ADE7754_15 datasheet(19/44 Pages) AD

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REV. 0

ADE7754

–19–

HPF

–

IB*

AAPGAIN

LPF2

AWGAIN

AAPOS

PHASE A

HPF

IB*

BAPGAIN

LPF2

BWGAIN

BAPOS

PHASE B

HPF

–

IB*

CAPGAIN

LPF2

CWGAIN

CAPOS

PHASE C

TOTAL INSTANTANEOUS

POWER SIGNAL

ACTIVE POWER

SIGNAL – P

2752545h

Figure 26. Total Active Power Consumption Calculation

For example, for WATMOD = 1, when all the gains and offsets

corrections are taken into consideration, the formula that is

used to process the active power is

Total Active Power

AAPGAIN

BAPGAIN

AAPOS

AWG

CAPGAIN

BAPGAIN

CAPOS

CWG

×+









×−

























×+









+×









×−

























×+









Depending on the polyphase meter service, an appropriate for-

mula should be chosen to calculate the active power. The

American ANSI C12.10 standard defines the different configu-

rations of the meter. Table II describes which mode should be

chosen for each configuration.

Table II. Meter Form Configuration

ANSI

Meter Form

WATMOD

WATSEL

5S/13S

3-wire Delta

3 or 5 or 6

6S/14S

4-wire Wye

8S/15S

4-wire Delta

9S/16S

4-wire Wye

Different gain calibration parameters are offered in the ADE7754

to cover the calibration of the meter in different configurations.

Note that in Mode 0, the APGAIN and WGAIN registers have

the same effect on the end result. In this case, APGAIN regis-

ters should be set at their default value and the gain adjustment

should be made with the WGAIN registers.

ENERGY CALCULATION

As stated earlier, power is defined as the rate of energy flow.

This relationship can be expressed mathematically as

(7)

where P = power and E = energy.

Conversely energy is given as the integral of power.

Pdt

= ∫

(8)

The ADE7754 achieves the integration of the active power

signal by continuously accumulating the active power signal in

an internal non readable 54-bit energy register. The active

energy register (AENERGY[23:0]) represents the upper 24 bits

of this internal register. This discrete time accumulation or

summation is equivalent to integration in continuous time.

Equation 9 expresses the relationship

Ep t dt

Lim

p nT

∫

















→=

∞

()

(

)

(9)

where n is the discrete time sample number and T is the

sample period.

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