Digital multirate algorithms for measurement of voltage, current, power and flicker

Digital multirate processing, i.e. signal processing that involves more than one sample rate, permits computationally efficient estimation of several electrical quantities. The new multirate algorithms for active power, voltage and current do not require periodicity of the input signals or synchronous sampling and give excellent accuracy. They replace the integration or summation of conventional methods with digital low pass filtering, implemented very efficiently in a decimator. A multirate flicker meter algorithm is also introduced, completed with a novel method which allows the evaluation of individual flicker sources of the power system while other sources remain active