Description
Functional role in the grid
This is a dedicated line protection IED, not a bay controller and not a busbar protection relay.
Core operating principle:
- Measures phase currents at both ends of a protected line
- Exchanges data through fiber optic or dedicated communication channel
- Performs real-time differential current calculation
- Issues trip command when internal fault is detected
External fault → currents balance → restrained operation
Internal fault → current imbalance → fast trip (sub-cycle class depending configuration)
Key technical specifications (field-oriented summary)
- Series: ABB Relion 670
- Device type: Line differential protection relay
- Part number: 1MRK002810-AC
- Protection function: 87L line differential protection
- Communication: Fiber optic / pilot wire inter-substation link
- CT input: 1 A / 5 A secondary systems (variant dependent)
- CT supervision: CT saturation detection and restraint logic
- Backup protection: Overcurrent, earth fault, distance protection (optional configuration)
- Fault recording: COMTRADE disturbance records + event logs
- IEC 61850: Station bus communication support (system dependent)
- Mounting: 19-inch rack plug-in modular design
- Auxiliary supply: DC supply typical for substation systems (variant dependent)
- Operating environment: Industrial substation class, wide temperature range depending hardware revision
