Intelligent Electronic Device. These are the digital brains of a substation, combining the functions of protection relays, meters and control switches into a single networked unit. They read voltages and currents from instrument transformers, run logic to detect faults, and send commands to trip circuit breakers. They also stream operational data back to the SCADA system.
The new transformer bay needs three IEDs configured for differential protection before we can commission it.
While older substations had walls covered in single-function electromechanical relays, a single IED can handle protection, metering and control for an entire bay.
Also heard as
- Intelligent Electronic Device
Related terms
SCADA
Supervisory control and data acquisition: the system that lets a control room watch and switch remote plant.
Protection relay
Device that watches currents and voltages and orders a circuit breaker to trip when it detects a fault.
Circuit breaker
A mechanical switching device capable of making, carrying and breaking currents under normal and fault conditions.