Abstract: A method determines the frequency of an alternating input signal includes storing the input signal, sampling the input signal at a first sampling frequency, a first calculation and a first angular comparison of two phasors representing the input signal at two respective instants, as a function of the input signal sampled at the first sampling frequency, estimating the frequency of the input signal, and searching for a modification of frequency of the input signal. When a modification is detected the method includes, determining a second sampling frequency, sampling the stored input signal with the second sampling frequency, a second calculation and a second angular comparison of two phasors representing the input signal, at two respective instants, as a function of the input signal sampled at the second sampling frequency and of the stored input signal sampled at the second sampling frequency, and estimating the frequency of the input signal.

Abstract: Method for the directional determination of an earth fault in an electric power distribution network, characterised in that it comprises the steps of: Determining (E2) a residual current phasor and a residual voltage phasor, Determining (E3) an active current, Comparing (E7) the residual voltage phasor module with a threshold (SVR), and as long as the residual voltage phasor module remains higher than the threshold (SVR) or a fraction of the threshold (SVR), and for a predetermined number of iterations: Determining (E9, E12) the integral of the active current and of its sign, Determining the number of times when the residual current phasor module is greater than a predetermined threshold (SIR), during the predetermined number of iterations, If the residual current phasor module is greater than the predetermined threshold (SIR) at least one time, during the predetermined number of iterations, Determining (E16) the location upstream or downstream of the fault according to the number of times when the sign of

Abstract: A method of estimating a periodic voltage, such as an input voltage, of one of the phases of an electrical circuit with at least two phases including a voltage sensor for each of its phases, each voltage sensor being capable of outputting a signal representative of at least a part of period of the periodic voltage of the phase. The method including the following steps: measure the representative signal starting from the voltage sensor; amplify the representative signal by a gain determined in the absence of an electrical fault in the circuit and based on a reference voltage common to all phases in the electrical circuit (1); use the amplified representative signal to estimate the periodic voltage. A device for estimating a voltage and an electrical circuit including such a device.

Abstract: A method determines the frequency of an alternating input signal includes storing the input signal, sampling the input signal at a first sampling frequency, a first calculation and a first angular comparison of two phasors representing the input signal at two respective instants, as a function of the input signal sampled at the first sampling frequency, estimating the frequency of the input signal, and searching for a modification of frequency of the input signal. When a modification is detected the method includes, determining a second sampling frequency, sampling the stored input signal with the second sampling frequency, a second calculation and a second angular comparison of two phasors representing the input signal, at two respective instants, as a function of the input signal sampled at the second sampling frequency and of the stored input signal sampled at the second sampling frequency, and estimating the frequency of the input signal.

Abstract: Method for the directional determination of an earth fault in an electric power distribution network, characterised in that it comprises the steps of: Determining (E2) a residual current phasor and a residual voltage phasor, Determining (E3) an active current, Comparing (E7) the residual voltage phasor module with a threshold (SVR), and as long as the residual voltage phasor module remains higher than the threshold (SVR) or a fraction of the threshold (SVR), and for a predetermined number of iterations: Determining (E9, E12) the integral of the active current and of its sign, Determining the number of times when the residual current phasor module is greater than a predetermined threshold (SIR), during the predetermined number of iterations, If the residual current phasor module is greater than the predetermined threshold (SIR) at least one time, during the predetermined number of iterations, Determining (E16) the location upstream or downstream of the fault according to the number of times when the sign of

Abstract: A method of estimating a periodic voltage, such as an input voltage, of one of the phases of an electrical circuit with at least two phases including a voltage sensor for each of its phases, each voltage sensor being capable of outputting a signal representative of at least a part of period of the periodic voltage of the phase. The method including the following steps: measure the representative signal starting from the voltage sensor; amplify the representative signal by a gain determined in the absence of an electrical fault in the circuit and based on a reference voltage common to all phases in the electrical circuit (1); use the amplified representative signal to estimate the periodic voltage. A device for estimating a voltage and an electrical circuit including such a device.