The sizing of instrument transformers is not fixed; rather, it is determined by the current or voltage levels of the specific application. For instance, current transformers are typically selected based on 1.2 to 1.5 times the rated current, while voltage transformers are sized according to the system's rated voltage. In general, specific sizing should be determined by consulting relevant electrical standards and considering actual project requirements.
Instrument transformers play a vital role in power systems by proportionally converting high voltages or large currents into low voltages or small currents suitable for measurement, protection, and control. So, how should they be sized? This ultimately depends on the specific application scenario and system requirements.