CHAPTER 2: PRODUCT DESCRIPTION SPECIFICATIONSC70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL 2-192Blocking (forward load, reverse fault): <8 ms, typicallyNEUTRAL DIRECTIONAL OVERCURRENTDirectionality: Co-existing forward and reversePolarizing: Voltage, Current, Dual, Dual-V, Dual-IPolarizing voltage: V_0 or VXPolarizing current: IGOperating current: I_0Level sensing: 3 × (|I_0| – K × |I_1|), IGIndependent for forward and reverseRestraint, K: 0.000 to 0.500 in steps of 0.001Characteristic angle: –90 to 90° in steps of 1Limit angle: 40 to 90° in steps of 1, independent for forward and reverseAngle accuracy: ±2°Offset impedance: 0.00 to 250.00 Ω in steps of 0.01Pickup level: 0.002 to 30.000 pu in steps of 0.01Dropout level: 97 to 98%Operation time: <16 ms at 3 × pickup at 60 HzNEGATIVE SEQUENCE DIRECTIONAL OCDirectionality: Co-existing forward and reversePolarizing: VoltagePolarizing voltage: V_2Operating current: I_2Level sensing:Zero-sequence: |I_0| – K × |I_1|Negative-sequence: |I_2| – K × |I_1|Restraint, K: 0.000 to 0.500 in steps of 0.001Characteristic angle: 0 to 90° in steps of 1Limit angle: 40 to 90° in steps of 1, independent for forward and reverseAngle accuracy: ±2°Offset impedance: 0.00 to 250.00 Ω in steps of 0.01Pickup level: 0.015 to 30.000 pu in steps of 0.01Dropout level: 97 to 98%Operation time: <16 ms at 3 × pickup at 60 HzPHASE CURRENT UNBALANCEOperation: per phaseAuto-setting: on demand from keypad, per phaseNumber of elements: 1 per CT bank, maximum of 3Inherent unbalance factor: –0.1000 to 0.1000 in steps of 0.0001, per phaseNumber of trip/alarm stages: 4 per phase with individual timers per stagePickup threshold: 0.001 to 5.000 pu of split-phase CT nominal in steps of 0.001Pickup level accuracy: 0.002 pu for <1 pu current and <20 CT mismatch between phase and differential CTHysteresis: 3% or 0.001 pu, whichever is greaterPickup delay: 0 to 600.00 s in steps of 0.01Timer accuracy: ±3% of operate time or ±35 ms, whichever is greaterOperate time: <35 ms at 60 HzNEUTRAL CURRENT UNBALANCEAuto-setting: on demand from keypadNumber of elements: 1 per CT bank, to a maximum of 3Inherent unbalance factor: magnitude of 0 to 0.1500 in steps of 0.0001, angle of 0 to 359° in steps of 1Number of trip/alarm stages: 4, with individual timers per stagePickup threshold: 0.001 to 5.000 pu of ground input CT in steps of 0.001Pickup level accuracy: 0.002 pu for <1 pu current and < 20 CT mismatch between phase and neutral CTHysteresis: 3% or 0.001 pu, whichever is greater
