High-voltage switchgear plays an important role in the transmission of the generated power from power plants to consumers. There are two types of substations. The first are air-insulated substations (AISs) that are in constant use and the second are gas-insulated substations (GISs), which are substations that are enclosed and insulated with SF6 gas and that can be installed indoors or outdoors. Air-insulated substations (AISs) are widely used wherever ambient conditions are disregarded and there is no space limitation. AISs can be designed at a high voltage up to 800kV. The installation costs of AISs are low. Components of substations with outdoor switchgear are installed at the facility. Since components are out in the open, it is dangerous to carry out live maintenance and to touch them. These substations are directly exposed to climate and ambient conditions.

A substation is a facility where devices, which take electricity from one or more high-voltage energy transmission lines and distribute it to the feeders of subscribers at medium and low voltage, are installed. Substations are installed on a field in an open area due to the magnitude of the voltage. Electricity undergoes various processes until it reaches a subscriber after being generated in a power plant. First, the voltage of electricity is increased at the outlet of the power plant. Thus, transmission takes place at a high voltage. High voltage is reduced to medium voltage at the entrance of cities and towns. Finally, medium voltage is converted to low voltage by distribution transformers. Transformers of various sizes and properties can be used while carrying out these operations. Facilities where these transformers and auxiliary elements are installed are called substations. There are some aspects that are needed to be taken into consideration when establishing a substation. The location on which the substation will be established and the type of substation depend on the properties and size of the transformer, which will be installed. A substation must be suitable esthetically and in terms of power distribution and safety.