A Transformer Protection Scheme Based on Leakage Flux Model Matching Method

Under the new requirements posed by the advancement of new power system construction and dual-carbon strategic goals, large-and medium-sized power transformers, as critical equipment in power grids, are confronted with heightened reliability challenges for their primary protection systems. Traditional protection schemes based on electrical quantities exhibit inherent limitations: Differential protection requires inrush blocking modules that introduce operational delays, while setting calculations must balance multiple constraints prone to mis-operations such as refusal to operate, failing to meet the demand for rapid and precise protection of critical equipment. This study innovatively proposes a leakage flux model matching-based protection methodology for power transformers. By introducing the leakage flux state angle as a fault characteristic quantity and employing dual criteria of model matching degree, the method achieves precise identification of internal faults. Simulations and experimental tests demonstrate that the proposed method remains immune to magnetizing inrush currents while enabling rapid discrimination of transformer faults.