The need to carry out experiments and network studies persuaded Italy’s large electromechanical companies (Pirelli, SAE, Ercole Marelli, Ansaldo), along with most of the electricity sector (Edison, SADE, Montecatini, Falck), together with the majority of electrical industries (Edison, SADE, Montecatini, Falck), that they needed a “Great Power Laboratory”. In the early 50s, the "X Laboratory" was born. In the 1956, the partners established that the Laboratory will take the name of CESI (Italian Electrical and Technical Experimental Center). At the end of the decade, CESI developed a leadership position in determining short-circuit power inside transmission lines and load flow problems.