Phase Current - GE N60 Instruction Manual

CHAPTER 5: SETTINGS

5.7.4 Phase current

5.7.4.1 Menu
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  PHASE CURRENT
 PHASE CURRENT

The phase current elements can be used for tripping, alarming, or other functions. The actual number of elements depends
on the number of current banks.
5.7.4.2 Inverse TOC curve characteristics
The inverse time overcurrent curves used by the time overcurrent elements are the IEEE, IEC, GE Type IAC, and I
curve shapes. This allows for simplified coordination with downstream devices.
If none of these curve shapes is adequate, FlexCurves can be used to customize the inverse time curve characteristics. The
definite time curve is also an option that can be appropriate if only simple protection is required.
Table 5-29: Overcurrent curve types
IEEE
IEEE Extremely Inverse
IEEE Very Inverse
IEEE Moderately Inverse
A time dial multiplier setting allows selection of a multiple of the base curve shape (where the time dial multiplier = 1) with
the curve shape ( ) setting. Unlike the electromechanical time dial equivalent, operate times are directly proportional
CURVE
to the time multiplier (
TD MULTIPLIER
or base curve values. Setting the multiplier to zero results in an instantaneous response to all current levels above pickup.
Time overcurrent time calculations are made with an internal energy capacity memory variable. When this variable
indicates that the energy capacity has reached 100%, a time overcurrent element operates. If less than 100% energy
capacity is accumulated in this variable and the current falls below the dropout threshold of 97 to 98% of the pickup value,
the variable must be reduced. Two methods of this resetting operation are available: "Instantaneous" and "Timed." The
"Instantaneous" selection is intended for applications with other relays, such as most static relays, which set the energy
capacity directly to zero when the current falls below the reset threshold. The "Timed" selection can be used where the
relay must coordinate with electromechanical relays.
N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL
 PHASE TOC 1



 PHASE TOC 6


 PHASE IOC 1



 PHASE IOC 12


 PHASE

 DIRECTIONAL 1

 PHASE

 DIRECTIONAL 3
IEC
IEC Curve A (BS142)
IEC Curve B (BS142)
IEC Curve C (BS142)
IEC Short Inverse
) setting value. For example, all times for a multiplier of 10 are 10 times the multiplier 1
See page 5-226
See page 5-229
See page 5-230
GE type IAC
IAC Extremely Inverse
IAC Very Inverse
IAC Inverse
IAC Short Inverse
GROUPED ELEMENTS
2
t standard
Other
2
I t
FlexCurves A, B, C, and D
Recloser Curves
Definite Time
5-221
5