YOKOGAWA WT332E User Manual page 121

7.3 Accuracy
Item
Power factor influence
When the line filter is turned
ON
Temperature coefficient
Accuracy when the crest
factor is set to 6 or 6A
Accuracy of apparent power
S
Accuracy of reactive power
Q
Accuracy of power factor λ
Accuracy of phase
differenceφ
7-8
Specifications
When power factor (λ) = 0 (S: apparent power)
• ±0.1% of S for 45 Hz ≤ f ≤ 66 Hz.
• ±{(0.1 + 0.15 × f)% of S} for up to 100 kHz as reference data.
f is frequency of input signal in kHz.
When 0 < λ < 1 (φ: phase angle of the voltage and current)
(power reading) × [(power reading error %) + (power range error %) × (power range/indicated
apparent power value) +
{tanφ × (influence when λ = 0)%}]
45 to 66 Hz: Add 0.3% of reading.
Less than 45 Hz: Add 1% of reading.
Same as the temperature coefficient for voltage and current
Accuracy obtained by doubling the measurement range error for the accuracy when the crest factor
is set to 3.
Voltage accuracy + current accuracy
Accuracy of apparent power +(√(1.0004−λ
±[(λ–λ/1.0002) + |cosφ – cos{φ + sin
when λ= 0%/100)}|] ± 1 digit
when voltage and current are at the measurement range rated input
−1
±[|φ – cos (λ/1.0002)| + sin
when λ= 0%)/100}] deg ± 1 digit
when voltage and current are at the measurement range rated input
2 2
)−√(1−λ )) × 100 % of range
−1
(influence from the power factor
−1
{(influence from the power factor
IM WT310E-02EN