DT 33KV250 Transformer Bushing Insulators

This specification refers to a Transformer Bushing Insulator with the following key characteristics: 

Voltage Rating: 33kV - This typically indicates the nominal system voltage (Un​) for which the bushing is designed. 33kV is a common distribution or sub-transmission voltage level. The corresponding maximum continuous operating voltage (Um​) for such a system is usually 36 kV. The bushing must be rated to withstand this maximum voltage. 

Current Rating: 250A

This is the rated continuous current the bushing's conductor can safely carry without exceeding its thermal limits. 

Component Type

An electrical insulator designed to allow a conductor to pass safely through the grounded wall or cover of a transformer tank (usually oil-filled). 

Function

Provides high electrical insulation between the live conductor (at 33kV nominal) and the grounded tank.

Provides a sealed passage for the conductor. 

Acts as a mechanical support for the conductor and external connections. 

Serves as the external connection point for power lines or cables. 

Application

Typically used on power transformers or distribution transformers operating in 33 kV nominal voltage networks. Depending on the specific design (creepage distance, sealing), it could be intended for indoor or outdoor use, though outdoor is common for this voltage class. 

Material: Usually made from high-quality electrical porcelain (brown glazed)

Construction: Includes a central conductor rod, an insulating body (often with weather sheds for outdoor use to increase creepage distance), a mounting flange for attachment to the transformer, and terminals for electrical connection. 

Standards: While designated "DT", a bushing with these ratings would typically be designed and tested according to major standards like IEC 60137, potentially DIN 42532/42533, or ANSI/IEEE C57.19.00/01 to ensure safety and interoperability. 

Creepage Distance: This critical parameter (distance along the insulator surface) is not specified by "DT 33KV250". It would need to be chosen based on the intended application environment (e.g., indoor, outdoor clean, outdoor polluted) and would typically range from approx. 720 mm to over 1100 mm for a 36kV (Um​) outdoor bushing, depending on the required pollution level performance.