GE TRANSFORMER MANAGEMENT RELAY 745 Instruction Manual page 157

6 ACTUAL VALUES
c) TOTAL HARMONIC DISTORTION (THD)
PATH: ACTUAL VALUES
THD
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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 stan-
dard 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 pro-
grammed frequency band (in terms of harmonic number) over which THD is being calculated.
d) HARMONIC DERATING FACTOR
PATH: ACTUAL VALUES
HARMONIC DERATING
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The Harmonic Derating Factor for each of the windings shows the effect of non-sinusoidal load currents on power trans-
former's rated full load current. The calculations are based on ANSI/IEEE standard C57.110-1986. The actual values mes-
sages display the harmonic derating factor for Windings 1 through 3.
GE Multilin
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A2 METERING HARMONIC CONTENT
ð
W1 THDa (2nd-21st):
ENTER
0.0% ƒo
ESCAPE
W1 THDb (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
W1 THDc (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
W2 THDa (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
W2 THDb (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
W2 THDc (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
W3 THDa (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
W3 THDb (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
W3 THDc (2nd-21st):
ESCAPE
0.0% ƒo
MESSAGE
A2 METERING HARMONIC CONTENT
ð
W1 HARMONIC DERATING
ENTER
FACTOR: 1.00
ESCAPE
W2 HARMONIC DERATING
ESCAPE
FACTOR: 1.00
MESSAGE
W3 HARMONIC DERATING
ESCAPE
FACTOR: 1.00
MESSAGE
745 Transformer Management Relay
2ND HARMONIC
HARMONIC DERATING
6.3 A2 METERING
6
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