Energies, Vol. 18, Pages 6012: Standard Parameter Generation Strategy for Power Transformer Residual Flux Detection and Verification Platform

Energies, Vol. 18, Pages 6012: Standard Parameter Generation Strategy for Power Transformer Residual Flux Detection and Verification Platform

Energies doi: 10.3390/en18226012

Authors:
Yuwei Wang
Wenjuan Dong
Azan Delinuer
Xingang Wang
Wufuer Renaguli
Hao Wang
Changao Ji
Chunwei Song
Jinlong He
Gang Li

Residual magnetism in power transformer cores can cause severe inrush currents, threatening grid safety. The accuracy of residual magnetism testers depends on reference values from calibration platforms, yet current calibration platforms suffer from three key limitations: (1) low-precision hysteresis modeling that fails to reflect real magnetic material behavior; (2) unstable generation of residual magnetism reference values; and (3) lack of standardized methods for dynamic inductance adjustment during testing. To address these challenges, this paper proposes a comprehensive reference parameter generation framework for high-accuracy calibration systems. First, an enhanced Preisach-based analytical model is developed using the Everett integral distribution, enabling precise characterization of ferromagnetic hysteresis. Second, a novel “demagnetize-then-magnetize” strategy is introduced to establish stable and repeatable residual flux references: demagnetization is achieved through a semi-cyclically decaying AC excitation over 20 cycles, effectively eliminating initial magnetic history; subsequent magnetization combines full positive/negative saturation pulses with reverse micro-pulse fine-tuning to achieve accurate residual flux control within ±6% error. Third, integrating hysteresis loop features, a dynamic inductance adjustment method is developed using quadratic polynomial fitting of excitation current peaks and normalized inductance. Tests verify that the proposed approach enables the calibration platform to produce high-accuracy, stable residual magnetism and dynamic inductance references, supporting full-condition calibration of test instruments.