GE C70 Instruction Manual page 349

CHAPTER 5: SETTINGS
The 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 12
ground instantaneous overcurrent elements are available, dependent on the CT/VT modules ordered with the relay. Three
neutral 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(3)
 NEUTRAL TOC1

The neutral time overcurrent element can provide a desired time-delay operating characteristic versus the applied current
or be used as a simple definite time element. The neutral current input value is a quantity calculated as 3Io from the phase
currents and can be programmed as fundamental phasor magnitude or total waveform RMS magnitude as required by the
application.
Two methods of resetting operation are available: "Timed" and "Instantaneous" (see the Inverse TOC Curve Characteristics
section for details on curve setup, trip times, and reset operation). When the element is blocked, the time accumulator
resets according to the reset characteristic. For example, if the element reset characteristic is set to "Instantaneous" and
the element is blocked, the time accumulator clears immediately.
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
 NEUTRAL TOC 3


 NEUTRAL IOC 1



 NEUTRAL IOC 12


 NEUTRAL

 DIRECTIONAL OC1
 NEUTRAL CURRENT

 UNBALANCE 1

 NEUTRAL CURRENT

 UNBALANCE 3
NEUTRAL TOC1

FUNCTION: Disabled
NEUTRAL TOC1 SIGNAL

SOURCE: SRC 1
NEUTRAL TOC1

INPUT: Phasor
NEUTRAL TOC1

PICKUP: 1.000 pu
NEUTRAL TOC1

CURVE: IEEE Mod Inv
NEUTRAL TOC1

TD MULTIPLIER: 1.00
NEUTRAL TOC1

RESET: Instantaneous
NEUTRAL TOC1 BLOCK:

Off
NEUTRAL TOC1

TARGET: Self-reset
NEUTRAL TOC1

EVENTS: Disabled
GROUPED ELEMENTS
See page 5-184
See page 5-185
See page 5-190
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: Phasor, RMS
Range: 0.020 to 30.000 pu in steps of 0.001
Range: see Overcurrent Curve Types table
Range: 0.00 to 600.00 in steps of 0.01
Range: Instantaneous, Timed
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
5
5-183