A Two-Stage Method for Phase-by-Phase Identification of Low-Voltage Feeder Area Consumers Based on Complex Admittance Increment Correlation and Voltage–Power Residuals

In response to issues such as the susceptibility of single-feature correlation in phase identification for consumers in low-voltage feeder areas to measurement noise and synchronous changes in load, this paper proposes a two-stage method for phase identification of consumers in low-voltage feeder areas. In the first stage, complex admittance increments are constructed based on voltage, active power and reactive power data from smart meters, and consumers are classified into two groups—high-confidence and low-confidence. According to maximum correlation strength and the distinguishability of candidate phases, results are output directly for high-confidence consumers. In the second stage, a voltage–power residual model—which combines the consumer’s own power variations with those of the load power for the remaining candidate phases—is employed to perform selective verification of low-confidence consumers. Simulations on a 31-node radial feeder with 60 consumers showed that, in the baseline white-noise case, Stage 1 and the complete method achieved 98.3 % and 100 %, versus 91.1 % and 94.5 % for voltage- and power-correlation benchmarks. Robustness testing showed that, when white noise increased to 2 percent, the Stage 1 and overall accuracy rates remained at approximately 82.6 % and 83.2 %. For feed scales ranging from 31/60 to 200/400, the overall accuracy of the method fell from 97.2 percent to 86.2 percent, whilst the running time increased from 13 s to 79 s; when the feed scale was increased whilst the noise level doubled, the accuracy fell further to 76.1 percent. The simulations also demonstrated that confidence stratification can filter some potentially misclassified consumers into the low-confidence set; the second stage can then correct errors for those consumers with sufficient residual discriminability, whilst rejecting candidate results where evidence is insufficient.