33kv 50kva Two Winding Oil Immersed Transformer

Pre commissioning Inspection and Testing of 33kv 50kva oil immersed Transformers

1. Visual Inspection of Appearance and Structure

A comprehensive visual inspection shall be carried out to ensure that the 33kv 50kva two winding oil immersed transformer is free from any visible damage, deformation, or oil leakage. All external components, including the tank, radiators, bushings, and pressure relief device, shall be checked to confirm they are in good condition and properly installed. All mechanical connections shall be verified for tightness. In addition, the grounding system shall be inspected to ensure it is correctly installed and provides reliable earthing, which is essential for operational safety.

2. Insulation Resistance Test

The insulation resistance test is a key method for evaluating the condition of the 33kv 50kva two winding oil immersed transformer insulation system. A megohmmeter shall be used to measure the insulation resistance between phase to phase and also between each phase to the earth. The obtained values shall be compared with the manufacturer’s specified reference data to confirm that the insulation performance meets the required standards.

3. Dielectric Dissipation Factor Test

The dielectric loss test, which is also called tan δ test, is used to assess moisture ingress, insulation aging, or possible partial discharge within the 33kv 50kva two winding oil immersed  transformer. By measuring the dielectric dissipation factor, the condition of the insulation materials can be evaluated more comprehensively. This test is typically performed together with the insulation resistance test to obtain a more complete assessment of insulation health.

4. Turns Ratio and Vector Group Verification

The transformer turns ratio shall be verified to ensure compliance with the design specifications, which includes confirming the correct ratio between the primary voltage and secondary voltage windings of 33kv 50kva two winding oil immersed transformers. At the same time, the vector group shall be checked to ensure proper phase displacement and correct connection of the three phase windings, in accordance with the requirements of the power system.

5. No Load Test

The no load test is conducted with the 33kv 50kva two winding oil immersed transformer energized on the primary side while the secondary side remains open circuited. The purpose is to measure no load current and no load losses. This test provides important information regarding the quality of the core, magnetic flux distribution, and winding symmetry. It also helps identify possible abnormalities in the magnetic circuit.

6. Short Circuit Test

During the short circuit test, a reduced voltage is applied to the primary voltage winding while the secondary voltage winding is short circuited, which allows measurement of short circuit impedance and load losses. The test provides valuable data on the performance of 33kv 50kva two winding oil immersed transformer under load conditions,which includes thermal behavior, short circuit withstand capability, and mechanical strength of the windings.

7. Oil Quality Analysis and Oil Level Inspection

For 33kv 50kva two winding oil immersed transformers, the condition of the insulating oil directly affects operational performance and service life. Prior to commissioning, oil samples shall be taken for laboratory analysis to check parameters such as moisture content, acidity, and impurity levels. All results shall comply with applicable standards. In addition, the oil level inside the tank shall be verified to ensure it is within the required range, guaranteeing effective cooling and insulation during operation.

In summary, a series of strict inspections and tests must be completed before an 33kv 50kva two winding oil immersed transformer is put into service. These procedures ensure stable performance, operational safety, and long term reliability. Proper pre commissioning testing not only reduces the risk of potential failures but also provides a solid foundation for safe and efficient long term operation of the 33kv 50kva two winding oil immersed transformer.

Technical Specification:

Workshop

Equipment

Test