Substations interconnect different voltage levels and are the critical link between transmission, distribution and consumption. Primary equipment like power transformers, circuit breakers and disconnect switches located in the switchyard of the substation transform, protect and manage the grid power supply. Secondary equipment like protection relays and terminal units, typically placed away from the switchyard inside panels of a control room, protect, control and monitor the primary equipment.
Measuring electrical parameters in a conventional substation
Conventional instrument transformers like potential transformers (PTs) and current transformers (CTs) measure the high voltages and currents passing through primary equipment. Copper wires connect the analog output from the transformers to secondary equipment, and the number of copper wires increases depending on the application.