Oil Immersed Transformer

•Oil filled transformer Easily adopt to the grid, easy connection process
•Oil filled distribution transformer adopts Seven-step silicon steel lamination insulated on both sides, guaranteeing low losses and low noise
•Liquid filled Transformers can be custom according to the requirement
•LV winding has stronger resistance to short circuit
•Efficiency: The sealed design contributes to improved electrical performance and efficiency. Reduced moisture content and better insulation lead to lower losses and enhanced energy transmission.
•Excellent cooling effect by corrugate cooling way
•High temperature design
•The transformer tank adopts a fully sealed structure, which extends the service life and no maintenance

1. Iron Core

The iron core forms the central element of every transformer. High-grade, cold-rolled – and, depending on requirements laser-treated . Superior silicon lamination for steel core, the lamination joint is processed by oblique cut angle and the latest new technology“seven-step”, which ensures small no-load loss and current. Varelen's fluid-immersed distribution transformers achieve an especially good flux distribution at the joints, resulting in exceptionally low losses and minimal no-load noise.

10KV oil immersed transformer

oil immersed transformers

500kva oil transformers

drawings

For each transformer are prepared and issued a test report, in accordance with IEC 60076. except for routine tests, we also offer type tests and specialised tests to meet all customer requirements. We make what matters work for our customers in a safe and reliable way.

Varelen has launched online FAT plan for customers. Our factory can make acceptance testing ( either witnessed and on-line) in order to show all technical and quality requirements have been done before shipment.

Routine test

Measurement of winding resistance
Measurement of voltage ratio and check of phase displacement
Measurement of short-circuit impedance and loss
Measurement of no-load loss and current
Dielectric routine tests
Tests on on-load tap-changers, where appropriate
Leak testing with pressure for liquid-immersed transformers(tightness test)
Tightness tests and pressure tests for tanks for gas-filled transformers
Check of the ratio and polarity of built-in current transformers
Check of core and frame insulation for liquid immersed transformers with core or frame insulation

Type test

Temperature-rise type test
Dielectric type tests
Determination of sound level for each method of cooling for which a guaranteed sound level is specified
Measurement of the power taken by the fan and liquid pump motors
Measurement of no-load loss and current at 90% and 110% of rated voltage

Special Test

Dielectric special tests
Winding hot-spot temperature-rise measurement
Determination of capacitances windings-to-earth, and between windings
Measurement of dissipation factor(tanδ) of the insulation system capacitances
Determination of transient voltage transfer characteristics
Measurement of zero-sequence impedance(s) on three-phase transformers
Short-circuit withstand test
Measurement of d.c. insulation resistance each winding to earth and between windings
Vacuum deflection test on liquid immersed transformers
Pressure deflection test on liquid immersed transformers
Vacuum tightness test on site on liquid immersed transformers