Introduction - GE 745 Instruction Manual

GE
Grid Solutions
2.1

Introduction

2.1.1 Description
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
745 Transformer Protection
Chapter 2: Overview
Overview
These instructions do not purport to cover all details or variations in equipment nor provide
for every possible contingency to be met in connection with installation, operation, or
maintenance. Should further information be desired or should particular problems arise
which are not covered sufficiently for the purchaser's purpose, the matter should be
referred to the General Electric company.
To the extent required the products described herein meet applicable ANSI, IEEE, and
NEMA standards; but no such assurance is given with respect to local codes and
ordinances because they vary greatly.
The 745 Transformer Protection System™ is a high speed, multi-processor based, three-
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 total harmonic distortion
(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 transformer 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
System
2–1