GDRZ Transformer Winding Deformation Tester

Overview: based on the measurement of the characteristic parameters of the transformer internal windings, the transformer winding deformation tester uses the frequency response analysis (FRA) method for internal faults currently being developed and refined in the developed countries, and it can make an accurate judgement of transformer internal faults. The instrument quantifies the response variation of the transformer internal winding parameters across different frequency domains. From the magnitude of the change, together with the amplitude, region and trend of the frequency response variation, it determines the degree of change of the transformer internal windings, and from the measurement results it can then judge whether the transformer has already been severely damaged and whether it needs major repair.

For transformers already in service, regardless of whether frequency-domain characteristic plots were saved in the past, the fault severity can be judged by comparing the differences between the characteristic spectra of the coils of the faulty transformer. Naturally, if a set of the original winding characteristic plots has been saved, it is easier to provide a more accurate and powerful basis for the operating condition of the transformer, for post-accident analysis and for maintenance and repair. The instrument is built from a notebook computer and a single-chip microcomputer forming a high-precision measurement system. It has a compact structure and simple operation, with reasonably complete test and analysis functions, so it can be operated by following the user manual or after short-term training.

Features: acquisition control uses a high-speed, highly integrated microprocessor. The notebook computer communicates with the instrument over a USB interface, and a wireless Bluetooth interface is available as an option. The hardware core uses dedicated DDS digital high-speed sweep technology from the USA, so testing can accurately diagnose faults such as winding twisting, bulging, displacement, tilting, inter-turn short-circuit deformation and phase-to-phase contact short circuits. High-speed dual-channel 16-bit A/D sampling is used, and changing the tap changer during a field test produces an obvious change in the waveform curve. The signal output amplitude is adjusted in software to a maximum peak amplitude of 10 V.

Further features: the computer analyses the test results automatically and generates a Word electronic document. The instrument provides both linear sweep measurement and segmented sweep measurement, so it is compatible with the two measurement modes currently used in China. The amplitude-frequency characteristics conform to the national technical specification for amplitude-frequency characteristic testers. The horizontal axis, which is frequency, has both linear and logarithmic scaling, so the printed curve can be either linear or logarithmic as the user requires.

Analysis: the detection data automatic analysis system performs a horizontal comparison between phases A, B and C for winding similarity, returning very good consistency, good consistency, poor consistency or very poor consistency. It performs a vertical comparison of A-A, B-B and C-C, retrieving the original data and the current data for the same phase to compare winding deformation, returning normal winding, mild deformation, moderate deformation or severe deformation. A Word electronic document is generated automatically for saving and printing.

Standard: the instrument fully meets the technical conditions of the power standard DL/T911-2004, Frequency Response Analysis Method for Winding Deformation of Power Transformers.