Method for managing an electrical system comprising electricity production units, electricity consumption units, and an electricity distribution network linking the electricity production units to the electricity consumption units, characterized in that it comprises: - a step of measurement and/or estimation of operating quantities for the electrical system by at least one sensor and/or a software and/or hardware component, such as electrical quantities for the electrical system such as frequency and voltage, - a step of estimation of at least one stability parameter for the electrical system that is based on the magnetic energy reserve and kinetic energy reserve that it accumulates, from a calculation implemented by at least one software and/or hardware component of a management unit of the electrical system taking into account at least one measurement and/or estimation of an operating quantity for the electrical system, in that it comprises a step of calculation of the stability parameter(s) of the electrical system by means of at least one sensor and/or a software and/or hardware component from the power budget of the electrical system, then in that it comprises a step of analysis of two separate transitory regimes, one transitory regime during which the power budget considers the variation in the magnetic energy of the electrical system at constant kinetic energy under consideration, and one transitory regime during which the power budget considers the variation in the kinetic energy of the electrical system at constant magnetic energy under consideration, and characterized in that the power budget of the electrical system is calculated from thermodynamic modelling of the electrical system and is defined by the following equation: P meca − in = P meca − out + P Joule + dF dt + dE cin dt where - E cin denotes the kinetic energy stored in the various parts of the electrical system; - P meca-in denotes the mechanical power supplied to the system by the shaft of the turbines of the alternators; - P meca-out denotes the mechanical power produced by the motors; - P joule represents the heat extracted from the electrical system; - F represents the magnetic energy stored in the various parts of the electrical system. - a step of measurement and/or estimation of operating quantities for the electrical system by at least one sensor and/or a software and/or hardware component, such as electrical quantities for the electrical system such as frequency and voltage, - a step of estimation of at least one stability parameter for the electrical system that is based on the magnetic energy reserve and kinetic energy reserve that it accumulates, from a calculation implemented by at least one software and/or hardware component of a management unit of the electrical system taking into account at least one measurement and/or estimation of an operating quantity for the electrical system, - E cin denotes the kinetic energy stored in the various parts of the electrical system; - P meca-in denotes the mechanical power supplied to the system by the shaft of the turbines of the alternators; - P meca-out denotes the mechanical power produced by the motors; - P joule represents the heat extracted from the electrical system; - F represents the magnetic energy stored in the various parts of the electrical system.