GE 745 TRANSFORMER MANAGEMENT RELAY

ii
745 Transformer Management Relay
GE Power Management
TABLE OF CONTENTS
3.2.19 DIELECTRIC STRENGTH TESTING ...................................................... 3-14
4. FRONT PANEL
OPERATION
4.1 FRONT PANEL
4.1.1 DESCRIPTION .......................................................................................... 4-1
4.2 DISPLAY, INDICATORS, AND FRONT PORT
4.2.1 DISPLAY.................................................................................................... 4-2
4.2.2 LEDS..........................................................................................................4-2
4.2.3 STATUS INDICATORS.............................................................................. 4-2
a IN SERVICE............................................................................................... 4-2
b SELF-TEST ERROR.................................................................................. 4-2
c TEST MODE.............................................................................................. 4-2
d DIFFERENTIAL BLOCKED ....................................................................... 4-3
e LOCAL ....................................................................................................... 4-3
f MESSAGE................................................................................................. 4-3
4.2.4 SYSTEM STATUS INDICATORS.............................................................. 4-3
a TRANSFORMER DE-ENERGIZED........................................................... 4-3
b TRANSFORMER OVERLOAD .................................................................. 4-3
c LOAD-LIMIT REDUCED............................................................................ 4-3
d SETPOINT GROUP 1................................................................................ 4-3
e SETPOINT GROUP 2................................................................................ 4-3
f SETPOINT GROUP 3................................................................................ 4-3
g
SETPOINT GROUP 4................................................................................ 4-3
4.2.5 CONDITION INDICATORS........................................................................ 4-4
a TRIP........................................................................................................... 4-4
b ALARM....................................................................................................... 4-4
c PICKUP...................................................................................................... 4-4
d PHASE A (B/C).......................................................................................... 4-4
e GROUND................................................................................................... 4-4
4.2.6 PROGRAM PORT ..................................................................................... 4-4
4.3 KEYPAD
4.3.1 SETPOINT KEY......................................................................................... 4-5
4.3.2 ACTUAL KEY............................................................................................. 4-5
4.3.3 ESCAPE KEY ............................................................................................ 4-5
4.3.4 ENTER KEY............................................................................................... 4-5
4.3.5 MESSAGE UP/DOWN KEY....................................................................... 4-5
4.3.6 VALUE UP/DOWN KEY............................................................................. 4-5
4.3.7 NUMBER KEYS......................................................................................... 4-6
4.3.8 HELP KEY ................................................................................................. 4-6
4.3.9 RESET KEY............................................................................................... 4-6
4.3.10 NEXT KEY ................................................................................................. 4-6
5. SETPOINTS
5.1 OVERVIEW
5.1.1 SETPOINT GROUPS ................................................................................ 5-1
5.1.2 SETPOINT ENTRY.................................................................................... 5-2
5.1.3 SETPOINT WRITE ACCESS..................................................................... 5-2
5.2 AUTO-CONFIGURATION
5.2.1 DESCRIPTION .......................................................................................... 5-3
5.2.2 A TYPICAL POWER TRANSFORMER ..................................................... 5-3
5.2.3 DYNAMIC CT RATIO MISMATCH CORRECTION ................................... 5-3
a PROBLEM 1:USE OF STANDARD CT RATIOS ....................................... 5-3
b PROBLEM 2: ONLOAD TAP CHANGER .................................................. 5-4
5.2.4 PHASE SHIFTS ON THREE-PHASE TRANSFORMERS......................... 5-6
5.2.5 PHASE ANGLE CORRECTION ................................................................ 5-8
5.2.6 ZERO-SEQUENCE COMPONENT REMOVAL......................................... 5-9