A power transformer is used to provide power (to your home, for example), an instrument transformer is used to measure voltage or current (for metering, for example).

Both are same. This is an instrument transformer used for metering & protections.

Instrument Transformer

Transformer or instrument transformer. It can increase and decrease current output.

The term 'burden' is used to describe the secondary load applied to an instrument transformer; the reason for this is so that it is not confused with the 'load' supplied by the high-voltage circuit to which the transformer's primary is connected. A burden is either a measuring instruments (ammeter,voltmeter, wattmeter, etc.) or protective relay, depending on the function of the instrument transformer. 'V.A' is the symbol for 'volt ampere', which defines the 'power' rating of the instrument transformer.