I would like to know what are the characteristics of the transformer winding deformation tester

The test methods of transformer winding deformation mainly include low-voltage pulse analysis method, frequency response analysis method, impedance analysis method, water wave analysis method and ultrasonic analysis method.

The frequency response winding deformation tester is an instrument for measuring the winding deformation of the transformer according to the national power industry standard DL T911 2004, mainly by detecting the amplitude and frequency response characteristics of each winding of the transformer, and comparing the detection results longitudinally or horizontally, and judging the possible winding deformation of the transformer according to the degree of change in the amplitude and frequency response characteristics.

The application principle of the impedance method is that when the short-circuit impedance of the transformer is when the load impedance is zero, the reactance component of the equivalent impedance and short-circuit impedance inside the transformer, that is, the short-circuit reactance, is the leakage reactance of the winding, and the leakage reactance is determined by the geometric size of the winding.

Low-voltage pulse method, frequency response analysis method, characteristic test method.

Transformer winding deformation, can be tested with a bridge, or with a total megger.

Transformer winding deformation tester English name: Transformer winding deformation testerThe transformer winding deformation tester is an instrument that measures the winding deformation of the transformer according to the national power industry standard DL T911 2004, mainly by detecting the amplitude-frequency response characteristics of each winding of the transformer, and comparing the detection results longitudinally or horizontally, and judging the possible winding deformation of the transformer according to the degree of change in the amplitude-frequency response characteristics.

According to the measurement of the characteristic parameters of the internal windings of the transformer, the transformer winding frequency response tester adopts the FRA method of internal fault frequency response analysis that is currently being developed and perfected in developed countries in the world, which can make accurate judgments on the internal faults of the transformer.

Methods of transformer winding deformation test:

1) Low-pressure pulse method. It uses waveform changes caused by small changes in the distribution parameters lo, co, and into each small unit of the equivalent circuit, to reflect changes in the winding structure, which can be clearly reflected when the applied pulse wave has sufficient steepness, i.e., contains sufficient high-frequency components, and when an oscilloscope with sufficient response is used.

2) Frequency response analysis method. It uses a special set of sine wave voltages from a set of different sweep generators to add to the end of the transformer winding, and plots the amplitude and phase of the signal obtained from the other terminals of the selected transformer as a function of frequency and noise, and its frequency response characteristics are determined when the transformer structure is formed. Once the transformer windings are deformed, the location and number of resonance points change.

The computer sends a command to make the scanning generator unit output a series of sine wave voltages to be applied to the transformer under test, at the same time, the two-channel analysis unit analyzes and processes the UI and UO signals, and transmits them to the computer for storage, after the data acquisition is completed, the computer determines whether the transformer under test is deformed, and can display or draw the frequency response characteristic curve of the transformer under test on the screen.

3) Characteristic test methods. Some units have adopted single-phase low-voltage no-load test and short-circuit test to detect the deformation of 220kV and 120kVA power transformer windings and received good results; For example, the short-circuit test measured that the short-circuit impedance of phases B and C between the high phase and the intermediate phase increased significantly compared to phase 4, where phase C increased, and in other cases, phase B and phase C decreased and decreased compared to phase A, the most common being phase C between the medium and low voltage bends, up to 17, in addition, by measuring the capacitance, it was found that the capacity of the transformer's high and medium voltage windings increased, and the capacitance of the low leakage winding increased, so it was thought that the transformer was hit by a short circuit, and the capacitance changed by more than 1% Most likely, the windings have been deformed.

Huatian Electric Power specializes in the production of power testing equipment, which is your trusted choice, and all power workers are welcome to consult.

How to choose a "Power Transformer Winding Deformation Tester"?

What are the hazards of transformer winding deformation: Usually after the transformer suffers from the short-circuit fault current impact, the winding will be partially deformed, even if it is not immediately damaged, it may also be disturbed by the serious fault hidden danger.

At present, there are three kinds of "winding deformation testers" on the market, which are:1Impedance method winding deformation characteristics tester 2

Frequency response winding deformation characteristics Zheng Bang tester 3Frequency response method plus impedance method winding deformation characteristics tester. We use "GY-801 Winding Deformation Tester" to illustrate.

The principle of the impedance winding deformation tester is to carry out short-circuit impedance (%) test on the power transformer on site, and compare it with the nameplate value or factory value, and can find the winding displacement, deformation and other defects caused by serious fault currents in transportation, installation and operation after the factory test, the main test parameters are: transformer short-circuit impedance, short-circuit reactance, three-phase impedance voltage; It can display the voltage, current, power, frequency and other parameters of each test.

The frequency response method winding deformation tester uses the frequency sweep method to test the windings of the transformer, which is to detect the amplitude-frequency response characteristics of each winding of the transformer, and compare the test results longitudinally or horizontally, and judge the possible deformation of the transformer winding according to the degree of change of the amplitude-frequency response characteristics.

Frequency response method plus impedance method transformer winding deformation tester is the most used test method in China, with the above two test methods, is the most advanced test method in China.

The transformer winding deformation tester (also known as the deformation winding tester) produced by Huatian Electric Power adopts the internal fault frequency response analysis (FRA) method that is currently being developed and perfected in developed countries in the world to make accurate judgments on the internal fault of the transformer according to the measurement of the characteristic parameters of the internal winding of the transformer.

After the design and manufacture of the transformer is completed, the coil and internal structure are determined, so for a multi-winding transformer coil, if the voltage level is the same and the winding method is the same, the corresponding parameters (CI, LI) of each coil should be determined. Therefore, the characteristic response of each coil in the frequency domain is also determined, and the frequency spectrum between the corresponding three-phase coils is comparable.

The distribution parameters of the transformer winding will change due to the short circuit between turns and phases during the test, or the collision during transportation, resulting in the relative displacement of the coil, and the deformation of the coil due to electromagnetic tension during the short circuit and fault state during operation. In turn, it affects and changes the original frequency domain characteristics of the transformer, that is, the amplitude change of frequency response and the deviation of resonant frequency points. The transformer winding tester developed according to the response analysis method is such a novel non-destructive testing equipment for transformer internal faults.

It is suitable for internal structure fault detection of 63kV 500kv power transformer.

The transformer winding deformation tester judges the transformer by the measured waveform. Use the same winding deformation tester to test different transformers. Their waveforms are not necessarily the same. The same transformer is tested using different winding deformation testers. The waveforms are not necessarily the same.

Testing the same transformer with the same transformer winding deformation tester only needs to be compared with the previous waveform, and if it is consistent, it means that there is no problem with the transformer. If two different winding deformation testers are used to measure waveforms measured by the same transformer, the feature points of the two waveforms will be compared. For example, the same frequency is one of the peaks, while the other is not.

If the difference is large, there is a problem with the transformer. If the same frequency is a peak or a valley, there is no problem with the transformer.

Respondent: Huatian Power.