The dry type transformer is a power transformer that has windings covered in epoxy resin. Being dry and having no need for cooling-oil, dry-type transformers are easy to install. Besides, they even don’t need a fire-proof vault. The epoxy layer protects the transformer against corrosion and dust.
The dry-type transformers are actively used in various applications and are likely to install at outdoor locations.
Having adequate knowledge about the design of the transformer, whether new or replacement installation is very important to building operation, specifically in industrial applications.
The dry type transformer design in industrial buildings
Reliability and efficiency are very important in today’s building industry. And, the electrical system must go well with this suit. The design and building service of any electrical distribution system starts with a transformer.
Having a decent knowledge of the design of a transformer is very important to building operation, specifically in an industrial application. Various difficulties involved with the design and installation process of a transformer.
To have a successful project, a few things here are very essential to overcome the hurdles commonly appearing in the design process.
Identify the types and applications of industrial transformers
The very first step to take while processing the transformer design is to identify a proper type of it. Including the most important factors like cost, system configuration, and location many other factors are important to take into account when choosing the right type of transformer.
In consideration of types of industrial transformers, they are categorized into two parts: liquid-field and dry-type transformers.
Generally, dry-type transformers are used for indoor applications that require less than 5 MVA (Mega Volt-Amp); whereas, liquid-filled transformers are used for exterior or large applications.
These dry-type transformers are further divided into three main types:
- VPI (vacuum pressure impregnated) – The VPI transformers are more affordable than VPE and Cast Coil transformers, and the best option to use in electrical rooms that are adequately conditioned and have a dry environment.
- Cast coil – Cast coil transformers are more expensive than the other two types of dry transformers. The sealed core and coil construction of cast coils make them suitable to install in harsher environments.
- VPE (vacuum pressure encapsulated) – Both cost-wise and in environmental suitability, VPEs fall in between cast coils and the VIPs.
The benefit of dry transformers is that they are installed in the interiors. On the contrary, there are some disadvantages.
Particularly, designing ventilation systems required for the rejection of heat allied with the transformer and also project fix engineered paths and procedures for future replacement.
Liquid-filled transformers spring up with several disadvantages when compared with the dry-type transformers; particularly, meeting the recommended code and insurance regulations for the onsite settings, containment, and close protection from damage.
The most important predetermining item for transformers is the temperature-rise rating. The three traditional temperature-rise values of dry-type transformers are 80 degree Celsius, 115 degree Celsius, and 150 degree Celsius; whereas the liquid-filled transformers come up with the temperature rise values of 55 degree Celsius and 65 degree Celsius.
This temperature rating symbolizes the greatest level of increase in the temperature that the transformer will then catch while operating at rated full load.
The insulation of the standard rating of a transformation is 220 degrees Celsius, whereas the lower ratings of temperature result in a higher margin between the utmost amount of transformer’s temperature and the insulation rating.
Transformers with lower temperature-rise require high-pitched initial costs, for both- dry-type as well as liquid-filled transformers.
They indeed have effective operations and a possible ability to address the overloads resulting from lower operating temperature.
Learning the codes
For proper installation of transformers, the governing codes are very important to understand on the whole. Some of the several codes required for transformer installation are-
- IBC (International Building Code), and
- IFC (International Fire Code)
It will be superseded by the state building codes and also by the local AHJ (authority having jurisdiction).
Based on the code requirements, whether national or international, the property insurance provider may come up with special requirements for the transformer installation.
Sizing is very important to have a reliable process for both- new and replacement transformer installation. Appropriate sizing of transformers can moreover result in a considerable amount of saving in not only initial capital but also in the overall operational costs.
When creating transformers effective for buildings, the connected and demand loads both are identified. The connected load is usually larger than the transformer rating. Consequently, the demand load develops a lesser value.
The three major approaches to maximize the transformer sizing are denoting the cooling package, seizing the NEC metering for replacement processes, and creating detailed load calculations that symbolize reasonable peak-loading settings for the new installations.
Mainly, the cooling package of a transformer includes liquid cooling or natural air, forced air or liquid cooling, or gas-insulated cooling.
The transformer cooling package adds to the capacity of dry transformers and moreover increases the capacity of the liquid type transformers. The approximate amount of increase depends on the number and type of cooling stages used in the functioning.
In summary, various other factors are incorporated in the design and installation of service transformers in buildings that include types and applications of transformers, knowledge of codes, sizing, and more. Visit ElectPower.com to learn more about industrial transfers and types.