Every transformer must undergo a series of standardized electrical tests before leaving the manufacturing facility. At VKE Transformer, we regard these routine tests as an essential final step in the manufacturing process and a core ritual for fulfilling our quality commitment to customers. The purpose is very clear - to verify that the product fully meets all requirements outlined in the design specifications. This represents not only VKE's commitment to its own brand but also our responsibility to ensure the safe and stable operation of the power grid.
The routine tests conducted by VKE are systematic and comprehensive, with a rigorous process centered around the following key aspects: verifying performance parameters, assessing insulation strength, and ensuring structural integrity.
Verifying the basic performance parameters of a transformer serves as the foundation for its qualification. On VKE's production line, winding resistance measurement is the initial step. We employ high-precision DC bridge methods to accurately measure the DC resistance of each phase winding at every tap position. The core purpose of this test is to examine whether the material, cross-sectional area, welding quality of the winding conductors, and the contact resistance of the tap changer are all in optimal condition.
Next comes the measurement of the voltage ratio and the verification of the vector group. Our engineers verify that the actual voltage transformation ratio under all tap positions matches the values indicated on the nameplate, and that the winding connection configuration is correct. At VKE, even the slightest deviation triggers our tracing and correction mechanisms to ensure absolute precision in every product.
No-load loss and no-load current measurements are conducted at VKE's test center. We precisely measure the power and current required to establish the main magnetic flux by applying rated voltage to one winding while keeping the other open. No-load loss must meet or even exceed the guaranteed values stipulated in the contract. This directly impacts the customer's long-term operational costs and serves as the validation of VKE's energy-efficient design.
Correspondingly, load loss and short-circuit impedance measurements are performed. This test simulates rated load conditions to measure winding losses and calculate impedance voltage. These two parameters are vital for the transformer's operational efficiency and system stability.
The assessment of the insulation system includes both the conventional applied voltage withstand test and the more critical induced voltage withstand test. The latter, conducted at elevated frequency and voltage levels, not only evaluates inter-turn, inter-layer, and inter-phase insulation but also simulates over-voltage conditions that may occur during actual operation.
For oil immersed transformers, VKE simultaneously performs precise partial discharge measurements during this process. Partial discharge is a sign of minor defects within the insulation, and we assess the magnitude of these discharges to sensitively evaluate the purity and integrity of the insulation system.
In addition, VKE implements a series of tests targeting specific types and components. For oil immersed transformers, insulating oil testing is a mandatory procedure. VKE utilizes advanced oil treatment and analysis equipment to ensure that key parameters - such as breakdown voltage and dielectric dissipation factor - for every batch of insulating oil filled into the transformer exceed basic standards.
The oil tank's sealing test is conducted by applying pressure to inspect all welds and sealing interfaces. And the on-load tap changer, as a precision component, undergoes a specified number of operational cycle tests on the transformer itself to verify that its switching actions are accurate and fault-free.
In summary, at VKE Transformer, routine tests are not merely simple checkpoints but rather an interconnected quality verification system. Each test targets a specific critical characteristic of the product, collectively forming a health certificate that serves as a trust credential to our customers.