How to choose a test transformer based on Cost and Application

When choosing a test transformer, the decision depends largely on both cost considerations and application needs. Here’s a breakdown of the three main types:

1. Oil-Immersed Test Transformers

   • Cost: These are generally the most affordable due to their simple structure and effective heat dissipation. This makes them an economical choice for most applications.
   • Application: Ideal for standard high-voltage testing, especially in environments where moisture and dust aren’t a concern. They provide stable performance and are highly reliable for common testing requirements across a range of voltage levels and capacities (10-200kV, 0.5-50KVA).

2. Gas-Filled Test Transformers

   • Cost: Slightly more expensive than oil-immersed transformers, as they use SF6 gas for insulation, which is more costly.
   • Application: Suitable for environments requiring higher insulation performance, such as high-altitude or humid areas. The SF6 gas provides excellent insulation and is effective in reducing the risk of oxidation or moisture ingress, which is ideal for specialized high-voltage applications.

3. Dry-Type Test Transformers

   • Cost: The most expensive option—around twice the price of oil-immersed transformers—due to the high-quality materials and complex construction needed for insulation.
   • Application: Best suited for locations where oil or gas-filled transformers may pose a risk, such as in tight spaces or flammable areas. They are also effective in applications needing frequent transportation, as dry-type transformers are generally lighter and less maintenance-intensive.

Capacity and Control Box Selection

• Capacity and Voltage Needs: The selection should match the testing voltage and capacity requirements. Typical capacities range from 0.5-50KVA, and voltages from 10-200KV. Selecting a transformer with adequate capacity is crucial to avoid overstressing the transformer.
• Control Box Selection: For capacities up to 10KVA, a compact control box structure suffices, while a control console is advisable for 15KVA and above for ease of use and additional control options.

In summary, oil-immersed transformers are optimal for routine, cost-effective testing, gas-filled transformers are best in challenging environmental conditions, and dry-type transformers serve as the safest, albeit most costly, choice for specialized applications.