Introduction - Toshiba GRE110 Instruction Manual

1. Introduction

GRE110 series relays provide non-directional overcurrent protection for radial distribution
Medium Voltage class networks, and back-up protection for distribution networks.
Note: GRE110 series relays are non-directional, and are applicable to systems where fault current
flows in a fixed direction, or flows in both directions but there is a significant difference in
magnitude. In systems where a fault current flows in both directions and there is not a significant
difference in the magnitude of the fault current, the directional overcurrent protection provided
by GRE140 facilitates fault selectivity.
The GRE110 series provides the following protection schemes in all models.
• Overcurrent protection for phase and earth faults with definite time or inverse time
characteristics
• Instantaneous overcurrent protection for phase and earth faults
The GRE110 series provides the sensitive earth fault protection scheme depending on the models.
The GRE110 series provides the following functions for all models.
• Two settings groups
• Configurable binary inputs and outputs
• Circuit breaker control and condition monitoring
• Trip circuit supervision
• Autoreclosing function
• Automatic self-supervision
• Menu-based HMI system
• Configurable LED indication
• Metering and recording functions
• Front mounted USB port for local PC communications
• Rear mounted RS485 serial ports for communications
Table 1.1.1 shows the members of the GRE110 series and identifies the functions to be provided by
each member.
 6 
6 F 2 T 0 1 7 2