Line Differential Protection GRL100

GRL100 provides high-speed, phase-segregated line differential protection, with communication over dedicated optical fibre links, 64 kbit/s multiplexed communication channels or microwave links.The relay can be applied in various EHV/HV network configurations, including overhead lines or underground cables, two-terminal or three-terminal lines, short or long distance lines. The main protection is supported by a complete range of back-up protections, auto-reclosing with check-synchronising and enhancements such as highly accurate fault location, metering, data recording and communications. A GPS-synchronised model is now available, designed for use over SDH/SONET communication networks in which propagation delays may differ between the send and receive paths.

1. Phase-segregated line differential protection for use with digital telecommunication systems

2. Zero-sequence current differential protection for high resistance earth faults

3. Applicable to various lines
   - Two-terminal or three-terminal lines
   - Overhead lines or underground cables, etc.

4. Operating time typically 1 cycle

5. Master/master design

6. Automatic transmission delay compensation

7. Charging current compensation

8. Overcurrent backup protection

9. Stub fault protection for one-and-a-half breaker scheme

10. Broken conductor detection

11. Direct intertripping

12. Out-of-step protection

13. Breaker failure protection

1. Metering
   - Power system voltages, Local and remote terminal currents, differential currents, power, frequency

2. Recording
   - Event record
   - Fault record
   - Disturbance record

3. Fault location

4. Calendar and Time
   - IRIG-B port for external clock

1. Single-shot autoreclose
   - single-phase / three-phase / single- and three-phase autoreclose
   - Multi-phase autoreclose for double circuit line

2. Multi-shot autoreclose
   - three-phase autoreclose

1. Liquid Crystal Display (LCD) display with operation keys
   - Relay setting and data display

2. Personal computer (PC) interface
   - Relay setting
   - Recorded data display
   - Waveform analyzing

1. Automatic monitor

1. Serial redundancy for tripping