1. 11/33kV Substation:
   • An 11/33kV substation is a type of electrical substation that transforms voltage from 11kV to 33kV or vice versa. These substations are commonly used in distribution systems to step up or step down voltage levels as required for transmission and distribution purposes.
   • They serve as key nodes in the electrical grid, facilitating the transfer of electricity between different voltage levels to ensure efficient distribution and supply to consumers.
2. 132/33kV Substation:
   • A 132/33kV substation is designed to step down high-voltage electricity (132kV) from the transmission system to a lower voltage level (33kV) suitable for distribution.
   • These substations are typically located at strategic points along the transmission network to regulate voltage levels and manage the flow of electricity across the grid.
   • They play a crucial role in ensuring the reliability and stability of the power supply by providing voltage transformation and distribution capabilities.
3. 11/33kV GIS (Gas Insulated Switchgear) Indoor Substation:
   • An 11/33kV GIS indoor substation is a type of substation that incorporates gas-insulated switchgear technology for the control, protection, and isolation of electrical circuits.
   • GIS substations utilize sulfur hexafluoride (SF6) gas as the insulating medium, which offers superior dielectric properties and allows for more compact substation designs compared to traditional air-insulated substations.
   • These indoor substations are particularly suitable for urban areas or locations with limited space, where land availability is a constraint.
   • GIS technology provides enhanced reliability, safety, and operational efficiency by minimizing the risk of electrical faults, reducing maintenance requirements, and optimizing space utilization within the substation.

In summary, 11/33kV, 132/33kV, and 11/33kV GIS indoor substations are integral components of the electrical infrastructure, playing critical roles in voltage transformation, distribution, and system reliability. Their design and configuration are tailored to meet the specific requirements of transmission and distribution networks while ensuring optimal performance and safety standards.