Transformer Turns Ratio Tester - Three-Level Contracting Qualification Detection Principle:
Under the action of a higher frequency voltage, each winding of a 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 internal distributed inductance, capacitance, and other parameters will inevitably change, causing the zeros and poles of the equivalent network transfer function H(jω) to change, thereby altering the frequency response characteristics of the network.
The amplitude-frequency response characteristics of transformer windings are obtained using the frequency sweep method. By continuously changing the frequency f of the external sinusoidal excitation source VS (angular frequency ω=2πf), the ratio of the response terminal voltage V2 to the excitation terminal voltage V1 at different frequencies is measured, obtaining the amplitude-frequency response curve of the winding under the specified excitation and response terminals. L, K, and C represent the distributed inductance, distributed capacitance, and 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.
1. During the measurement, do not touch the test object.Transformer Turns Ratio Tester - Three-Level Contracting Qualification Notes::
2. If the test leads are short-circuited or the high and low voltage leads are reversed, the fuse will blow. After the fuse blows, if a measurement is performed, the display will stop after showing "Measuring, please wait!", please turn off the power. Replace the fuse with one of the same capacity and measure again.
3. The test leads must make good contact. The instrument should be properly grounded!
4. The working place of the instrument should be far away from strong electric fields, strong magnetic fields, and main frequency equipment. The less interference in the power supply, the better. It is advisable to use lighting lines. If the power supply interference is still significant, an AC purified power supply can be used to power the instrument. A capacity greater than 200VA for the AC purified power supply is sufficient.
5. During operation, if the LCD display is disordered, all keys do not respond, or the measured value differs greatly from the actual value, press the reset key or turn off the power and restart the operation.
Test Procedure
1. First, check whether the grounding of the transformer 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 operating conditions are abnormal, as well as the tap changer position under the current test conditions of the transformer under test, and carefully input the information into the test object registration window.
3. Based on the condition of the test object, create a subdirectory for the test object data file; after the test is completed, back up the measured data to this directory and pay attention 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, stop any cooling measures applied to it to maintain temperature, to avoid excessive temperature changes during measurement affecting the consistency of the 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.
Product List:
1. One tester 2. One power cord 3. One set of test leads 4. One product instruction manual 5. One certificate of conformity 6. One instrument test report
