Many industry standards limit the difference between the distribution and power transformer with the KVA rating, such as distribution transformer is rated as between 5 to 200 or 500 or 1500KVA.
As per IEEE this is discouraged, as there is up to 5000KVA distribution transformer is now available. So the difference is what there purpose in type of use.
Distribution and power transformer- difference as per IEEE
As per IEEE (C57.12.80);
Definition of Distribution transformer
Distribution transformer is a transformer for transferring electrical energy from a primary distribution circuit to a secondary distribution circuit or a consumer circuit.
Definition of Power transformer
Power transformer transfers electrical energy in any parts of electrical circuit between generator and primary distribution circuit.
Special requirements for distribution transformer
- Low iron loss as distribution transformer is energized for 24 hour even if it is not in load.
- Maximum efficiency at low load, as they are not usually operated at full load.
- Leakage reactance should be kept minimum to avail minimum voltage regulation and hence to achieve higher efficiency. As usually there is no provision of tap changers.
Special requirements for power transformer
- Higher insulation and cooling class.
- Tap changer to cope up with voltage regulation.
- To be able to cope up with higher mechanical and electro-dynamic stress.