GE 745 TRANSFORMER MANAGEMENT RELAY, Instruction Manual

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GE Power Management 745 Transformer Management Relay 1-1
1 PRODUCT OVERVIEW 1.1 INTRODUCTION
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1 PRODUCT OVERVIEW 1.1 INTRODUCTION 1.1.1 DESCRIPTION
The 745 is a high speed, multi-processor based, 3-phase, two or three winding, Transformer Management
Relay™ intended for the primary protection and management of small, medium and large power transformers.
The 745 combines Percent Differential, Overcurrent, Frequency and Overexcitation protection elements along
with monitoring of individual harmonics, and THD in one economical package.
The relay provides a variety of adaptive relaying features:
• Adaptive Harmonic Restraint which addresses the problem of false tripping during inrush
• Adaptive Time Overcurrent Elements which will adjust their pickup settings based on the calculated trans-
former capability when supplying load currents with high harmonic content
• Multiple Setpoint Groups which allow the user to enter and dynamically select from up to four groups of
relay settings to address the protection requirements of different power system configurations
• Dynamic CT Ratio Mismatch Correction which monitors the on-load tap position and automatically corrects
for CT ratio mismatch
• FlexLogic™ which allows PLC style equations based on logic inputs & protection elements to be assigned
to any of the 745 outputs.
The 745 also includes a powerful testing and simulation feature. This allows the protection engineer the ability
to test the relay operation based on captured or computer generated waveform data which can be converted to
a digitized format and downloaded into the 745’s simulation buffer for “playback”.
The 745 also provides its own Waveform Capture function which will record waveform data for fault, inrush or
alarm conditions.
The Auto-Configuration function eliminates the need for any special CT connections by having all CTs con-
nected in wye.