This article aims to show the design of the Automation System of the Jamondino 1, Jamondino 2, and Yumbo bays of the San Bernardino Substation, located in Popayan, department of Cauca. The substation serves as a connection to the National Interconnected System, which arises as a strategy to improve the maintenance of Substation Automation Systems, sas. The article includes the design and tests of the sas of San Bernardino, which allows the operator to have all the signals concentrated in one place, in order to carry out their operational actions in a safer way, providing the necessary information in the opportune time to avoid making mistakes in the operation of the substation, and even speed up the replacement of circuits in the face of unforeseen events. This system makes it easier for the operator to perform maintenance and upgrades on the system without incurring high operating expenses.