GE MLJ1000 User Manual

GEK - 105560
24
6.1 READOUT SEQUENCE
This is the typical sequence for the MLJ as well as the power-up sequence. It is divided into a series of
“Functions”, each corresponding to different types of information. These functions are numbered from
1 to 12 and are identified by the letter F followed by the number of the function.
In normal operation, and shortly after being connected,
the MLJ displays the state of the line and bus. The left-
hand segment represents the state of the line and the
right-hand segment, the state of the bus. If both are live,
two horizontal upper segments will light up. This is the
reading assigned to the last function,
F12
.
If the
ENTER
button is now pressed and held down,
F0
will appear.
While the button is pressed, this code will remain on the
display. It tells us that we are in Function 0 of the Readout
Sequence. This function, which will appear as soon as the
button is released, indicates the Status of the relay.
If the ENTER button is pressed a second time, the
second function,
F1
will appear. This function shows the
value of the line voltage, and will be seen as soon as the
ENTER
button is released.
In this fashion, pressing and releasing the
ENTER
button, we can go through the entire Readout
Sequence. On the front of the relay, under the word “
DISPLAY
” there is a list of all of the functions.
They are listed below:
F0:
STATUS State of relay
F1:
VL Line voltage
F2:
VB Bus voltage
F3:
∆
V
Modulus of voltage difference
F4:
∆θ
Phase angle
F5:
∆
f
Frequency slip
F6:
LAST VL VL in the last close enable
F7:
LAST VB VB in the last close enable
F8:
LAST
∆
V
∆
V in the last close enable
F9:
LAST
∆θ ∆θ
in the last close enable
F10:
LAST
∆
f
∆
f in the last close enable
F11:
TEST Display test, LEDs and inputs
F12:
VL VB State of line and bus
Each of these functions are covered in further detail.
ENT

GE MLJ1000 Specifications

General

Brand	GE
Model	MLJ1000
Category	Relays
Language	English

Summary

1. DESCRIPTION

2. APPLICATION

2.1 DESIGN CHARACTERISTICS

Details the MLJ's measurement accuracy and resistance to harmonics for precise synchronism checking.

2.2 APPLICATIONS

Explains the MLJ's synchronism check applications and the formula relating frequency slip, angle, and time.

3. OPERATION PRINCIPLES

3.1 CONFIGURATION UNIT

Unit for selecting frequency, unit number, and communication speed.

3.2 SYNCHRONISM CHECK UNIT

Analyzes voltage magnitudes between line and bus to determine synchronism conditions for circuit breaker closure.

3.3 UNDERVOLTAGE UNIT

Monitors undervoltage and overvoltage for dead/live line/bus scenarios, enabling safe closure.

3.4 INPUT UNITS

Describes digital inputs for circuit breaker status and mode control.

3.5 SELF-CHECK UNIT

Monitors internal components like memory, settings, and circuits to verify integrity and detect failures.

3.6 OUTPUT UNITS

Details how synchronism, undervoltage, and alarm signals activate outputs.

3.7 POWER SUPPLY

Provides internal voltages for relay operation from auxiliary voltage, isolating from perturbations.

4. TECHNICAL CHARACTERISTICS

4.1 MODEL LIST

Defines MLJ models by specifying communication options, auxiliary voltage, and case type.

4.2 TECHNICAL CHARACTERISTICS

Lists key specifications including frequency, voltage, power, temperature ranges, humidity, and contact ratings.

4.3 INSULATION

Details insulation testing procedures and voltage withstand requirements as per IEC 255-5 standards.

4.4 TYPE TESTS

Encompasses various type tests like noise immunity, impulse, electrostatic discharge, and vibration compliance.

5. DESCRIPTION OF HARDWARE

5.1 CASE

Describes the robust steel plate case, front cover seal, and method for withdrawing the relay from its housing.

5.2 INTERNAL CONNECTIONS

Details the rear terminal blocks for external wiring, each containing 12 screw terminals.

5.3 IDENTIFICATION

Explains how to identify the complete relay model on the nameplate and the labeling of terminal blocks.

5.4 MLJ FRONT DEVICES

Lists front panel elements: three push buttons for control and three LEDs for status indication.

6. OPERATION OF MLJ (KEYPAD AND DISPLAY)

6.1 READOUT SEQUENCE

Procedure to access and display relay status, voltage values, frequency slip, and logged data.

6.2 SEQUENCE OF SETTINGS

Provides instructions for navigating and modifying the relay's operational settings using the keypad interface.

6.3 CALIBRATION SEQUENCE

Information on the calibration sequence, noting that calibration is typically performed at the factory.

6.4 SUMMARY OF SETTINGS

A summary table listing all MLJ relay settings, their ranges, steps, default values, and factory settings.

7. ACCEPTANCE TESTS

7.1 INTRODUCTION

Introduction to acceptance testing, emphasizing verification of relay measurement accuracy and logic implementation.

7.2 VISUAL INSPECTION

Procedure for visually inspecting the relay, checking the nameplate, and for any signs of damage from transport.

7.3 INSULATION

Guidelines for performing insulation tests on the relay to ensure electrical isolation and safety.

7.4 SYNCHRONISM UNIT

Focuses on testing the synchronism unit's accuracy for voltage difference and phase angle measurements.

7.5 UNDERVOLTAGE UNIT

Details the testing procedure for the undervoltage unit, including voltage thresholds and LED indications.

7.6 CONTINUOUS AND MANUAL MODE TESTS

Tests the relay's operation in both continuous and manual modes, verifying correct delay and function.

7.7 CALIBRATION

Notes on the necessity of calibration, recommending factory calibration and referencing the relevant sequence.

7.8 GROUNDING

Explains the importance of proper grounding for personal safety, protection against overvoltage, and noise reduction.