What are the routine electrical tests for transformers? (Part 2)
In the previous article, we introduced three routine electrical tests: voltage ratio test, winding resistance measurement, and insulation resistance and absorption ratio or polarization index measurement. In addition to those mentioned in the previous article, there are three electrical tests introduced below.

Content

●tanδ measurement
The tanδ measurement determines the degree of insulation moisture absorption and defects in the insulation structure through dielectric loss. The magnitude of the dielectric loss factor tanδ reflects the energy loss of the insulation material under the action of an electric field. When the insulation is moistened or there are defects, the tanδ value will increase. By measuring tanδ, insulation problems can be found in time to avoid transformer damage caused by insulation faults.

●Oil tests
Internal faults will affect the properties of the oil. Therefore, through tests such as oil withstand voltage, tanδ, acid value, trace moisture, and gas content in the oil, the internal defects of the transformer can be indirectly reflected. Transformer oil plays the role of insulation and heat dissipation. Conducting various tests on it can understand the internal operating state of the transformer. For example, the oil withstand voltage test can detect the insulation strength of the oil. The tanδ test can reflect the dielectric loss of the oil. Tests such as acid value, trace moisture, and gas content can judge the aging and moisture absorption degree of the oil.

●Withstand voltage test and no-load and load tests
The withstand voltage test of a transformer can be used to judge the insulation status between phases and to the ground. This test detects the insulation performance of the transformer by applying a high voltage to ensure good insulation under normal operation and fault conditions. The no-load and load tests compare the measured values with the original values to determine whether there are faults such as interlayer and intersegment short circuits in the winding. The no-load test can detect the iron loss and no-load current of the transformer. The load test can detect the copper loss and load current of the transformer. By comparing the differences between the measured values and the original values, it can be judged whether the performance of the winding is normal.

In Summary

In short, the routine electrical tests of transformers detect their performance in many aspects. Through these tests, problems can be found in time to ensure the safe operation of the transformer, extend its service life, and provide strong support for the stability of the power system. Strictly implementing the tests and ensuring the reliable operation of the transformer are of great significance for the development of the power industry.

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LuShan, est.1975, is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single-phase transformer, three-phase isolation transformers,electrical transformer,distribution transformer, step down and step up transformer, low voltage transformer, high voltage transformer, control transformer, toroidal transformer, R-core transformer;DC inductors, AC reactors, filtering reactor, line and load reactor, chokes, filtering reactor, and intermediate,high-frequency products.

Our power transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering(furnace), central air conditioning.

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