What are main transformers and box-type transformers? What are the differences between them?
main transformer
Main transformer, abbreviated as "main transformer". It is mainly used to convert the high-voltage electrical energy generated by power plants into low-voltage electrical energy suitable for transmission, distribution, and use through transformers, which is the process of converting high voltage into low voltage.
The working principle of the main transformer is mainly based on the principles of electromagnetic induction and voltage transformation. When the high-voltage coil is powered by an AC power source, an alternating current is generated in the high-voltage coil, which generates an alternating magnetic field in the high-voltage coil and is then conducted to the low-voltage coil through the iron core. According to Faraday's law of electromagnetic induction, the alternating magnetic field in a low-voltage coil will cause an induced electromotive force in the low-voltage coil, thereby achieving the conversion of electrical energy from high voltage to low voltage.
The composition of the main transformer is mainly composed of the body, oil tank and cover, protective device, cooling system, and outlet bushing. Among them, the body directly converts electromagnetic energy and is composed of iron core, coil, lead wire, and insulation. The fuel tank and tank cover are mainly composed of the box body, tank cover, tank bottom, and accessories (such as oil sample valve, oil drain plug, grounding bolt, etc.). The protective device mainly consists of an oil storage tank, an oil gauge, an oil purifier, a flow relay, a moisture absorber, a signal thermometer, etc.
The application of main transformers: widely used in three fields of power systems: transmission, distribution, and consumption. In addition, it is widely used in industrial, construction, and residential fields, such as power machinery, welding and arc furnaces, power supply and distribution, indoor lighting systems, etc.
Characteristics of Box type Substation:
Compact structure. Integrating multiple devices such as transformers, high and Low Voltage Switchgear, and protective equipment into one box greatly reduces the footprint and facilitates transportation and installation.
High security. The fully enclosed structural design can effectively prevent the invasion of small animals and humid air, protecting the equipment from external environmental influences. At the same time, there are comprehensive protective devices installed internally to ensure safe and reliable operation.
Strong flexibility. Customization can be made according to the actual needs of users, including different capacities, voltage levels, and configurations. In addition, it can also achieve mobile power supply, making it convenient to use in temporary places or emergency situations.
Structure of Box Transformer:
A transformer substation is generally composed of a high voltage chamber, a transformer chamber, and a low voltage chamber, and its structure is generally divided into a zigzag shape and a mesh shape.
Application of Box type Substation:
Commonly used in residential areas, factories, shopping malls, and other places, it combines aesthetics and practicality. Both European and American type transformer substations have advantages over traditional civil power rooms in low load power systems. Box type substations have much lower construction costs than ordinary substations and have a beautiful appearance. European style box type substations can also use landscape type enclosures, which not only have a beautiful appearance but also occupy a small area, making them a beautiful scenery.
The difference between the two
power rating
The power levels of the main transformer and the box transformer are different. The power of the main transformer is generally 1000 kVA or above, suitable for large places such as medium and large power grids and power stations. The power of the box transformer is generally in the range of 10-630 kVA, which is much lower than that of the main transformer, making it suitable for small power grids such as residential areas and factories.
Scope of application
The main transformer is mainly used in large places such as medium and large power grids and power stations. It can be used to reduce and increase voltage as needed, adjust the voltage of the power grid to a predetermined value, and ensure the normal operation of the power grid. Box type transformers are relatively more common in daily life and are commonly used in residential areas, factories, shopping malls, and other places. By using box type transformers, the voltage of the high-voltage power grid is reduced to the low-voltage power grid, making power supply convenient, safe, and reliable.
Reliability Requirements
Due to the importance of the main transformer in the power system, its capacity is generally large and requires high reliability in operation. Although box type transformers also have certain reliability requirements, their reliability requirements are relatively low compared to main transformers.
Design differences
Due to the need to carry high voltage and current, the main transformer is usually designed to be relatively large and heavy, requiring installation on a larger site. The main transformer generally includes components such as the transformer body, cooling equipment, incoming and outgoing lines. Box type transformers are much smaller than main transformers and are usually designed in a box like manner for quick and convenient installation in cities or residential areas.