For more information visit:
www.EatonElectrical.com
Initial Release
SECTION 3: OPERATION
3-1 INTRODUCTION
This section specifically describes the operation and
functional use of the MD-3000 Protective Relay. It does
not address in detail rear power connections. This is
covered in SECTION 5 entitled “INSTALLATION,
STARTUP AND TESTING.” It would be helpful to become
familiar with the relay’s wiring diagram before proceeding
with the rest of this section (Figure 3-1).
3-2 POWER-UP AND SELF TESTING
When the proper ac or dc control voltage is applied to
power supply input terminals, the unit will initiate a “Power
On Reset” to its chip circuitry. This causes the unit’s
firmware to perform some self-testing and initialization of
its ROM, RAM and E2 (non-volatile) memory. If any
problem exists, a diagnostic message will be displayed in
the Settings/Test Time/Trip Cause Window. A complete list
of messages and their meanings are listed in Table 3.2.
Additionally, if a problem does exist, the “Operational LED”
will light red and the “Protection Off Alarm” relay will not
energize. When all self checks are good the “Operational
LED” will blink green.
3-3 PANEL OPERATIONS
Begin by reviewing the material presented in SECTION 2
entitled “FUNCTIONAL DESCRIPTION.” Since basic
definitions and explanations were given in SECTION 2, no
further explanation as to function will be offered in this
section. It is assumed that the operator is now familiar with
MD-3000 terms, available settings and overall capabilities.
3-3.2 PROGRAM MODE
MD-3000 PROTECTIVE RELAY SETTINGS MUST
BE PROGRAMMED BEFORE THE RELAY IS PUT
INTO OPERATION. CARE MUST BE TAKEN WHEN
PROGRAMMING THE MD-3000 WHILE THE
BREAKER IS CLOSED AND CURRENT IS
FLOWING. AN INCORRECT SETTING
CONFIGURATION COULD CAUSE THE RELAY TO
TRIP THE BREAKER WHEN SETTINGS ARE
SAVED.
Notes:
1.
The settings that are altered during a programming
session will not be saved until the Save Settings
pushbutton is pressed and released.
2.
When programming is concluded and new set points
saved, the Program Mode pushbutton should be
pressed and released to exit the Program Mode.
3.
The Program Mode is also exited if the Reset
pushbutton is pressed and released or if there is no
programming activity for approximately 2-1/2 minutes.
To enter the Program Mode, open the protective access
cover and press and release the Program Mode On/Off
pushbutton. The Program LED will blink green, indicating
that the Program Mode has been entered. The present
value of the first set point to be programmed (Differential
Pickup) will appear in the Settings/Test Time/Trip Cause
Window, which will be referred to as the Alpha-numeric
Display for the rest of this discussion. The Differential
Pickup LED will be blinking green. The Raise or Lower
pushbuttons can now be used to change the value of the
set point. Keep in mind that the Raise and Lower
pushbuttons will roll over from highest to lowest and lowest
to highest respectively. If either of the pushbuttons is held
down and not released, their function is accelerated. This
is true for all white pushbuttons on the panel face.
Pressing and releasing the Select Settings pushbutton will
cause the unit to step to the next set point. This is the
Time setting. The Time LED will blink green.
After the Raise and/or Lower pushbuttons are used to
arrive at the desired Time setting, the Select Settings
pushbutton can be pressed and released to step to the
next set point, which is the Frequency setting.
When this selection is made and the Select Settings
pushbutton is pressed and released, the relay steps to the
Phase CT Ratio Setting.
The programmed value for the phase CT will appear in the
alphanumeric display. Once this selection is made and
programmed, the Select Settings pushbutton is pressed
and released to move to the last set point.
To save the new settings at any time, press and release
the Save Settings pushbutton. When the Save Settings
pushbutton is pressed and released, the unit will blank the
alphanumeric display for two seconds, and then display
the last setting. At this moment, the unit will use the new
set points for protection. After pressing the Save Settings
pushbutton, the Program Mode can be exited by any one
of three ways:
1. Press and release the Program Mode On/Off
pushbutton.
2. Press and release the Reset pushbutton.
3. Perform no programming activity for 2 1/2 minutes.
THE SAVE SETTINGS PUSHBUTTON MUST BE
PRESSED AND RELEASED BEFORE EXITING
THE PROGRAM MODE. OTHERWISE, THE
CHANGED SETPOINTS WILL NOT BE SAVED. IN
ADDITION, AFTER THE PROGRAMMING OF
SETTINGS IS COMPLETE, IT IS VERY
IMPORTANT TO VERIFY ALL THE SETTINGS BY
DEPRESSING THE “VIEW SETTINGS”
PUSHBUTTON AND STEPPING THROUGH THE
SETTINGS.
