Pulse Output - GE Multilin 489 Instruction Manual

5.11.6 Pulse Output

PULSE
5–94
Courtesy of NationalSwitchgear.com
MVA DEMAND
MESSAGE
ALARM EVENTS: Off
The 489 can measure the demand of the generator for several parameters (current, MW,
Mvar, MVA). The demand values of generators may be of interest for energy management
programs where processes may be altered or scheduled to reduce overall demand on a
feeder. The generator FLA is calculated as:
Generator FLA
------------------------------------------------------------------------------------------------------------- -
=
3
Power quantities are programmed as per unit calculated from the rated MVA and rated
power factor.
Demand is calculated in the following manner. Every minute, an average magnitude is
calculated for current, +MW, +Mvar, and MVA based on samples taken every 5 seconds.
These values are stored in a FIFO (First In, First Out buffer).The size of the buffer is dictated
by the period that is selected for the setpoint. The average value of the buffer contents is
calculated and stored as the new demand value every minute. Demand for real and
reactive power is only positive quantities (+MW and +Mvar).
Demand
where: N = programmed Demand Period in minutes,
n = time in minutes
160
140
120
100
80
60
40
20
0
t=0 t+10 t+20
FIGURE 5–27: Rolling Demand (15 Minute Window)
PATH: SETPOINTS S10 MONITORING
POS. kWh PULSE OUT
[ ] RELAYS (2-5): ----
POS. kWh PULSE OUT
MESSAGE
INTERVAL: 10 kWh
POS. kvarh PULSE OUT
MESSAGE
RELAYS (2-5): ----
Range: On, Off
Generator Rated MVA
× Generator Rated Phase-Phase Voltage
N
1
∑
--- Average
=
N
N
n 1
=
t+30 t+40 t+50 t+60 t+70
TIME
PULSE OUTPUT
Range: Any combination of Relays 2 to
Range: 1 to 50000 kWh in steps of 1
Range: Any combination of Relays 2 to
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
(EQ 5.40)
(EQ 5.41)
t+80 t+90 t+100
808717A1.CDR
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