GE SR345 Instruction Manual page 213

CHAPTER 6: SETPOINTS
NOTE:
NOTE
345 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
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NTRL TOC1(2) RESET
Range: Instantaneous, Linear
Default: Instantaneous
Selection of an Instantaneous or Linear reset time is provided using this setting. If
Instantaneous reset is selected, the Neutral TOC element will reset instantaneously
providing the current drops below 97-99% below the Neutral TOC PKP level before the
time for operation is reached. When Linear reset is selected, the time to reset is
calculated based on the following linear equation:
where:
T - reset time in seconds;
RESET
E - energy capacity reached (per unit);
M - curve multiplier;
C - characteristic constant (5 for ANSI, IAC, Definite Time.
R
The 100% "energy capacity" for the TOC element is defined by the selection of PKP, TDM
and the points from the inverse curve. A memory variable based on actual values
currents is monitored for accumulation of energy capacity, where if it reaches a level of
100% of the set energy capacity level, the element operates, and if it goes below 97-99%
of this level, will tend to reset. The accumulated energy capacity is used as an input for
computation of the reset time when "Linear" reset is selected as a setting.
RLY1 TRIP W1 BKR and RLY2 TRIP W2 BKR
Range: Do Not Operate, Operate
Default: Do Not Operate
The menu for the two trip output relays - RLY1 TRIP W1 BKR and RLY2 TRIP W2 BKR - is
available only if the Trip setting is selected as a function for the Neutral Timed
Overcurrent element. One or both trip output relays can be selected to operate upon
Neutral TOC operation.
The "RLY1 TRIP W1 BKR" and "RLY2 TRIP W2 BKR" setpoints will be displayed on the OC
menu regardless of the selected OC function. These output relays will not operate if
either Alarm or Latched Alarm is selected as an OC function, regardless of the Operate/
Do Not Operate value selected. The output relays are operational only if the OC function
is selected as Trip.
OUTPUT RELAY 3 to 6
Range: Do not operate, Operate
Default: Do not operate
Any, or all of the output relays 3 to 6 can be selected to operate, upon Neutral TOC
operation. The selection of relay outputs operation is available no matter whether the
Latched Alarm, Alarm, or Trip function is selected.
BLOCK 1/2/3
Range: Off, Contact Input 1 to 10, Virtual Input 1 to 32, Remote Input 1 to 32, Logic
Element 1 to 16
Default: Off
There are three independent blocking inputs in the Neutral TOC menu. The function is
blocked if any of the three blocking inputs is detected "high". The selection of a block
input includes Contact input, Virtual Input, Remote Input, or Logic Element.
S3 PROTECTION
Eq. 18
6–101