Technology Class

In the power supply system, nonlinear issues arise from various elements. For instance, harmonics are generated during the normal operation of generators. Transformers within the grid also contribute to harmonic production. Additionally, DC transmission introduces harmonics, and high-voltage transmission lines can amplify these harmonics. The installation of parallel capacitors in substations is another factor that can lead to the emergence of harmonics. Among these, DC transmission is currently a major source of harmonics in power systems.

As a key equipment in the power system, the stable operation of transformers is crucial to the safety of the power grid. However, transformers may cause deformation of the windings for various reasons during testing, transportation and operation, which in turn affects their performance. In this paper, we will analyze the causes and effects of transformer winding deformation, and discuss effective detection techniques.

Transformer oil in the power industry, is widely used in substations, dielectric strength is a comprehensive index for the transformer oil.RDJDH-100kV integrated insulating oil dielectric loss factor tester, fully automatic completion of the process of heating, temperature control, high-speed data sampling, computing, display, printing and storage.

DC withstand voltage mainly test the insulation strength of the cable, is to check the oil and paper cable dry, bubbles, paper insulation in the mechanical damage and process wrapping defects in an effective method, DC leakage current test can be sensitive to reflect the cable insulation moisture and deterioration conditions.

The power test regulations require a series of insulation performance tests for numerous power equipment such as cables, motors, generators, transformers, mutual inductors, high-voltage switches, lightning arresters, etc. The first step is to perform insulation resistance tests using an intelligent insulation resistance tester.

The AC withstand voltage test is a destructive test in the insulation test. It can only be carried out after other non-destructive tests (such as insulation resistance and absorption ratio test, DC leakage test, dielectric loss tangent and insulation oil test) are passed. After this test is passed, the transformer can be put into operation.

The DC resistance of a transformer refers to the DC resistance value of each phase winding. The purpose of measuring the DC resistance of a transformer is to check the welding quality of the winding joints and whether there is a short circuit between the winding turns; to check whether the contact of the tap changer is good and whether the actual position of the tap is correct.

Dielectric loss refers to the sum of polarization loss and conductivity loss caused by transformer oil under the action of alternating electric field. Dielectric loss factor can reflect the insulation characteristics of transformer, the aging degree of transformer oil under the action of electric field, oxidation and high temperature, and the degree of pollution of polar impurities transformer and charged colloid in oil.

On the one hand, in addition to the problem of low power factor, a variety of converters and other power electronic devices are increasingly widely used for the introduction of a large number of harmonics into the power grid; on the other hand, a large number of precision instruments are very susceptible to the impact of power harmonics, the power quality of the requirements of more and more high. It is imperative to actively and effectively manage power quality on the user side.