Abstract: To address the challenges of the high concealment of fixed leakage currents on the consumer side of the meter, low efficiency in on-site troubleshooting, and the limitations of existing methods which rely heavily on monitoring the total residual current of the transformer district and face constraints in practical application, a method for identifying fixed leakage currents based on the neutral and live line currents of residential electricity meters is proposed. This method utilizes only the daily data of the 24-point neutral and live line currents from residential meters to construct a sequence of absolute differences between neutral and live line currents, thereby characterizing the degree of circuit imbalance. The ratio of the difference between adjacent time points and the root mean square deviation from 1 is introduced to construct a difference consistency index. On this basis, a hierarchical analysis strategy is established that combines extreme imbalance criteria, difference amplitude criteria, and difference consistency criteria, and a method combining statistical analysis and ROC curve optimization is adopted to determine key thresholds. Field application results indicate that, among a sample of 40 residential users verified to have leakage currents across four power supply stations, 37 households were successfully identified, achieving a detection rate of 92.50%. The proposed method requires no additional monitoring equipment or transformer substation modifications, demonstrating good engineering practicality and potential for widespread adoption.

Key words: residential electrical leakage, neutral and live wire currents, residual current, anomaly detection