A2 Metering
745
Transformer Management Relay
Actual
V
alues
http://www.GEindustrial.com/multilin
6–8
GE Multilin
Harmonic Content
a) Main Menu
PATH: ACTUAL VALUES
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A2 METERING
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HARMONIC CONTENT
The 745 can determine the harmonic components of every current that it measures.
This allows it to calculate total harmonic distortion (THD) as well as a harmonic
derating factor that can be used to adjust phase time overcurrent protection to
account for additional internal energy dissipation that arises from the presence of
harmonic currents.
b) Harmonic Sub-Components
PATH: ACTUAL VALUES
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A2 METERING
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HARMONIC CONTENT
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2nd(21st) HARMONIC
The 745 is capable of measuring harmonic components up to a frequency of 21
times nominal system frequency. An actual value is calculated for each phase of
each monitored winding. The example above shows what is displayed in a typical
case for harmonic components (in this case the second harmonic). Similar displays
exist for all harmonics up to the 21
st
.
The second harmonic magnitude for each phase current of Windings 1 through 3 are
displayed. Values are expressed as a percentage of magnitude of the corresponding
fundamental frequency component.
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HARMONIC
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CONTENT
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2nd HARMONIC
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↓
MESSAGE
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21st HARMONIC
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MESSAGE
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THD
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MESSAGE
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HARMONIC
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DERATING
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2nd HARMONIC
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W1 (% f0) H2a: 0.0
H2b: 0.0
H2c: 0.0
MESSAGE
W2 (% f0) H2a: 0.0
H2b: 0.0
H2c: 0.0
MESSAGE
W3 (% f0) H2a: 0.0
H2b: 0.0
H2c: 0.0
Summary of Contents for Multilin 745
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