GE 745 Instruction Manual page 218

A2 METERING
6.3.1.8 Ground Differential Current
 GROUND
DIFFERENTIAL
6.3.2 Harmonic Content
6.3.2.1 Main Menu
 HARMONIC
CONTENT
6.3.2.2 Harmonic Sub-components
 2nd HARMONIC [
6–10
PATH: ACTUAL VALUES


[ ]
MESSAGE
MESSAGE
The ground differential current magnitudes for windings 1 through 3 are shown.
PATH: ACTUAL VALUES


[ ]
MESSAGE
MESSAGE
MESSAGE
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.
PATH: ACTUAL VALUES


]
MESSAGE
MESSAGE
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
st
to the 21 .
A2 METERING CURRENT

W1 GND DIFFERENTIAL
CURRENT: 0.00 x CT
W2 GND DIFFERENTIAL
CURRENT: 0.00 x CT
W3 GND DIFFERENTIAL
CURRENT: 0.00 x CT
A2 METERING HARMONIC CONTENT



2nd HARMONIC [ ]
↓


21st HARMONIC [ ]


THD [ ]


HARMONIC [ ]
DERATING
A2 METERING HARMONIC...

W1 (% f0) H2a: 0.0
H2b: 0.0 H2c: 0.0
W2 (% f0) H2a: 0.0
H2b: 0.0 H2c: 0.0
W3 (% f0) H2a: 0.0
H2b: 0.0 H2c: 0.0
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 6: ACTUAL VALUES
GROUND DIFFERENTIAL

See page 6–10
See page 6–10
See page 6–11
See page 6–11
2nd(21st) HARMONIC
