Abstract: In response to the problem of difficulty in accurately and quickly monitoring the current imbalance status of multiple types of grounding return cables, a monitoring method for the current imbalance status of multiple types of grounding return cables based on R-ECT and RMS calculation is proposed. Firstly, the R-ECT array is used to synchronously collect the transient current of each grounding return cable, and its non-magnetic saturation and wideband response characteristics are utilized to overcome high current impulse distortion; Secondly, the RMS values of each channel current are calculated by sliding the window, and three characteristic quantities are defined: phase to phase imbalance, neutral line imbalance, and fluctuation mutation rate; Finally, based on historical statistical data, an adaptive threshold is generated to achieve a three-level state judgment of "normal attention abnormal". Conduct experiments on 10kV cable lines in four scenarios: normal, poor contact, water ingress in cross interconnection boxes, and instantaneous impact. The results showed that the monitoring results of this method for three types of grounding return cables were completely consistent with the actual state, with a continuous 24-hour false alarm rate of less than 2% and a monitoring time of no more than 2 minutes. Compared with existing methods, the false alarm rate was reduced by more than 15%, verifying its effectiveness in accurate and rapid monitoring in complex electromagnetic environments.