5-206 L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUALFLEXLOGIC CHAPTER 5: SETTINGS5Figure 5-105: FlexElement input mode settingFLEXELEMENT 1 PICKUP — This setting specifies the operating threshold for the effective operating signal of the element. Ifset to “Over,” the element picks up when the operating signal exceeds the FLEXELEMENT 1 PICKUP value. If set to “Under,” theelement picks up when the operating signal falls below the FLEXELEMENT 1 PICKUP value.FLEXELEMENT 1 HYSTERESIS — This setting controls the element dropout. Notice that both the operating signal and thepickup threshold can be negative, facilitating applications such as reverse power alarm protection. The FlexElement can beprogrammed to work with all analog actual values measured by the relay. The FLEXELEMENT 1 PICKUP setting is entered inper-unit values using the following definitions of the base units.Table 5-27: FlexElement base unitsUnit Description87L SIGNALS(Local IA Mag, IB, and IC)(Diff Curr IA Mag, IB, and IC)(Terminal 1 IA Mag, IB, and IC)(Terminal 2 IA Mag, IB and IC)IBASE = maximum primary RMS value of the +IN and –IN inputs(CT primary for source currents, and 87L source primary current for line differential currents)87L SIGNALS(Op Square Curr IA, IB, and IC)(Rest Square Curr IA, IB, and IC)BASE = Squared CT secondary of the 87L source
