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5.1 OVERVIEW
Prior to commissioning the 745 relay, setpoints defining transformer characteristics, inputs, output relays, and
protection settings must be entered, via one of the following methods:
•
Front panel, using the keypad and display.
•
Front RS232 or rear terminal RS485/RS422 communication ports, and a portable computer running the
745PC software or a SCADA system running user-written software.
Any of these methods can be used to enter the same information. A computer, however, makes entry much
easier. Files can be stored and downloaded for fast, error free entry when a computer is used. Settings files
can be prepared and stored on disk without the need to connect to a relay.
All setpoint messages are illustrated and described in blocks throughout this chapter. The 745 relay leaves the
factory with setpoints programmed to default values, and it is these values that are shown in all the setpoint
message illustrations. Some of these factory default values can be left unchanged.
There are many 745 setpoints that must be entered for the relay to function correctly. In order to safeguard
against installation when these setpoints have not been entered, the 745 does not allow signaling of any output
relay. In addition, the IN SERVICE indicator is off and the SELF-TEST ERROR indicator on until the setpoint
S1 745 SETUP/INSTALLATION/745 SETPOINTS is set to Programmed. This setpoint is defaulted to Not Programmed
when the relay leaves the factory. The following diagnostic message appears until the 745 is put in the pro-
grammed state:
S SETPOINTS HAVE NOT
5
S BEEN PROGRAMMED
Messages may vary somewhat from those illustrated because of installed options. Also, some messages asso-
ciated with disabled features (or optional features which have not been ordered) are hidden. These messages
are shown with a shaded message box.
•
KEYPAD ENTRY: See Section 2.1: USING THE FRONT PANEL DISPLAY on page 2–1 for details on
maneuvering through the messages, viewing actual values, and changing setpoints.
•
COMPUTER ENTRY: Setpoint values are grouped together on a screen in the 745PC software. The data
is organized in a system of menus. See the Chapter 9: 745PC SOFTWARE for details.
•
SCADA ENTRY: Details of the complete communication protocol for reading and writing setpoints are
given in Chapters 8 and 9. A programmable SCADA system connected to the RS485/RS422 terminals can
make use of communication commands for remote setpoint programming, monitoring, and control.
The 745 design incorporates hardware and passcode security features to provide protection against unautho-
rized setpoint changes.
A hardware jumper must be installed across the setpoint access terminals on the back of the relay to program
new setpoints using the front panel keys. When setpoint programming is via a computer connected to the com-
munication ports, no setpoint access jumper is required.
Passcode protection may also be enabled. When enabled, the 745 requests a numeric passcode before any
setpoint can be entered. As an additional safety measure, a minor self-test error is generated when the pass-
code is entered incorrectly three times in a row.
5-2
745 Transformer Management Relay
5 SETPOINTS
5.1.2 SETPOINT ENTRY
5.1.3 SETPOINT WRITE ACCESS
GE Power Management
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