CHAPTER 5: SETTINGS GROUPED ELEMENTSC70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL 5-2055The C70 contains protection elements for neutral time overcurrent (ANSI device 51G), neutral instantaneous overcurrent(ANSI device 50G), and neutral current unbalance (ANSI device 60N). A maximum of six ground time overcurrent and 12ground instantaneous overcurrent elements are available, dependent on the CT/VT modules ordered with the relay. Threeneutral current unbalance elements are available.5.7.4.2 Neutral time overcurrent (ANSI 51N, IEC PTOC)SETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) NEUTRAL CURRENT NEUTRAL TOC1(6)The neutral time overcurrent element can provide a desired time-delay operating characteristic versus the applied currentor be used as a simple definite time element. The neutral current input value is a quantity calculated as 3Io from the phasecurrents and can be programmed as fundamental phasor magnitude or total waveform RMS magnitude as required by theapplication.Two methods of resetting operation are available: “Timed” and “Instantaneous” (see the Inverse TOC Curve Characteristicssection for details on curve setup, trip times, and reset operation). When the element is blocked, the time accumulatorresets according to the reset characteristic. For example, if the element reset characteristic is set to “Instantaneous” andthe element is blocked, the time accumulator clears immediately. NEUTRAL TOC 6 NEUTRAL IOC 1See page 5-206 NEUTRAL IOC 12 NEUTRAL DIRECTIONAL OC1See page 5-207 NEUTRAL CURRENT UNBALANCE 1See page 5-212 NEUTRAL CURRENT UNBALANCE 3 NEUTRAL TOC1 NEUTRAL TOC1FUNCTION: DisabledRange: Disabled, Enabled NEUTRAL TOC1 SIGNALSOURCE: SRC 1Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6 NEUTRAL TOC1INPUT: PhasorRange: Phasor, RMS NEUTRAL TOC1PICKUP: 1.000 puRange: 0.020 to 30.000 pu in steps of 0.001 NEUTRAL TOC1CURVE: IEEE Mod InvRange: see Overcurrent Curve Types table NEUTRAL TOC1TD MULTIPLIER: 1.00Range: 0.00 to 600.00 in steps of 0.01 NEUTRAL TOC1RESET: InstantaneousRange: Instantaneous, Timed NEUTRAL TOC1 BLOCK:OffRange: FlexLogic operand NEUTRAL TOC1TARGET: Self-resetRange: Self-reset, Latched, Disabled NEUTRAL TOC1EVENTS: DisabledRange: Disabled, Enabled
