Line Differential Protection
General Information
- Description
The line differential protection is used to protect strictly selective areas at high speed. The simple measuring principle of current comparison requires a communication link between the partner devices.
While in former times, analog measured values used to be transmitted (current balance principle), modern devices use the advantages of digital communication. SIPROTEC4 line differential protection devices can protect system configurations with up to six ends.
Our Portfolio (3)
7SD60
Numerical pilot-wire current comparison protection relay
- Description
- Function overview
The 7SD600 relay is a numerical current differential protection relay, simple to set, operating in conjunction with the remote station via a two pilot-wire link. It is connected to the primary current transformers via an external summation current transformer. The primary field of application of the relay is protection of short overhead lines and cables with two line ends. However, transformers and reactors may be located within the protection zone. Features like inrush restraint, lockout, modern PCM-intertrip facilities, full self-monitoring facilities, local and remote interrogation are integrated in the unit.
Differential protection relay for overhead lines and cables
- Current differential protecrion with external summation current transformer 4AM49 (87L)
- Suitable for use for distances of aprox. 12km max. via two pilot wires (1200 Ω loop resistance)
- Differential protection can be combined with an overcurrent release
- Pilot-wire monitorung function
- Bidirectional remote tripping
- Circuit-breaker intertripping at the remote station
- Seal-in of the TRIP command until manual reset (Lockout function)
- Minimal current transformer requirements due to integrated saturation detector
- Restraint against inrush/undelayed trip for high differential fault currents
- Emergency overcurrent protection
Operational measured values
- Local and remote current
- Differential current
- Restraint current
Monitoring functions
- Hardware
- Firmware
- Spill current supervision
Hardware
- Local operation by means of integrated keyboard
- LCD display for setting and analysis
- Housing
– Flush-mounting housing 1/6 19" 7XP20
– Surface-mounting housing 1/6 19" 7XP20
Communication
- Via personal computer and DIGSI 3
- Via RS232 <-> RS485 converter
- With modem
- With substation control system via IEC 60870-5-103 protocol
- 2 kV isolated RS485 interface, bus connection possible
