ABB Relion 670 Series Applications Manual page 256

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Multipurpose protection

ANSI05000535 V1 EN-US

Figure 120: Loss of excitation

Undercurrent protection for capacitor bank

Following example explains how an undercurrent protection within CVGAPC function can be used for the

disconnection of shunt capacitor bank (SCB) in case of very low voltages at the busbar.

This functionality can be achieved by using one CVGAPC function and following shall be done to ensure

proper operation of the function:

Connect three-phase terminal currents to CVGAPC function and no need of voltage input, that is,

connect GRP_OFF from FXDSIGN to U3P of CVGAPC.

Set operation = On, select CurrentInput = MaxPh and set VoltageInput to default value

Set Operation_UC1 = On

Set EnBlkLowl_UC1 = On

Set BlkLowCurr_UC1 = 10.0 %IB

Set StartCurr_UC1 = 70.0 %IB

Set tDef_UC1 = 5.00 s

Set tResetDef_UC1 = 0.0 s

Set HarmRestr_UC1 = Off

Operating Region

Operating region

1MRK 505 370-UUS Rev. K

en05000535_ansi.vsd

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Busbar protection REB670

Application manual

Relion reb670