Transformer assembly for electric grids and a related control method

A method for controlling a tap changer included in a transformer assembly for electric grids, said transformer assembly comprising:

• an electric transformer comprising a magnetic core, a first side including one or more first windings enchained with said magnetic core and adapted to be electrically connected to a first grid section and a second side including one or more second windings enchained with said magnetic core and adapted to be electrically connected to a second grid section, the first side and the one or more first windings forming a primary side and primary windings of the electric transformer, and the second side and the one or more second windings forming a secondary side and secondary windings of the transformer;
• and
• a tap changer operatively associated with said electric transformer to vary the number of turns enchained with said magnetic core for said one or more first windings,
• the method comprising:
• acquiring input data indicative of an electrical connectivity condition of said second grid section with said second windings;
• basing on said input data, determining whether said transformer is in a load condition or in a no-load condition;
• and
• if said transformer is in a no-load condition, commanding said tap changer to set a maximum available number of turns for said one or more first windings.

A control unit for an electric transformer, the control unit configured to:

• operatively couple with a tap changer associated with the electric transformer to control the operation of said tap changer to vary a number of turns enchained with a magnetic core for one or more primary windings of a primary side of the electric transformer;
• said control unit configured to:
• acquire input data indicative of an electrical connectivity condition of a grid section with one or more secondary windings of a secondary side of the electric transformer;
• basing on said input data, determine whether said transformer is in a load condition or in a no-load condition;
• and
• if said transformer is in a no-load condition, command said tap changer to set a maximum available number of turns for said one or more primary windings.