What is an Intelligent Electronic Device?
The term Intelligent Electronic Device or an IED refers to a broad definition of any electronic device that possesses intelligent function in . The term came into existence to describe a device that has versatile electrical protection functions, advanced local control intelligence, monitoring abilities, and the capability of extensive communications directly to a SCADA system.
The functions of a typical IED can be classified into five main areas, namely:
- Non-directional earth fault protection (low-set, high-set and instantaneous function blocks)
- Directional three-phase overcurrent (low-set, high-set and instantaneous function blocks, with low-set selectable as long time-, normal-, very-, or extremely inverse, or definite time)
- Directional earth fault protection (low-set, high-set and instantaneous function blocks)
- Phase discontinuity protection
- Three-phase overvoltage protection
- Residual overvoltage protection
- Three-phase undervoltage protection
- Three-phase transformer inrush/motor start-up current detector
- Auto-reclosure function
- Under frequency protection
- Over frequency protection
- Synchro-check function
- hree-phase thermal overload protection.
|Typical IED Configuration | Source: General Electric|
- Local and remote control of up to twelve switching objects (open/close commands for circuit breakers, isolators, etc.)
- Control sequencing
- Bay level interlocking of the controlled devices such as status information and information of alarm channels
- HMI panel on the device.
- Circuit-breaker condition monitoring, including operation time counter, electric wear, breaker travel time, scheduled maintenance
- Trip circuit supervision
- Internal self-supervision
- Gas density monitoring (for SF6 switchgear)
- Event recording
- Other monitoring functions, like auxiliary power, relay temperature, etc.
- Three-phase currents
- Neutral current
- Three-phase voltages
- Residual voltage
- Active power
- Reactive power
- Power factor
- Transient disturbance recorder
|IEC Network Interface|