Transformer Winding Deformation Tester
Features:
1. The transformer winding deformation tester consists of a measurement part and analysis software. The measurement part is controlled by a high-speed microcontroller, comprising signal generation and signal measurement. The analysis part is completed by a laptop. The measurement part connects to the laptop via a USB universal interface, plug-and-play, and is easy to use.
2. During the test, only the connecting busbars of the transformer need to be removed; all tests can be completed without lifting the transformer cover or disassembling it.
3. The instrument has dual-system measurement functions: linear sweep frequency measurement and segmented sweep frequency measurement, compatible with the two technical schools of measurement modes currently in China. Among them, the linear sweep frequency measurement has a scanning frequency up to 2MHz, providing more analysis of transformer deformation.
4. The instrument is highly intelligent and easy to use, with functions such as automatic range adjustment and automatic sampling frequency adjustment.
5. The software uses the Windows platform and is compatible with Windows 98/2000/winXP.
6. Provides historical curve comparison analysis, can load multiple historical curves for observation simultaneously, and can specifically select any frequency band to zoom in for horizontal and vertical analysis. Equipped with an expert intelligent analysis and diagnosis system, it can automatically diagnose the state of transformer windings, load up to 6 curves simultaneously, automatically calculate the relevant parameters of each curve, automatically diagnose the deformation of windings, and give diagnostic reference conclusions.
7. The software has powerful management functions, fully considering the needs of field use. It automatically saves environmental condition parameters to provide a basis for transformer winding deformation diagnosis. Measurement data is automatically saved, and it has color printing functions, making it convenient for users to generate test reports.
8. The software is highly user-friendly. Most measurement conditions are options. Detailed transformer parameters can be saved for diagnostic reference and do not need to be entered on site; information can be added or modified later, making it more convenient to use.
9. The software is highly intelligent. After connecting the input and output signals and setting the condition parameters, all measurement work can be completed, and historical waveform curves can be opened for comparison and observation at any time during measurement, and measurement can be stopped.
10. The time required for each phase measurement is less than 60 seconds. For a power transformer with high, medium, and low voltage windings (capacity and voltage level unlimited), the total time for winding deformation measurement does not exceed 10 minutes.
11. When measuring the transformer, the wiring personnel can arbitrarily place the signal input and output leads without affecting the measurement results. The wiring personnel can stay on the transformer oil tank without coming down, reducing labor intensity.
Detection Principle:
Under the action of higher frequency voltage, each winding of the transformer can be regarded as a passive linear two-port network composed of distributed parameters such as linear resistance, inductance (mutual inductance), and capacitance. Its internal characteristics can be described by the transfer function H(jω). If the winding deforms, the distributed inductance, capacitance, and other parameters inside the winding will inevitably change, causing the zeros and poles of the equivalent network transfer function H(jω) to change, thereby changing the frequency response characteristics of the network.
The amplitude-frequency response characteristics of the transformer winding are obtained by frequency sweep. By continuously changing the frequency f of the external sinusoidal excitation source VS (angular frequency ω=2πf), the ratio of the signal amplitudes of the response terminal voltage V2 and the excitation terminal voltage V1 at different frequencies is measured to obtain the amplitude-frequency response curve of the winding under specified excitation and response terminals. L, K, and C represent the distributed inductance, distributed capacitance, and distributed capacitance to ground per unit length of the winding, respectively. V1 and V2 are the excitation terminal voltage and response terminal voltage of the equivalent network, VS is the sinusoidal excitation signal source voltage, RS is the output impedance of the signal source, and R is the matching resistor.
Test Procedure:
1. First, check whether the transformer grounding is good, and all bushing leads should be completely disconnected.
2. Record in detail the nameplate data of the test object and whether the original working condition is abnormal, as well as the tap changer position under the current test condition of the test transformer, and carefully input it into the test object registration window.
3. Create a subdirectory for the test object data file according to the situation of the test object; after the test is completed, the measured data should be backed up to this directory, and attention should be paid to organizing the work.
4. Data storage format: files are stored in ASCII code format.
5. For measuring a transformer that has just been taken out of operation, try to let it cool down before measurement; however, during the entire measurement process, the cooling measures applied to it should be stopped to maintain temperature, so as to avoid excessive temperature changes during measurement that could affect the consistency of measurement results.
6. During on-site testing, to prevent accidental damage to the instrument, use the provided power isolation transformer. The best domestic manufacturers of transformer winding deformation testers include Wuhan High Voltage Research Institute, Beijing Electric Power Research Institute, and professional manufacturers such as Hengdian Gaoche Electric, etc.
