Calculate transformer iron and copper losses accurately using IEC and IEEE standards with our easy-to-use Transformer Losses Calculator. . In the Detailed losses => Ohmic losses dialog, you have the possibility to define the following configurations: One or several Medium Voltage transformers for the whole system. PVsyst will distribute equally the power output of all inverters to all transformers. Heat loss to the ambient air from some typical electrical equipment are indicated below: Transformers are. . Transformers are essential in power systems, and understanding losses ensures efficiency, reliability, and reduced operational costs.