Differences, advantages and disadvantages between dry-type transformer and oil-immersed transformer

Dry-type transformer is a completely static solid-state equipment, which needs less maintenance to provide trouble-free service. The transformer does not contain any moving parts. Unlike liquid-filled transformers, these transformers only use high-temperature insulation systems because they are very safe to the environment. These transformers provide a safe and consistent power supply, and do not need a fire vault, otherwise it will emit toxic gases. These safety factors will allow these transformers to be installed in different applications that require fire safety, such as schools, buildings, hospitals, factories and chemical industries.

Important factors in the design of dry-type transformer

Many important factors need to be considered when designing this type of transformer. they are

Selection of insulation type

expected life

Selection of Magnetic Core Materials with Low Hysteresis Loss

Insulation grade

lose

Selection of winding materials

rule

Neutron multiplication coefficient

Overloaded

Test of dry-type transformer

Insulation breakdown is the most common fault in this kind of transformer, which will lead to serious faults, such as grounding fault or phase winding fault. According to the test, only the insulation state of components (such as iron core, winding and bushing) in transformer can be determined. In oil-immersed transformer, winding insulation can be determined by common methods such as dissolved gas analysis, but it cannot be realized in dry-type transformer. There are different tests, including the following.

Partial discharge test

Insulation resistance test

Frequency response analysis

Polarization index test

Thermal imaging research

Measurement and test of dielectric loss angle

Acoustic emission test

Advantages of dry-type transformer

The advantage is that

It is pollution-free

These are used in polluted and humid areas.

Simple installation

They are durable because of dielectric heating and low heat.

Protect property and personnel

They are highly resistant to short-circuit currents.

Low side clearance

The performance was excellent.

High capacity to support overload

Disadvantages of dry-type transformer

These transformers are expensive.

Maintenance difficulty

If the transformer coil is not cleaned properly, it may cause a fire.

Maintenance of these devices requires downtime and shutdown.

The electrical losses of these transformers are much higher.

The cooling system is necessary to control the heat loss.

Working noise is very high, so they are not suitable for some indoor applications.