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Based on the measurement of internal winding characteristic parameters of transformers, this transformer winding deformation tester adopts the internal fault frequency response analysis (FRA) method currently being developed and perfected in developed countries, enabling accurate judgment of internal faults in transformers.
After the transformer is designed and manufactured, its coils and internal structure are determined. Therefore, for a multi-winding transformer coil, if the voltage levels are the same and the winding methods are the same, the corresponding parameters (Ci, Li) of each coil should be determined. Thus, the frequency domain characteristic response of each coil is also determined, and the frequency spectra of the corresponding three-phase coils have a certain comparability.
During testing, if inter-turn or phase-to-phase short circuits occur, or if collisions during transportation cause relative displacement of coils, or if electromagnetic forces during short circuits and fault conditions cause coil deformation, the distributed parameters of the transformer winding will change. This in turn affects and alters the original frequency domain characteristics of the transformer, such as amplitude changes in frequency response and shifts in resonance frequency points. The HTBX-H transformer winding frequency response tester, developed based on the response analysis method, is such a novel non-destructive testing device for internal faults in transformers. It is suitable for detecting internal structural faults in 63kV to 500kV power transformers.
It quantifies the response changes of internal winding parameters in different frequency domains, and determines the degree of change in the internal winding based on the magnitude of the change, the amplitude, region, and trend of the frequency response change. Based on the measurement results, it can determine whether the transformer has been severely damaged and whether major repairs are needed.
For transformers in operation, regardless of whether frequency domain characteristic graphs have been saved in the past, the degree of fault can also be judged by comparing the differences in characteristic spectra between the coils of the faulty transformer. Of course, if a set of original winding characteristic graphs of the transformer is preserved, it is easier to provide more accurate and powerful evidence for the operating condition, post-accident analysis, and maintenance and repair of the transformer.
The transformer winding deformation frequency response tester consists of a laptop computer and a microcontroller forming a high-precision measurement system. It is compact, easy to operate, and has relatively complete testing and analysis functions. It can be operated by following the instruction manual or after short-term training.
Product aliases: power transformer winding deformation tester, transformer winding deformation detector, transformer winding deformation measuring instrument, transformer winding deformation analyzer
Technical indicators:
The instrument comes with one channel of DDS signal output as the sweep excitation signal; the signal output is a sine wave, the output amplitude can be adjusted by software, with a maximum amplitude of ±5V, and the output impedance is 50Ω
Two acquisition channels, one for acquiring the excitation signal and one for acquiring the response signal, used to calculate the transfer function
The excitation channel measurement has a fixed range: ±5V; the response channel has 8 ranges, which are automatically adjusted during measurement, with a maximum input signal of ±25V
Acquisition channel quantization accuracy: 12 bits
Maximum static error of acquisition channel: 0.5%
Maximum storage capacity per channel: 64K sample points
Maximum sampling rate per channel: 20Msps
Input impedance of acquisition channel: 1MΩ
Sweep frequency measurement range: 1K-1MHz
Scanning method: linear distribution sweep measurement method
Scanning frequency accuracy: the frequency accuracy of the sine signal output by the signal source is not greater than 0.01%
Sweep frequency measurement points: 1K-1MHz, 1000 measurement points
Using Vittal original chassis
Complies with national power industry standard: DL/T911-2004
Note: The above information and technical parameters are compiled and released by Yangzhou Dali Electric Co., Ltd.
