4-16 L90 Line Current Differential System GE Multilin4.3 FACEPLATE INTERFACE 4 HUMAN INTERFACES4• TROUBLE: This LED indicates that the relay has detected an internal problem.• TEST MODE: This LED indicates that the relay is in test mode.• TRIP: This LED indicates that the FlexLogic operand serving as a trip switch has operated. This indicator alwayslatches; as such, a reset command must be initiated to allow the latch to be reset.• ALARM: This LED indicates that the FlexLogic operand serving as an alarm switch has operated. This indicator isnever latched.• PICKUP: This LED indicates that an element is picked up. This indicator is never latched.The event cause indicators in the first column are described below.Events cause LEDs are turned on or off by protection elements that have their respective target setting selected as either“Enabled” or “Latched”. If a protection element target setting is “Enabled”, then the corresponding event cause LEDsremain on as long as operate operand associated with the element remains asserted. If a protection element target settingis “Latched”, then the corresponding event cause LEDs turn on when the operate operand associated with the element isasserted and remain on until the RESET button on the front panel is pressed after the operand is reset.All elements that are able to discriminate faulted phases can independently turn off or on the phase A, B or C LEDs. Thisincludes phase instantaneous overcurrent, phase undervoltage, etc. This means that the phase A, B, and C operate oper-ands for individual protection elements are ORed to turn on or off the phase A, B or C LEDs.• VOLTAGE: This LED indicates voltage was involved.• CURRENT: This LED indicates current was involved.• FREQUENCY: This LED indicates frequency was involved.• OTHER: This LED indicates a composite function was involved.• PHASE A: This LED indicates phase A was involved.• PHASE B: This LED indicates phase B was involved.• PHASE C: This LED indicates phase C was involved.• NEUTRAL/GROUND: This LED indicates that neutral or ground was involved.The user-programmable LEDs consist of 48 amber LED indicators in four columns. The operation of these LEDs is user-defined. Support for applying a customized label beside every LED is provided. Default labels are shipped in the label pack-age of every L90, together with custom templates. The default labels can be replaced by user-printed labels.User customization of LED operation is of maximum benefit in installations where languages other than English are used tocommunicate with operators. Refer to the User-programmable LEDs section in chapter 5 for the settings used to programthe operation of the LEDs on these panels.b) STANDARD FACEPLATEThe standard faceplate consists of three panels with LED indicators, keys, and a communications port. The RESET key isused to reset any latched LED indicator or target message, once the condition has been cleared (these latched conditionscan also be reset via the SETTINGS INPUT/OUTPUTS RESETTING menu). The RS232 port is for connection to a com-puter.The USER keys are used by the breaker control feature.Figure 4–19: LED PANEL 1PICKUPALARMTRIPTEST MODETROUBLEIN SERVICESTATUSUSER 3USER 2USER 1RESETNEUTRAL/GROUNDPHASE CPHASE BPHASE AOTHERFREQUENCYCURRENTVOLTAGEEVENT CAUSE842781A1.CDR
