The main purpose of transformer no-load test is to measure the no-load current and no-load loss, analyze their variation patterns, discover local or overall defects in the magnetic circuit, and discover winding defects. The precautions for transformer no-load test include:
1. The test should be conducted at the rated tap, and the applied voltage is required to be a sinusoidal waveform and rated voltage at the rated frequency.
2. When conducting the rated no-load test of three-phase transformers, the test power supply should have sufficient capacity.
3. The test voltage should be stable. When using the three-phase power supply method for testing, it is required that the three-phase voltage is symmetrical, that is, the negative sequence component does not exceed 5% of the positive sequence component, and the three-phase line voltage difference does not exceed 2%. If the three-phase power supply does not meet the requirements, the single-phase power supply method can be used for testing.
4. When wiring, attention must be paid to the polarity of the current coil and voltage coil of the power meter. The indication of the power meter may be positive or negative.
5. During the no-load test, the polarity of the transformer must be connected correctly, with the primary and secondary connections corresponding, and the secondary terminals corresponding to the polarity of the meter. It should also be noted that the transformer should have a secondary terminal for safe grounding. For three-phase transformers or three single-phase transformers, they should be grounded at the same terminal and grounding point. The current circuit should be firmly connected to prevent interruption during the test process.
6. In order to ensure accurate measurement results, the connecting wires should have sufficient cross-sectional area, with a current line of no less than 2.5 square meters and a voltage line of no less than 1.5 square meters, and good contact. When the loss of the tested transformer itself is small, the measured loss value should be subtracted from the loss of the test instrument itself.
7. During the three-phase transformer split phase no-load test, do not connect to the transformer casing during a short circuit.
8. During the testing process, if any abnormalities are found in the meter indication, such as discharge noise, abnormal noise, smoke, or oil injection in the tested transformer, the power should be immediately disconnected and the test stopped. The cause should be identified and dealt with, otherwise the test cannot continue.
9. Low voltage no-load test should be conducted before insulation resistance measurement and leakage current measurement. If residual magnetism is believed to exist in the equipment to be tested during the test, demagnetization is necessary to eliminate the impact of residual magnetism on the test results.
KST-202B transformer capacity and empty load testing tester is a new instrument specially developed and designed by our company to solve the problem of bad power users evading basic electricity charges and privately increasing capacity. It is a high-precision instrument for measuring transformer capacity, no-load, load and other characteristic parameters. This instrument is a multifunctional measuring instrument, equivalent to the usual two types of testing instruments: transformer capacity tester and transformer characteristic parameter tester. It can accurately measure a series of power frequency parameters such as capacity, type, no-load current, no-load loss, short circuit (load) loss, impedance voltage, etc. of various transformers.
This product has many advantages such as small size, light weight, high measurement accuracy, good stability, and simple operation. It can completely replace the previous method of using multiple meters to measure transformer losses and capacity, making wiring simpler, testing and recording more convenient, and greatly improving your work efficiency.
Kvtester Electronics Technology Co.,Ltd. is a high-tech enterprise specializing in power testing, testing, research and development, production, and sales of testing equipment. It has been engaged in the electrical testing industry for many years, and its products are of high quality. We welcome customers to come and purchase.
