GE GEK-106273L, Instruction Manual, Page: 20 / 209

PRODUCT DESCRIPTION
GEK-106273L MIF Digital Feeder Protection 2-1
2. PRODUCT DESCRIPTION
2.1 INTRODUCTION
2.1.1. GENERAL OVERVIEW
The MIF relay is a microprocessor-based relay designed for the following applications:
1. Main Protection for Medium and Low voltage feeders.
2. Main Protection for Medium size Motors.
3. Main Protection for Medium and Low power Transformers (less than 10MVA).
4. Differential Protection for Motors, if a CT differential connection is available.
5. Backup Protection for power Transformers (for any power level).
6. Backup Protection for Generators.
7. Backup Protection for Transmission lines.
8. Backup Protection for substation bus bars.
9. Thermal Image Protection/Supervision for Cables, Power Transformers, Grounding Resistors and Generation
Units.
Negligible over-travel and a high drop out to pick up ratio (>97%), along with the possibility of adjust a time delay for
the instantaneous units, allow optimal co-ordination without compromising selectivity.
Both faceplate RS232 port and rear RS485 port may be used to connect a PC for programming settings, monitoring
actual values and for retrieving stored information (list of events, oscillography, etc.). All serial ports use the Modbus®
RTU protocol and may be connected to system computers with baud rates from 300, 600, 1200, 4800, 9600 and
19200 bps. The rear RS485 port can be converted into an RS232 port or into a fibre optic (plastic or glass) serial port
by using the GE
DAC300 module. The ENERVISTA MII SETUP communication software is the Windows® based
program used to communicate with the relay.
The MIF uses flash memory technology, which allows field upgrading (through ENERVISTA MII SETUP software) as
new features are added. This upgrade can be performed only through the communications port on the front of the
unit.
The following single line diagram (figure 2.1) illustrates the relay functionality using ANSI (American National
Standards Institute) device numbers.