Design of a wireless current monitoring system for distribution feeders

In typical medium voltage feeder wireless current monitoring systems, the current measuring units send computed RMS values to a receiver unit. But these RMS values cannot be further processed by advanced algorithm and more information about faults cannot be extracted. To have more powerful computing capabilities, the measuring unit will have to use more powerful CPU which in turn requires higher power consumption. This is a limitation because the measuring unit has to be self-powered by current induction from the feeder line, and oftentimes there is inadequate current available. In this paper, we design the monitoring system so that the measuring unit wirelessly sends all the raw data of the sinusoidal waveforms to a receiving unit using high sampling rate (256 samples per cycle). The receiving unit is powered by low voltage distribution lines therefore removing the constraint of insulations and power consumption. We can then put the powerful CPU at the receiving unit end to process and analyses received raw data. Our wireless current monitoring system also used the split-core type current transformer (CT) for easier installation than conventional CT. We studied and presented the output results of the monitoring system under influence of 3 fault scenarios.