Winding Deformation Tester is the core equipment for diagnosing the mechanical structure health of power transformer windings
It is known as the “structural doctor” that safeguards transformer safety. It determines whether there are invisible mechanical deformations caused by short-circuit impacts, transportation collisions, etc., by detecting the electrical response characteristics of transformer windings within a specific frequency range.
⚙️ Core Principle: Frequency Response Analysis (FRA)
The core technology of the Winding Deformation Tester is Frequency Response Analysis (FRA). Its basic principle is as follows:
Equivalent Network Model: Under high-frequency signal excitation, each winding of the transformer can be regarded as a complex passive linear two-port network composed of distributed inductance (L), distributed capacitance (C), and resistance (R).
Transfer Function Change: The frequency response characteristics (i.e., the transfer function H(jω)) of this network are uniquely determined by its internal parameters such as L and C. When any form of mechanical deformation occurs in the winding, such as axial twisting, radial bulging, or inter-turn short circuit, the internal distributed inductance and capacitance parameters will inevitably change accordingly.
Characteristic Curve Comparison: This parameter change will cause the “fingerprint” characteristics of its frequency response curve to change, such as the position, amplitude, and number of resonance peaks shifting or distorting. The instrument injects a continuous sweep signal from low frequency to high frequency (typically 1kHz-2MHz) into the winding, measures its response, and plots the amplitude-frequency characteristic curve.
