Introduction Overview - GE 845 Instruction Manual

GE
Digital Energy
845 Transformer Protection System
Chapter 1: Introduction
Overview
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
Introduction
The 845 Transformer Protection Systems are microprocessor-based units intended for the
management and primary protection of the medium to large size medium voltage (MV)
and high voltage (HV) power transformers. Both 2-winding and 3-winding transformers are
supported. 845 Transformer Protection Systems provide a number of primary and backup
current and voltage based protection functions. This system allows for control of the circuit
breakers at each winding plus a number of monitoring and control functions are also
provided.
These relays contain many innovative features. To meet diverse utility standards and
industry requirements, these features have the flexibility to be programmed to meet
specific user needs. This flexibility will naturally make a piece of equipment difficult to
learn. To aid new users in getting basic protection operating quickly, setpoints are set to
typical default values and advanced features are disabled. These settings can be
reprogrammed at any time.
Programming can be accomplished with the front panel keys and display. Due to the
numerous settings, this manual method can be somewhat laborious. To simplify
programming and provide a more intuitive interface, setpoints can be entered with a PC
running the EnerVista 8 Setup software provided with the relay. Even with minimal
computer knowledge, this menu-driven software provides easy access to all front panel
functions. Actual values and setpoints can be displayed, altered, stored, and printed. If
settings are stored in a setpoint file, they can be downloaded at any time to the front panel
program port of the relay via a computer cable connected to the serial port of any
personal computer.
A summary of the available functions and a single-line diagram of protection and control
features is shown below. For a complete understanding of each feature operation, refer to
Chapter 4: Setpoints. The logic diagrams include a reference to every setpoint related to a
feature and show all logic signals passed between individual features. Information related
to the selection of settings for each setpoint is also provided.
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