Method for monitoring an electrical system comprising electrical loads (1062, 1064...), an electrical network and energy sources, each of the electrical loads being connected to an electrical network via a high to medium voltage transformer (1042, 1044, 1046), said electrical network being supplied by at least one transformer (1022, 1024) and by at least one local energy source, comprising the following steps: - acquiring averaged RMS values, over a predetermined period of time, for the voltage and current at the high to medium voltage transformer, - acquiring active and reactive power values, over said predetermined period of time, for the voltage and current at at least a portion of said local energy sources, - acquiring active values, over said predetermined period of time, for the voltage and current at feeders of said high to medium voltage transformer, - acquiring active and reactive power values, over said predetermined period of time, for the voltage and current at a first sub-assembly of said portion, each of the electrical loads of said first sub-assembly being equipped with a remote reading means, - acquiring the energy metering data history, over a second period of time, for each of the electrical loads of the electrical loads not belonging to the first sub-assembly, the method further comprising a step of calculating monitoring instructions on the basis of data representing the state of the electrical system at a current time, the method further comprising a step prior to a step of applying said monitoring instructions resulting from said calculation to the electrical system, comprising the step of: - calculating a virtual state of a digital model of the electrical system at a later time on the basis of a current state of the digital model at the current time and a digital application of the monitoring instructions to said current state of the digital model, and the following comparison step: ∘ if the virtual state calculated in this way falls within the network operating domain, applying said monitoring instructions, ∘ otherwise, modifying said monitoring instructions and reapplying said step of calculating the virtual state of the digital model at the later time on the basis of said modified monitoring instructions. - acquiring averaged RMS values, over a predetermined period of time, for the voltage and current at the high to medium voltage transformer, - acquiring active and reactive power values, over said predetermined period of time, for the voltage and current at at least a portion of said local energy sources, - acquiring active values, over said predetermined period of time, for the voltage and current at feeders of said high to medium voltage transformer, - acquiring active and reactive power values, over said predetermined period of time, for the voltage and current at a first sub-assembly of said portion, each of the electrical loads of said first sub-assembly being equipped with a remote reading means, - acquiring the energy metering data history, over a second period of time, for each of the electrical loads of the electrical loads not belonging to the first sub-assembly, the method further comprising a step of calculating monitoring instructions on the basis of data representing the state of the electrical system at a current time, the method further comprising a step prior to a step of applying said monitoring instructions resulting from said calculation to the electrical system, comprising the step of: - calculating a virtual state of a digital model of the electrical system at a later time on the basis of a current state of the digital model at the current time and a digital application of the monitoring instructions to said current state of the digital model, and the following comparison step: ∘ if the virtual state calculated in this way falls within the network operating domain, applying said monitoring instructions, ∘ otherwise, modifying said monitoring instructions and reapplying said step of calculating the virtual state of the digital model at the later time on the basis of said modified monitoring instructions. - calculating a virtual state of a digital model of the electrical system at a later time on the basis of a current state of the digital model at the current time and a digital application of the monitoring instructions to said current state of the digital model, and the following comparison step: ∘ if the virtual state calculated in this way falls within the network operating domain, applying said monitoring instructions, ∘ otherwise, modifying said monitoring instructions and reapplying said step of calculating the virtual state of the digital model at the later time on the basis of said modified monitoring instructions. ∘ if the virtual state calculated in this way falls within the network operating domain, applying said monitoring instructions, ∘ otherwise, modifying said monitoring instructions and reapplying said step of calculating the virtual state of the digital model at the later time on the basis of said modified monitoring instructions.