The Ultimate FAQs Guide To Main Transformer

What is the Main transformer?

The main transformer is a type of transformer typically operating at voltages of 66 kV and above. It possesses a significant capacity ranging from 10 MVA to several hundred MVA. Known as high-voltage transformers due to their primary voltage, main transformers are widely utilized in power plants and substations. They are responsible for stepping up generator voltage for transmission or stepping down transmission line voltage for distribution.

What is the Function of the Main Transformer?

The primary function of the main transformer is to convert large quantities of electricity from one voltage level to another. For example, it can receive electricity at 66,000 volts and output it at 21,000 volts. This capability is crucial for voltage upconversion from generators for transmission or voltage downconversion from transmission lines for distribution.

Different Voltage Levels and Functions:

Main transformers are designed for various voltage levels to fulfill specific functions within the power system.

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1000 kV Main Transformer

It serves as the backbone network framework for the energy internet, connecting regions over longer distances and facilitating energy interconnection between large regions.

500 kV Main Transformer

This transformer's primary role is to connect large regions and inter-provincial network connections. For instance, it supports energy interconnection between the Northeast Power Grid and the North China Power Grid.

230 kV Main Transformer

The primary purpose of the 230 kV main transformer is to transmit electricity between cities within a province, connecting power supply centers across provinces and serving as the backbone network for power transmission within the province.

Distribution Network Transformers

Transformers for distribution networks operate at voltage levels of 115 kV and 69 kV. They are instrumental in distributing electric energy obtained from the main transformer within a city to load centers in various districts, effectively dividing the city into blocks.

Power Transformer Uses

Power transformer uses many applications in power system and industry. Next, we introduce the common power transformer used one by one.

Power Transmission Line

 Power transformers have major advantages when it comes to long-distance power transmission. They effectively reduce the loss of electrical energy during the transmission process, leading to improved efficiency in delivering electricity over extended distances. They ensure efficient and reliable power delivery to distribution networks.

Try for free: Transmission Transformer | At The Power Lines Core

Electric Power Distribution

 Power transformers step down the high-voltage electricity received from transmission lines to lower voltages suitable for distribution to homes, offices, and industrial facilities. They enable the safe and efficient distribution of electricity across various areas.

Industrial Applications

Power transformers are extensively used in industrial settings to supply electricity for running machinery, equipment, and processes. They provide the necessary voltage levels to meet the specific power requirements of different industries, such as manufacturing, mining, and chemical processing.

However, it's important to note that different industries may require different types of main transformers. While power transformers are prevalent in the industry, substitution transformers and pad-mounted transformers find frequent usage in distribution systems.

Get it now: The Top 10 Best Industrial Transformer Manufacturers in The Word

Commercial Buildings

Power transformers are essential in commercial buildings, including offices, shopping centers, hospitals, and hotels. They ensure a reliable power supply for lighting, air conditioning, elevators, and other electrical systems necessary for smooth business operations.

Renewable Energy Systems

With the increasing use of renewable energy sources like wind farms and solar power plants, power transformers play a vital role in connecting these energy sources to the grid. They step up the generated electricity to high voltages for efficient transmission and integration into the power system.

Reading on: Solar Transformer - Your ultimate guide

Substations

Main power transformers are essential and widely used equipment in substations. They play a critical role in regulating voltage levels, both stepping up and stepping down the power in the electrical system. They provide a reliable guarantee for the supply of electricity to the next level of circuits.

In summary, power transformers uses have a wide range of applications across various industries, making them indispensable for economic development, infrastructure construction, residential life, and industrial growth. Power transformers play a crucial role in facilitating the efficient distribution and utilization of electricity, supporting the needs of businesses, homes, and overall industrial development.

Keep reading: Basic guide for transformers in Substation

Main types of Transformers

Daelim primarily manufactures four types of transformers, each catering to specific applications:

Pad-Mounted Transformers

These oil-filled transformers are installed on concrete pads or steel platforms. They find extensive use in commercial, industrial, and underground distribution systems. Pad-mounted transformers are hermetically sealed to protect against environmental conditions such as dust, dirt, and moisture. Cooling systems, employing natural convection or forced-air cooling, dissipate heat. Daelim offers a range of pad-mounted transformers from 75 kVA to 3,000 kVA, suitable for indoor and outdoor applications.

Substation Transformers

These oil-filled transformers are employed in skid-mounted portable substations, renewable energy systems, and battery energy storage systems. Substation transformers step up or step down the voltage in electric power transmission systems. They are categorized based on voltage levels, with popular classes including 44 kV, 34.5 kV, 23 kV, 13.8 kV, 13.2 kV, 12.47 kV, 12 kV, 7.2 kV, and 6.9 kV. Daelim manufactures a wide range of substation transformers, from small units with a capacity of 750 kVA to large units with a capacity of 20 MVA, suitable for both indoor and outdoor applications.

