GE Multilin 489 User Manual

5–60 489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
5.8 S7 Power Elements
5.8.1 Power Measurement Conventions
Generation of power will be displayed on the 489 as positive watts. By convention, an
induction generator normally requires reactive power from the system for excitation. This
is displayed on the 489 as negative vars. A synchronous generator on the other hand has
its own source of excitation and can be operated with either lagging or leading power
factor. This is displayed on the 489 as positive vars and negative vars, respectively. All
power quantities are measured from the phase-phase voltage and the currents measured
at the output CTs.
FIGURE 5–13: Power Measurement Conventions
I
1
I
2
I
3
I
4
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^
^
^
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GE Multilin 489 Specifications

General

Brand	GE
Model	Multilin 489
Category	Relays
Language	English