AEM 3945-B Manual

A SERVICE OF

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88

Power Quality Analyzer Model 3945-B

APPENDIX A

MATHEMATICAL FORMULAS

FOR VARIOUS PARAMETERS

Half-period Voltage and Current RMS Values

[] [][ ]

2

Vdem

:

2

∑

⋅=

Next Zero

Zeron

niV

NSHC

i

Single rms voltage half-period i + 1 phase

[] [][ ]

2

Udem

Compound rms voltage half-period i + 1 phase

:

2

∑

⋅=

Next Zero

Zeron

niU

NSHC

i

[] [][ ]

2

Adem

:

2

∑

⋅=

Next Zero

Zeron

niA

NSHC

i

Rms current half-period i + 1 phase

NSHC:numberofsamplesperhalfcycle(betweentwoconsecutivezeros)

n:sample(0;255)

i:phase(0;1;2)

MIN / MAX Values for Voltage and Current

Vmax[i]=max (Vdem[i]), Vmin[i]=min (Vdem[i]), Vavg=1/6000 Σ Vdem[i]

Umax[i]=max (Udem[i]), Umin[i]=min (Udem[i]), Aavg=1/6000 Σ Adem[i]

Amax[i]=max (Adem[i]), Amin[i]=min (Adem[i]) (Avg calculation on 1s)