Active power measurement comparison between analog and digital methods

The measurement method used in this paper compares the power measurement on analog wattmeter and digital systems. One analyzes, in the first part, the metrological behavior of an electrodynamics wattmeter and in the second part one uses a multifunction measurement numerical method. This method uses tow Hall sensors and an electronic analog multiplication process to adapt the network voltage and current and also the power measurement. Via an interface board of the type CIGAL M23, one acquires directly the normalized power using a statistical measurement method which increases the accuracy. Using an 8255 timer, one measures the phase angle between the voltage and the current load. The intelligent system allows us to measure the phase angle, the active, reactive and apparent power and to identify the load type (inductive or capacitive one). A comparison in the active power was made between the electrodynamics wattmeter and the smart system. The measurement ranges of this power systems are: An input voltage of 220V and a maximum load current of 5A. The accuracy is less than 0.2%.