Distribution Transformers
Distribution Transformers
DRY TYPE DISTRIBUTION TRANSFORMER
Dry type transformers are non-explosive fire resistant, oil insulated, and are cooled by natural circulation of air through ducts provided in the windings. High temperature and high dielectric insulating materials like glass fiber reinforced, nomex Insulating tapes are used in such a way that the entire assembly is capable of withstanding high electrical and mechanical stresses with good dissipation of heat causing low temperature rise within the prescribed limit of insulation class.
General Trend of Voltage During Day Time
| 9:00 to 12:00 Hrs. | 12:00 to 14:00 Hrs. | 14:00 to 18:00 Hrs. | 18:00 to 22:00 Hrs. | 22:00 to 5:00 Hrs. | 5:00 to 9:00 Hrs. |
|---|---|---|---|---|---|
340 V - 400V | 400 V - 440V | 340 V - 400V | 400 V - 430V | 400 V - 470V | 400 V - 450V |
The Dry Type transformers are manufactured to comply with National International Standards BIS IS 11171, IEC 76, IS1180.
The winding ore is made up of electrolytic Grade, Soff and bright annealed copper conductors covered with nomex insulating tapes. The wound coils are preheating and impregnated with silicon varnish under vacuum pressure and undergo a curing cycle. The low voltage coils are wound over glass fiber reinforced cylinders having high mechanical strength. The high voltage colls are supported over yoke on glazed porcelain or resin Insulators, The core is made of CRGO silicon steel laminations duly annealed after shearing and assembled in mitred construction for low "NO LOAD" LOSS.
The yoke frame has adjustable pressure plates to clamp & secure the coils adequately. Lifting arrangements are provided on the top yoke frame so that the core and coil assembly is lifted. OFF-CIRCUIT TAPPING if required are provided on HV winding and terminated on fiber gloss terminal board for changing the transformer ratio in "OFF Circuit" position.
Fire safety and environmental aspects are of increasing importance especially in respect of energy supply. The substitution of oil-filled transformers by dry type transformers is one of the most important steps towards it. Dry Type transformer is used when it has to be located near load center and in a fire hazardous place. As there is no oil used in the transformer and special types of fire resistant insulation are used for the windings the fire risk is considerably reduced.
| Capacity | Up to 2500 KVA |
| No. of Phases | 3 Phase |
| Frequency | 50 Hz. |
| Voltage Range | 11 KV & 33KV |
| Tapping | On Load Tap Changer to provide + 5% to-15% Taps in steps of 1.25% on the H.T. Side. Else. Off Circuit Tap Links for 5% Taps on H.T. Side in steps of 2.5% each. |
| Insulation | Class F (for Dry Type Trf.) |
| Vector Group | Dyn 11 |
Copper Wound Continuous
As per requirement
DRY TYPE TRANSFORMERS HAS THE FOLLOWING ADVANTAGE
More efficient
Non toxic
Highly safe
Non flammable
• Space saving by placing near the load end Low Noise
• Low Maintenance
• Can be supplied with off circuit links