The winding deformation tester is mainly used to determine whether the transformer has suffered from short-circuit current impact
The Transformer Winding Deformation Tester is a key professional device in the power system used to detect the mechanical integrity of transformer windings. It is mainly used to determine whether the internal windings have experienced deformation faults such as displacement, distortion, bulging, or inter-turn short circuits after short-circuit current impact, transportation vibration, or long-term operation.
Below is a summary of the core information about this instrument:
1. Main Testing Principles
Currently, mainstream winding deformation testers typically use one or a combination of the following two methods:
Frequency Response Analysis (FRA): The most commonly used and most sensitive method.
Principle: Inject a swept frequency signal (usually from tens of hertz to several megahertz) into the transformer winding and measure the amplitude-frequency response characteristic curve of the winding.
Judgment Basis: A normal transformer winding has its fixed "fingerprint" curve. When the winding deforms, its distributed capacitance and inductance parameters change, causing the response curve to shift. By comparing the lateral comparison between three phases (A/B/C phase curves should coincide) or the longitudinal comparison with historical data, the degree and location of deformation can be determined.
Standard: Complies with China's electric power industry standard DL/T 911-2016 "Frequency Response Analysis Method for Power Transformer Winding Deformation".
Low Voltage Impedance (LVI) Method:
Principle: Apply voltage on the low-voltage side and measure the short-circuit impedance value of the winding.
Judgment Basis: Winding deformation causes changes in leakage flux, leading to changes in the short-circuit impedance value. Usually compared with the factory value or the last test value, a change exceeding a certain threshold (e.g., ±2%) is considered abnormal.
Standard: Complies with DL/T 1093-2008 "Guidelines for Detection and Judgment of Power Transformer Winding Deformation by Reactance Method".
Advanced Models: Modern high-end instruments (such as the intelligent type mentioned in search results) often have both FRA and impedance methods, complementing each other to improve diagnostic accuracy.
2. Main Application Scenarios
Diagnosis after Short-Circuit Impact: After a short-circuit fault occurs at the transformer outlet, immediate testing is required to confirm whether the winding is damaged and decide whether it can continue to operate.
Commissioning Test: Before a new transformer is installed and put into operation, establish original "fingerprint" data as a baseline for future comparison.
Preventive Test: Combined with major repairs or regular maintenance, monitor the winding condition.
Transportation Inspection: After long-distance transportation of large transformers, check whether internal looseness or deformation has occurred due to bumps.
3. Test Result Judgment
The instrument typically generates waveform graphs and correlation coefficients (such as correlation coefficient
