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350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
Negative sequence
overvoltage
The relay has one Negative Sequence Overvoltage element per protection group. The
negative sequence overvoltage may be used to detect the loss of one or two phases of the
source, a reversed voltage phase sequence , or non-system voltage conditions.
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) > NEGATIVE SEQ. OV
NEG SEQ OV FUNCTION
Range: Disabled, Alarm, Latched Alarm, Trip
Default: Disabled
The selection of the Latched Alarm, Alarm, or Trip setting enables the Negative Sequence
OV function. The output relay #1 “Trip” will operate, if the function is selected as a Trip
and the negative sequence voltage computed by the relay is above the NEG SEQ OV PKP
setting for a time greater than the selected NEG SEQ OV DELAY time. The “ALARM” LED
will not turn on, if the neg. sequence OV function is set to Trip. The “ALARM” LED will flash
upon an OV operating condition with the neg. sequence OV function selected as Alarm,
and will self-reset, when the operating condition clears. If Latched Alarm is selected as a
neg. seq. OV function, the “ALARM” LED will flash during the OV condition, and will stay
“ON” after the condition clears, until the reset command is initiated. The output relay #1
“Trip” will not operate if the Latched Alarm or Alarm setting is selected. Any or all of the
output relays 3 to 6 can be selected to operate when the neg. seq. OV function is
selected as Latched Alarm, Alarm, or Trip.
NEG SEQ OV PKP
Range: 0.00 to 1.25 x VT in steps of 0.01
Default: 0.30 x VT
This setting defines the negative sequence OV pickup level.
NEG SEQ OV DELAY
Range: 0.1 to 600.0 sec in steps of 0.1 sec
Default: 2.0 s
This setting specifies the time delay before OV operation.
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 a Negative Seq. OV
condition. The selection of relay outputs operation is available no matter whether
Latched Alarm, Alarm, or Trip function is selected.
BLOCK 1/2/3
Range: Off, Contact Input 1 to 10[8], Virtual Input 1 to 32, Remote Input 1 to 32, Logic
Element 1 to 16
Default: Off
Three blocking inputs are provided in the Neg. Seq. OV menu. One blocking input “high” is
enough to block the function. The available selections for each block include Contact
input, Virtual Input, Remote Input, or Logic Element.
