Pin type insulators are commonly used in electrical power systems for various applications. However, their main field of application is in the distribution system.

- Distribution system:
The distribution system is responsible for delivering electrical power from the transmission system to the end consumers. It operates at lower voltages and covers a smaller geographical area compared to the transmission system. Pin type insulators are widely used in the distribution system due to several reasons:

1. Voltage levels:
Pin type insulators are suitable for low to medium voltage levels typically found in distribution systems. These insulators are designed to withstand voltages up to a certain range, usually up to 33 kV. For higher voltage levels, other types of insulators, such as suspension or post insulators, are preferred.

2. Mechanical strength:
Pin type insulators are designed to withstand mechanical stresses, such as wind and ice loads, that are commonly encountered in distribution systems. These insulators are mounted vertically on the supporting structure, providing stability and resistance against mechanical forces.

3. Ease of installation:
Pin type insulators are relatively easy to install and maintain. They can be directly mounted on the supporting structure using a pin or bolt. This simplicity in installation and maintenance makes them cost-effective for distribution systems, where a large number of insulators are required.

4. Compact design:
Pin type insulators have a compact design, which allows for efficient use of space on the supporting structure. This is particularly advantageous in distribution systems, where multiple conductors are often installed on the same structure.

In contrast, the transmission system operates at higher voltage levels and covers larger distances. Insulators used in the transmission system need to have higher voltage withstand capabilities and be able to handle larger mechanical loads. Therefore, pin type insulators are not commonly used in the transmission system. Other types of insulators, such as suspension or post insulators, are preferred for their higher voltage and mechanical strength.

In summary, the main field of application of pin type insulators is in the distribution system. These insulators are suitable for low to medium voltage levels, offer good mechanical strength, are easy to install and maintain, and have a compact design that optimizes space utilization on the supporting structure.