CHAPTER 6: SETPOINTS
S3 PROTECTION
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
6–63
1.03 × Pickup, ..., 20.00 × Pickup
Range: 0 to 65535 ms in steps of 1
Default: 0 ms
These settings specify the time to operate at the following pickup levels 1.03 to 20.00.
This data is converted into a continuous curve by linear interpolation between data
points. To enter a custom FlexCurve™, enter the operate time for each selected pickup
point.
NOTE
NOTE:
Each FlexCurve can be configured to provide inverse time characteristic to more than one
Time Overcurrent Element. However, for computation of the curve operating times, one
must take into account the setting of the Time Delay Multiplier from the FlexCurve menu,
and the Time Delay Multiplier setting from TOC menu. The true TDM applied to the TOC
element when FlexCurve is selected is the result from the multiplication of both TDM
settings. For example, for FlexCurve Multiplier = 5, and Phase TOC Multiplier = 2, the total
Time Dial Multiplier will be equal to 10. To avoid confusion, it is suggested to keep the
multiplier from the TOC menu equal to 1, and change only the multiplier from the selected
FlexCurve. This way, one can see from the FlexCurve setup, the curve operating times as
related to the multiples of pickup.
Phase timed
overcurrent
protection
The relay has one Phase Time Overcurrent protection element per protection group. The
settings of this function are applied to each of the three phases to produce trip or pickup
per phase. The TOC pickup flag is asserted, when the current on any phase is above the
PKP value. The TOC trip flag is asserted if the element stays picked up for the time defined
by the selected inverse curve and the magnitude of the current. The element drops from
pickup without operation, if the measured current drops below 97-98% of the pickup value,
before the time for operation is reached. The selection of Definite Time as a base time
delay of 0.1 s, multiplied by the selected TD multiplier. For example the operating time for
TOC set to Definite Time and a TDM set to 5 will result in 5*0.1 = 0.5 s.
The following path is available using the keypad. For instructions on how to use the
keypad, please refer to
Chapter 3 - Working with the Keypad
.
PATH
:
SETPOINTS > S3 PROTECTION > SETPOINT GROUP 1(2) > PHASE TOC
PH TOC FUNCTION
Range: Disabled, Latched Alarm, Alarm, Trip
Default: Disabled
The selection of the Latched Alarm, Alarm, or Trip setting enables the Phase TOC
function. The output relay #1 “Trip” will operate when the Trip setting is selected, and the
Phase TOC operates. The “ALARM” LED will not turn on if the TOC operates when set to
function Trip. The “ALARM” LED will flash upon phase TOC operation, with the TOC
function selected as Alarm, and will self-reset, when the operation clears. If Latched
Alarm is selected as a TOC function, the “ALARM” LED will flash during TOC operation,
and will stay “ON” after the operation clears until the reset command is initiated. The
output relay #1 “Trip” will not operate if the Latched Alarm or Alarm setting is selected.
PH TOC PKP
Range: 0.04 to 20.00 x CT in steps of 0.01 x CT
Default: 1.00 x CT
This setting sets the time overcurrent pickup level. For example, a PKP setting of 0.9 x CT
with 300:5 CT translates into 270A primary current.
