The disclosure relates to a process of configuring a standalone self-supplied numeric controlled relay for providing phase and earth over current protection to electrical systems by accurate current measurement. The arrangement for current measurement with control algorithms is provided for power control by providing amplified and conditioned current for optimization between the current to power an electronic circuit and the fidelity of a measured current waveform so that they both are at the acceptable levels at the same time. This disclosure describes the current sensing and associated algorithm for power control in a truly self-powered relay.