Automatic switching control circuit for two parallel transformers

In order to make the transformer operate economically, it is often necessary to put in or cut off the transformers operating in parallel according to the change of the load. For
this purpose, the automatic switching control circuit as shown in the figure can be used .
    First, calculate the economic operating points of the two transformers, and then convert it into the corresponding load current
Ij according to the capacity at the economic operating point. When the load current is less than Z}, exit one transformer, leaving only one operating} When the load current At the end of the day, both
transformers were put into operation.