Common Setpoints; Setpoint Access Security - GE 750 Instruction Manual

Overview
WARNING
Setpoint Access
Security

Common Setpoints

GE Multilin
The relay leaves the factory with setpoints programmed to default values, and it is
these values that are shown in all the setpoint message illustrations. Many of these
factory default values can be left unchanged.
At a minimum, the
S2 SYSTEM SETUP
function correctly. To safeguard against the installation of a relay whose setpoints
have not been entered, the relay
addition, the Self-Test Warning relay will be de-energized. Once the relay has been
programmed for the intended application, the
setpoint should be changed from "Not Ready" (the default) to "Ready".
OPERATION
Some messages associated with disabled features are hidden. These context
sensitive messages are illustrated with a dotted border on the message box. Before
putting the relay in the Ready state, each page of setpoint messages should be
worked through, entering values either by keypad or computer.
Hardware and passcode security features are designed into the relay to provide
protection against unauthorized setpoint changes.
To program new setpoints using the front panel keys, a hardware jumper must be
installed across the setpoint access terminals on the back of the relay. These
terminals can be permanently wired to a panel mounted key switch if desired.
Attempts to enter a new setpoint without the electrical connection across the
setpoint access terminals will result in an error message. The jumper does not
restrict setpoint access via serial communications.
The relay has a programmable passcode setpoint which may be used to disallow
setpoint changes from both the front panel and the serial communications ports.
This passcode consists of up to eight (8) alphanumeric characters.
The factory default passcode is "0". When this specific value is programmed into the
relay it has the effect of removing all setpoint modification restrictions. Therefore,
only the setpoint access jumper can be used to restrict setpoint access via the front
panel and there are no restrictions via the communications ports.
When the passcode is programmed to any other value, setpoint access is restricted
for the front panel and all communications ports. Access is not permitted until the
passcode is entered via the keypad or is programmed into a specific register (via
communications). Note that enabling setpoint access on one interface does not
automatically enable access for any of the other interfaces (i.e., the passcode must
be explicitly set in the relay via the interface from which access is desired).
A front panel command can disable setpoint access once all modifications are
complete. For the communications ports, access is disabled by writing an invalid
passcode into the register previously used to enable setpoint access. In addition,
setpoint access is automatically disabled on an interface if no activity is detected for
thirty minutes.
The EnerVista 750/760 Setup software incorporates a facility for programming the
relay's passcode as well as enabling/disabling setpoint access. For example, when
an attempt is made to modify a setpoint but access is restricted, the program will
prompt the user to enter the passcode and send it to the relay before the setpoint is
actually written to the relay. If a SCADA system is used for relay programming, it is
up to the programmer to incorporate appropriate security for the application.
To make the application of this device as simple as possible, similar methods of
operation and therefore similar types of setpoints are incorporated in various
features. Rather than repeat operation descriptions for this class of setpoint
throughout the manual, a general description is presented in this overview. Details
that are specific to a particular feature will be included in the discussion of the
feature. The form and nature of these setpoints is described below.
• FUNCTION setpoint: The
operational characteristics of each feature. The range for these setpoints is two
or more of: "Disabled", "Enabled", "Trip", "Trip & AR", "Alarm", "Latched Alarm",
and "Control".
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Feeder Management Relay
setpoints must be entered for the system to
Relay Not Ready self-test warning is displayed. In
S1 RELAY SETUP
<ELEMENT_NAME> FUNCTION
750/760
INSTALLATION 760
setpoint determines the
5–5