The pre-operation test of dry-type transformers is to ensure the safe and reliable operation of the transformer and to check whether the performance indicators of the transformer meet the requirements. The pre-operation test of dry-type transformers generally includes three measurements, three inspections and three tests.

The three measurements refer to the measurement of the winding resistance, insulation resistance and core grounding resistance of the transformer. These measurements can check whether the transformer winding has short circuit, open circuit or grounding faults, and whether the insulation is aging or damp.

The three inspections refer to the inspection of the appearance, connection and accessories of the transformer. Appearance inspection mainly checks whether the shell, cooling fan, thermometer, etc. of the transformer are intact and free from defects such as cracks, deformation or rust. Connection inspection mainly checks whether the high and low voltage terminals, wiring posts, grounding wires, etc. of the transformer are firm and reliable, and whether there are phenomena such as loosening, burning or oxidation. Accessory inspection mainly checks whether the protective devices, signal devices and control devices of the transformer are working normally and whether there are faults or misoperations.

The three tests refer to no-load test, short-circuit test and dielectric strength test on the transformer. The no-load test mainly measures the no-load current, no-load loss and no-load voltage ratio of the transformer, as well as the phase difference between the high and low voltage windings. These parameters can reflect the excitation characteristics and electromagnetic coupling of the transformer. The short-circuit test mainly measures the short-circuit impedance, short-circuit loss and short-circuit current of the transformer, as well as the phase difference between the high and low voltage windings. These parameters can reflect the load characteristics and internal distribution of the transformer. The dielectric strength test mainly applies a voltage test to the insulation of the transformer to test its withstand capacity and insulation level.

LuShan, est. 1975,  is a Chinese professional manufacturer specializing in power transformers and reactors for 48 years. Leading products are single-phase transformer, three-phase transformers, DC inductors, AC reactors, filtering reactor, expoxy resin high-voltage transformer and intermediate, high-frequency products. Our 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, central air conditioning.

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