In modern society, electricity, like an invisible blood vessel, nourishes every corner of human civilization. From the dazzling lights of bustling cities to the precise operation of factory floors, from the comforts and conveniences of home life to the breakthroughs and innovations of cutting-edge technology, electricity is everywhere. Within this vast and complex power system, power transformers undoubtedly occupy a crucial position at the core, playing an irreplaceable and important role.

I. Working Principle: The Miraculous Application of Electromagnetic Induction
Power transformers operate based on the principle of electromagnetic induction. When alternating current passes through the transformer's primary winding, it stirs up an invisible "magnetic storm" in the iron core, generating alternating magnetic flux. This alternating magnetic flux possesses a magical power. Not only does it tightly connect to the primary winding, inducing self-induced voltage, but it can also travel through space and cleverly interact with the secondary winding, inducing mutual induction voltage in the secondary winding. Like two sympathetic partners, through this mysterious medium of magnetic flux, they achieve efficient transmission of electrical energy between different voltage levels.

Ideally, a transformer's voltage conversion follows a simple yet beautiful mathematical relationship: the turns ratio is equal to the ratio of the number of primary winding turns to the number of secondary winding turns. When the turns ratio is greater than 1, the transformer acts like a magical "step-up wizard," boosting low voltage to high voltage, paving the way for efficient long-distance transmission of electrical energy. When the turns ratio is less than 1, it transforms into a "step-down messenger," converting high voltage to a low voltage suitable for user use. Throughout this process, the law of conservation of energy acts as a loyal guardian, ensuring that input and output power remain balanced, negligible losses. Current is inversely proportional to the number of turns, creating a harmonious symphony of electrical energy conversion.

II. Structural Components: The Precision-Cooperating "Heart" of Power

A power transformer is like a meticulously crafted precision instrument. Its core components, including the core, windings, and a series of essential accessories, together form an efficiently operating whole, much like the heart of the human body, continuously supplying power for the stable operation of the power system. The iron core, the transformer's "skeleton" and "magnetic core," is meticulously constructed from high-permeability, low-loss cold-rolled silicon steel sheets. This ingenious design significantly enhances mutual inductance, allowing magnetic flux to flow smoothly through the core. Like a superhighway for magnetic energy, it efficiently transfers energy from the primary winding to the secondary winding, significantly improving transformer efficiency.

The windings, the transformer's "conductive nerves," are typically made of highly conductive materials such as high-quality copper or aluminum, tightly wound with insulated wire. Concentric windings, like closely spaced concentric circles, nest low-voltage and high-voltage windings in an orderly fashion. The oil channels between them not only effectively dissipate heat but also provide critical electrical isolation. Interleaved windings, like carefully stacked building blocks, alternate high-voltage and low-voltage windings. Their excellent insulation and strong load-bearing capacity ensure safe and stable power transmission.

Transformers also feature numerous accessories with diverse functions. The oil tank acts as a sturdy fortress, securely protecting the core and windings. Filled with insulating oil, it not only enhances heat dissipation but also provides reliable insulation. The safety air duct and gas relay act as loyal guards, constantly monitoring the pressure and gas conditions within the transformer. If an anomaly is detected, they quickly activate protective mechanisms to ensure the safety of equipment and personnel. The tap changer and tap changer act as flexible "voltage regulators," precisely adjusting the turns ratio between the primary and secondary windings to adapt to varying power demands. The insulating bushings safely guide the high-voltage leads out of the transformer, safeguarding the output of power.

III. Diversity: The Power "Chameleon" that Meets Diverse Needs

The power transformer family is diverse, like a colorful army, each member carrying a unique mission to meet the diverse needs of different fields and scenarios.

Based on the number of phases, there are single-phase and three-phase transformers. Single-phase transformers are suitable for single-phase loads, such as household electricity, bringing convenience to daily life. Three-phase transformers, with their powerful power transmission capabilities, are widely used in industrial production and large-scale power distribution, supporting the vigorous development of modern industry.

Based on the number of windings, they can be categorized as two-winding transformers, three-winding transformers, and autotransformers. Two-winding transformers are the most common type, with their simple structure and widespread use in various aspects of power transmission and distribution systems. Three-winding transformers can simultaneously convert three different voltage levels, providing a flexible solution for complex power networks. Autotransformers, through their ingenious winding design, enable the sharing of common windings, offering significant advantages such as small size, low cost, and high efficiency. They play an important role in specific power transmission and voltage regulation applications.

Depending on their cooling method, they can be divided into oil-immersed transformers, dry-type transformers, and gas-filled transformers. Oil-immersed transformers, thanks to the excellent heat dissipation and insulation properties of insulating oil, dominate the transmission of high-capacity, high-voltage power. Dry-type transformers, favored for their environmental friendliness, fire resistance, and maintenance-free nature, are highly sought after in urban power grids, high-rise buildings, and other environmentally sensitive locations. Gas-filled transformers, using a special gas as an insulating and cooling medium, offer advantages such as a small footprint and high reliability, making them suitable for specialized applications.

IV. Application Scenario: The "Backbone" of Power Transmission

Power transformers are widely used in power generation, transmission, distribution, and consumption. Like invisible threads, they tightly connect the entire power system, making them the undisputed "backbone" of power transmission.

In the power generation process, the electricity generated by the generator needs to be increased in voltage by a step-up transformer to reduce energy losses during long-distance transmission. The step-up transformer acts as a powerful "booster," transmitting electricity at high voltage and low current over the long transmission journey, ensuring efficient and stable transmission to distant power users. In the power transmission sector, high-voltage and ultra-high-voltage transmission lines crisscross the country, acting as the "aorta" of the power system. Transformers are key nodes along these "aortas." They flexibly adjust voltage levels based on grid needs, enabling seamless connectivity and smooth transmission of power between power grids of varying voltage levels, ensuring reliable power delivery across vast regions.

The distribution sector is the "last mile" between the power system and users. Here, step-down transformers gradually reduce high-voltage power to a voltage suitable for users. Like a caring "steward," they precisely distribute power to thousands of households, factories, businesses, and public spaces, meeting the electricity needs of daily life and production.

In the industrial sector, transformers for various special purposes play an indispensable role. For example, rectifier transformers convert alternating current (AC) to direct current (DC), providing a stable DC power source for industrial processes like electroplating and electrolysis. Furnace transformers specifically provide high-power power for furnaces, meeting the specialized demands of high-temperature processes like metal smelting and heat treatment.

V. Industry Development Trends: Towards a Green Future

With the rapid advancement of technology and society's growing demand for energy, the power transformer industry is undergoing a profound transformation, striding towards intelligent and green development, injecting new vitality into building a more efficient, reliable, and sustainable power system.

Green environmental protection concepts are also profoundly influencing the development of the power transformer industry. Against the backdrop of global advocacy for energy conservation and emission reduction to combat climate change, the research and development and production of highly efficient, energy-saving, and environmentally friendly transformers have become an industry consensus. On the one hand, researchers are continuously exploring and adopting new materials, such as amorphous alloys, which exhibit extremely low hysteresis and eddy current losses, significantly reducing transformer energy consumption during operation and contributing to efficient energy utilization. On the other hand, optimizing transformer design and manufacturing processes is improving energy conversion efficiency, reducing waste and pollutant emissions, and making transformers more environmentally friendly and sustainable throughout their entire lifecycle. The booming new energy industry, including the widespread access to distributed energy sources such as solar and wind power, is placing higher demands on transformers that are adapted to the characteristics of these new energy sources. This is driving continuous innovation in the transformer industry, leading to the development of new products better suited for the transmission and conversion of renewable energy power.​