GE 745 - 6.3.2.3 Total Harmonic Distortion (THD); 6.3.2.4 Harmonic Derating Factor

CHAPTER 6: ACTUAL VALUES A2 METERING
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL 6–11
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.
6.3.2.3 Total Harmonic Distortion (THD)
PATH: ACTUAL VALUES
 A2 METERING  HARMONIC CONTENT  THD
THD is calculated and displayed. Every THD value is calculated as the ratio of the RMS
value of the sum of the squared individual harmonic amplitudes to the RMS value of the
fundamental frequency. The calculations are based on IEEE standard 519-1986.
The actual values messages display the total harmonic distortion for phase A, B, and C
currents for windings 1 through 3, expressed as a percentage of the fundamental
frequency component. The numbers in parentheses indicate the programmed frequency
band (in terms of harmonic number) over which THD is being calculated.
6.3.2.4 Harmonic Derating Factor
PATH: ACTUAL VALUES
 A2 METERING  HARMONIC...  HARMONIC DERATING
NOTE
Note
These actual values are shown only if the harmonic derating function is enabled.
 THD [] W1 THDa (2nd-21st):
0.0% ƒo
MESSAGE
W1 THDb (2nd-21st):
0.0% ƒo
MESSAGE
W1 THDc (2nd-21st):
0.0% ƒo
MESSAGE
W2 THDa (2nd-21st):
0.0% ƒo
MESSAGE
W2 THDb (2nd-21st):
0.0% ƒo
MESSAGE
W2 THDc (2nd-21st):
0.0% ƒo
MESSAGE
W3 THDa (2nd-21st):
0.0% ƒo
MESSAGE
W3 THDb (2nd-21st):
0.0% ƒo
MESSAGE
W3 THDc (2nd-21st):
0.0% ƒo
 HARMONIC []
DERATING
W1 HARMONIC DERATING
FACTOR: 1.00
MESSAGE
W2 HARMONIC DERATING
FACTOR: 1.00
MESSAGE
W3 HARMONIC DERATING
FACTOR: 1.00