while simultaneously supporting and fixing structures such as windings and cores. Based on their function and location, insulating components can be broadly categorized as follows: Main Insulating Components These include insulation barriers, insulation cylinders, and insulation end rings between high and low-voltage windings. They primarily withstand high-voltage stress and must possess excellent dielectric strength and heat resistance. Longitudinal Insulating Components These are used for inter-turn and inter-layer insulation within windings, such as turn insulation paper and layer spacers, preventing partial discharge and inter-turn short circuits. Supporting and Fixing Insulating Components Examples include insulation pressure bolts, insulation blocks, and insulation brackets. In addition to electrical insulation properties, these components require sufficient mechanical strength to withstand short-circuit electromagnetic forces and long-term vibration. Liquid Insulating Medium in Oil-Immersed Transformers Transformer oil itself acts as an insulating medium. Together with solid insulating components, it forms a composite insulation system that enhances the overall insulation level. III. Common Insulating Materials and Their Characteristics Traditional transformer insulating components primarily utilize plant fiber materials (such as electrical pressboard and insulation paper) and mineral oil. However, with technological advancements, new synthetic materials and composite insulation structures have gradually entered the application stage. 1. Plant Fiber Materials
The advantages of these materials lie in their low cost and ease of processing; however, they exhibit strong hygroscopicity and must be used in dry, oil-immersed environments. 2. Synthetic Polymer Materials
3. Liquid-Solid Composite Insulation Systems In oil-immersed transformers, insulating oil works in conjunction with solid insulating components. The oil provides not only insulation but also cooling and arc-quenching functions. Modern transformer oils undergo refining processes to reduce moisture and impurity content, thereby improving breakdown voltage and oxidation resistance. IV. Development Trends in Insulation Technology 1. High-Temperature Resistance and Long-Life Materials As transformers develop toward higher capacities and voltages, insulating components are required to operate long-term at elevated temperatures. Nanomodified insulating materials and polymers with thermal resistance exceeding 200°C are being progressively adopted, significantly extending transformer service life. 2. Environmentally Friendly Insulating Media In response to environmental protection requirements, halogen-free, low-toxicity, and biodegradable insulating materials have become a focus of R&D. For instance, natural ester insulating oils (rapeseed oil-based) are replacing mineral oils. These not only offer renewability but also feature higher flash points and biodegradability rates. 3. Intelligent Detection and Condition Assessment By integrating technologies such as fiber optic temperature measurement and online partial discharge monitoring, the operational status of insulating components can be monitored in real-time. This allows for the early detection of aging and moisture ingress, enabling predictive maintenance and reducing sudden failures. 4. Precision Manufacturing and Simulation Optimization Finite Element Analysis (FEA) is utilized to simulate electric field distribution, optimizing insulation structures to avoid localized high field intensity. Meanwhile, CNC machining and automated forming processes have improved dimensional accuracy and consistency of insulating components. V. Conclusion Although transformer insulating components are classified as auxiliary parts, they represent a critical link in ensuring the safe and reliable operation of transformers. Advances in material science and manufacturing technology have continuously enhanced the electrical performance, mechanical strength, and environmental adaptability of these components. Looking ahead, driven by the increasing demand for efficiency, environmental protection, and intelligence within power systems, transformer insulating components will continue to evolve toward high performance, long life, and green solutions, providing a solid guarantee for the secure and stable operation of the power grid. |
