Able to function as a standalone unit or alongside other relays in the General Electric Multilin 745 series, the 745-W3-P5-G5-HI-E Transformer Management Relay is invaluable for directing and protecting transformers of any size. Manufactured with a wide range of adaptive capabilities, the 745 can adjust to a transformer system’s unique variables and requirements.
The 745 does not only respond to these variables; it can also record and trend this data within the EnerVista 745 software program. Computers with EnerVista 745 installed can utilize the RS232 port or RS422/485 port to successfully connect to the relay. From there, setpoints can also be assigned, edited, deleted, or added as users see fit.
This version of the model comes with an enhanced display, which boasts a wider screen, expanded keypad, and twenty LEDs that provide quick reference for system health. Some of these LEDs include self-test error, differential blocked, transformer de-energized, and transformer overload. The LEDs can be green, amber, or red depending on the condition of these processes, with amber and red functioning as different levels of severity.
The GE Multilin 745 includes both time/overcurrent elements and instantaneous differential elements. While some users question if both of these elements are necessary, the combination of both features provides more sensitive protection. This is because the instantaneous differential element can be set to a lower value than overcurrent elements, limiting damage and time consumption. Differential protection is also selective (operating within a specified zone, clearing faults more quickly) while O/C protection is not selective and therefore more delayed.