GE Multilin L90 Line Current Differential System 7-37 COMMANDS AND TARGETS 7.1 COMMANDS77.1.5 RELAY MAINTENANCEPATH: COMMANDS ÖØ RELAY MAINTENANCEThis menu contains commands for relay maintenance purposes. Commands for the lamp test and order code are activatedby changing a command setting to “Yes” and pressing the ENTER key. The command setting will then automatically revertto “No”. The service command is activated by entering a numerical code and pressing the ENTER key.The PERFORM LAMPTEST command turns on all faceplate LEDs and display pixels for a short duration. The UPDATEORDER CODE command causes the relay to scan the backplane for the hardware modules and update the order code tomatch. If an update occurs, the following message is shown.There is no impact if there have been no changes to the hardware modules. When an update does not occur, the ORDERCODE NOT UPDATED message will be shown.The SERVICE COMMAND is used to perform specific L90 service actions. Presently, there is only one service action available.Code “101” is used to clear factory diagnostic information stored in the non-volatile memory. If a code other than “101” isentered, the command will be ignored and no actions will be taken. Various self-checking diagnostics are performed in thebackground while the L90 is running, and diagnostic information is stored on the non-volatile memory from time to timebased on the self-checking result. Although the diagnostic information is cleared before the L90 is shipped from the factory,the user may want to clear the diagnostic information for themselves under certain circumstances. For example, it may bedesirable to clear diagnostic information after replacement of hardware. Once the diagnostic information is cleared, all self-checking variables are reset to their initial state and diagnostics will restart from scratch.7.1.6 PHASOR MEASUREMENT UNIT ONE-SHOTPATH: COMMANDS ÖØ PMU ONE-SHOTThis feature allows pre-scheduling a PMU measurement at a specific point in time. This functionality can be used to test foraccuracy of the PMU, and for manual collection of synchronized measurements through the system, as explained below.When enabled, the function continuously compares the present time with the pre-set PMU ONE-SHOT TIME . When the twotimes match, the function compares the present sequence number of the measured synchrophasors with the pre-set PMUONE-SHOT SEQUENCE NUMBER. When the two numbers match, the function freezes the synchrophasor actual values andthe corresponding protocol data items for 30 seconds. This allows manual read-out of the synchrophasor values for the pre-set time and pre-set sequence number (via the faceplate display, supported communication protocols such as Modbus orDNP, and the EnerVista UR Setup software).When freezing the actual values the function also asserts a PMU ONE-SHOT OP FlexLogic™ operand. This operand may beconfigured to drive an output contact and trigger an external measuring device such as a digital scope with the intent to ver-ify the accuracy of the PMU under test.With reference to the figure below, the PMU one-shot function (when enabled) controls three FlexLogic™ operands: COMMANDS RELAY MAINTENANCEPERFORM LAMPTEST?NoRange: No, YesUPDATE ORDER CODE?NoRange: No, YesSERVICE COMMAND:0Range: 0, 101UPDATING...PLEASE WAIT COMMANDS PMU ONE-SHOTPMU ONE-SHOTFUNCTION: DisabledRange: Enabled, DisabledPMU ONE-SHOTSEQUENCE NUMBER: 0Range: 0 to nominal frequency – 1 in steps of 1PMU ONE-SHOT TIME:2005/06/14 7:58:35Range: 24h time format