Dry Type Transformers

Dry type transformers are a variant of main transformers that utilize air as the primary cooling medium. These transformers are commonly employed in indoor applications such as office buildings and hospitals, where noise-free and fume-free operation is essential.

Daelim provides dry-type transformers in different sizes, equipped with features like thermal protection and protective enclosures. These transformers ensure durability, longevity, and low operating costs.

Main Transformer in Substation

A substation consists of one or two power transformers, distribution equipment, control and protective devices, and auxiliary equipment. The main function of a transformer in a substation is to step up or step down the voltage in an electric power transmission system.

The main transformer in a substation is responsible for facilitating the connection between the primary and secondary windings of the power transformer. This connection is typically established through busbars made of copper or aluminum.

By utilizing the main transformer, substations can effectively modify the voltage levels in an electric power transmission system. This ability to change voltages ensures seamless electricity transmission over long distances while optimizing the efficient utilization of electricity by matching it to the requirements of end users.

More detail about the Main Transformer In The Substation

Main Transformer Protection

Main transformer protection systems are crucial in monitoring current, voltage, frequency, oil pressure, and gas levels to prevent damage from overload and faults. They play a vital role in identifying internal problems with high sensitivity, de-energizing the transformer, and providing backup protection against external faults.

Primary Protection Content

Gas protection: Monitoring transformer body gas and on-load gas using heavy gas for tripping and light gas as an alarm signal.

Three-phase longitudinal differential protection.

Fallback Protection Content

Overcurrent protection on the high voltage side.

Overcurrent protection on the low voltage side.

Zero-sequence current and zero-sequence voltage protection.

Overload protection

High-voltage side busbar protection: including differential protection and circuit breaker failure protection.

Low-voltage side busbar-related protection: such as differential protection.

Daelim's design team customizes the protection scheme for each main transformer based on user requirements and specific functions.

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Difference Between Main Transformer and Substation

The main transformer is a device that steps up or steps down voltage, while a substation is a facility consisting of multiple transformers and additional equipment like switchgear and breakers. The main transformer is one of the equipments in the substation. Substations control the flow of electricity and provide power to larger areas. Main transformers, on the other hand, supply electricity to smaller areas.

66kV Main Transformer

A 66kV main transformer operates at a voltage of 66,000 volts and is commonly used in high-voltage applications such as power lines, substations, wind farms, and solar power plants. It is designed with advanced technologies and meets domestic and international standards for durability and performance.

69kV Main Transformer

The main 69kV transformer operates at a voltage of 69,000 volts and is suitable for high-voltage applications in power lines, substations, industrial, and commercial settings. These transformers are designed with optimized coils, cores, and components, utilizing both domestic and foreign technologies to ensure reliability and performance.

110kV Main Transformer

The main 110kV transformer operates at a voltage of 110,000 volts and is commonly used in substations and power plants. It serves the purpose of connecting different parts of the grid together or changing the voltage to make it suitable for residential and commercial use. These transformers are known for their high security, and reliability, and are frequently employed in wind farms and solar power plants. They are designed with an emphasis on economy and efficiency to reduce operational costs and network loss.

How to Choose a Main Power Transformer?

When selecting a main power transformer, various factors need to be considered, including voltage, power, frequency, and size. The type of transformer required, such as oil immersed type or dry type, is also crucial.

The main power transformer is a sophisticated and large-scale device that carries a substantial cost, often amounting to millions of dollars. Due to its complexity and importance, it necessitates the expertise of professional engineers. These skilled individuals play a vital role in the design, installation, and maintenance of power transformers, ensuring their optimal performance and reliability in various applications.

However, you need not worry as Daelim's professional team can assist you in choosing the most economical and efficient transformer. They provide tailor-made optimal solutions based on your requirements. You can share your transformer requirements with Daelim's team at pingruidan@daelim-electric.com.

It is important to purchase transformers from reputable dealers or manufacturers. Verify if the manufacturer possesses quality system documents, ISO certificates, and product quality certification certificates (e.g., UL/cUL, CSA, IEEE) to ensure compliance with international standards. If feasible, arranging a third-party inspection of the transformer manufacturing facility can be beneficial. Testing the transformer's performance through video conferences or third-party supervision during the production process is also recommended.

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Benefits of Using Main Power Transformer

Using the main power transformer offers several advantages, such as energy consumption reduction, minimizing line losses, and improving power quality. Main power transformers are known for their long lifespan and low maintenance requirements, making them a cost-effective solution for energy needs.

Another benefit of using main power transformers is their ability to interconnect different sections of the grid, ensuring a reliable and uninterrupted power supply. Transformers also enable voltage conversion to match the requirements of residential and commercial users.

Choosing a professional main power transformer supplier can enhance procurement efficiency, reduce costs, and extend the service life of transformers. With over 20 years of experience, Daelim is a reputable supplier and manufacturer based in China, specializing in the international market. They can be your best choice for transformer solutions.