Current Demand - GE 339 Instruction Manual

CHAPTER 6: SETPOINTS

Current demand

339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
the number of blocks as set by the programmed time interval. Each new value of
Demand becomes available at the end of each time interval.
• Rolling Demand: This selection calculates a linear average of the quantity (RMS
current, real power, reactive power, or apparent power) over the programmed
Demand time interval, in the same way as Block Interval. The value is updated every
minute and indicates the Demand over the time interval just proceeding the time of
update.
The Current Demand for each phase is calculated individually, and the Demand for each
phase is monitored by comparison with a single Current Demand Pickup value. If the
Current Demand Pickup is equalled or exceeded by any phase, the relay can cause an
alarm or signal an output relay.
Path:
S6 MONITORING > DEMAND > CURRENT DEMAND 1
FUNCTION
Range: Disabled, Alarm, Latched Alarm
Default: Disabled
For details see Common
MEASUREMENT TYPE
Range: Blk Interval, Exponential, Rolling Dmd
Default: Blk Interval
This setting sets the measurement method. Three methods can be applied.
THERMAL 90% RESPONSE TIME
Range: 5 min, 10 min, 15 min, 20 min, 30 min
Default: 15 min
This setpoint sets the time required for a steady state current to indicate 90% of the
actual value and allows the user to approximately match the response of the relay to
analog instruments. The setpoint is visible only if MEASUREMENT TYPE is "Exponential".
TIME INTERVAL
Range: 5 min, 10 min, 15 min, 20 min, 30 min
Default: 20 min
This setpoint sets the time period over which the current demand calculation is to be
performed. The setpoint is visible only if MEASUREMENT TYPE is "Block Interval" or
"Rolling Demand".
PKP
Range: 10 to 10000 A in steps of 1 A
Default: 1000 A
This setpoint sets the Current Demand Pickup level.
OUTPUT RELAY X
For details see Common
BLOCK
For details see Common
setpoints.
setpoints.
setpoints.
S6 MONITORING
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