Post Go back to editing

# Regarding Reactive power measurement using AVAR register in ADE7953

Category: Hardware

I'm trying to measure the reactive power absorbed by a RLC load using ADE7953 IC. I'm trying to read the AVAR(0x214) register of ADE7953, but the reading I'm getting at 1.17kVAR value are much more smaller than the value I'm getting while measuring the Active or Apparent power for the measurements of the similar order. What is the reason for this behaviour and how can we solve this problem?

I'm also attaching the links for the measurement readings for all the three parameters i.e., P,Q and S.

Active power(0.9kW)

Reactive Power(1.17kVAR)

Apparent Power(1.17kVA)

If preview to the file isn't available, kindly download it.

Thanks for the help.

• What do you expect for values? What are the RLC?

What is your sensor what is your voltage divider?

What is your IRMS what is your VRMS? Did you calibrate these? I need to know the Amps Voltage and ADC values for each.

Using the numbers you provided

 VA VAR WATT 191543 478568 385955

PF = WATT/ (SQRT(WATT^2+ VAR^2)) = 0.63 = 51deg  I used WATT and VAR to calculate VA because they are the same scale.

Since VAR is bigger it may be 90-51= 39 DEG PF= 0.77

All I can do with what you gave me is calculate the PF based on the WATT and VAR.

Dave

• Dear Dave

Thanks for the reply.

I should have made my query more clear. My apologies for that.

What is your sensor what is your voltage divider?

The current sensor which is used for current measurement is LEM LA 25-P with a burden resistance of 200Ω and for voltage measurement resistance divider of (1/100) is being used. The outputs of both the current sensor and divider circuit are then given to difference circuits to produce single ended outputs for the IC.

What is your IRMS what is your VRMS?

The following are the parameters for the test conducted by me:

V_rms = 217.5V

I_rms = 8.32A

f = 50Hz

pf = 0.773

P = 1400W

Q = 1148Vars

S = 1810VA

What are the RLC?

R = 50Ω

L = 7.5mH

C = 400μF