Beyond Commissioning: Evidence Validity and Revalidation of Changing Photovoltaic Plants in Weak Grids

Commissioning evidence applies only to the photovoltaic (PV) plant configuration and grid conditions it represents. Firmware updates, controller retuning, equipment replacement, fleet changes, topology modification and grid evolution can shift impedance, synchronisation, current-limiting, protection and plant-control boundaries, especially in weak grids. This critical integrative review examines when historical models, tests and commissioning records remain applicable after such change. The evidence base contains substantial PV and inverter-based-resource testing, modelling, guidance and field-event evidence, but longitudinal same-asset evidence that follows a PV plant through successive documented configurations with repeated claim-level validation remains sparse. The review therefore proposes a six-step, claim-specific decision framework linking change, affected mechanism, challenged claim, supporting evidence, applicable domain, residual uncertainty and closure action. Structured R0–R6 response classes retain unaffected evidence while escalating only challenged claims from record reconciliation and model updating to targeted analysis, hardware-in-the-loop or device testing, partial recommissioning or full reassessment. A quantitative worked example demonstrates the non-compensatory decision gates and uncertainty-margin logic. AI is treated only as optional decision support for detection, diagnosis, uncertainty/OOD assessment and test prioritisation under accountable human approval. Retrospective cases and internal rule-consistency scenarios establish interpretability and face validity; prospective multi-vendor and inter-assessor evaluation remains necessary before standardised industrial use.