Distribution Transformer

Distribution Transformers

A distribution transformer or service transformer is basically a transformer that provides final voltage transformation in an electrical distribution system (of electricity boards or utilities). It does so by Stepping down the Voltageused in the Distribution Lines to the level used by the customer e.g., three phase supply for industrial/commercial use (433V) & single phase supply for domestic/household use(250V) purpose.These are usually low to medium rating transformers (6 kVA to 2500 kVA) They are generally used for auxiliary supply for appliances, lighting, motorized machine and power loads.

Distribution transformers are classified into different categories based on factors such as:

1. Mounting location Pole mounted or Plinth mounted

2. Type of cooling / insulation liquid-immersed or dry-type

3. Tapping mode- Off ckt. Tap switch or On load tap changer

IS 1180 : 2014 is a reference standardFor Oil immersed Distribution Transformers up to 2500 kVA

For Distribution transformer mandatory requirements from manufacturer are as listed below-
Manufacturer must have valid (Renewed) BIS license for manufacturing of a particular rating. Manufacturer must have valid Type Test Certificate & its inclusion endorsement by BIS in License of a particular rating to sale in a market.

NOTE- For any standard rating of distribution transformer (with IS 1180:2014) if manufacturer manufactures & sales a particular rating WITHOUT valid Type Test Certificate & its inclusion endorsement by BIS, then it amounts for breach of BIS guidelines of License & criminal offence as per Gazette.

Salient Features

1. Pole mounted or Plinth mounted type

2. Confirming to latest Indian Standard (IS 1180)

3. Range From 63 kVA to 2500 kVA (up to 36 kV)

4. Type tested ratings at CPRI, Banglore or ERDA, Vadodara

5. ISI marked (approved by BIS- Bureau of Indian Standards)

6. Low loss energy efficient (Almost 0.85 % of rated kVA) transformers

7. Both Hermetically sealed & Non-sealed options available

8. Better cost of ownership due to minimum energy bills