GE L90 Instruction Manual page 8

7. COMMANDS AND
TARGETS
8. THEORY OF OPERATION
viii
TABLE OF CONTENTS
6.2 STATUS
6.2.1 CONTACT INPUTS ............................................................................................6-3
6.2.2 VIRTUAL INPUTS ..............................................................................................6-3
6.2.3 REMOTE INPUTS ..............................................................................................6-3
6.2.4 DIRECT INPUTS ................................................................................................6-4
6.2.5 CONTACT OUTPUTS ........................................................................................6-4
6.2.6 VIRTUAL OUTPUTS ..........................................................................................6-4
6.2.7 AUTORECLOSE.................................................................................................6-5
6.2.8 REMOTE DEVICES............................................................................................6-5
6.2.9 CHANNEL TESTS ..............................................................................................6-6
6.2.10 DIGITAL COUNTERS.........................................................................................6-7
6.2.11 SELECTOR SWITCHES ....................................................................................6-7
6.2.12 FLEX STATES ....................................................................................................6-7
6.2.13 ETHERNET ........................................................................................................6-8
6.3 METERING
6.3.1 METERING CONVENTIONS .............................................................................6-9
6.3.2 87L DIFFERENTIAL CURRENT.......................................................................6-12
6.3.3 SOURCES ........................................................................................................6-13
6.3.4 SYNCHROCHECK ...........................................................................................6-16
6.3.5 TRACKING FREQUENCY................................................................................6-17
6.3.6 FLEXELEMENTS™ ..........................................................................................6-17
6.3.7 TRANSDUCER INPUTS/OUTPUTS.................................................................6-18
6.4 RECORDS
6.4.1 FAULT REPORTS ............................................................................................6-19
6.4.2 EVENT RECORDS ...........................................................................................6-21
6.4.3 OSCILLOGRAPHY ...........................................................................................6-21
6.4.4 DATA LOGGER ................................................................................................6-22
6.4.5 BREAKER MAINTENANCE .............................................................................6-22
6.5 PRODUCT INFORMATION
6.5.1 MODEL INFORMATION ...................................................................................6-23
6.5.2 FIRMWARE REVISIONS..................................................................................6-23
7.1 COMMANDS
7.1.1 COMMANDS MENU ...........................................................................................7-1
7.1.2 VIRTUAL INPUTS ..............................................................................................7-1
7.1.3 CLEAR RECORDS .............................................................................................7-1
7.1.4 SET DATE AND TIME ........................................................................................7-2
7.1.5 RELAY MAINTENANCE .....................................................................................7-2
7.2 TARGETS
7.2.1 TARGETS MENU ...............................................................................................7-3
7.2.2 TARGET MESSAGES ........................................................................................7-3
7.2.3 RELAY SELF-TESTS .........................................................................................7-3
8.1 OVERVIEW
8.1.1 L90 DESIGN .......................................................................................................8-1
8.1.2 L90 ARCHITECTURE.........................................................................................8-1
8.1.3 REMOVAL OF DECAYING OFFSET .................................................................8-2
8.1.4 PHASELET COMPUTATION .............................................................................8-2
8.1.5 DISTURBANCE DETECTION ............................................................................8-3
8.1.6 FAULT DETECTION...........................................................................................8-3
8.1.7 CLOCK SYNCHRONIZATION............................................................................8-4
8.1.8 FREQUENCY TRACKING AND PHASE LOCKING...........................................8-4
8.1.9 FREQUENCY DETECTION ...............................................................................8-5
8.1.10 PHASE DETECTION ..........................................................................................8-6
8.1.11 PHASE LOCKING FILTER .................................................................................8-9
8.1.12 CLOCK IMPLEMENTATION ............................................................................8-10
8.1.13 MATCHING PHASELETS ................................................................................8-10
8.1.14 START-UP ........................................................................................................8-10
8.1.15 HARDWARE AND COMMUNICATION REQUIREMENTS ..............................8-11
8.1.16 ONLINE ESTIMATE OF MEASUREMENT ERRORS ......................................8-11
L90 Line Differential Relay GE Multilin