5-150 L60 Line Phase Comparison System GE Multilin5.5 GROUPED ELEMENTS 5 SETTINGS5i) CHARGE CURRENT COMPENSATIONPATH: SETTINGS GROUPED ELEMENTS PHASE COMPARISON ELEMENTS CHARGE CURRENT COMPENSATION• CHARGING CURRENT COMPENSATN: This setting enables and disables the charging current calculations and cor-rections of the mixed current used as an operating quantity for fault detectors and square pulses. The voltage signalsused for charging current compensation are taken from source 3 or 4 assigned with the three-phase voltage bank onthe L5 voltage bank. As such, it is critical to ensure that three-phase line voltage is assigned to this source and voltagebank settings are entered correctly. Half (or one-third for the three-terminal line, as defined by the 87PC SCHEMESELECT setting) of the line charging current is subtracted from the line current.This setting is forced to “Disabled” if a phase VT bank is not assigned at either source 3 or source 4.The following diagram shows possible configurations.Figure 5–58: CHARGING CURRENT COMPENSATION CONFIGURATIONS• CHARGE COMPENST BLOCK: This setting selects an input to block charging current compensation. This input istypically the VT fuse fail element of the source, where the three-phase VT is configured with this setting to block com-pensation. Blocking charging current compensation at one end of the line does not block charging current compensa-tion on the other end. However, even with compensation operating at one end ½ (or 1/3) of the charging current is stillremoved from the net phase comparison current. Alternatively, the customer may choose to switch to another settinggroup with more conservative phase comparison settings during a VT fuse fail condition.• POSITIVE and ZERO SEQUENCE CAPACITIVE REACTANCE: The values of positive and zero sequence capacitivereactance of the protected line are required for charging current compensation calculations. The line capacitive reac-tance values should be entered in primary kilo-ohms for the total line length. Details of the charging current compen-sation algorithm can be found in Chapter 8: Theory of operation.If shunt reactors are also installed on the line, the resulting value entered in the POS SEQ CAPACITIVE REACTANCE andZERO SEQ CAPACITIVE REACTANCE settings should be calculated as follows:1. No shunt reactors on the line or reactor current is subtracted from the line current, forcing the L60 to measure theuncompensated by shunt reactors load/fault current plus the full charging current.(EQ 5.7) CHARGE CURRENT COMPENSATIONCHARGE CURRENTCOMPENSATN: DisabledRange: Disabled, EnabledMESSAGE CHARGE COMPENST BLK:OffRange: any FlexLogic operandMESSAGE POS SEQ CAPACITIVEREACTANCE: 0.100 KΩRange: 0.100 to 65.535 kohms in steps of 0.001MESSAGE ZERO SEQ CAPACITIVEREACTANCE: 0.100 KΩRange: 0.100 to 65.535 kohms in steps of 0.001Possible 3-Reactorarrangement Line Capacitive ReactanceXreact XreactXreact_nX1line_capacX0line_capacPossible 4-ReactorarrangementA B C A B C831731A3.CDRX C1 X1line_capac= , X C0 X0line_capac=
