RootTrace: Root Cause Localization for Settlement Discrepancies in Multi-Party Electricity Trading via Trusted Path Traceability

Settlement discrepancies in multi-party electricity trading are difficult to localize because final outcomes are produced by multi-stage pipelines that combine heterogeneous data, rule versions, parameters, and execution contexts across organizational boundaries. In such settings, numerical reconciliation is not enough: investigators must identify where divergence entered the pipeline and support that judgment with evidence that can be checked independently. We formulate discrepancy localization as an auditable inference problem and introduce RootTrace, a trusted path-traceability method for this setting. Settlement processing is represented as an evidence graph over versioned artifacts and explicit events; RootTrace uses backward tracing and version-difference tracing to derive a suspect set of stages and/or artifact versions. The same pipeline exports a verifiable evidence bundle that preserves the trace used in localization. To support accountability under an explicit threat model, RootTrace includes trusted recording and verification procedures for tamper-evident capture and minimal-disclosure bundle export. On a semi-synthetic benchmark with ten independent replications, RootTrace achieves mean Top-1/Top-5/MRR of 0.47/0.83/0.60, compared with Top-1 0.17 and 0.04 for representative rule-based and stage-order baselines; exported bundles verify cleanly with full detection of the configured tamper classes (mean verification latency below 5ms on our grid); and an eight-hour unattended stress run completes over 1.3×10⁶ iterations without runtime failure.