Electronic grounding system which is connectable in series with a neutral and with the grounding of a power transformer in any of its possible configurations in a high-voltage distribution network, wherein said electronic grounding system is an electronic active grounding system configured to act on a current flowing through said grounding, said electronic active grounding system comprising means for injecting a current which is controlled at all times in amplitude, phase and frequency components into said grounding, wherein said means for injecting a current comprise at least one voltage capturing element and at least one current capturing element, - and at least one protection and control system receiving the captured magnitudes ( V N, I N, I 0L, U ref), of the at least one voltage capturing element and of the at least one current capturing element, and which is configured to calculate a value of said current to be injected, characterized in that said voltage and current capturing elements (6, 7) are configured to obtain the following measurements: - V N: neutral voltage measured as the voltage drop between the neutral and ground of the network, the frequency component of which at frequency f is V N f ̅; - I N: neutral current measured directly in the neutral of the network, the frequency component of which at frequency f is l N f ̅; - I 0L: zero-sequence current of each line of the network measured in each of such lines, the frequency component of which at frequency f is I 0 ⁢ L f ̅ and, - U ref: reference magnitude corresponding to the measurement of a phase-to-phase voltage of the mentioned network, the electronic active grounding system further comprising: - at least one electronic converter element the output of which is connected in series with said neutral, which is configured to generate said current the value of which is calculated by the protection and control system, which electronic converter is configured to inject a current the frequency of which is between 5 and f0 Hz, being for the nominal network frequency, and the value of which is less than 20% of the capacitive current of the network, and with such current the total equivalent capacitive impedance of the network at the frequency component f, X C f, and then at f0, X C f ⁢ 0, is calculated as: X C f = V N f I N f ⋅ sin Φ V N f - Φ I N f → X C f ⁢ 0 = f f ⁢ 0 ⋅ X C f - X PAT f ⁢ 0 ⋅ f f ⁢ 0 where X PAT f is the total equivalent inductive impedance of the neutral of the network of frequency component f Φ V N f is the angle of neutral voltage of frequency component f Φ l N f is the angle of neutral current of frequency component f. - V N: neutral voltage measured as the voltage drop between the neutral and ground of the network, the frequency component of which at frequency f is V N f ̅; - I N: neutral current measured directly in the neutral of the network, the frequency component of which at frequency f is l N f ̅; - I 0L: zero-sequence current of each line of the network measured in each of such lines, the frequency component of which at frequency f is I 0 ⁢ L f ̅ and, - U ref: reference magnitude corresponding to the measurement of a phase-to-phase voltage of the mentioned network, - at least one electronic converter element the output of which is connected in series with said neutral, which is configured to generate said current the value of which is calculated by the protection and control system, which electronic converter is configured to inject a current the frequency of which is between 5 and f0 Hz, being for the nominal network frequency, and the value of which is less than 20% of the capacitive current of the network, and with such current the total equivalent capacitive impedance of the network at the frequency component f, X C f, and then at f0, X C f ⁢ 0, is calculated as: X C f = V N f I N f ⋅ sin Φ V N f - Φ I N f → X C f ⁢ 0 = f f ⁢ 0 ⋅ X C f - X PAT f ⁢ 0 ⋅ f f ⁢ 0 where X PAT f is the total equivalent inductive impedance of the neutral of the network of frequency component f Φ V N f is the angle of neutral voltage of frequency component f Φ l N f is the angle of neutral current of frequency component f. X PAT f is the total equivalent inductive impedance of the neutral of the network of frequency component f Φ V N f is the angle of neutral voltage of frequency component f Φ l N f is the angle of neutral current of frequency component f.