Trafostation

Trafostation, or transformer station, is a facility in electrical power systems where voltage is transformed and directed between different grid levels. It typically houses power transformers and switchgear and serves as a link between transmission networks and distribution networks, enabling voltage levels to meet system requirements and local demands.

Core components include transformers (oil-filled or dry-type), switchgear such as circuit breakers and disconnectors, busbars, protection relays, and control equipment. Many stations also contain metering, remote monitoring equipment, and sometimes modular gas-insulated switchgear. Cooling systems, such as oil radiators or air cooling, and fire protection are common. Substations may be installed outdoors or indoors, depending on location and design.

Substations vary by voltage level and configuration. High-voltage (HV) substations connect transmission lines to feeders, while medium-voltage (MV) substations feed distribution networks. In urban areas, indoor or GIS (gas-insulated switchgear) installations are common to reduce footprint and improve safety. Some substations feature on-load tap changers to regulate voltage on the distribution network.

Operation and maintenance are conducted by utility operators using protection and control systems, often with SCADA for remote monitoring. Regular tasks include transformer insulation checks, oil quality management, cooling system maintenance, leakage detection, and relay testing. Faults are cleared by circuit breakers, and redundancy enhances reliability.

Trafostations play a central role in grid reliability and efficiency. Environmental and safety considerations include proper siting, containment of insulating fluids, and handling of SF6 in gas-insulated setups. Standards from IEC, IEEE, and national grid codes guide design, protection schemes, and safety practices.