230 kV 33 MVA OLTC Transformer

230 kV 33 MVA Transformer for a Solar Power Plant Project in Los Angeles

Transformer Key Features

Power Rating

The transformer is designed and developed to offer three different power ratings to match the solar power plant current electrical power generating capacity. This is specially needed in solar power plants as these power plants can have variation in their day to day power generation capacity due to weather and other factors.

The transformer offers power rating of

• 20 MVA
• 26.6 MVA
• 33.3 MVA

Power rating with each offering a different current rating based on the ongoing transformer voltage rating. From the above three different power ratings, the 20 MVA power rating works as the base line transformer power rating and all other factors like impedance, load losses and no load loss are considered and shown on this specific power rating.

Voltage and Current Rating

The high voltage winding of the transformer is designed and developed to work on a wide range of voltage ratings and thus the corresponding current rating. The high voltage side of the transformer can work under 17 different voltages.

For each voltage the transformer high voltage winding processes three different current values depending on the three different power ratings of the transformer. The high voltage side of the transformer winding has star grounded configuration.

The low voltage side of the transformer winding has delta configuration and works under a single voltage of 13.8 kV for all three power ratings. Each power rating has its unique current rating.

Tap Changer Details

The transformer is provided with an on load tap changer to change the tap position of the transformer to match the solar power plant input and attached load while the transformer is still energized.

The transformer offers 17 different tap positions for each of the power ratings and each tap position has its own voltage and current rating. At the base voltage rating of 230 kV the tap position is considered as base position.

From that position we have 8 different tap positions for higher voltage and 8 different tap positions for lower voltage and thus 17 different tap positions.

Load Performance

This power transformer is designed to have maximum efficiency possible with minimum losses associated with the transformer working. The transformer has 9.89 % impedance at the base power rating with no load losses of 23.779 KW and load losses of 54.547 KW.

The transformer is also equipped with a number of safety and performance features like sensors that are integrated with IoT for remote monitoring and controlling of transformer parameters to ensure high efficiency.

Cooling and Fluid System

This power transformer is designed with a cooling system that operates in three different stages depending on the power rating and waste heat being generated at the transformer winding and core section. This transformer has

• Oil natural air natural cooling system
• Oil natural air forced cooling system no 1
• Oil natural air forced cooling system no 2

The first cooling system is needed when the transformer is working at the minimum load and not a lot of waste heat is being produced by the transformer. At moderate load the transformer needs to power one of its cooling fans that force air on to its fins to induce force convection heat transfer that removes waste heat faster. At maximum load, the transformer operates another cooling fan to remove more waste heat.

Transformer Weight

It is an oil immersed power transformer with a removable radiator to control cooling of the transformer. Based on the attached parts and operating features, the weight of the transformer can vary.

International Standard Compliance and Safety Features

This transformer is designed and built for a solar power plant in Los Angeles USA, so it was designed in order to comply with all international standards that are compulsory for transformers of solar power plants and to be used in the USA. Transformers comply with all IEEE international standards that are necessary for a transformer to comply before being commissioned in the USA. This transformer follows

• IEEE 693-2005
• IEEE C57.12.00
• IEEE C57.131

Transformer is also featured with all types of safety features like

• Remote thermal monitoring sensors
• Oil level sensors
• Oil remote monitoring sensors
• Proper grounding of all critical transformer parts
• High quality insulation of all critical parts

Why Choose Daelim

Daelim Transformer has unmatched expertise in delivering custom engineered high performance transformers like this 230 kV 33 MVA OLTC transformer for renewable engineering systems. This project shows our technical leadership and deep understanding of solar based power infrastructure and expertise in transformer design in accordance with international standards like IEEE C57.12.00, IEEE C57.131 and IEEE 693-2005. Our transformer meets all USA compliance requirements for utility and renewable applications.

If you have any questions about electrical transformers, contact our team and they will be happy to help you.