RFL offers two relays for high voltage Transmission line protection, a current differential and line distance relay. Both are based on the GARD 8000 Global Architecture Relaying Device (GARD) which is a revolutionary product platform that provides the user with a fully programmable system that can be use for current differential or line distance protection, along with communications, and integrated telemetry and Teleprotection.

The system uses fully programmable logic and settings that can be uploaded or downloaded using the built-in TCP/IP (electrical or optical) interface. Communicating with the system is done with a PC using a web browser or by the Touch Screen Display (TSD) mounted on the GARD front panel. A most unique feature of the product is that the user manual and customer system and application drawings are stored in the GARD 8000 in Adobe PDF format easily accessible from the web browser interface.

Current Differential Relay
The Current Differential Protection Module in the GARD 8000 System is a proven Current-only, high speed line protection system. The advantages with current-only schemes are well known:

• Potentials not required
• Unaffected by CCVT transients
• Never over reach, never under reach
• Is not affected my mutual coupling on parallel lines
• Unaffected by Power swings

The GARD 8000 Current Differential Protection System can be used for two- or three-terminal lines as well as tapped load applications.

Click here to download the brochure for the Current Differential Relay Module

Line Distance Relay
The Distance Protection Module in the GARD 8000 System is a full-featured Line Distance Relay with all protection functions required for a complete line protection terminal. It can be used a stand-alone Main protection, to provide channel independent back-up for the current differential protection, or in parallel with the Current Differential Module, providing an independent, different, measuring principle.

The Distance Protection Module has four measuring zones, where all zones can be set Forward or Reverse. A Reverse Zone 4 is used in pilot schemes and/or as a back up zone for bus faults behind the relay.

Click here to download the brochure for the Line Distance Relay Module.