Transformer Turns Ratio Tester - Three-Level Undertaking 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 its 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 by frequency sweep method. By continuously changing the frequency f of the externally applied 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 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 Undertaking 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 show "Measuring, please wait!" and then stop. Please turn off the power. Replace the fuse with one of the same capacity and measure again.
3. The test leads must have 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 smaller the interference of 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 of more than 200VA for the AC purified power supply is sufficient.
5. During operation, if the LCD screen displays disorderly, all keys do not respond, or the measured value is far 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 working condition is abnormal, as well as the tap changer position under the current test condition of the transformer under test, and carefully input the information into the test object registration window.
3. Create a subdirectory for the test object data file based on the condition of the test object; after the test, the measured data should be backed up to this directory, and attention should be paid to organizing the work.
4. Data storage format: The file is 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 the temperature, so as to avoid excessive temperature changes during measurement that could affect the accuracy 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 High Voltage Testing Electrical.
Product List:
1. One tester 2. One power cord 3. One set of test leads 4. One user manual 5. One certificate of conformity 6. One test report of the instrument
