alajaamad

Alajaamad, or substation, is an electrical facility in a power transmission and distribution network that connects high-voltage and medium- or low-voltage circuits. In Estonian technical usage, alajaamad refers to a substation. It serves as a node where voltage is transformed, switched, and routed to deliver electrical power to consumers and other parts of the grid.

Its primary functions include stepping voltage up or down through transformers, protecting equipment and lines from faults, isolating sections of the network for maintenance, and coordinating power flow with control systems. Substations also enable switching of circuits to reroute power, connect or disconnect parts of the network, and provide a point for sectionalizing the grid during faults or maintenance.

Substations come in various forms. Transmission substations operate at high voltages to interconnect generation and main transmission lines. Distribution substations reduce voltage for local networks and feeders. Substations may be air-insulated or gas-insulated (GIS); they can be outdoor or indoor, compact or integrated with buildings. Main components include transformers, switchgear, circuit breakers, disconnectors, busbars, protection relays, and communication and control equipment. Many modern substations host automation equipment and remote control interfaces to monitor and manage operations.

Automation and protection: modern substations use SCADA and substation automation systems; IEC 61850 is common for interoperability; protective schemes coordinate relays to clear faults rapidly. Safety and standards: design and operation follow national and international standards; sites require secure fencing, clearance distances, and trained personnel. Substations are essential for reliability, voltage regulation, and the secure delivery of electric power.